Urinary System Anatomy of the Kidneys: Lie against the dorsal body wall against the retroperitoneal position beneath the parietal peritoneum in the superior lumbar region. Extend from the T12 to the L3 vertebrae. They receive some protection from the lower part of the rib ri b cage Right kidney is slightly lower than the left Adult kidneys are about the size of a large bar of soap Has a medial indentation called the renal hilus where the ureters, renal blood vessels, and nerves enter/exit the kidneys Adrenal gland is on top of each kidney The renal capsule encloses each kidney and the adipose capsule holds the kidney against the trunk wall. y
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y y y
y y
Regions of the Kidney: y
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y y
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y
Renal Cortex:
Thin outer layer of the kidney. Usually light in
color. Renal Hilus: Medial indentation in the kidneys. The ureters, renal blood vessels, and nerves enter/exit the kidney here. Renal Medulla: Inside the cortex. Is a dark redish color. Medullary Pyramids: Striped in appearance. Separated by renal columns. Calyces: Extensions of the renal pelvis that form cup shaped areas that enclose the tops of the pyramids. Calyces collect urine that drains from the tips of the pyramids. Renal Pelvis: Inner collecting tube. Is continuous with the ureters leaving the hilus. Urine flows from the pelvis to the ureter, which transports urine to the bladder. Renal Columns: Separate the renal pyramids made of cortex like tissue.
Nephrons: Nephrons are the structural and functional units of the kidneys that are responsible in the formation of urine. They are the tiny filtering units. There are over 1,000,000 nephrons per kidney. Entire blood volume is filtered 60 x per day. y
y y
Parts of a Nephron: Glomerulus: Knot of capillaries. Blood pressure is very high here because it receives and feeds out blood. Extremely high BP forces fluid and solutes smaller than proteins out of the blood into the glomerular capsule. - Afferent Arteriole: Arises from the interlobular artery and is the feeder vessel for the nephron. Larger diameter than the efferent arteriole. - Efferent Arteriole: Receives blood that has passed through the glomerulus. Peritubular capillaries arise from the efferent arteriole and drains into the glomerulus. These capillaries are low pressure that are adapted for absorption. y
y y
y
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Renal Tubule:
Knot of capillaries. Everything BUT the collecting duct. Glomerular/Bowmans Capsule: The closed end of the renal tubule that is enlarged and cup-shaped and completely surrounds the glomerulus. Blood gets put out of here. The substance looks like plasma. Podocytes: The inner/visceral part of the capsule is made of up highly modified cells. Have long branching processes called foot processes that interwine with one another and cling to the glomerulus. Filtration slits exist between the extensions and form a porous membrane around the glomerulus. Proximal Convoluted Tubule (PCT): Covered with microvilli to increase its surface area. Reabsorption begins here where 80% of the water is absorbed by filtrate. Loop of Henle: The hair pin of the nephron. 100% of glucose and amino acids reabsorb and go back to the blood stream. Distal Convoluted Tubule (DCT): Reabsorption of water occurs here to go back into the bloodstream. An additional 19% of water is reabsorbed and = 99% total water reabsorbed. 19% of ADH ADH hormone (Anti-diuretic) is also reabsorbed with the water to recover the water in the blood. Aldosterone is also reabsorbed with the water which reabsorbs salt with water following. Collecting Ducts: Receives urine from many nephrons and runs downward through the medullary pyramids, giving them their striped appearance. They deliver the final urine product into the calyces and renal pelvis.
Urine Formation: Filtration: A nonselective, passive process. The filtration that is formed is essentially blood plasma without blood proteins. Glomerulus acts a filter and is where it first occurs. Everything except for RBCs and proteins is forced from glomerulus into the Bowmans capsule. Reabsorption: Filtrate takes up many useful ions, amino acids, glucose, and some water. These ions must be reclaimed by the filtrate and this is wher e reabsorption for the substances to go back to the bloodstream. Tubular reabsorption occurs as soon as the filtrate enter s the proximal convoluted tubule. Nitrogenous wastes such as urea, uric acid, and creatinine. These ailments are found in high concentrations in the urine. Most reabsorption occurs in the proximal convoluted tubule Secretion: Essentially reabsorption in reverse. Additional harmful substances are added to the uri ne(drugs, medications, etc.) and can control blood pH. Occurs in the collecting duct. y
y
y
Function of the Kidneys: y
The kidneys filter gallons of fluid from the bloodstream. The kidneys remove nitrogenous wastes to be e xcreted out of the body while returning the valuable nutrients to the blood stream. The kidneys also regulate the bloods volume and chemical makeup so that the proper balance between water and salts and between acids and bases in maintained. They also regulate blood pressure. Lastly, they manufacture urine.
Disorders: y y y y y y
Polyuria: excrete large volumes of urine Anuria: excreting less than 100 ml of urine a day Oliguria: excreting between 100 and 400 ml of urine a day Diuresis: urine production Diabetes Mellitus: Lack of insulin Diabetes Insipidus: Lack of ADH
Composition of Normal Urine Volume is about 1000-1500 ml Sterile Slightly aromatic pH=6 (slightly acidic) Specific Gravity of 1.001-1.020 Does not contain glucose, bile, rbcs , hemogl obin, or wbcs Clear pale to deep yellow because of urochrome y y y y y y y
y
Has
sodium, potassium, urea, uric acid, creatinine, ammonia, and bicarbonate ions.
