Neurophysiology

Question 1

3 general function of CNS?

Answer 1

• Collects information
• Processes evaluates information from CNS
• Initiates response

Question 2

2 cell types in nervous tissue?

Answer 2

• Neurons (nerve cells)

- Glial (neuroglial, supporting cells)

Question 3

5 characteristics of neurons?

Answer 3

• excitability
• conductivity
• secretion (of neurotransmitters)
• extreme longevity
• amitotic

Question 4

A given neuron releases only one type of ____ with excitatory of inhibitory effect on target

Answer 4

neurotransmitter

Question 5

Myelin sheath is composed of ____ and functions to ___ and ___ the axon, which increaes the speed of nerve impulses.

Answer 5

• neuroglia
• covers
• insulates

Question 6

Sensory neurons have somas located outside the CNS in the _____ and have axons that synapse with ____ in CNS

Answer 6

• posterior ganglion root

- interneurons

Question 7

what structure are most sensory neurons?

Answer 7

unipolar

Question 8

Motor neurons receive signals from ____ and carry signals to effectors

Answer 8

interneurons

Question 9

Most motor neurons have somas located in the ____, while its axons are located in the ____

Answer 9

• CNS

- PNS

Question 10

____ is the thick outer layer of the nerve that provides support and protection

Answer 10

Epineurium

Question 11

____ is the layer of the nerve that wraps bundles of axons and supports blood vessels

Answer 11

Perineurium

Question 12

_____ is the delicate layer of the nerve that separates and electrically insulates each axon

Answer 12

Endoneurium

Question 13

____ are the most abundant glial cells in CNS

Answer 13

Astrocytes

Question 14

____ help form the blood-brain barrier and occupies the space of dying neurons

Answer 14

Astrocytes

Question 15

____ are glial cells that line the ventricles of the brain and central canal of spinal cord

Answer 15

Ependymal cells

Question 16

Ependymal cells and nearby blood vessels form the ____, which produces ____.

Answer 16

• Choroid plexus

- CSF

Question 17

____ are the least abundant glial cells that engulf microorganisms and cell debris

Answer 17

Microglia

Question 18

____ are glial cells that form the myelin sheath in the CNS

Answer 18

Oligodendrocytes

Question 19

____ are glial cells that form the myelin sheath in the PNS

Answer 19

Schwann cells

Question 20

____ are glial cells that regulate exchange of nutrients and wastes between neurons and their environment

Answer 20

Satellite cells

Question 21

What is the most important in establishing the Resting Membrane Potential?

Answer 21

K+ leak channels

Question 22

The RMP is ____ mV

Answer 22

-70 mV

Question 23

The K+ leak channel allows K+ to diffuse from ____ of the cell to the ____, going ____ its concentration gradient

Answer 23

• diffuse from INSIDE of the cell to OUTSIDE

- DOWN its concentration gradient

Question 24

____ has minor influence on the resting membrane potential

Answer 24

Na+ leak channel

Question 25

In establishing the RMP, K+ leaves the cell creating a ____ charge outside, leaving a ____ charge inside

Answer 25

- POSITIVE outside | - NEGATIVE inside

Question 26

In graded potentials, the permeability of a neuron membrane is determined by ____

Answer 26

ligand-gated K+ and Na+ channels

Question 27

In action potentials, the permeability of the resting neuron membrane is determined by ____

Answer 27

voltage-gated Na+/K+ channels

Question 28

when do voltage-gated channels open?

Answer 28

when the membrane is depolarized

Question 29

____ is the reduction in membrane potential in which the inside of the membrane become less negative

Answer 29

Depolarization

Question 30

____ is the increase in membrane potential in which the inside of the membrane becomes more negative

Answer 30

Repolarization

Question 31

____ is the increase of membrane potential above RMP in which the inside of the membrane becomes more negative that the resting potential

Answer 31

Hyperpolarization

Question 32

____ increases the probability of producing nerve impulses, whereas ____ reduces this probability

Answer 32

- depolarization | - hyperpolarization

Question 33

____ is the propagation of action potential along the axon

Answer 33

Nerve impulse

Question 34

When local potential first reaches threshold, ____ fully open quickly causing rapid depolarization.

Answer 34

voltage-gated Na+ channels

Question 35

As the rising potential passes 0 mV (becoming more positive), ____ channels close.

Answer 35

voltage-gated Na+ channels

Question 36

When the voltage peaks at +35 mV, ____ fully open quickly, resulting in rapid ____

Answer 36

- voltage-gated K+ channels | - repolarization

Question 37

____ channels stay open longer, resulting in hyperpolarization

Answer 37

voltage-gated K+ channels

Question 38

In the SNS, preganglionic somas are located in the ______

Answer 38

Lateral horn of T1-L2

Question 39

In the SNS, ganglia are located ____

Answer 39

far from target organs | closer to vertebrae

Question 40

What neurotransmitters are released by postganglionic neurons in SNS?

Answer 40

Ach or NE

Question 41

In the PSNS, where are preganglionic neurons located?

Answer 41

- Brainstem (CN 3, 7, 9, 10) | - Lateral gray matter of S2-S4

Question 42

True or False: No cranial nerves are sympathetic fibers

Answer 42

TRUE

Question 43

alpha-1 receptors

Answer 43

- vasoconstrict blood vessels (skin, GI, kidneys) | - contract erector pili, uterus, ureters, internal, urethral sphincters

Question 44

alpha-2 receptors

Answer 44

- inhibit insulin secretion | - contract GI sphincters

Question 45

beta-1 receptors

Answer 45

- stimulate increased HR and contractility | - stimulate renin secretion

Question 46

beta-2 receptors

Answer 46

- vasodilation (going to heart, liver, muscles) - bronchodilation lungs - relax uterus, GI, tract, bladder

Question 47

which alpha-blocker causes an irreversible blockade of postganglionic synapses in exocrine glands and smooth muscle

Answer 47

nonselective alpa blocker | Phenoxybenzamine

Question 48

alpha blockers can be either competitive at binding site or not, while beta-blockers _____

Answer 48

competitively bind

Question 49

in the heart, what do beta blockers compete with

Answer 49

NE and epi

Question 50

In PSNS, what do postganglionic neurons release? to what receptors on target organs

Answer 50

- Ach | - muscarinic receptors

Question 51

In SNS, postganlionic neurons can secrete either ____ to ____ receptors -OR- ____ to _____ receptors

Answer 51

- ACh to muscarinic receptors | - NE to adrenergic receptors

Question 52

which has higher affinity for epinephrine: alpha 1 or beta 2

Answer 52

beta 2

Question 53

at high concentrations of epinephrine, what effect occurs

Answer 53

vascular smooth muscle contraction | bc more alpha-1 receptors