Nervous System

Question 1

What do oligodendrocytes produce; and where

Answer 1

myelin in this CNS

Question 2

purpose of myelin and what is it

Answer 2

a fatty membrane that prevents signal loss or crossing of signals; also increases the speed of conduction along the axon

Question 3

dendrites purpose

Answer 3

receive incoming messages from other cells

Question 4

What do Schwann cells do

Answer 4

produce myelin in the PNS

Question 5

What are the nodes of ranvier; purpose

Answer 5

small breaks in the myelin sheath allow for rapid signal conduction.

Question 6

The nerve terminal or synaptic bouton (knob) purpose

Answer 6

maximizes transmission of the signal to the next neuron and releases neurotransmitters

Question 7

together the synaptic cleft, nerve terminal, and postsynaptic membrane are known as the _

Answer 7

synapse

Question 8

What are the 3 types of nerves; signal direction

Answer 8

sensory (afferent) sensory receptors to the CNS
motor (efferent) CNS to muscles and glands
mixed (interneurons) in brain and spinal cord; linked to reflexive behavior

Question 9

neurons must be supported and myelinated by other cells called

Answer 9

glial cells or neuroglia

Question 10

Types of glial cells and their functions

Answer 10

astrocytes= nourish neurons and form the blood-brain barrier.
Ependymal cells= line the ventricles of the brain and produce cerebral spinal fluid, serves as a shock absorber
Microglia= are phagocytic cells that ingest and break down waste products and pathogens in the CNS
oligodendrocytes and schwann cells= create myelin

Question 11

purpose of the blood brain barrier

Answer 11

controls transmission of solutes from the bloodstream into nervous tissue

Question 12

which two types of glial cells, if nonfunctioning, will make an individual most susceptible to a CNS infection

Answer 12

microglia and astrocytes

Question 13

Neurons use all of nothing messages called

Answer 13

action potentials

Question 14

321 Nokia mnemonic

Answer 14

3 Na out, 2 K in, 1 ATP used. Na/K ATPase

Question 15

What is the resting membrane potential for neurons

Answer 15

-70 mV

Question 16

What makes the resting membrane potential of neurons dynamic

Answer 16

slow leak sodium and potassium channels

Question 17

Neurons can receive both excitatory and inhibitory input. Excitatory input causes _ and inhibitory input causes _

Answer 17

depolarization

hyper-polarization

Question 18

When is an action potential triggered?

Answer 18

when the axon hillock receives enough excitatory input to reach the threshold.

Question 19

Explain the two types of summation in signaling

Answer 19

temporal summation= multiple signals are integrated during a relatively short period of time
Spatial summation= the additive effects are based on the number and location of the incoming signals (can be both excitatory and inhib)

Question 20

When a neuron is brought to threshold what happens; mechanism

Answer 20

V-gated sodium channels open

Question 21

When do V-gated Na channels become inactivated in a neuron

Answer 21

when Vm approaches +35 mV

Question 22

Describe the 3 states of V-gated Na channels during action potential

Answer 22

open @ threshold to +35 mV
closed @ resting to threshold
inactive @ +35mV to resting potential

Question 23

the efflux of K+ in neurons causes _

Answer 23

hyperpolarization

Question 24

When do V-gated K+ channels open

Answer 24

positive potential inside the cell caused by Na+ influx

Question 25

What are the two types of refractory periods

Answer 25

``` absolute= no amount of stimulation can cause another action potential to occur. relative= must be a greater than normal stimulation to cause an action potential ```

Question 26

increased length of the axon results in _

Answer 26

higher resistance and slow conduction

Question 27

When the signal "hops" from node to node it is called

Answer 27

saltatory conduction

Question 28

When action potential reaches the nerve terminal _ opens; and triggers _ of _ causing exocytosis of _

Answer 28

v-gated Ca channels open fusion of membrane-bound vesicles the neurotransmitter

Question 29

Neurotransmission must be regulated; what are the 3 mechanisms that do this and examples

Answer 29

- acetylcholine (ACh) is broken down by acetylcholinesterase (AChE) (ENZYMATIC DEGRADATION) - neurotransmitters like serotonin, dopamine, and norepinephrine can be brought back into the presynaptic neuron by reuptake carriers (REUPTAKE) - gaseous signaling neurotransmitters like nitric oxide can diffuse out of the synaptic cleft (DIFFUSION)

Question 30

What neural structure initiates the action potential

Answer 30

the axon hillock

Question 31

What is white and grey matter; and location in the brain and spinal cord

Answer 31

white matter consists of axons in myelin sheaths grey matter consists of unmyelinated cells bodies and dendrites. in the brain white matter lies deeper than grey matter in the spine grey matter lies deeper than white matter

Question 32

What does the somatic nervous system consist of

Answer 32

sensory and motor neurons in skin, joint, and muscles

Question 33

What does the autonomic nervous system do

Answer 33

regulates heartbeat, respiration, digestion, and grandular secretion

Question 34

Key signaling difference between SNS and ANS

Answer 34

the ANS requires both a preganglionic and postganglionic neuron; requires 2 instead of 1

Question 35

The ANS is divided into the _ and _ ; purposes, Neurotransmitter

Answer 35

``` parasympathetic= conserve energy, sleeping and resting stages, reduces heart rate and constricts bronchi, ACh sympathetic= activated via stress, fight or flight, increases HR, relaxes bronchi, dilates eyes, epinephrine ```

Question 36

Describe polysynaptic and monosynaptic reflex arcs and examples

Answer 36

monosynaptic arcs= single synapse between sensory neuron; knee-jerk reaction polysynaptic arcs= 1 interneuron between the sensory and motor neurons; withdraw reflex, stepping on a nail.

Question 37

What is the difference between nerves and tracts

Answer 37

nerves may carry more than one type of information; tracts can carry only one type of information

Question 38

What is the likely consequence if a surgeon slips a dorsal root ganglion

Answer 38

loss of sensation at that level