Physiology 2 Sensory

Front 1

what are the 3 basic functions of the nervous system?

Back 1

1. detection of stimulus
2. processing information
3. transmission of response

Front 2

how does detection of a stimulus travel to the CNS?

Back 2

via afferent (or sensory) neurons

Front 3

what type of neurons are used for processing information and decision making?

Back 3

interneurons (or association neurons)

Front 4

what type of neurons are used in response to decision effectors?

Back 4

efferent or motor neurons

Front 5

nervous system

Back 5

the body's control system that governs actions a/o reactions.

Front 6

brain and spinal cord

Back 6

analysis and integration of sensory and motor information

Front 7

the brain and spinal cord (CNS) goes to the

Back 7

motor components (PNS)

Front 8

what are the two types of motor components?

Back 8

somatic and autonomic

Front 9

somatic

Back 9

motor neurons, voluntary

Front 10

autonomic

Back 10

motor system, involunatary, sympathetic, parasympathetic, and enteric divisions

Front 11

what do the motor components go to?

Back 11

effectors

Front 12

what are the two subdivisions of effectors?

Back 12

1. skeletal muscles
2. smooth m.
cardiac m.
glands

Front 13

how does the environment interact with the nervous system?

Back 13

sensory components of the PNS

Front 14

what are the 2 subdivisions of the sensory components of the PNS?

Back 14

somatic and special sensory
autonomic sensory receptors and neurons

Front 15

what is ENS?

Back 15

enteric nervous system, sensory receptors PNS

Front 16

synapse

Back 16

communication between neurons

Front 17

axons

Back 17

where communication between nerve cells flows

Front 18

what do synpases require

Back 18

flow of ions: electrical currents

Front 19

what are the two main types of ionic channels?

Back 19

leakage and gated

Front 20

what are the 3 subdivisions of gated channels?

Back 20

voltage-g
ligand-g
mechanical-g

Front 21

ionic flow through channels can generate two types of electrical signals in nerves:

Back 21

action potential
graded potential

Front 22

how does information flow in action potentials?

Back 22

along axons

Front 23

how does information flow in graded potentials?

Back 23

across axons

Front 24

what channels do action potential need?

Back 24

voltage-gated Na+ channels
voltage-gated K+ channels

Front 25

which way does Na+ flow?

Back 25

into cell, influx

Front 26

which way does K+ flow?

Back 26

out of the cell; efflux

Front 27

what causes hyperpolarization?

Back 27

slow closure of K+ channels

Front 28

what restores Na-K ion concentrations?

Back 28

sodium potassium pump

Front 29

how do local anesthetics work?

Back 29

most local anesthetics inhibit voltage-gated Na+ channels-> block information flow along neuorns

Front 30

what initiates graded potentials?

Back 30

release of NT from presynaptic neuron causing
EPSP or IPSP

Front 31

how to graded potentials produce action potentials?

Back 31

thousands of PSPs are summed up (spatial and temporal)-> can activate voltage-gated channels->action potentials at axon hillocks

Front 32

where is the action of most CNS drugs?

Back 32

synapses are the site of action of most CNS affecting drugs, many therapuetic drugs, natural toxins and pesticides.

Front 33

what are the three main structural classifications of transmitters?

Back 33

1. small molecule NT (~20)
2. large molecule NT= neuropeptides (50-100)
3. non-traditional NT

Front 34

what are the two subdivisions of small molecule NT?

Back 34

1. amino acids
2. amines

Front 35

what are some examples of amino acid NT?

Back 35

glutamate, gaba, glycine, aspartate

Front 36

what is the most common excitatory NT?

Back 36

Glutamate

Front 37

what is the most common inhibitory NT?

Back 37

GABA

Front 38

what are some examples of amine NT?

Back 38

dopamine, norepinephrine, epinephrine, serotonin, histamine, acetylcholine

Front 39

what are some examples of large-molecule NT?

Back 39

beta-endophin, enkaphalins, dynorphin, substance P, neuropeptide Y, somatostatin, oxytocin, vasopressin

Front 40

what are some examples of non-traditional NT?

Back 40

ATP
NO
CO

Front 41

what are the 3 steps of the release of NT into synpatic cleft?