Abnormal Urine Components & Disorders: Glucose: excessive intake of sugary foods, diabetes mellitus Blood proteins: physical exertion, pregnancy, glomerulonephritis, hypertension Red blood cells: bleeding in the urinary tract because of trauma, kidney stones, or infection Hemoglobin: transfusion reaction, hemolytic anemia White blood cells/pus: urinary tract infection Bile: liver disease (hepatitis) Ketones: product of fat metabolism when in starvation mode or when the body cant digest glucose because of diabetes. y y y y y y y
Functions of Urinary System Organs: Ureters: 10-12 inches long, carry urine by peristalsis Bladder: transitional cells, adipose tissue, renal capsules. Temporary storage sac for urine. Urethra: males 8 inches long, females 1 inch, carries urine to the outside of the body. y y y
Sphincters: y
y
Superiorly located and is voluntary. Once the internal sphincter is filled and the person feels the urge to void, we can choose to hold in our urine or release it. The external sphincter can be relaxed so that the urine is flushed from the body. Internal Urethral Sphincter: Inferiorly located and is involuntary. As the contractions become stronger, stored urine is forced past the internal urethral sphincter. It is then that a person finally feels the urge to void. - Control the flow of urine from the bladder. The bladder continues to collect urine until about 200 mL. At this point, stretching of the bladder wall activates stress receptors. Impulses transmitted to the sacral region of the spinal cord and then back to the bladder via the pelvic sphincter. - Bladder can hold 750 mL of urine before voiding involuntarily External Urethral Sphincter:
ADH Regulation of Water Balance in Kidneys: When the ADH hormone is released, a final 19% of water is reabsorbed into the paritubular capillaries at the distal convoluted tubule. It concentrates the urine. y
Aldosterone Regulation of Water Balance in Kidneys: Aldosterone causes kidney tubule cells to reclaim sodium ions and secrete more potassium ions into the urine when sodium is reabsorbed, water follows. y
Nervous
System
General Functions of the Nervous System: y y y
To monitor changes occurring inside and outside the body (sensory input). To interpret the changes. Affect a response in muscles or glands (motor output).
Organization
of the Nervous System: Central Nervous System: brain, spinal cord, integrating and command center. Interpret incoming sensory information and issue instructions based on past experience and current conditions. y y
Peripheral Nervous System: 12 pairs of cranial nerves, 31 pairs of spinal nerv es Link all parts of the body by carrying impulses from the sensory receptors to the CNS and from the C NS to the appropriate glands gl ands and muscles. Somatic Nervous System: Allows us to consciously control our skeletal muscles. Autonomic Nervous System: Regulates events that are automatic. Examples include the activity of smooth and cardiac muscles. - Peripheral and sympathetic y y
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y
y y
Neurons
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in PNS are classified as being visceral or somatic. Visceral: Impulse are carried to or from a body organ Visceral Afferent : Organs Brain Visceral Efferent: Brain Organs Somatic: Impulses are carried to or from the skin or muscle Somatic Afferent: Skin Brain Somatic Efferent: Brain Skeletal Muscles
Neurons and Neuroglia: Neurons: nerve cells; transmit messages (cannot divide) Neuroglial (Glial) Cells: supporting, insulating, protective cells (can divide). Glia are not able to transmit nerve impulses and they never lose their ability to divide. - Astrocytes, Microglia, ependymal, obligodendrocytes. y y
Gray y y
and White Matter: Gray Matter: unmyelinated and contains cell bodies White Matter: dense collections of myelinated fibers
Functional Properties of Neurons: Irritability: ability to respond to stimuli Conductivity: ability to transmit an impulse y y
Neuron Classification: Multipolar: many extensions from the cell body Bipolar: one axon and one dendrite y y
y
Unipolar: have a short single process leaving the body
Reflexes: y
y y y
Reflex y
Rapid, predictable, and involuntary responses to stimuli - Somatic Reflexes: Reflexes that stimulate the skeletal muscles. Ex. Pulling hand away from hot stove - Autonomic Reflexes: Regulate the activity of smooth muscles, the heart, and glands. Regulate digestion, elimination, blood pressure, and sweating. Ex. Secretion of saliva Once a reflex begins it always goes in the same direction The more synapses there are in a refle x pathway, the longer the reflexes take to happen. Many spinal refle xes involve only spinal cord neurons and occur without brain involvement Reflexes:
Arcs: All reflex arcs have a minimum of five elements : - Sensory Receptor: Reacts to a stimulus - Effector Organ: The muscle or gland eventually stimulated - Sensory Neurons: Connect the sensory and effector organs. - Motor Neurons: Connect the sensory and effector organs - Integration Center (Association Neuron): The synapse between the sensory and motor neurons
Nerve Impulse: 1. Resting membrane is polarized. There are fewer positive ions sitting on the inner face of the neurons plasma membrane than there are in the outer face. 2. A stimulus reverses the polarization causing depolarization 3. A wave of depolarization is the action potential/nerve impulse 4. The action potential continues down the length of the axon 5. The axon repolarizes to restore polarization 6. Refractory period- resting period. The initial concentrations of the sodium and potassium ions inside and outside of the neuron are restored by activation of the sodium-potassium pump. This pump uses ATP (cellular energy) to pump excess sodium ions out of the cell and to bring potassium ions back into it. *Occur along unmyelinated fibers. Fibers that have myelin sheaths conduct impulses much faster because the nerve impulses jump from each Node of Ranvier Saltatory Conduction Major Brain Areas: Cerebrum: - Surface is made from ridges (gyri) and sulci (grooves) - Fissures (deep groves) divide the hemispheres - Connected to each side via corpus callosum - Somatic sensory area receives impulses from the bodys sensory receptors. Located in the parietal lobe posterior to the central sulcus - Primary motor area sends impulses to skeletal muscles. Located in the frontal lobe - Brocas area involved in our ability to speak. - Gray Matter: ¼ inch outer layer, unmyelinated, mostly cell bodies - White Matter: Myelinated, fiber tracts (bundles of nerve fibers) that carry impulses to or from the cortex, and contains the corpus callosum which connects the cer ebral hemispheres and allows both hemispheres to communicate with one another y
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Lobes of the Cerebrum:
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Frontal: thinking and voluntary movement Parietal: interprets sensations Temporal: hearing (auditory cortex) and smell (olfactory area) Occipital: visual cortex (vision)
Brain Stem: - Medulla Oblongata: Controls breathing, heartrate, and blood pressure. Is a fiber tract area. - Pons: Relay center made mostly of fiber tracts. Controls breathing - Midbrain: Controls pupil reflex, reflexes for vision and hearing. Has cerebral peduncles (convey ascending and descending impulses) and corporo quadrig emina Diencephalon: - Located on top of the brain stem and is enclosed by the cerebral hemisphere - Thalamus: Relay center for sensory impulses. Surrounds the third ventricle. Transfers impulses to the correct part of the cortex for localization and interpretation - Epithalamus: Pineal body and choroid ple xus - Hypothalamus: Controls hunger, thirst, temperature, sleep, emotions, ADH, and oxytocin - Also plays an important role in the limbic system - Regulates the pituitary gland Cerebellum - Muscle coordination and balance - Outer cortex = gray matter - Inner cortex = white matter - Monitors what the brains intentions are to what the body is re ally doing. Sends messages to correct this if necessary.
