Biol 252 - Exam 2

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3 levels of neural integration in the somatosensory system: 1)receptor level- sensory receptors
2)circuit level- ascending pathways
3)perceptual level- neuronal circuits in the cerebral cortex
fibers in nonspecific ascending pathways transmit:: pain, temperature, coarse touch impulses, emotional aspects of perception, nondiscriminatory, general info
fibers in specific ascending pathways transmit:: discriminative aspects of touch (tactile discrim), vibration, pressure, conscious proprioception (limb and joint position)
endoneurium: delicate layer of loose conn. tissue around each axon that also encloses fiber's myelin sheath (neurilemma)
perineurium: coarser conn. tissue wrapping around fascicles (groups of fibers bound together)
epineurium: tough fibrous sheath enclosing all the fascicles to form the nerve
mixed nerves: nerves containing both sensory and motor fibers, transmitting impulses both to and from the CNS (most nerves are mixed)
sensory (afferent) nerves: carry impulses only toward CNS
motor (efferent) nerves: carry impulses only away from CNS
ganglia: collections of neuron cell bodies associated w/nerves in PNS
I. Olfactory Nerve: sensory- travels to brain from where its innvervating; originates from cerebral hemisphere; "smell" nerve fibers travel into nasal region; runs from upper part of nasal cavity up to brain; goes to olfactory cortex of frontal lobe
II. Optic Nerve: sensory fxn; originates from cerebral hemisphere; travels from retina to thalamus and primary visual cortex of occipital lobe
III. Oculomotor Nerve: motor fxn- moves 4 of 6 eye muscles; has a parasymp. fiber associated with it- PS fibers involved with glands; fibers originate from midbrain
IV. Trochlear Nerve: motor fxn; name means "pulley" - goes to 1 eye muscle which rotates eye counterclockwise from pons
V. Trigeminal Nerve: mixed fxn; largest cranial nerve; supplies sensory fibers to face and motor fibers to chewing muscles, teeth and part of tongue- sensation of touch, not taste of tongue; 3 divisions- responsible for cutaneous sensation; cover entire face and top of head
VI. Abducens Nerve: motor fxn; controls lateral rectus muscle that abducts eye (moves out towards lateral area)
VII. Facial Nerve: mixed fxn; has parasymp fibers; innervates glands of mouth (2 of 6 salivary glands), muscles of face for facial expression, to tongue; innervates lacrimal gland (produces tears)
VIII. Vestibulocochlear (Auditory) Nerve: sensory and some motor fxn; innervates inner ear responsible for hearing and balance (body position); cochlea- sensory hearing apparatus; vestibule- tells brain which direction head is moving
IX. Glossopharyngeal Nerve: mixed fxn; parasymp fibers; innervates 3rd pair of salivary glands; goes to back of tongue responsible for taste and sense; carotid sinus in carotid artery has receptors sensing O2 and CO2 levels.
