L6 Nerve Physiology

Question 1

Neurons ____ and _____ a signal to another location. They have _____, do not _____, have high ____ and require abundant _____ and ______.

Answer 1

receives
transmits
longevity
divide
metabolic rate
oxygen, glucose

Question 2

Dendrites _____ the signal and carry the ____ conduction towards the _____.

Answer 2

receive
nerve
cell body

Question 3

Axon Hillock is the area on the ____ where the AP builds up ____ it transmits the signal down the axon.

Answer 3

soma
before

Question 4

Axoplasmic transport is the movement of ____ and ____ between the _____ and _____.

Answer 4

nutrients
wastes
cell body
axon terminals

Question 5

What are the classifications of neurons?

Answer 5

Multipolar
-many dendrites & 1 axon
Bipolar
-2 processes extend from opposite sides of soma.
Unipolar
-1 short process emerging from soma, branches into a T.

Question 6

Sensory neurons transmit impulses towards the _____. They originate in the _____ and terminate in the ____.

Answer 6

CNS
PNS
CNS

Question 7

Motor neurons transmit impulses from the ___ to_______. They originate in the ____ and terminate in the ____.

Answer 7

CNS
efferent organs
CNS
PNS

Question 8

Interneurons connect ___ neurons to ____ neurons within the ____ and _____. They originate and terminate in the _____.

Answer 8

sensory
motor
spinal cord
brain
CNS

Question 9

What are the 5 types of glial cells?

Answer 9

Oligodendrocytes
Astrocytes
Microglia
Schwann cells
Ependymal cells

Question 10

Oligodendrocytes are ____ and ___ cells. They form ______ in the CNS to speed up the _________. _____ acts as a electrical ____.

Answer 10

large
complex
myelin sheath
nerve conduction
Myelin
insulator

Question 11

Between the myelin sheaths are the ______ which are the ___ regions of axonal membranes only found in ____ axons.

Answer 11

Nodes of Ranvier
bare
myelinated

Question 12

Unmyelinated axons have ___ conduction
Myelinated axons have ____ conduction

Answer 12

linear
saltatory

Question 13

Benefits of saltatory conduction?

Answer 13

-Much faster
-Energy efficient. Na+ K+ pump has to restore ions only at the Node of Ranvier compared to throughout the nerve fibers.
(less ATP used )

Question 14

_______ is another cell that forms myelin sheath but in the ____. Each cell only forms ____ myelin sheath.

Answer 14

Schwann cells
PNS
one

Question 15

Astrocytes ____ its arms around capillaries and ____ to physically support them. They transmit _____ from capillaries to neurons. They form ______ to protect then neuron from harmful substances in the blood.

Answer 15

wrap
neurons
materials
blood-brain-barrier ( BBB)

Question 16

_____ act as macrophages and become actively ____ during injury. They are supporting cells in the ____.

Answer 16

Microglia
phagocytic
CNS

Question 17

Ependymal cells secrete _____, functions as ____ cells, act as ____ between compartments.

Answer 17

CSF
neural stem
barrier

Question 18

A synapse is the ____ at which ___ neurons communicate, or a neuron and its target organ.

Answer 18

site
two

Question 19

The neuron that conducts the signal towards the synapse is called _______. and transmits the signal away is called ______,

Answer 19

presynaptic neuron
postsynaptic neuron

Question 20

The space between neurons is called ________.

Answer 20

synaptic cleft

Question 21

The AP travels from the ____ of ____neuron -> ______ -> ___ of ____ neuron

Answer 21

axon, presynaptic
synaptic cleft
dendrite, postsynaptic

Question 22

What are the 3 types of synapses?

Answer 22

Axosomatic ( axon touches soma )
Axodendritic ( axon touches dendrite )
Axoaxonic ( axon touches axon )

Question 23

The enlarged knob of the axon is called the ____.

Answer 23

presynaptic terminal

Question 24

The vesicles of axon terminals contain the neurotransmitter ______.

Answer 24

acetylcholine

Question 25

The process of conduct of impulses from one nerve to another nerve is called as ___.

Answer 25

synapse

Question 26

What are the events occuring at synapse?

Answer 26

1. An arriving AP depolarizes the synaptic knob.
2. Ca2+ ions enter the cytoplasm and ACh is released by synaptic vesicles through exocytosis.
   3.ACh binds to sodium channel at postsynaptic membrane, producing a graded depolarization.
3. Depolarization ends as ACh is broken down into choline and acetate by acetylcholinesterase.
4. The synaptic knob reabsorbs choline from the synaptic cleft and uses it to synthesize new molecules of ACh.