Exam 5 Study Guide

Question 1

external ear

Answer 1

sound waves travel from auricle and are funneled into external acoustic meatus and then to the tympanic membrane.

Question 2

inner ear

Answer 2

bony labyrinth is filled with fluid called perilymph.
membranous network is filled with endolymph.
sound waves send fluids into motion.

Question 3

vestibulae

Answer 3

bony labyrinth composed of perilymph.
has two membranous labyrinths, the utricle and the saccule, which have receptors for equilibrium and balance called maculae. maculae respond to linear acceleration and change in head position

Question 4

semicircular canals

Answer 4

bony labyrinth has membraneous labyrinths called semicircular ducts. has ampulla with receptors cristae ampullaris. responds to angular acceleration and rotation of head

Question 5

cochlea

Answer 5

membranous labyrinth in each turn of cochlea is cochlear duct. duct contains spiral organ of Corti or receptor of hearing.
each turn of cochlea there are three chambers and bony labyrinths, the cochlear duct (endolymph), Scala vestibuli and Scala tympani (perilymph).
when fluid is set in motion, it activates the spiral organ of Corti which is the receptor for hearing.

Question 6

spiral organ of Corti

Answer 6

inside cochlear duct and contains a basilar membrane and tectorial membrane, and supporting and hairs cells sandwiched in between.

Question 7

sound wave path

Answer 7

auricle catches waves, funnels waves into EAM, then vibrates the tympanic membrane, which vibrates ossicles, which pushes on oval window, and that sets perilymph in Scala vestibuli in cochlea in motion.
sounds with frequency below our hearing generates waves in s. vestibuli and they stay in the bony labyrinth and Scala tympani.
sounds within hearing range go into cochlear duct or membranous labynth.
cochlear duct bends, the basilar membrane of organ of Corti also bends, so an action potential will be generated in the cochlear nerve.
sound waves then go to the Scala media and then die out.

Question 8

Interpretation of sound

Answer 8

sound wave or pressure waves is a pressure disturbance and regions of compressed air molecules and lower pressure air molecules.
sound is interpreted from pitch (frequency of wavelengths) and loudness (amplitude of each wave).

Question 9

middle ear

Answer 9

membrane vibrates are sounds waves are transferred to ossicle bones (males, incus, stapes). stapes sits in oval window. middle ear connects to throat via eustatian tube, which is why ear infections can occur with sore throat.

Question 10

determining frequency/pitch

Answer 10

basilar membrane has stuff and floppy fibers, so frequency can be determined by where the membrane is bent or deflected. high pitch/frequency sounds are stronger so the stiff fibers will be bent more.

Question 11

sound transduction

Answer 11

when there is a deflection of basilar membrane, hair cells (stereocillia are mechanosensitive, so they respond to bending.) are bent and generate action potentials on cochlear nerve, which are sent to the brain for sound interpretation.
bending of stereocillia and generates tension in tip links and opens channels which causes graded depolarization of hair cells. NT is then released at synapse with cochlear nerve, and AP is generated on cochlear nerve.

Question 12

pitch

Answer 12

basilar membrane allows pitch discrimination

Question 13

auditory pathway

Answer 13

ascending multi neuronal path. start with neurons innervating spiral organ of Corti. bring AP to two neurons in medulla. then neurons bring info to synapse at inferior colliculi or auditory reflex center. then synapses at thalamus which relays sensory info about sound to primary auditory cortex.

Question 14

conduction deafness

Answer 14

sound conduction path is impaired from perforated tympanic membrane or otosclerosis (stiffening of ossicles, so they won’t vibrate).

Question 15

sensorineural deafness

Answer 15

damage to neural structures from loss of hair cells or stroke affecting brain structures that relay sound info

Question 16

static equilibrium

Answer 16

sensing changes in head position or linear head position

Question 17

anatomy of maculae

Answer 17

each macula has many hair cells and supporting cells.
has stereocillia (long microvilli) with ion channels
1 kinocillium- an individual cilium, longest protrusion on hair cells and helps with directionality
has otoliths or little rocks that increase mass or inertia in the gel or membrane (otolith membrane)

Question 18

Utricle

Answer 18

macula is oriented horizontally and responds to head tilt or horizontal acceleration

Question 19

saccule

Answer 19

macula sits on the side of the membranous labyrinth and the hair cells are horizontal, so the hair cells respond to vertical acceleration

Question 20

difference between organ of Corti and maculae

Answer 20

In organ or Corti, bending of hair cells causes action potentials.
in maculae, bending of hair cells increases or decreases action potentials

Question 21

dynamic equilibrium

Answer 21

crista ampullaris senses changes in dynamic equilibrium because hair cells (with stereocillia and a kinocillium) that are embedded in a gel to increase the mass called ampullary cupula.