Back 41

1. mobilization
2. docking
3. release

Front 42

synapsin

Back 42

in a resting neuron, NTs are stored in vesicles and vesicles are bound to cytoskeleton via a binding protein- synapsin

Front 43

what are the steps of mobilization

Back 43

AP
depolar.
open Ca2+ channels
Ca2+ influx
Ca2+ binds to calmodulin
complex act. enzymes
degrades synapsin
vesicles detach

Front 44

what are the steps in docking

Back 44

the vesicles synaptobrevin forms a binding complex with the binding proteins of the bouton membrane syntaxin and snap-25

Front 45

what are the steps in release of NT

Back 45

vesicles synaptotagmin binds Ca2+
membranes fuse
exocytosis of transmitters into synaptic cleft followed by recycling of vesicular membrane

Front 46

latroxtoxin

Back 46

black widow spider venom

Front 47

what does latrotoxin do?

Back 47

induces formation of cation leakage channels at presynaptic membrane of neuromuscular jxn.

Front 48

what is the overall effect of latrotoxin poisoning?

Back 48

depolarization with calcium influx -> massive release of Ach-> uncontrolled muscle tremors, followed by subsequent failure of muscle activation.

Front 49

lambert-eaton myastheic syndrome

Back 49

autoimmune dz in some cancer patients

Front 50

what happens in lambert-eaton myasthenic syndrome?

Back 50

antibodies block voltage-gated Ca2+ channels at neuromuscular jxn. -> decrease Ca2+ influx-> decrease Ach release-> muscle weakness

Front 51

what is the response of the postsynaptic neuron to a NT mediated by?

Back 51

receptors

Front 52

one NT can have ____ receptor types initiating diverse responses.

Back 52

various

Front 53

A given neuron typically has receptor sites for several ____.

Back 53

neuortransmitters

Front 54

what are the two major functional receptor classes?

Back 54

Ionotropic
metatrophic

Front 55

ionotrophic

Back 55

fast, direct effect on ion channels

Front 56

metatrophic

Back 56

slower, indirect effects on ion channels or by initiating metabolic changes

Front 57

what kind of channels do ionotrophic receptors have?

Back 57

chemically-gated ion channels

Front 58

what do the ionotrophic receptors consist of ?

Back 58

several membrane-spanning protein subunits with external domain for ligand binding

Front 59

what do GABA receptors bind?

Back 59

gamma-aminobutryic acid

Front 60

what does GABA allow?

Back 60

selective flow of Cl- -> hyperpolarization (IPSP)

Front 61

what do GABA receptors also have binding sites for?

Back 61

other ligands e.g. alcohol, barbiturates, benzodiazepines, and some steriods which potentiate GABA action= inhibitory

Front 62

what are the 3 important areas affected by CNS areas ?

Back 62

1.limbic system
2. reticular formation
3. thalamus

Front 63

limbic system

Back 63

emotions

Front 64

reticular formation

Back 64

wakefulness

Front 65

thalamus

Back 65

major relay station for sensory impulses to the cortex, involvement in motor control and consciousness

Front 66

what are metabolic receptors composed of?

Back 66

single membrane-spanning protein

Front 67

what does the extracellular domain of metabolic receptors bind?

Back 67

NT or hormone

Front 68

what does binding to metabolic receptors do?

Back 68

binding leads to configurational change, which changes enzyme activities, which catalyze metabolic change.

Front 69

what is the most common receptor in synapses?

Back 69

G-protein-coupled recpetor

Front 70

what three things does the g-protein coupled metabotrophic receptor contain?

Back 70

receptor
g-protein
membrane-bound enzyme

Front 71

what are the four refractive interfaces of the eye?

Back 71

air/ cornea
cornea/ aqueous humor
aqueous humor/lens
lens/vitreous humor

Front 72

how do animals focus their eyes?

Back 72

change the curvature of the lens (birds, reptiles, some mammals)

changing distance between lens and retina (invertebrates)

Front 73

what is the fibrous tunic composed of?

Back 73

cornea and sclera

Front 74

what is the vascular tunic composed of?

Back 74

choriod + cilary body + iris

Front 75

what is the retina?

Back 75

start of the visual pathway

Front 76

what is the anterior cavity?

Back 76

anterior + posterior chamber

Front 77

what it the posterior cavity?

Back 77

vitreous chamber

Front 78

how does the lens change shape?

Back 78

ciliary muscles of the lens

Front 79

what is the purpose of pigment epithelium?

Back 79

contains melanin to absorb light, focus, sharp image.

Front 80

what is the tapetum lucidum?

Back 80

reflects light and increases sensitivity

Front 81

what does the neuronal epithelium of the eye consist of?

Back 81

1. ganglion cells
2. amacrine cells
3. bipolar cells
4. horizontal cells
5. photoreceptor cells

Front 82

what are the 3 parts of the neuronal epithelium responsible for vertical information flow?

Back 82

1. ganglion cells
2. bipolar cells
3. photoreceptors-rods and cones

Front 83

what are the 2 parts of the neuronal epithelium responsible for lateral information flow?