Meninges: Three protective connective tissue membranes that insulate the central nervous system Dura Matter: outermost covering. Has two layers that are fused together. Arachnoid Matter: middle covering y
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y
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Pia Matter: inner covering
Cerebrospinal Fluid Flow: Watery broth similar to its makeup to blood plasma, from which it forms Continually formed from blood by the choroid ple xusesclusters of capillaries hanging from the roof of each of the brains ventricles Protects the nervous tissue from trauma Flow: Lateral ventricleThird ventricleCerebral aqueductFourth ventricleCentral canal of spinal cord y
y
y y
Blood Brain Barrier: Separates neurons from blood borne substances allowing only water, glucose, and essential amino acids to pass through the walls of these capillaries. Metabolic wastes are prevented from entering the brain tissue. (urea, to xins, proteins, drugs) Useless against fats, respiratory gases, and other fat soluble molecules. y
y y
Electroencephalogram (EEG):
Traces the pattern of electrical activity of neurons. Evaluates brain functioning by placing electrodes on a patients scalp. Measures brain waves (alpha, beta, delta, etc.) Taken as evidence for clinical death.
Nervous System Malfunctions/Disorders: Cerebrovascular Accident (CVA): Commonly called a stroke. The result of a ruptured blood vessel supplying a region of the brain. Half body paralysis, cant talk, slurred speech, droopy eye. Ahlzheimers: Progressive degenerative brain disease. Abnormal protein deposits and twisted neurons. C ant remember. Dimension. Concussion: slight brain injury, no permanent brain damage. Vomiting, sleepy, dizzy, lose conscientiousness briefly. Contusion: Coma. Nervous tissue destruction occurs, nervous tissue does not regenerate. Unconscious. Spina Bifida: when the vertebrae form incompletely. In serious cases, meninges, nerve roots, and parts of the spinal cord protrude from the skin paralyzing lower limbs. Anencephaly: the cerebrum fails to develop resulting in a child who cannot hear, see, or process sensory inputs. Cerebral Palsy: occurs when theres a temporary lack of oxygen in the delivery process. y
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Spinal Cord: y y y y y y
Central canal filled with cerebrospinal fluid. Provides a two-way conduction pathway to and from the brain Major reflex center Cushioned and protected by meninges No possibility of damaging the cord beyond L3 31 pairs of spinal nerves
Spinal Nerves: y y
y
Serves the skin and muscles whereas the Ventral Rami: Serves the muscles between the ribs and the skin and muscles of the anterior and lateral trunk. Form complex networks of nerves called plexuses. Plexuses: Serve the motor and sensory needs of the limbs. - Cervical: (Phrenic Nerves) Serves the diaphragm and muscles of the shoulder and neck - Brachial: (Axillary, Radian, Medial, Musculocutaneous, & Ulnar Nerves) Serves the deltoid muscle of shoulder; triceps and extensor muscles of the forearm; the flexor muscles of forearm Dorsal Rami:
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and some muscles of the hand; the flexor muscles of the arm; and the wrist and many hand muscles. Lumbar: (Femoral & Obturator) Lower abdomen, butt, anterior thighs, skin; the adductor muscles of the medial thigh and small hip muscles, skin of medial thigh and hip joint. Sacral: (Sciatic, Common Fibular, Tibial, & Superior and Inferior Gluteal) : Lower trunk and posterior surface of the thigh; lateral aspect of l eg and foot; posterior aspect of leg and foot; butt muscles of hip.
Cranial Nerves: 12 pairs of nerves that mostly serve the head and neck. Numbered in order, front to back. Most are mixed nerves, but three are sensory only. y y y
Cranial Nerve Classification: I. Olfactory smell II. Optic vision III. Oculomotor motor fibers to eye muscles IV.. Trochlear motor fiber to eye muscles V. Trigeminal sensory for the face; motor fibers to chewing muscles VI. Abducens motor fibers to eye muscles VII. Facial taste; motor fibers to the face VII. Vestibulococholear balance and hearing IX. Glossopharyngeal taste; motor fibers to the pharynx X. Vagus pharynx, larynx, and viscera XI. Accessory neck and upper back XII. Hypoglossal tongue Nerve: a bundle of neuron fibers found outside the C NS. Mixed Nerves- both sensory and motor fibers. Afferent (sensory) Nerves- carry impulses toward the CNS. Efferent (motor) Nerves carry impulses away from the C NS. Endoneurium surrounds each fiber Groups of fibers are bound into fascicles by perineurium Fascicles are bound together by epineurium y y y y y y
Autonomic Nervous System: Sympathetic: Mobilizes the body during e xtreme situations. Fight-or-Flight Parasympathetic: Conserves energy. Rest and Digest y y
Factors that are Harmful to Brain Development: Teratogens, drugs, low blood pressure, constipation, poor nutrition, depression, smoking, radiation, various drugs, alcohol y
Brain Aging: Occurs as the aging process is enacted. However, it is more serious in individuals who are chronic alcoholics and professional boxers. y
The Nervous System Peripheral Nervous System (PNS)
Central Nervous System (CNS)
Nerves in the body that extend outside the C NS.
Part of the nervous system that contains the brain and spinal cord that controls mind and behavior. Sensory info comes in and decisions come out.