X. Vagus Nerve: mixed fxn; parasymp innervation; "wanderer" - only nerve that goes beyond head and neck to thorax and abdomen down to colon, abdominal organs, heart, lungs; innervates carotid artery - senses pressure difference in blood; baro-receptors: respond to pressure in blood
XI. Accessory Nerve: motor fxn; travels down to innervate muscles of neck- sternocleidomastoid and trapezius which move the head
XII. Hypoglossal Nerve: motor fxn; "under tongue"- innervates muscles just below tongue
spinal nerves: 31 pairs from spinal cord; all are mixed nerves; 8 cervical; 12 thoracic; 5 lumbar, 5 sacral, 1 occygeal nerve; first 7 exit vertebral canal superior to vertebrae; C8 inferior, all after leave inferior too
the large onion-shaped receptors deep in dermis and subcutaneous tissue that respond to deep pressure are:: Pacinian corpuscles
proprioceptors include:: muscle spindles; golgi tendon organs, joint kinesthetic receptors; (not Merkel cells)
dorsal root ganglia contain:: cell bodies of sensory neurons
nerve that causes pupillary constriction: oculomotor
nerve thats the major sensory nerve of face: trigeminal nerve
serves sternocleidomastoid and trapezius muscle: accessory nerve
are purely sensory (2 nerves): olfactory and optic nerves
serves tongue muscles: hypoglossal nerve
allows to chew food: trigeminal
is impaired in Bell's palsy: facial nerve
helps to regulate heart activity: vagus nerve
helps hear and maintain balance: vestibulocochlear nerve
contains parasymp. motor fibers (4 nerves): III. Oculomotor; VII. Facial; IX. Glossopharyngeal; X. Vagus
receptors involved in enjoying ice cream cone: exteroceptor; chemo and thermoreceptor
scalding yourself w/hot coffee: exteroceptor; nociceptor and thermoreceptor
retinas of eye are stimulated: exteroceptor; photoreceptor
bump into someone: exteroceptor; mechanoreceptor
reaching toward light switch in dark room: proprioceptor; mechanoreceptor
feeling uncomfortable after large meal: interoceptor; mechanoreceptor
How does autonomic nervous system 2-neuron chain work?: preganglionic neuron (cell body of 1st neuron) in brain/spinal cord has the preganglionic axon which synapses w/the ganglionic neuron (2nd motor neuron) in an autnomic ganglion outise CNS; postganglionic axon (of ganglionic neuron) extends to effector organ; conduction much slower b/c pregang axons lightly myelinated an dpostgang are unmeyelinated
sympathetic fibers release the neurotrans:: norepinephrine
parasymp fibers releas: acetylcholine
ANS has:: 2-neuron efferent chain; presence of nerve cell bodies in CNS and in ganglia; but no innervation of skeletal muscles
preganglionic neurons develop from: neural tube cells
accessory structures of the eye: eyebrows, eyelids, conjunctiva, lacrimal apparatus, extrinsic eye muscles
3 layers of eyeball: fibrous, vascular, sensory layers
fibrous layer: outermost layer; has sclera ("white of eye") and cornea (bulges out from sclera)
vascular layer (uvea): has 3 regions: choroid, ciliary body, iris
inner layer (retina): 2 layers; outer pigmented layer, inner neural layer (has photoreceptors, bipolar cells, and ganglion cells)
3 processes required for close vision of eye: 1) accomodation of lenses -increases refractory power of lens- bulges it to allow for closer focal point
2) constriction of pupils- reduces size to prevent blurred vision
3) convergence of eyeballs- when eyes fixate on close object
how does rhodopsin- opsin interaction work?: 11-cis retinal is attached to rhodopsin; when exposed to light, 11-cis changes to all-trans retinal, is released from the now-opsin complex, and the process repeats once its dark again
external ear consists of:: auricle/pinna-directs sound into external acoustic meaturs- produces earwax; tympanic membrane/eardrum- boundary btwn outer and middle ears which vibrates when hit by sound waves
middle ear/ tympanic cavity: has superior oval window and inferior round window; pharyngotympanic(auditory) tube; auditory ossicles: malleus, incus, stapes
internal ear/ labyrinth: 2 divisions:
1) bony labyrinth- has the vestibule, cochlea, semicircular canals; filled with perilymph
2)membranous labyrinth;- suspended in perilymph, interior has endolymph
vestibule: has saccule (continuous w/membranous labyrinth extending anteriorly into cochlea) and utricle (continuous w/semicirc. ducts extending into semicirc canals); these 2 have equil. receptor regions tha trespond to pull of gravity and report on changes of head position