Question 22

bending and basal firing

Answer 22

bending in one direction increases firing and bending in opposite direction decreases basal firing because of the endolymph movement.

Question 23

3 layers of the eye

Answer 23

outer fibrous, middle vascular, and inner layer

Question 24

outer fibrous layer

Answer 24

dense connective tissue, avascular. composed of the sclera and cornea

Question 25

cornea

Answer 25

allows light to enter the eye, light bending apparatus

Question 26

vascular layer/pigmented layer

Answer 26

contains blood vessels and melanocytes for pigment and functions to absorb light that enters the eye composed of the choroid, the cilliary body, and the iris.

Question 27

choroid

Answer 27

dense in melanin and blood vessels

Question 28

cilliary body

Answer 28

has smooth muscle called cilliary muscles and cilliary processes that function for producing aqueous humor, and provides a point of attachment for ligaments the cilliary zonule or suspensory ligaments hold the lens in place and change the shape of it

Question 29

iris

Answer 29

composed of an inner smooth muscle layer called sphincter papillae, smooth muscle cells are oriented circularly. parasympathetic input causes pupil to constrict. outer layer is dilator papillae and cells are oriented radially. contracted pulls on the sphincter papillae. sympathetic input causes pupil to dilate.

Question 30

inner layer/retina

Answer 30

external pigmented layer inner neural layer is composed of modified neurons in sequence, the axons of the last neuron become a part of the optic nerve. neurons from ext. to int. are photoreceptors, bipolar cells, and ganglion cells. axons of ganglion cells become a part of the optic nerve and send sensory info about light to the brain. light passes through bipolar and ganglion cells to activate photoreceptors. the opening at the back of the retina called the optic disc/blind spot is where optic nerve exits the eye. anterior limit of neural layer is sawtooth region (name)

Question 31

rods

Answer 31

very sensitive so used to sense dim light and important for peripheral vision. located more so on the periphery. cannot interpret color and cannot produce sharp images.

Question 32

cones

Answer 32

are used for bright light and for color and sharp/detailed vision. not distributed uniformly, most concentrated in macula lutea. foveae centralis is the central pit of the macula lutea. good for visual acuity

Question 33

internal structures

Answer 33

behind the lens to back of eye: posterior segment: filled with virtuous humor developed in the fetus and persists for life. very important for structural support to posterior regions off the eye and keeps layers of eye held together. important for maintaining intraocular pressure. back of the lens forward: anterior segment: filled with aqueous humor secreted by cilliary processes and provides nutrients to anterior eye structures, and drains into scleral venus sinus. flows from post to anterior chamber and then drains back into venus blood anterior segment can be divided into chambers. iris to cornea is anterior chamber

Question 34

glaucoma

Answer 34

scleral venus sinus doesn't drain aqueous humor properly and increases pressure within the eye and can damage eye structures, especially neural layer

Question 35

lens

Answer 35

separates anterior and posterior regions of the eye. extremely flexible because of protein called crystalline. needs flexibility to change shape for near vision. in cataracts, there is clouding of the lens because crystalline proteins start to accumulate and causes the lens to be less flexible.

Question 36

x

Answer 36

light appears to bend or refract and the speed changes when passing from one medium to another of a different density.

Question 37

light bending apparatus

Answer 37

cornea, lens- trying to bend and refract light tays and converges in the retina

Question 38

convex lens

Answer 38

refracts light so regardless of where light rays hit the lens, the shape of the lens causes bending of light so the light converges on the same focal point on the other side of the lens. Image is inverted and brain flips image back.