Somatic
Autonomic Fight, flight, feeling, and reproductive behavior. Brain
Spinal Cord Parasympathetic Rest, energy storage
Sympathetic Action, energy
mobilization
Involuntary movements and sensation. Rest and digest. Refle xes
Special Senses Vision: y y
70% of sensory receptors in the body are located in the eye Requires the most learning
Accessory Eye Structures & Functions: Extrinsic Eye Muscles: - Muscles attach to the outer surface of the eye - Produce eye movements - Six total muscles Eyelids: - Protect the eye anteriorly - Eyelashes: Projected for further protection - Tarsal Glands: Produce oily secretion that lubricates the eye - Ciliary Glands: Modified sweat glands that lie between the eyelashes Conjuctiva: - Lines the eyelids and covers part of the outer surface of the eyeball - Secretes mucus to lubricate the eyeball Lacriminal Apparatus: - Lacriminal Gland: Release tears onto the anterior source of the eyeball through several small ducts. Flush into - Lacriminal Canals Lacriminal Sac Nasocriminal Duct Nasal Cavity - Lacriminal secretion contains antibodies and lysozyme, enzyme that destroys bacteria, to clean and protect the eye surface y
y
y
y
Layers of the Eye: y
Outermost Tunic:
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Sclera (Fibrous Tunic):
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Cornea:
y
Outermost protective tunic Thick, white, connective tissue White of the eye
Clear, outer covering (oxygenated by aqueous humor and air) Most exposed part Light enters the eye Contains many nerve endingsmostly pain fibers Only tissue in the body that can be transplanted to anyone Middle (Vascular Tunic): - Choroid: Blood rich nutritive tunic that contains a dark pigment prevents light from scattering inside the eye Ciliary body is where the lens is attached by a suspensory ligament called the ciliary zonule. - Iris: Muscle which controls the size of the pupil
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Pupil:
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Allows light to enter
Fovea:
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Focal point Creates a clear, color picture Highest concentration of cones Innermost (Sensory) Tunic: - Retina: Contains photoreceptor cells (rods and cones) Lens: Changes shape to focus light - Aqueous Humor: Water fluid which provides nutrients and oxygen to the cornea Lasts forever Helps maintain intraocular pressure Reabsorbed into the venous blood through the canal of Schlemm - Vitreous Humor: Thick fluid which maintains the shape of the eyeball Continually produced Optic Disc (Nerve): - Carries the real image to the brain - No photoreceptors
Rod & Cone Functioning: y y
Rods: Allow
us to see in gray tones in dim light and provide our peripheral vision i n color under bright light conditions Cones: (Discriminatory Receptor) Allows us to see the details in - Three types: Blue, green, and red wavelength types
How Images Form on the Retina: The rays of light are refracted by the lens. The greater the bulge or convexity of the lens the more the light is bent. If the lens is flatter, it bends less. At 20 feet away, the lens does not bend very much. For a close object, the lens bulges more by the ciliary body contracting. This process is called accommodation. The image lands on the retina where photoreceptors process it. The image that lands is a real image which means it is reversed from left to right, upside down, and smaller than the object on the retina. y
Pathway of Light: 1. Cornea 2. Aqueous Humor 3. Through the Iris by way of the Pupil 4. Lens 5. Vitreous Humor (RNCTTO) Photoreceptors of the retina Optic Nerve Optic Nerve crosses at the Optic Chiasma Optic Tracts Thalamus Visual cortex of the Occipital Lobe
Visual Pathway: y
Vision Abnormalities: y y y y y
Accommodation: Ability to focus for close vision under 20 feet Astigmatism: Blurred vision, resulting from unequal curvatures of the lens or cornea Blind Spot: Area in your eye that lacks photoreceptors Cataract: Clouding in the lens resulting in loss of sight Emmetropia: Normal 20/20 vision
y
y y y
Glaucoma:
Condition of increasing pressure inside the eye, resulting from blocked drainage to the aqueous
humor. Hyperopia: Farsighted. Treat with a convex lens Myopia: Nearsighted. Treat with a concave lens Refraction: Light bending
Eye Reflexes: y y
y
y
Internal Muscles: Controlled by the autonomic nervous system External Muscles: Controlled by the rectus and oblique muscles (Somatic Fibers of Cranial Nerves III, IV, & VI). Control eye movements and make it possible to follow moving objects. - Convergence: Reflexive movement of the eyes medially when we view close objects - Both eyes aim toward the object being viewed Photopupillary Reflex: Eyes are exposed to bright light and pupils immediately constrict. Prevents e xcessively bright light from damaging photoreceptors Accommodation Pupillary Reflex: When pupils constrict reflexively when we view close objects.
Audition: Mechanoreceptors: Hearing receptors y
Ear Structures & Functions: y
External Ear:
Pinna: Collects sound waves External Auditory Canal: Lined with wax/ceruminous glands to collect foreign objects Middle Ear: - Tympanic Membrane: Vibrates in response to sound waves. Ossicles: Malleus, incus, and stapes Pass vibrations to cochlea - Auditory Tube: Connects the middle ear with the throat. Allows for equalizing pressure during yawning or swallowing. Inner Ear: - Includes sense organs for hearing and balance - Filled with perilymph (plasma-like fluid) - Cochlea: 32,000 hair like receptors and perilymph - Semicircular Canals: Involved in balance, endolymph (thicker fluid in l abyrinth) - Vestibule: Between semicircular canal and cochlea.
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y
y
Equilibrium Organs: y
Static Equilibrium:
- Moves head forward and backward. - Found in vestibule - Maculae: Receptors in the vestibule that report on the position of the head and help keep head erect. cells are embedded in the otolithic membrane. Otoliths float in the gel around the hair cell s and movements cause otoliths to bend the hair cells. Dynamic Equilibrium: - Action of angular head movements - Found in semicircular canals - Crista Ampullaris: Receptors in the semicircular canals that \have a tuft of hair surrounding it and a gelatinous cap called the cupula covering the hair cells. - The cupula stimulates the hair cells Hair
y
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Impulse is sent via the vestibular nerve to the cerebellum
Organ of Corti: y
y y y
Located within the cochlea. Sound waves reach the cochlea through vibrations of the eardrum, ossicles, and oval window set the cochlear fluids into motion. Receptors: hair cells on the basilar membrane Gel-like tectorial membrane is capable of bending hair cells Cochlear nerve attached to hair cells transmits nerve impulses to auditory cortex on temporal lobe.
