Physiology- Nervous System Quiz Sept 5Th

Front 1

Define resting membrane potential.

Back 1

voltage diff between + charges outside and - charges inside the cell membrane during resting phase; Na+, K+ and Cl- are held in a steady state on either side of the membrane ( membrane impermeable to Na+ ions)

Front 2

What is the normal resting potential of a nerve cell?

Back 2

-85mV

Front 3

Why the cells are in a state of resting potential?

Back 3

- charge on inside attracts + charges into cell, # of particles increase inside cell and osmotic pressure draws water into cell, could lead cell to burst-- to prevent burst more positive ions move out of cell leaving a more negative charge on the inside.

Front 4

What is a stimulus?

Back 4

anything that can disturb the resting membrane potential of a nerve cell (mechanical or chemical)

Front 5

What is a threshold stimulus?

Back 5

a stimulus that can depolarize the resting membrane potential & is strong enough to produce an action potential

Front 6

What is the trigger point or what change in resting potential voltage can trigger an action potential?

Back 6

-59mV ( up from -85mV)

Front 7

What is depolarization of a nerve fiber?

Back 7

reversal of resting membrane potential-- cell membrane increases permeability to Na+ions and allows them to move into the cell, opening more Na+ channels making inner side of cell locally positive

Front 8

Name the ions that start moving into cell to depolarize it, when stimulus is applied.

Back 8

Na+ (sodium) ions

Front 9

WHat is repolarization?

Back 9

closing of Na+ channels and exit of additional K+, bringing membrane back to resting state

Front 10

Name the ions that move out of the cell to repolarize it.

Back 10

K+ (potassium)

Front 11

What is hyperpolarization?

Back 11

membrane goes past -85mV (-90mV, -95mV etc..) due to so many K+ ions moving out

Front 12

What is an action potential (nerve impulse)?

Back 12

movement of electric charges in and out of the cell membrane that causes reversal in electrical potential, starts from cell body and spreads throughout length of nerve fiber

Front 13

What changes occur in the permeability of plasma membrane to initiate an action potential?

Back 13

depolarization cause the first change in cell membrane, opens Na+ channel allowing Na+ ions to diffuse into cell

Front 14

Does the speed of an action potential remain the same in a given nerve fiber?

Back 14

yes

Front 15

What are the factors the affect the speed of conduction in a nerve fiber?

Back 15

diameter of nerve fiber and myelination

Front 16

Why is the speed of conduction of an action potential faster in the mylinated nerve fibers as compared to unmylinated nerve fibers?

Back 16

Mylinated fibers are covered in a myelin sheath that is insulated and does not allow ions to move across membrane, sheath does not cover whole fiber-these breaks allow currents to jump from node to node causing impulse to move faster.

Front 17

What is saltatory conduction?

Back 17

conduction in which electrical current jumps from node to node

Front 18

What is the diff between absolute refractory period and relative refractory period?

Back 18

Absolute- during depolarization, cannot initiate another action potential because Na+ channels will not open

Refractory- during repolarization - can generate another action potential as long as the stimulus is stronger than previous threshold

Front 19

Define synapse.

Back 19

junction between 2 neurons or a neuron and a muscle cell or neuron and glands; electrochemical transmission site where nerve impulses pass from one neuron to another

Front 20

What is the diff between pre-synaptic and post-synaptic neurons?

Back 20

Pre- brings impulses towards synapse

Post- carries impulse away from synapse

Front 21

Does a synapse operate only in one direction.

Back 21

yes

Front 22

Name the excitory type of substances released at Type-I synapses.

Back 22

acetylcholine, epinephrine, nor-epinephrine, seratonin, dopamine

Front 23

Name the inhibitory type of substances released at Type-II synapses.

Back 23

GABA and Glycin

Front 24

What is EPSP? (Excitatory post synaptic potential)

Back 24

the change in post synaptic membrane potential produced by exitatory neurotransmitters

Front 25

Can a single EPSP produce and action potential?

Back 25

NO

Front 26

How many EPSP discharges are required at one spot to raise resting potential to trigger point (-59mV) to fire an action potential?

Back 26

at least 10

Front 27

Diff between convergence and divergence?

Back 27

Convergence- several neurons are making synapses with 1 neuron

Divergence- 1 neuron is making synapses with several neurons

Front 28

What is reflex action?

Back 28

automatic response of an organ to a stimulus ( at least 2 neurons make up a reflex arc)

Front 29

What are spinal reflexes? Example?

Back 29

reflex impulses that just reach the spinal cord for immediate response ( patellar reflex, thoracic limb withdrawl, sciatic etc....)

Front 30

Diff between somatic and visceral reflexes.

Back 30

somatic- involved with skeletal muscle

visceral- involved with body organs

Front 31

Which part of the brain contains reflex centers for thinking and memorization?

Back 31

Cerebrum

Front 32

Which part of the brain contains reflex centers for locomotion and balance?

Back 32

Cerebellum

Front 33

Reflex centers for coughing, sneezing, respiration, vomiting and swallowing are located in which part of the brain?

Back 33

Medulla oblongata

Front 34

Autonomic nervous system controls the activity of what type of muscles in the body?

Back 34

smooth muscles, cardiac muscles, and glands

Front 35

What is the main diff between the origin of sympathetic and parasympathetic nerve fibers?

Back 35

Sympathetic- originate from the thoracic and lumbar part of spinal cord

Parasympathetic- originate from sacral spinal nerves and a few cranial nerves

Front 36

What is the main function of the autonomic nervous system?

Back 36

to maintain a relatively stable internal body environment

Front 37

What are cholenergic fibers?

Back 37

fibers that release acetylcholine from terminal knobs

Front 38

What are adrenergic fibers?

Back 38

fibers that release nor-epinephrine from terminal fibers

Front 39

In general, what type of nerve fibers are considered cholenergic?

Back 39

parasympathetic

Front 40

In general, what type of nerve fibers are considered adrenergic?

Back 40

sympathetic

Front 41

Diff between local and general anesthetics?

Back 41

General- used in major body system surgeries that are needed to depress the whole body

Local- used in suppressing a part of the body only

Front 42

Good job

Back 42

THanks