Physiology Quiz 2

Front 1

Resting Membrane Potential

Back 1

The voltage difference between positive charges (+) outside and negative charges (-) inside the cell membrane during resting phase

Front 2

Normal resting membrane potential for nerve cell

Back 2

-85mV

Front 3

Reason cells are in a state of resting potential

Back 3

to prevent bursting of cell

Front 4

stimulus

Back 4

Any thing that can disturb the resting membrane potential of a nerve cell

Front 5

threshold stimulus

Back 5

If the stimulus can depolarize the resting membrane potential and is strong enough to produce an action potential (nerve impulse)

Front 6

Trigger point [change in resting potentialvoltage can trigger an action potential (nerve impulse)]

Back 6

-59mV

Front 7

Depolarization of nerve fiber

Back 7

It is the stage, when the cell membrane increases the permeablitly to sodium (Na+) ions and allow them to move into the cell, opening more Na+ channels.

Front 8

ions that start moving intothe cell to depolarize it, when a stimulus is applied

Back 8

NA+ ions

Front 9

repolarization

Back 9

increases the membrane permeability to K+ ions and allow them to diffuse out of the cell

Front 10

ions, that move out of thecell to repolarize it

Back 10

K+ ions

Front 11

hyperpolarization

Back 11

may go beyond -85 mV....to -90 mV or -100mV for a moment

Front 12

action potential (nerve impulse)

Back 12

The movement of electric charges (Na+ and K+) in and out of the cell membrane, that starts from the cell body (axon hillock) and spreads throughout the length of nerve fiber (axon)

Front 13

myelinated nerve cell action potential

Back 13

faster speed because of the myelin sheath which does not allow the ions to move across the membrane and prevents current flow

Front 14

unmyelinated nerve cell action potential

Back 14

slower speed

Front 15

factors that affect the speed of conduction in a nerve fiber

Back 15

diameter of the nerve fiber and myelination

Front 16

saltatory conduction

Back 16

impulse conduction where electric current can flow, jumping from one node to another

Front 17

absolute refractory period

Back 17

period when Na+ ions are rushing into the cells, depolarizing it

Front 18

relative refractory period

Back 18

This is the stage when K+ ions are moving out to repolarize the membrane

Front 19

synapse

Back 19

junction between two neurons or a neuron and a muscle cell or neuron and glands

Front 20

presynaptic neurons

Back 20

The neuron, that brings the impulses towards the synapse

Front 21

postsynaptic neurons

Back 21

The neuron that carries the impulses away from a synapse

Front 22

excitory substancesreleased at Type-I synapses

Back 22

acetylcholine, epinephrine, nor-epinephrine, seratonine and dopamine.

Front 23

inhibitory type ofsubstances released at Type-II synapses

Back 23

GABA and Glycin

Front 24

EPSP (excitatory postsynpatic potential)

Back 24

partial change in electric potential of postsynaptic membrane

Front 25

covergence

Back 25

when several neurons are making synapses with only one neuron

Front 26

divergence

Back 26

when one neuron is making synapses with several neurons

Front 27

reflex action

Back 27

response of an organ to a stimulus

Front 28

spinal reflexes

Back 28

reflex impulses that just reach to the spinal cord level for immediate response

Ex- thoracic limb withdrawal, patellar reflexes, pelvic limb withdrawal, siatic, cranial tibial, perineal

Front 29

somatic reflexes

Back 29

reflexes involved with skeletal muscles

Front 30

visceral reflexes

Back 30

involves body organs such as smooth muscles, cardiac muscles, or glands

Front 31

cerebellum

Back 31

contains reflex centers associated with locomotion and balance

Front 32

cerebrum

Back 32

reflex centers for thinking and memorization

Front 33

Medulla Oblongata

Back 33

Reflex centers forcoughing, sneezing, respiration, vomiting, and swallowing

Front 34

Hypothalamus

Back 34

contains reflex centers associated with temperature regulation and water balance like sweating, shivering, erection of hairs, urine excretion etc.

Front 35

autonomic nervous system controls

Back 35

smooth muscles, cardiac muscles, and glands

Front 36

sympathetic nerve fibers

Back 36

originate from thoracic and lumbar part of spinal cord

Front 37

parasympathetic fibers

Back 37

originates mainly from sacral spinal nerves and a few cranial nerves- III, VII, IX and X

Front 38

function of autonomic nervous system

Back 38

check system on all body organs

Front 39

cholenergic fibers

Back 39

fibers that release acetylcholine from their terminal knobs

sympathetic fibers

Front 40

adrenergic fibers

Back 40

release nor-epinephrine from their terminal knobs

parasympathetic fibers