Hearing Complications: Sensorineural Deafness: Results from damage to any of the nervous system components of the ear (Organ of Corti, Basilar Membrane, etc.) Is more permanent. - Possible Causes: Damage to cochlear nerve, blood clot in auditory corte x of brain, etc. Conduction Hearing Loss: Results in anything which disrupts the passage of sound waves from the outer e ar to the inner ear. Easier to correct with hearing aids. - Possible Causes: Buildup of earwax, ,fusion of ossicles, ruptured eardrum, otis media y
y
How One is Able to Localize the Source of Sound Since sound typically reaches one ear before the other, it can tell w hat ear the sound is closest to. The stimulation of nerves occurs later in the ear that is farther away and closer in the ear that it closest. y
Olfactory: y
y y
y
Receptors are found in a postage stamp sized area in the superior nasal conchae Chemicals must be volatile in order to be detected. Seven different smells: Peppermint, musky, camphorous, floral, ethereal, putrid, and pungent Olfactory Pathway: Olfactory hairsOlfactory Receptors Olfactory Nerve Olfactory Bulb Temporal Lobe of Brain
Taste: y y
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10,000 taste buds. Found in soft palate, tongue, and in ner surface of cheeks Tongue is covered with projections called papillae : - Filiform Papillae: Sharp with no taste buds - Fungiform Papillae: Rounded with taste buds - Circumvallate Papillae: Large papillae with taste buds. Gustatory Cells: Receptors of the tongue - Have gustatory hairs (long microvillli) - Hairs are stimulated by chemicals dissolved in saliva Impulses are carried to the gustatory complex by: - Facial, glossopharyngeal, and vagus nerves Taste Sensations: - Sweet Receptors: Sugars, saccharine, amino acids - Sour Receptors: Acids - Bitter Receptors: Alkaloids Help detect bad elements of body - Salty Receptors: Metal Ions Factors Affecting Taste: - Depends on stimulation of olfactory receptors of aromas - Temperature - Texture
Developmental Aspects of Special Senses: y
y
At Birth: - Formed early in embryonic development - Eyes are outgrowths of brain - All special senses are functional at birth - Vision is only special sense that is not fully functional at birth Eyes enlarge until age 8 or 9 Babies are hyperopic at birth Baby sees only in gray tones Baby is tearless for about five months Color vision is developed at age 5 Aging (Elderly): - Presbyopia (old vision) sets in around 40. Need reading glasses - Susceptible to glaucoma, cataracts - Presbycusis: Atrophy of the organ of Corti and an inability to hear high tones and speech sounds - Ability to taste and smell diminishes
Endocrine
System
Hormones: Chemical substances that are secreted by ce lls into the extracellular fluids that regulate the metabolic activity of other cells in the body. - Are produced by specialized cells - Cells secrete hormones into extracellular fluid - Blood transfers hormones to target sights, specific tissue cells or organs that a given hormone affects - Hormones regulate the activity of other cells y
Effects Caused by Hormones: y y y y
Changes in plasma membrane permeability or electrical state Synthesis of proteins, such as enzymes Activation or inactivation of enzymes Stimulation of mitosis
Amino-Acid Based Hormones: Mode of Action: - Hormone binds to a membrane receptor - Sets off a series of reactions that activates an enzyme - Catalyzes a reaction that produces a second messenger molecule Include: Proteins, peptides, and amines y
y
Steroids: y y
y
Cholesterol based Mode of Action: - Diffuse through the plasma membrane of target cells - Enter the nucleus - Bind to a specific protein within the nucleus - Bind to specific sites on the cells DNA - Activate genes that result in synthesis of new proteins Include: Sex hormones made by the gonads (ovaries and testes) and hormones made by the adrenal cortex
How Endocrine Glands Stimulated Many hormones can be secreted in response to environmental stimuli like a change in heat or light for e xample, when melatonin is released by the pineal gland which regulates the sleep/wake cycle by the amount of light in the environment Changes in concentration of extracellular ions or nutrients for e xample, If glucose concentration in the blood is high, insulin is secreted Nerve impulse can also release endocrine chemicals for e xample muscle contraction stimulates the release of acetylcholine Other hormones can also simulate the release of chemicals. For e xample, secretion of human gonadotropin releasing hormone (hGnRH) by the hypothalamus stimulates the anterior pituitary to secrete follicle stimulating hormone (FSH) and luteinizing hormone (LH) y
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Negative Feedback Mechanisms: The chief means of regulating blood levels of nearly all hormones. internal or external stimulus y
Hormone
secretion is triggered by some
Rising hormone levels inhibit further hormone release (even while promoting responses in their target organs) Blood levels of many hormones vary only within a narrow range because of this. Need to maintain homeostasis Endocrine Glands: Formed from epithelial tissue Ductless Glands: Produce hormones that they might rel ease into the blood or lymph. Very rich blood supply Pituitary: - Size of a grape - Hangs by a stalk from the hypothalamus - Protected by the sphenoid bone - Has two functional lobes - Anterior pituitary glandular tissue Growth Hormone: General metabolic hormone; Major effects are directed to growth of skeletal muscles and long bones; Causes amino acids to be built into proteins; Causes fats to be broken down for a source of energy Prolactin (PRL): Stimulates and maintains milk production following childbirth, and unction in males is unknown Thyroid Stimulating Hormone (TSH): Influences growth and activity of the thyroid Adrencorticotropic Hormone (ACTH): Regulates endocrine activity of the adrenal cortex Gonadotropic Hormones: Regulate hormonal activity of the gonads Follicle-Stimulating Hormone (FSH) - Stimulates follicle development in ovaries - Stimulates sperm development in testes Luteinizing hormone ( LH) - Triggers ovulation - Causes ruptured follicle to become the corpus luteum - Stimulates testosterone production in males - Referred to as interstitial cell-stimulating hormone (ICSH) - Posterior pituitary nervous tissue Is NOT an endocrine gland because it does not make the peptide hormones it releases. It simply acts as a storage area for hormones made by hypothalamic neurons. Oxytocin: Stimulates contractions of the uterus during labor; Causes milk eje ction Antidiuretic Hormone (ADH): Can inhibit urine production; In large amounts, causes vasoconstriction leading to increased blood pressure (vasopressin) Thyroid: - Located at the base of the throat - Consists of two lobes joined by an isthmus - Composed of hollow structures called follicles which store sticky colloidal material. - Thyroid Hormone: Contains thyroxine and triiodothyronine. Controls the rate at which glucose is oxidized and converted to body heat and chemical energ y. Also important for normal tissue growth and development in the reproductive and nervous systems. Thyroxine: Secreted by thyroid follicles. Has four bound iodine atoms. Triiodothyronine: Formed at target tissues by conversion of thyroxine to triiodothyronine. Has three bound iodine atoms. - Calcitonin: Decreases blood calcium levels by causing calcium to be deposited in the bones. Is made by C cells found in connective tissue between the follicles. IT is releases directly to the blood in response to increasing levels of blood calcium. Parathyroid: - Located on the posterior surface of the thyroid gland. y