accessory glands that produce an oily secretion are:: tarsal glands
portion of fibrous layer of eye that is white and opaque: sclera
4 refractory media of eye, listed in sequence in which they refract light:: cornea, aqueous humor, lens, vitreous humor
optic nerve formed by axons of:: ganglion cells
blind spot of eye is where:: optic nerve leaves the eye
sensory impulses transmitted over facial, glossopharyngeal, and vagus nerve involved in sensation of what sense?: taste
conduction of sound from middle ear to internal ear occurs via vibration of: stapes against tympanic membrane
the spiral organ of Corti:: sounds of high freq stimulate hair cells at basal end; "hairs" of receptor cells are embedded in tectorial membrane; basilar membrane acts as a resonator
structure that allows pressure in middle ear to be equalized w/atmospheric pressure is the: pharyngotympanic tube
important in balance of body:: visual cues, semicirc canals, saccule, propriocepors
static equil receptors that report position of head in space relative to pull of gravity:: maculae
lies closest to posterior pole of eyes: macula lutea
otoliths (ear stones) are:: important in equilibrium
Cyclic AMP Signaling Mechanism of amino acid-based hormones: 1) the hormone acting as the 1st messenger binds to receptor
2) this causes receptor to change shape- allowing it to bind to inactive G-protein, which is activated when GDP becomes GTP
3) activated G-protein binds to effector enzyme adenylate cyclase (either stimulating or inhibiting it); GTP becomes GDP and G protein becomes inactive
4) if activated, adenylate cyclase generates 2nd messenger cAMP from ATP
5) cAMP triggers chem rxns beginning w/activation of protein kinase A
PIP-Calcium Signal Mechanism of amino-acid based hormones: 1) hormone binding changes receptor shape
2) receptor binds to G-protein which is activated by becoming GTP
3) activated G-protein binds to and activates phospholipase C (effector enzyme)
4) that enzyme splits PIP2 into DAG and IP3- both act as 2nd messengers
5) DAG activates protein kinase C; IP3 triggers release of Calcium from endo. retic and other sites
6) liberate calc acts as 2nd mess. by directly altering activity of specific enzymes and plasma membrane calc channels or by binding to intracellular regulatory protein: calmodulin; after binding, enzymes activated that amplify cellular response
direct gene activation mechanism of steroid hormones: 1) lipid-soluble hormone (steroid/thyroid horm) diffues thru plasma membrane of target cell and binds to a receptor-chaperonin complex in nucleus
2) after bound, chaperonin dissocites from receptor and hormone-receptor complex binds to a specific sequence on DNA, initiating transcription of a certain gene
3) the mRNA formed migrates into cytoplasm, where it directs synthesis of a specific protein
permissiveness: 1 hormone can't exert full effects w/o another hormone being present
synergism: more than 1 hormone produces same effects at target cell and combined effects are amplified
antagonism: one hormone opposes actions of another
humoral stimuli: endocrine glands secrete hormones in direct response to changing blood levels of ions and nutrients; simplest endocrine control system
neural stimuli: nerve fibers stimulate hormone release
hormonal stimuli: hormones released in response to hormone produced by other endocrine organs
pituitary gland/hypophysis: has: 1) neurohypophysis (made of neural tissue in posterior); releases oxytocin and ADH
2) adenohypophysis (made of glandular tissue in anterior); produces growth hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, gonadotropins (follicle stimulating hormone and lutenizing hormone), prolactin
tropic hormones: 4 of 6 anterior pituitary hormones: TSH, adrenocort, FSH, LH; stimulate release of other hormones
growth hormone: anabolic effects- increasing protein synthesis, increasing size of bones;
released when stimulated by growth hormone releasing hormone (GHRH), and in turn releases somatomedins:
GHRH --> GH --> somatomedins
thyroid stimulating hormone (TSH): responsible for regulating release of thyroid hormone from thyroid gland; is regulated by hypothalamus hormones (thyroid releasing hormone)-(releasing or inhibitory):
TRH --> TSH --> thyroid hormone
