Nervous Tissue

Question 1

What is the long neuronal process that generally conducts impulses away from the soma of the nerve cells?

Answer 1

axon

Question 2

What are the shorter processes that receive impulses and carry them toward the soma of a neuron?

Answer 2

dendrite

Question 3

What term refers to the cellular mechanisms for producing electrical potentials and currents?

Answer 3

electrophysiology

Question 4

How does signal conduction along unmyelinated fibers work?

Answer 4

Unmyelinated fibers have voltage-gated channels along their entire length, and a zone of depolarization excites voltage-gated channels immediately distal to the action potential.

Question 5

List the events of a single action potential in order

Answer 5

1: Local potential depolarizes membrane;
2: Threshold is reached;
3: Depolarization spike;
4: Repolarization;
5: Hyperpolarization

Question 6

List the 6 kinds of neuroglia and tell whether they are in the central nervous system or the peripheral nervous system

Answer 6

CNS: Astrocytes, Microglia, Ependymal cells, Oligodendrocytes;
PNS: Satellite Cells, Schwann Cells

Question 7

What is the location/function of Satellite cells?

Answer 7

In PNS; surround somas of neurons in ganglia, provide electrical insulation, and regulate the chemical environment of neurons

Question 8

What is the location/function of Schwann cells?

Answer 8

In PNS; form neurilemma around all PNS fibers and myelin around most of them; aid in regeneration of damaged nerve fibers

Question 9

What is the location/function of Ependymal cells?

Answer 9

In CNS; line cavities of the brain and spinal cord; secrete and circulate CSF

Question 10

What is the location/function of Microglia?

Answer 10

In CNS; phagocytize microorganisms, foreign matter, and dead nervous tissue

Question 11

An electrical potential is a form of what type of energy?

Answer 11

Potential energy

Question 12

What are the three functional classes of neurons?

Answer 12

Interneurons, sensory neurons, motor neurons

Question 13

What is the function of somatic neurons?

Answer 13

carry impulses to skeletal muscles and from receptors in the skin

Question 14

What are some characteristics of neurons?

Answer 14

Excitability and conductivity

Question 15

What are some characteristics of neuroglia

Answer 15

Bind neurons together and provide a support scaffold; protect the neurons and help them function

Question 16

How does the endocrine system communicate?

Answer 16

Hormones

Question 17

How does the nervous system communicate?

Answer 17

sending quick electrical and chemical messages from cell to cell

Question 18

What are the two subdivisions of the autonomic nervous system, and what are their functions?

Answer 18

Sympathetic: arouse body for action;
Parasympathetic: has a calming effect

Question 19

What term is used to describe signal conduction along a myelinated axon?

Answer 19

Saltatory - signal passed from soma to first node of ranvier, where it activates a voltage-gated channel and gets boosted to next node, and so on and so forth up to the terminal. appears to “jump” from node to node

Question 20

List, in order, the basic steps that describe how the nervous system helps maintain homeostasis

Answer 20

1: Information received by sensory receptors and is transmitted to the CNS;
2: Information is processed and an appropriate response is determined;
3: A command is issued to effectors such as muscles or glands

Question 21

List the order of events involved in transmission at a cholinergic excitatory synapse, starting with a signal reaching the distal end of the presynaptic axon

Answer 21

1: Opening of calcium gates in synaptic knob as nerve signal arrives;
2: Exocytosis of ACh; diffusion across synaptic cleft;
3: Binding of ACh to receptors on postsynaptic neuron;
4: Opening of sodium gates on post-synaptic membrane allowing influx of sodium;
5: Depolarization of postsynaptic plasma membrane

Question 22

List the order of events initiated in an adrenergic synapse, after norepinephrine binds to its receptor.

Answer 22

1: G protein dissociates from receptor protein;
2: G protein binds to adenylate cyclase;
3: Adenylate cyclase is activated
4: ATP is converted to cAMP by adenylate cyclase
5: cAMP induces multiple effects in the cell

Question 23

Give the location and function of Substance P

Answer 23

Found in brain, small intestine, and pain-receptor neurons;

mediates pain transmission

Question 24

Give the location and function of Enkephalins

Answer 24

Various areas of the brain and spinal cord;

Act as analgesics by inhibiting substance P, secretion increases during labor

Question 25

Give the location and function of beta-endorphin

Answer 25

Found in digestive tract, spinal cord, and many parts of the brain;
Secreted as a hormone by the pituitary; suppresses pain; reduces fatigue; may produce “runner’s high”

Question 26

Give the location and function of Cholecystokinin (CCK)

Answer 26

Cerebral cortex and small intestine;

Suppresses appetite

Question 27

What are the two subdivisions of the peripheral nervous system and what are their purposes?

Answer 27

1: Somatic motor division - carries signals to the skeletal muscles
2: Visceral motor division (autonomic nervous system) - carries signals to glands, cardiac muscles, and smooth muscle