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y
y
Usually 2 glands on each thyroid lobe (Total of 4) Secrete Parathyroid Hormone (PTH): Most important regulator of calcium ion homeostasis of the blood. When blood calcium levels are low, the parathyroid release PT H to stimulate bone destruction cells to break down bone matrix and release calcium into the blood Adrenal: - Curve over the top of the kidneys. Is structurally and functionally two endocrine organs in one - Contains glandular (cortex) and neural (medulla) tissues/parts. - Adrenal Cortex: Produces three major groups of steroid hormones called corticosteroids. Mineralocorticoids: Produced by the outermost adrenal cortex cell layer Important for regulating the mineral (salt) content of the blood. Especially concentrations of sodium and potassium ions Regulate electrolyte and water balances in the body Ex. Aldosterone Glucocorticoids: Promote normal cell metabolism and help the body resist long-term stressors Decrease edema, reduce pain by inhibiting molecules called prostaglandins Released from the adrenal cortex in response to rising blood levels of ACTH Ex. Cortisone and cortisol Sex Hormones Ex. Androgens and estrogens - Adrenal Medulla: Develops from a knot of nervous tissue. Release catecholamines. Epinephrine ( Adrenaline) Norepinephrine (Noradrenalin) Increase heart rate, blood pressure, and blood-glucose levels More oxygen and glucose in the blood and faster circulation of blood to the body organs Cause alarm stage Work with glucocorticoids for fight-flight and burn- out response
-
y
y
y y
y y y
y
Pituitary-Hypothalamus Relationship: Release of hormones is controlled by releasing and inhibiting hormones produced by the hypothalamus Hypothalamus produces two hormones that are transported to neurosecretory cells of the posterior pituitary The posterior pituitary is not strictly an endocrine gland, but does release hormones y y y
Exocrine Glands: y y
y
y
Release products at the bodys surface/body cavities via ducts Pineal: - Found in the roof of the third ventricle of the brain - Melatonin: Sleep trigger that play an important role in establishing day-night cycle. Also helps regulate the reproductive system and growth. Thymus Glands: - Located in the upper thorax posterior to the sternum - Decreases in size as we age - Thymosin: During childhood the thymus acts as an incubator for the maturation of a special g roup of white blood cells that are important in the imm une response. Role is immunity! Pancreas: - Contains many small islets - Insulin: High levels of glucose in the blood stimulate the release of insulin from the beta cells Insulin is necessary for the use of glucose y the body cells. Without it, no glucose can get into the cells to be used. - Glucagon: Acts as an antagonist of insulin and helps to regulate blood glucose l evels. Release from alpha cells that are stimulated by low blood levels of glucose
y
Gonads (Testes & Ovaries):
y
Ovaries: Almond
sized organs located In the pelvis (females) Do not begin to function until puberty Estrogens: stimulate the development of the secondary se x characteristics in females. Work with progesterone to prepare the uterus to receive a fertilized egg. Also help maintain pregnancy and prepare the breasts to produce milk. Progesterone: Acts with estrogen to maintain the men strual cycle. Controls the muscles during a pregnancy so the baby develops safely as well as preparing the breasts for lactation. - Testes: Located in the scrotum Testosterone: Causes development of the male sex characteristics. Promotes the growth and maturation of the reproductive system organs and prepares them to reproduce Also physical growth developments (hair, etc.). Is necessary to continue production of sperm. Testosterone production is stimulated by L H Hypothalamus: Another exocrine gland. - The hypothalamus is the master control center of the endocrine system. - The brain (hypothalamus) receives information from the internal and e xternal environment and responds to these conditions with appropriate nervous system or endocrine signals. - It sends signals that directly control the pituitary gland, with in turn secretes hormones. - Release of hormones is controlled by releasing and inhibiting hormones produced in the hypothalamus. - The hypothalamus produces two hormones that are transported to neurosecretory cells of the posterior pituitary.
-
How Hormones Promote Body Homeostasis: Maintaining homeostasis is vital to life. One of the ways that homeostasis is maintained is through the re gulation of the endocrine system. - Ex. The thyroid regulates energy consumption, protein production and calcium in the blood. Another example is maintaining glucose and insulin levels. If glucose concentration in the blood is high, insulin is secreted. y y
Pathological Consequences of Hypersecretion a nd Hyposecretion: Addisons disease: a generalized hyposecretion of all the adrenal cortex hormones. Muscles weaken, hypoglycemia, burnout, immune system suppression Masculinization: hypersecretion of sex hormones in males or females resulting in more manly hair patterns, and other things. Hypersecretion of catecholamines leads to rapid heartbeat, high blood pressure, tendency to perspire and be very irritable. Pituitary Dwarfism: hyposecretion of GH. Little people. Gigantism: hypersecretion of GH. Big people. Hyposecretion of FSH or LH leads to sterility. Diabetes Insipidus: hyposecretion of ADH. Excessive urine output. y
y
y
y y y y
Effects of Aging & Body Homeostasis on the Endocrine System: y
y
The ovaries begin to decline causing menopause. Estrogen deficiency problems commonly arise, like arteriosclerosis and osteoporosis. Fatigue, nervousness, mood changes, etc. Men dont have a dramatic change. Endocrine system efficiency declines.