adrenocorticotropic hormone (ACTH): stimulates release of adrenal hormone; regulated by corticotropic releasing hormone:
CRH --> ACTH --> adrenal hormone
gonadotropic hormones: folliclue stimulating (FSH) lutenizing (LH): -regulate fxn of gonads; cause release of testosterone and estrogen; FSH stimulates gamete production; LH promotoes production of gonadal hormones; regulated by gonadotropin releasing hormone:
GnRH --> LH/FSH --> sex hormones
prolactin (PRL): after birth, PRL stimulates milk production in mother; stimulation by suckling of newborn- triggers release of PRL; PRL-inhibiting hormone (PIH) aka dopamine prevents prolactin secretion; prolactin releasing hormon e(PRH)- fxn unknown
oxytocin: -causes smooth muscle contraction of uterus; active at onset of pregnancy; involved in conjunction w/prolactin; contracts ducts that hold the milk; fxn in male less known; stimulated by impulses form hypothalamic neurons in response to uterine stretchin and suckling of infant at breast; inhibited by lack of appropriate neural stimuli
antidiuretic hormone (ADH): prevents water loss; responds to solute concentrations: high solute concentration = kidneys reabsorb water; stimulated by impulses from hypothalamic neurons in response to increased osmolality of blood or decreased blood volume; inhibited by adequate hydration of body and by alcohol;
thyroid gland: responsible for releasing thyroid hormone (T3, T4); thyroid hormone made of iodine; gland - made of follicle cells- produce TH in response to TSH
effects of TH: utilization of glucose - metabolically activate body - produces heat as a byproduct
calcitonin- responds to high levels of calc in blood; stimulates osteoblast activity to return calc levels to normal;
PTH- parathyroid hormone- antagonistic to calcitonin - stimulates osteoclast activity when low calc levels; produced in back of thyroid gland by PT gland
adrenal glands: has adrenal medulla (releases epineph and norepineph); triggered by neuronal stimuli
-adrenal cortex - responsible for adrenal cortex hormones- divided into 3 layers:
1)mineralocorticoids- produce aldosterone; responds to low sodium and ACTH; retains sodium n kidneys
2) glucocorticoids- produce cortisol; responds to ACTH; stimulates gluconeogenesis (raises blood glucose)
3)gonadocorticoids0 produces sex hormones/androgens; responds to ACTH; contributes to puberty, 2ndary sex characteristics, sex drive
pancreas: endocrine and exocrine fxn;
has small cells that make up 1% of volume; has spots called islets- 2 types:
1)alpha cells- produce glucagon -(targets liver- produces glucose when low glucose in blood; stimulates glycogen breakdown into glucose
2) beta cells- responsible for producing insulin --(responsible for glucose uptake; when high levels of glucose in blood, insulin causes reuptake of glucose from blood)

**Diabetes Type I- attacks beta cells; Type II- due to insulin insensitivity
gonads: ovaries-produce estrogen and progesterone
testes- produce testosterone
pineal gland: back of 3rd ventricle; produces melatonin- works antagonistic w/seratonin; responsible for depressed state of body; seratonin converted to melatonin at night--puts to sleep
thymus gland: important in children; development of immune system - often b4 birth
heart: responsible for secretion of ANP- responds to stretching of atrial stretching-- happens when blood volume/pressure is too high; causes you to lose sodium from body
kidneys: produces EPO - stimulates red blood cell production
major stimulus for release of parathyroid hormone is:: humoral
parathyroid hormone:: demineralizes bone and raises blood calcium levels
important anabolic hormone; many of its effects mediated by IGFs: growth hormone
involved in water balance; cause the kidneys to conserve water: antidiuretic hormone; aldosterone
stimulates milk production: prolactin
tropic hormone that stimulates gonads to secrete sex hormones: lutenizing hormone
major metabolic hormones of body: T3; T4
causes reabsorption of sodium ions by kidneys: aldosterone
tropic hormone that stimulates thyroid gland to secrete thyroid hormone: TSH
hypodermic injection of epinephrine would:: increase heart rate, increase blood pressure, dilate bronchi, decrease peristalsis
if there is adequate carbohydrate intake, secretion of insulin results in: lower blood glucose levels; increased cell utilization of glucose; storage of glycogen
Functions of Blood: 1) Distribution:
