Module 9: Fundamentals of the Nervous System

Question 1

2 main divisions

Answer 1

central nervous system

peripheral nervous system

Question 2

Central nervous system consists of

Answer 2

brain

spinal cord

Question 3

Peripheral nervous system consists of

Answer 3

nerves (cranial and spinal)

Ganglia

Question 4

PNS divided into 2 systems

Answer 4

Somatic nervous system (voluntary)

Autonomic nervous system (involuntary)

Question 5

Somatic nervous system

Answer 5

under voluntary control

stimulates skeletal muscles

Question 6

Autonomic nervous system

Answer 6

under involuntary control
Controls organs, glands, cardiac muscle, smooth muscle
Divided into sympathetic nervous system and parasympathetic nervous system

Question 7

Sympathetic nervous system

Answer 7

division of autonomic nervous system

reacts in emergency situations “fight or flight”

Question 8

Parasympathetic nervous system

Answer 8

division of autonomic nervous system
involved in digestion, elimination, glandular activities
“feed and breed”, “rest and digest”

Question 9

Functions of nervous system (3)

Answer 9

SIM
Sensory: gather info from external and internal environment
Integrative: info is processed/interpreted by brain (creates a plan)
Motor: nerves convey info from CNS towards muscles and glands (converts the plan into action)

Question 10

2 types of nervous tissue cells

Answer 10

neurons and neuroglia

Question 11

Neurons

Answer 11

nerve cell are electrically active cells
conduct messages throughout body
consist of cell body and branching fibers (dendrites and axon)

Question 12

Cell body

Answer 12

aka perikaryon or soma
contains all organelles except centrioles
Nissl bodies-specialized layers of rough ER

Question 13

Dendrites

Answer 13

processes that look like tree branches

receive and transmit stimuli towards the cell body

Question 14

Axon

Answer 14

long extension that transmits into away from cell body
axon forms branches near its ends (axon terminals, synaptic knobs)
side branches called collaterals
axons surrounded by myelin sheath

Question 15

Neuron classification (structural)

Answer 15

multipolar- 99% of neurons, many dendrites and 1 axon
bipolar- 1 axon and 1 dendrite
unipolar-one process that extends from cell body

Question 16

Neuron classification (functional)

Answer 16

sensory (afferent)-carry impulses from peripheral receptors to CNS
motor (efferent)- carry impulses from CNS to effectors
Interneurons (association)- lie entirely within CNS, receive input from sensory and communicate with motor neurons

Question 17

Neuroglia

Answer 17

aka glia
do not conduct nerve impulses
Role is to support, nourish and protect neurons
capable of mitosis

Question 18

6 types of neuroglia

Answer 18

Astrocytes (CNS)
Oligodendrocytes (CNS)
Microglia (CNS)
Ependymal cells (CNS)
Schwann cells/ neurolemmocytes (PNS)
Satellite cells (PNS)

Question 19

nerve

Answer 19

bundle of nerve cell fibers (axons and dendrites) following same path
usually contain sensory and motor neurons
found only in PNS

Question 20

Tract

Answer 20

bundle of nerve cell fibers

in CNS only

Question 21

Ganglia

Answer 21

clusters of neuron cell bodies

in PNS only

Question 22

Nuclei

Answer 22

clusters of neuron cell bodies

in CNS only

Question 23

Blood brain barrier

Answer 23

keeps harmful substances out of the brain

astrocytes form wall around outside of blood vessels

Question 24

Myelin sheath

Answer 24

formed by myelin/myelin sheath
protects and insulates the axons of nerve cells in CNS and PNS
IN PNS: neurolemmocytes/ Schwann cells form sheath (plasma membrane called neuolemma)
IN CNS: oligodendrocytes form sheath (gaps between sheaths are called nodes of Ranvier)

Question 25

White matter

Answer 25

nervous tissue in CNS appears white due to myelinated neurons

Question 26

Grey matter

Answer 26

nervous tissue in CNS appears grey due to unmyelinated neurons

Question 27

Cell membrane of neuron

Answer 27

Resting state- extracellular fluid dominated by Na and Cl, intracellular fluid dominated by K and proteins
Resting cell is polarized (charged) - excessive pos charges on outside of cell membrane, excessive neg charges on inside (membrane potential)
Action potential has developed and spot will become depolarized

Question 28

Synapse parts (3)

Answer 28

Presynaptic neuron - neuron sending the impulse
Synaptic cleft- space between presynaptic and postsynaptic
Postsynaptic neuron- neuron receiving the impulse

Question 29

How does action potential cross synaptic cleft to another cell

Answer 29

action potential arrives at synaptic knob
Presynaptic neuron releases neurotransmitter
Exocytosis(active transport)- neurotransmitter molecules released
Neurotransmitters diffuse across synaptic cleft until they reach receptors of postsynaptic neuron
Bind to receptors (opens ion channels and allows movement of Na across cell membrane)
Triggers the formation of an action potential in the postsynaptic cleft

Question 30

4 types of neurotransmitters

Answer 30

Acetylcholine (ACh) - between neurons and skeletal muscle cells
Norepinephrine (NE) - aka noradrenaline, stimulates postsynaptic neurons
Dopamin- found in brain, regulates body and facial movement
Serotonin- found in brain, for temp regulation, sensory perception and onset of sleep