Hormones of the Endocrine System Gland
& Hormones
Location
Hormone Prolactin Luteinizing
Hangs
from hypothalamus
Hangs
from hypothalamus
ADH
Parathormone
Base of throat
On top of the thyroid
Calcitonin
Mineral Corticoids
Glucocorticoids
Located on top of the kidneys
Hypersecretion (+)
Gigantism Excessive
milk production when not pregnant Frequent ovulations with multiple eggs
- Women: Eggs - Men: Sperm
Sterility
None
- Growth/activity of the thyroid gland
Underactive thyroid = low metabolism
Overactive thyroid = high metabolism
- Regulates the adrenal gland
Oxytoxin
Thyroxine
Hyposecretion (-)
Anterior Pituitary Gland - Targets skeletal Dwarfism muscles - Stimulates breast milk No milk formation production - Triggers ovulation and Sterility testosterone
Growth
Hormone Follicle Stimulating Hormone (FSH) Thyroid Stimulating Hormone (TSH) Adrenocorticotro pic Hormone (ACTH)
Functions
Diseases
of the adrenal gland
Posterior Pituitary Gland Prevents milk - Uterine contractions ejection and released during labor causes abnormal labor Diabetes Insipidus: - Conserves body water Frequent hypotonic urination Thyroid - Weight gain - Controls the rate of - Fatigue metabolism - Mental retardation Parathyroid Low blood calcium - Increases blood levels muscle calcium levels cramping - Decreases blood High blood calcium levels calcium levels Adrenal Cortex Addisons Disease: Muscles - Determines what weaken, minerals are hypoglycemia, excreted/kept burnout, immune system suppression - Long term stressors
Hypoglycemia
Diseases
of the adrenal gland
Prostate problems in men
High
water pressure from absorbing too much water
- High metabolic rate - Graves Disease: Extremely thin and very nervous
Massive bone destruction Decrease
in blood calcium Muscle cramping
High
blood pressure
Moon Face Buffalo Hump: Excessive water and sodium are retained in the blood
Epinephrine
Norpepinephrine
Insulin
Located on top of the kidneys
Close to the stomach
Glugacon
Melatonin
Root of the third ventricle
Thymosin
Located in the mediastinum
Estrogen
Located in the pelvis
Progesterone
Testosterone
Located in the scrotum
Adrenal Medulla - Increase blood - Low heart rate, pressure, blood glucose no rapid response levels, etc. to fight-or-flight - Fight-or-Flight stimuli Pancreas Diabetes Mellitus: Not enough - Reduces blood sugar insulin release levels and/or the body doesnt react Low blood sugar - Raises blood sugar levels Pineal - Biological rhythms - Sleep cycle Insomnia - Fertility Thymus Affects the - Helps T-cell immune system maturation by making it less - Programs lymphocytes effective Ovaries - Development of secondary sex characteristics - Stimulates uterine - Difficulty lining growth conceiving - Unfertile - Maintains menstrual cycle - Promotes growth of uterine lining Testes - Development of male secondary sex - Sterility characteristics
Excessively
rapid beating heart, high blood pressure, overperspiration, irritability
Insulin Shock: Dizzy, lose consciousness, coma
Too much sugar in the blood
Sleepy/Drowsy
None
- Frequent menstrual cycles
- Enhanced male growth
Reproductive System
Male Reproductive System: Testes: Fibrous connective tissue that has 2 coverings : - Tunica Albuginea: Capsule that surrounds each testis - Septa: Extensions of the capsule that extend into the testis and divide into lobules. Each lobule contains 1-4 seminiferous tubules. They are : tightly coiled structures, function as sperm forming factories, and empty sperm into the rete testis. Sperm travels through the rete testis epididymis. Interstitial cells produce androgens such as testosterone. Duct System: - Epididymis: Comma-shaped, tightly coiled tube. Is found on the superior part of the testis along the posterior lateral side. Functions to mature and store sperm cells for at le ast 20 days Expels sperm with the contraction of muscles in the epididymis walls of the vas deferens. - Ductus Deferens: Carries sperm from the epididymis to the ejaculatory duct. Passes through the inguinal canal and over the bladder. Moves sperm through peristalsis. Spermatic cord ductus deferens, blood vessels, and nerves in a connective tissue sheath. - Urethra: Extends from the base of the urinary bladder to the tip of the penis. Carries BOTH sperm and urine. Sperm enters from the ejaculatory duct Regions of the Urethra: Prostate Urethra: Surround the prostate Membranous Urethra: From prostate urethra to penis Spongy (Penile) Urethra: Runs the length of the penis Accessory Organs: y
y
y
y
y
y
-
Seminal Vesicle:
Located in the base of the bladder. It produces a thick, yellowish secretion (60% of
semen)
y
Sperm Contains: Fructose (sugar), vitamin C, prostaglandins, other substances that nourish and activate sperm - Prostate Gland: Encircles the upper part of the urethra. Secretes a milky fluid. Helps to activate sperm Enters the urethra through several small ducts - Bulbourethral Gland: Pea-sized gland inferior to the prostate. Produces a thick, clear mucus. Cleanses the urethra of acidic urine Serves as a lubricant during se x Secreted into the penile urethra External Genitalia: - Penis: Delivers sperm into the female reproductive tract. Regions of the penis include : Shaft, glans penis (enlarged tip), prepuce (foreskin) Often removed for circumcisions - Scrotum: Divided sac of skin outside the abdomen. Maintains testes at 3° C lower than normal body temp to protect sperm viability
Pathway of Sperm: Seminiferous Tubules Rete Testis Epididymus Ductus Deferens E jaculatory Duct Urethra
Meiosis: y
type of cell division that results in two daughter cells each with half the chromosome number of the parent cell
A
Spermatogenesis: y
The production or development of mature spermatozoa
Structure and Function of Sperm: y y
y
y
y
y
The sperm cell has three basic parts. The head contains the DNA to be injected into the ovum and also has chemotatic receptors for navigation towards the ovum. The Tail is at the other end and is a single flagella in healthy cells. This structure flips and twists in such a way as to pr opel the cell along. Finally between the two is the body of the cell which contains six mitochonria to power the movement of the flagel la. It is the joint between the body and the head that is broken during fertilization so that none of the mitochondria are from the father. The other structure in the mature sperm that plays a critical role in fertilization is the acrosome. Acrosome releases enzymes that helps the sperm enter the egg
FSH & LH on the Testes: FSH enhances the production of androgen-binding protein by the Sertoli cells of the testes and is critical for spermatogenesis. LH stimulates Lydig's cells to produce testosterone hormone y
y