Question 39

cornea

Answer 39

anterior bulge of the fibrous layer- bends majority light, and the amount of refraction is constant unlike the lens because it can't change shape.

Question 40

distant visiom

Answer 40

In distant vision, cornea does majority of refraction and lens in flattened because of sympathetic input sent to the eye that stimulates relaxation of the ciliary muscles, which causes tightening of the ciliary zonules which pulls on the lens. Tightens because of muscle orientation. causes pupil dilation.

Question 41

close vision

Answer 41

cornea refracts light, but lens plays a bigger role refracting and bulges from parasympathetic input. Ciliary muscle contracts and relaxes ciliary zonules. also causes pupil constriction.

Question 42

accomodation

Answer 42

viewing objects less that 20 feet away. parasympathetic input occurs so lenses bulge. Pupil constricts and eyes converge (cross eyed to view objects up close)

Question 43

presbyopia

Answer 43

lens becomes less flexible because of crystalline, so objects cannot be seen as close

Question 44

emmetropia

Answer 44

normal vision

Question 45

myopia

Answer 45

near sighted, eyeball is too long so focal point is in front of the retina. corrected with concave lens which moves focal point back so light converges on the retina

Question 46

hyperopia

Answer 46

farsighted, eyeball is too short, focal point is behind the retina. convex lens is used to bring focal point forward to let light converges on the retina

Question 47

astigmatism

Answer 47

unequal curvatures of the eye, causes blurs along one direction

Question 48

macular degeneration

Answer 48

degeneration of the macula lutea that causes progressive blind spot that appears at the center of vision.

Question 49

photoreceptors

Answer 49

outer segment, inner segment, cell body, synaptic endings

Question 50

outer segment of photoreceptor

Answer 50

outer segments consists of discs that contain pigments, retinal and opsin. retinal absorbs light and opsin determines what wavelength of light retinal can absorb. 4 different types of opsin that make 4 visual pigments. rods contain one type of opsin, cones have 3 opsins to absorb different wavelengths of light. wavelengths overlap to see a range of color.

Question 51

phototransduction

Answer 51

process of taking a stimulus (light) and transforming it into a graded potential. when visual pigment absorbs light, retinal changes shape from bent or kinked to straight and then, triggers transduction and production of a graded potential

Question 52

phototransduction in the dark

Answer 52

cyclic GMP gated channels are open and positively charged ions to flood to the photoreceptors, causing it to depolarize, which opens VG Ca channels, releasing an inhibitory NT, and the NT produces an IPSP, causing the bipolar cell to hyper polarize so there are no AP on ganglion cells that are part of optic nerve. photoreceptor are on, bipolar turns off, ganglion cells turn off

Question 53

in the light

Answer 53

retinal absorbs light rays and detaches from opsin, and cyclic AMP channels are going to close, so photoreceptor is not going to depolarization, so NT will not be released so the bipolar cells will not be inhibited. bipolar cells spontaneously depolarize and release an excitatory NT at the synapse with ganglion cell. Produces EPSP on the ganglion cells which will result in action potentials on ganglion cells that are part of optic nerve photoreceptors off, so bipolar turns on, ganglion cell turns on

Question 54

G protein signaling cascade

Answer 54

activates G protein transducer which activates PDE...

Question 55

crossing at the optic chiasma

Answer 55

ganglion cell axons make up optic nerve optic nerve crosses incompletely at optic chiasma, so some axons will cross and some will not. Some need to go left and some stay on one side depending on where they need to go in the brain. axons of thalamic cells travel in optic radiations to visual cortex branches to superior colliculi, pineal body, cerebellum

Question 56

endocrine gland vs endocrine tissue

Answer 56

if an entire organ functions for endocrine, it can be called an endocrine gland. Some organs have endocrine tissue but other things as well.

Question 57

endocrine glands

Answer 57

invagination of epithelial sheet, have no ducts (lose during development), secrete protein or steroid hormones into ECF and are picked up by blood stream and distributed systemically.