-delivering O2 and nutrients to all body cells
-transporting metabolic wastes to kidneys and lungs
-transporting hormones
2) Regulation:
-maintaining body temp
-maintaining pH
-maintaining adequate fluid volume in circulatory system
3) Protection
-clotting to prevent blood loss
-preventing infection
blood is made up of:: plasma (55%)
formed elements:
erythrocytes (45%)
leukocytes and platelets(<1%)
hemoglobin (in erythrocytes) made of: protein globin bound to red heme pigment; globin has 4 polypeptide chains (2 alpha, 2 beta) bound to ring-like heme; hemoglobin can transport 4 molecules of O2
erythropoietin: a glycoprotein hormone released when reduced O2 levels in blood trigger kidneys for its release (results from decreased RBC count, decreased amt of hemoglobin, or decreased availability of O2); it stimulates red bone marrow which hastens committed RBC formation- increases O2-carrying ability of blood and maintains homeostasis
destruction of erythrocytes: after 100-120 day life span, RBCs become trapped in circ. channels in spleen; are engulfed my macrophages; the heme split off from globin; iron is saved for reuse; heme group degraded to bilirubin- picked up by liver cells which secrete it as bile into intestine- leaves thru feces; globin broken into amino acids- released to circulation
leukocytes divided into:: granulocytes (neutrophils, basophils, eosinophils)
agranulocytes (lymphocytes, monocytes)
neutrophil: phagocytize bacteria
eosinophil: kill parasitic worms
basophil: realeases histamine and mediators of inflammation
lymphocyte (T cells/B cells): T cells- immune response against viruses and tumor cells;
B cells- produce plasma cells which produce antibodies released to blood
monocytes: phagocytosis- become macrophages in tissues
3 steps of hemostasis: 1) vascular spasms
2) platelet plug formation
3) coagulation
hormonal stimulus that prompts red blood cell formation:: erythropoietin
blood proteins have important role in:: blood clotting, immunity, maintenance of blood volume
lymphatic vessel fxns: 1)return excess tissue fluid to bloodstream
2)return leaked proteins to blood
3)carry absorbed fat from intestine to blood (thru lacteals)
entry of lymph into lymphatic capillaries promoted by:: one-way minivalves formed by overlapping endothelial cells; greater fluid pressure in the interstitial fluid
lymph nodes are densely clustered in:: axillae, groin, cervical region, (not in brain)
lymphoid organ that fxns primarily during youth and then begins to atrophy: thymus
2 intrinsic defense systems of immune system: 1) innate (nonspecific) defense system: provides 1st line of defense-outer skin and 2nd line of defense-phagocytes,antimicrobial proteins, etc.
2) adaptive (specific) defense system: attacks specific foreign substances as 3rd line of defense- B/T cells
inflammatory response: beneficial effects:
1) prevents spread of damaging agent
2) disposes of cell debris and pathogens
3) sets stage for repair

signs: redness, heat, swelling, pain
process of phagocyte mobilization after inflammation: 1) leykocytosis: leukocytosis-inducing factors released by injured cells promote release of neutrophils from red bone marrow
2) margination: blood flow slows and neutrophils roll down endothelium; when CAM's unite, neutrophils cling to inner walls of capillaries
3) diapedesis: netrophils squeeze thru capillary walls
4) chemotaxis: neutrophils attracted to inflammatory chemicals
small molecules that must combine w/large proteins to become immunogenic are:: haptens
lymphocytes that develop immunocompetence in the bone marrow:: B-cells
whats involved in activation of a B cell?: antigen, helper T cell, cytokine
complement fixation promotes:: cell lysis, inflammation, opsonization, chemotaxis of neutrophils and other cells, (not interferon release)
phagocytes include:: neutrophils, macrophages
release histamine: mast cell; basophil
release perforins: natural killer cells; cytotoxic T cells
lymphocyte: natl killer cells; cytotoxic T cell; B cell; helper T cell
can differentiate to form memory cells: cytotoxic T cells, B cell, helper T cell
antigen-presenting cell: dendritic cells; B cell; macrophage
3 primary embryo vessicles that form brain structures: prosencephalon, mesencephalon, rhombencephalon
5 secondary vessicles: telencephalon
diencephalon
mesencephalon
metencephelon
myelencephalon

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