Female Reproductive System: and broad Ovaries: Composed of ovarian follicles (sac-like structures). Supported by suspensory, ovarian, and ligaments. Contains: - Oocyte: - Follicular Cells: Stages include: Primary Follicle: Contains an immature oocyte Graafian (Vesicular Follicle): Growing follicle with a maturing oocyte Ovulation: When the egg is mature the follicle ruptures. Occurs about every 28 days. The ruptured follicle is transformed into corpus luteum Duct System: - Uterine Tubes (Fallopian Tubes): Receives the ovulated oocyte and is a site for fertilization. Fimbriae: Finger like projections at the distal e nd that receive the oocyte. Cilia inside the uterine tube slowly move the oocyte towards the uterus. Attaches to the uterus Does not physically attach to the uterus Supported by the broad ligament urinary bladder and rectum. It is a - Uterus: Located between the urinary hollow organ that functions to : Receive, retain, and nourish a fertilized egg. Regions: Body (Main portion); Fundus ( Area where uterine tube enters); Cervix (Narrow outlet that protrudes the vagina) Walls: Endometrium (Inner layer that allows for implantation of the fertili zed egg. Sloughs off if no pregnancy occurs); Myometrium (Middle layer of smooth muscle); Serous Layer (Outer visceral peritoneum) - Vagina: Extends from the cervix to the exterior of body. Is behind the bladder and in front of the rectum. Serves as the birth canal Receives the penis during sex Hymen: Partially closes the vagina until it is ruptured, usually through se x. External Genitalia: - Mons Pubis: Fatty area overlying the pubis symphysis. Is covered with pubic hair after puberty y
y
y
-
-
Skin folds that include the majora (outside) and minora (inside) Vestibule: Enclosed by the labia majora and contains the opening of the urethra and the greater vestibular glands (produce mucus) Clitoris: Contains erectile tissue that corresponds to the penis. Labia:
Female Reproductive System: Female reproduction begins during puberty and ends in their fifties or before Total supply of eggs is present at birth Reproductive ability ends around menopause Oocytes are matured in developing ovarian follicles y
y y y
Functions: Follicle: Contain immature eggs called oocytes surrounded by layers of follicle cells. As the developing egg within a follicle begins to ripen or mature, the follicle enlarges and develops the antrum. After it develops the antrum it becomes a vesicular (Graafian) follicle where the developing egg is ready to be ejected into the ovary ovulation After ovulation, the ruptured follicle is transformed into the corpus luteum, which eventually degenerates. The function of the corpus luteum is to produce progesterone in the presence of L H. Stops producing hormones 10-14 days after ovulation y y
y y
Walls of the Uterus: y
y
y
Endometrium: Inner
layer of the mucosa. If fertilization occurs, the fertilized egg implants into the Endometrium and resides there for the rest of its development. Myometrium: Middle layer of the uterus. Composed of smooth muscles and plays an active role in delivering babies by contracting rhythmically to force the baby out of the m others body. Perimetrium: Outer most layer.
Phases of the Menstrual Cycle: Cyclic changes of the Endometrium because of hormone shifts in the body Regulated by cyclic production of estrogens and progesterone Stages: - Menses: Days 1-5.Functional layer of the Endometrium is sloughed and period occurs - Proliferative Stage: Days 6-14. Regeneration of functional layer. Rising levels of estrogen - Secretory Stage: Days 15-28. Endometrium increases in size and readies for implantation. Rising levels of progesterone by corpus luteum. If the woman is not pregnant, the cycle restarts at menses. y y y
Oogenesis: y
y
y
y
Cell division that occurs in the ovaries to produce femal e gametes (sex cells) Oogonia (female stem cells) multiply to increase their number by undergoing mitosis to produce Primary Oocytes: Push into the ovary connective tissue where they become surrounded by cells that form primary follicles in the ovary. The oognia no longer exists by the time of birth. First meiotic division produces 2 cells that are dissimilar in size. Larger one is the secondary oocyte and the smaller cell is the polar body Oogenesis:
y
Second meiotic division
occurs if the secondary oocyte is penetrated by a sperm to produce another polar body and an ovum. Result = 1 functional ovum and three tiny polar bodies that deteriorate quickly
Hormones in the Ovarian Cycle: Follicle Stimulating Hormone (FSH): Stimulates a small number of primary follicles to grow and mature each month. Help maintain the ovarian cycle. Also helps the primary oocyte replicate its hormones and begin mei osis. Luteinizing Hormone (LH): Helps trigger ovulation to begin. Also triggers the ruptured follicle to change into the corpus luteum (glandular structure) y
y
Fertilization: Fertilization: the fusion of the nuclear material of an egg and sperm Zygote: the fertilized ovum. Produced by the union of two gametes. y
y
Implantation: The blastocyst attaches itself to the endometrium and starts to e rode it so it can be embedded in the mucosa. As this is happening, the three germ layers are being formed in the cell. The uterine mucosa grows over the cell after about 14 days. Chorionic villi grow from the trophoblast to cooperate with the uterine tissues to form the placenta. y y y y
Embryo vs. Fetus: y
Embryo:
y
the first 9 weeks of pregnancy. The building blocks are set. A lot of cell divi sion occurs. Developmental stage from the start of cleavage until the ninth week The embryo first undergoes division without growth The embryo enters the uterus at the 16-cell state The embryo floats free in the uterus temporarily Uterine secretions are used for nourishment
Fetus: after 9 weeks. - Unborn baby. Growth and organ specialization are key to this stage. - All organ systems are formed by the end of the eighth week - Activities of the fetus are growth and organ specialization - A stage of tremendous growth and change in appearance
Functions of the Placenta: The placenta forms a barrier between the baby and the mother that blood cannot transfer through. It delivers nutrients and oxygen. It removes waste from the blood of the embryo. It takes over for the corpus luteum and produces the hormones necessary for the baby including estrogen, progesterone, and others. y y y y
How Pregnancy Affects the Body: uterus enlarges the lumbar curvature widen Relaxin production creates relaxment of the pelvic ligaments and pubic symphysis morning sickness due to progesterone, heartburn because of organ crowding y y y y
y
constipation because the digestive tract declines in motility kidneys produce more urine because it is filtering more uterus compresses bladder nasal mucosa becomes swollen and congested vital capacity and respiratory rate increase body water rises blood volume increases blood pressure and pulse increase varicose veins common
y
.
y y y y y y y y
How Labor is Initiated: Estrogen levels rise uterine contractions begin The placenta releases prostaglandins Oxytocin is released by the pituitary gland y y y y
Three Stages of Labor: Dilation- cervix becomes dilated, uterine contractions begin and increase, the amion breaks (water broke) Expulsion- infant passes through the cervix and vagina Placental Stage: delivery of the placenta y y y
Agents that Interfere with Normal Fetal Development: Drugs, smoking, poor nutrition, alcohol y