Question 58

hormones

Answer 58

produced by endocrine cell in endocrine gland or tissue to be secreted and distributed have specificity, act at target tissues that contain receptors for hormone, functions for control can interact with one another

Question 59

permissiveness

Answer 59

one hormone needs anther hormone to exert its full effect ex. is reproductive and thyroid hormones needs each other for timely development

Question 60

synergism

Answer 60

hormones have effect at target cells ex. glucagon and epinephrine- both act at the liver to increase blood glucose levels

Question 61

antagonism

Answer 61

hormones oppose actions of one another insulin and glucagon

Question 62

chemical structure

Answer 62

chemical structure of hormone is very important for how it is transported in the blood stream, or at target tissues

Question 63

amino acid/protein based hormone

Answer 63

amino acid/protein based, which are polar and water soluble. can be transported directly in blood and do not need a transport protein carrier they are lipid insoluble so they cannot cross the lipid barrier, so they use an indirect or secondary messenger system to actually act at their target tissue

Question 64

steroid based hormone

Answer 64

lipids, lipid soluble, water insoluble they require a carrier protein in the blood stream because they are water insoluble. They can cross the membrane at their target cells because they are lipid soluble, so they act directly at the cells using direct gene activation ex. testosterone, estrogen, glucocorticoids

Question 65

eicosanoids

Answer 65

derived from polyunsaturated fatty acids, they are paracrine agents and local, are not distributed systemically ex. prostaglandins

Question 66

humoral stimulation

Answer 66

change in concentration in some molecule triggers the release of a hormone ex. change in calcium concentration triggers release of PTH from PTH glands

Question 67

neural stimulation

Answer 67

AP on neurons are sent to endocrine gland and stimulate release of a hormone ex. in CNS, single preganglionic neuron stimulates medulla of adrenal gland to secrete catecholamines

Question 68

hormonal stimulation

Answer 68

a hormone targets an endocrine gland and stimulates release of other hormones. ex. pituitary gland

Question 69

negative feedback mechanisms

Answer 69

inhibit hormonal release

Question 70

secondary messenger system

Answer 70

used by all amino acid water based hormones except thyroid hormone because it is small enough to sneak throughhormones travel to target tissues, using either indirect actin or direct gene activation

Question 71

Cyclic AMP

Answer 71

use G protein signaling cascade hormone binds to receptor on membrane and activates G protein and separates from receptor and activates an enzyme called adenylate cycles and catalyzes and produced cyclic AMP. cAMP activates protein kinases and that triggers a response within target cell

Question 72

direct gene activation

Answer 72

all steroid based hormones receptor is inside the cell and hormone crosses in because it is lipid soluble and binds to its receptor. receptor hormone complex goes into the nucleus, binds to DNA and makes a change. genes get transcribed, mRNA gets translated and new protein is synthesized. turns on a gene

Question 73

pituitary gland/ hypophesis

Answer 73

anterior/adenohypophesis: stores and releases 6 hormones posterior/neurohypophesis:2 hormones all hormones are amino acid based use secondary messenger system

Question 74

posterior pituitary/neural hypophesis

Answer 74

not a true endocrine gland complex of neural tissue and does not synthesize hormones neurosecretory cells in hypothalamus that reach down into PPT gland hormones are stored in axon terminals in PPT and then are released

Question 75

supraoptic nucleus SOAP

Answer 75

antidiuretic hormone

Question 76

paraventricular nucleus SOAP

Answer 76

oxytocin

Question 77

hypothalamic hypophyseal tract

Answer 77

carries hormones from hypothalamus to posterior pituitary neural stimulation

Question 78

antidiuretic hormone

Answer 78

targets kidneys and reduces water loss by decreasing urine volume stimulated by osmoreceptors in hypothalamus that monitor solute and water concentration in body fluids stimulated by low BP or low blood volume

Question 79

oxytocin

Answer 79

triggered from axon terminals in PPT by stretching of uterus and cervix and causes strong uterine contractions triggered by nursing or breast-feeding and produces milk

Question 80

anterior pituitary/adenohypophesis

Answer 80

true endocrine gland because it synthesizes hormones it released

Question 81

hypophyseal portal system

Answer 81

neurosecretory cells in hypothalamus that synthesis and release releasing and inhibiting hormones. released into hypophyseal portal system. target cells are in APT

Question 82

tropic hormones

Answer 82

hormonal stimulation 4 hormones in APT TSH ACTH FSH LH

Question 83

GH and prolactin

Answer 83

not tropic