Back 83

1. horizontal cells
2. amacrine cells

Front 84

what it the blind spot?

Back 84

where all ganglion cells leave they eye as the optic nerve, there are no photoreceptor cells here.

Front 85

vertebrates have inverse eyes, what does this mean?

Back 85

light passes neural componenets before stimulating photoreceptors

Front 86

what are the 3 segments of a photoreceptor?

Back 86

1. outer segment
2. inner segment
3. synaptic terminal

Front 87

what is the function of the outer segment of the photoreceptor?

Back 87

photorecptive part, where light is absorbed, the membrane contains photopigments

Front 88

what idoes the inner segment of the photoreceptor contain??

Back 88

nucleus and mitochondria

Front 89

what does the synpatic vesicle contain?

Back 89

transmitter vesicles

Front 90

what do photopigments consist of?

Back 90

glycoprotein (opsin) and vitamin A (retinol)

Front 91

rods + opsin=

Back 91

rhodopsin

Front 92

cones + opsin =

Back 92

photoptsins (3 different wavelenghts)

Front 93

what happens to the photoreceptors in unstimulated state?

Back 93

cis-retinal fits into opsin= pigment is colored

Front 94

what happens to photoreceptors in stimulated state?

Back 94

1. photons are absorbed by cis-retinal
2. isomerization from cis to trans-retinal
3. seperation from opsin-> bleaching of photopigment

Front 95

how are the photoreceptors regenerated back to colored state?

Back 95

1.retinal isomerase converts trans-retinal to cis-retinal
2. binds back to opsin = regeneration of colored pigment

Front 96

how fast do cones/photopsins regenerate?

Back 96

very fast 50% in 90 sec. -> adapted to bright light conditions

Front 97

how fast to rods/rhodopsins regenerate?

Back 97

very slowly 50% in 5 min.
100% in 30-40 minutes

Front 98

in darkness, where photorectors are unstimulated what is happening physiologically?

Back 98

1. ligand gated Na+ channels have Na+ flowing though
2. ligand is GMP
3. membrane is slightly depolarized
4. glutamate is being released (inhibitory)
5. IPSP at bipolar cells, very few signals

Front 99

in light, photoreceptors are stimulated, what is happening physiologically?

Back 99

1. isomerization of cis- to trans-retinal activates enzymes.
2. enzymes breakdown GMP
3. ligand gated Na+ channels close
4. Hyperpolarization
5. glutamate is not released
6. IPSP is switched off

Front 100

what wavelength of color are rods stimulated by?

Back 100

a wide spectrum of light, mostly blue and green wavelength, night colors.

Front 101

what are the wavelengths of color for cones/ photopsin?

Back 101

stimulated by:
1. blue wavelength
2. green wavelength
3. red wavelength

Front 102

who has more cones for color vision most mammals or humans?

Back 102

humans
e.g. cattle can't see red, horses can't see blue

Front 103

who has more photopigments for color vision, most animals or humans?

Back 103

most animals

Front 104

who am I?
contain more photopigment, regenerate slowly, used in night vision, stimulated by a single photon, very sensitve, not suitable for strong light conditions?

Back 104

rods

Front 105

who am I?
less photopigment, stimulated by >100 photons only, high threshold, adapted for day vision, quick regeneration of bleached pigments,

Back 105

cones

Front 106

pupillary reflex

Back 106

initated by light intensity to control how much light is falling onto retina-

Front 107

mydriasis

Back 107

pupil dilation

Front 108

miosis

Back 108

pupillary constriction

Front 109

who causes contstiction of the pupil via circular muscles of the iris?

Back 109

parasympathetic

Front 110

who cause dilation of the pupil via radial iris muscles?

Back 110

sympathetic

Front 111

what happens in photopigment concentration of darkness?

Back 111

1. pigment epithelium stores vit. A
2. vit A is converted into cis-retinal
3. which diffuses into photoreceptors to increase the amount of light sensitive pigment= sensitization

Front 112

what happens to photopigment concentration in the light?

Back 112

1. cis-retinal is converted back and stored as vitamin A.
2. amount of light sensitve pigment is reduced = desensitization

Front 113

tapetum lucidum

Back 113

either present or absent increases light sensitivity

Front 114

what is the visual field?

Back 114

the segment of the external world seen by the fixed eye in the fixed head.

Front 115

what is the binocular field?

Back 115

field seen with both eyes in 3D view, in predatory animals

Front 116

what is monocular field?

Back 116

peripheral field, seen by one eye, large monocular fields enable good survellience of external world (prey animals)