Nervous Tissue and Physiology I: Lecture 18

Question 1

human nervous system

Answer 1

physically connected network of cells, tissues, and organs that allow us to communicate with and react to the environment and perform life activities

Question 2

brain nerve cells

Answer 2

100 billion by adulthood

Question 3

speed of message transmission

Answer 3

180 mph

Question 4

nervous system

Answer 4

controls perception and experience of world;
voluntary movement, consciousness, personality, learning, memory, homeostasis

Question 5

CNS main components

Answer 5

brain- billions of neurons
spinal cord- millions of neurons; enables brain to communicate with body

Question 6

PNS main components

Answer 6

all nerves outside protection of skull and vertebral column
nerves- bundled axons of neurons, blood, CT
cranial- 12 pairs
spinal- 31 pairs
ganglia- neuron cell bodies

Question 7

primary functions of the nervous system

Answer 7

sensory input, integration, motor output

Question 8

functional divisions of nervous system

Answer 8

sensory (afferent) -> somatic and visceral
motor (efferent) -> somatic and autonomic
autonomic -> sympathetic/parasympathetic

Question 9

sensory/afferent division

Answer 9

touch, pain, pressure, vibration, temp, proprioception, chemical changes, stretch

Question 10

motor/efferent division

Answer 10

motor innervation of muscles

Question 11

nervous tissue makeup

Answer 11

80% cells- neurons and neuroglia
20% ECM- ground substance and glycoproteins

Question 12

main functional regions of neurons

Answer 12

receptive- dendrites and cell body
conducting- axon
secretory- axon terminal

Question 13

cell body

Answer 13

contains nucleus and maintains cytoplasm, mitochondria, organelles

Question 14

nissal bodies

Answer 14

neuron specific; dark staining associations of ribosomes and rough ER

Question 15

neurofibrils

Answer 15

intermediate filament cytoskeleton

Question 16

dendrites

Answer 16

receptive region; short, highly branched processes
generate local potentials only (NOT action potentials)

Question 17

axons

Answer 17

processes that can generate and conduct action potentials (conduct signals)
-AP turn into chemical signals
wrapped in myelin sheath

Question 18

neuron function

Answer 18

generates and transmits nerve impulse along axolemma, initiated at trigger zone, conducted to terminals

Question 19

anterograde transport

Answer 19

away from cell body

Question 20

retrograde cell body

Answer 20

towards cell body

Question 21

kinesin or dynein transport

Answer 21

transport that uses ATP-dependent motor proteins

Question 22

myelin sheath

Answer 22

protein-lipid extension of glial plasma membrane
acts as insulation, increases transmission speed

Question 23

Nodes of Ranvier

Answer 23

gaps in myelin sheath

Question 24

white matter

Answer 24

myelinated cell bodies

Question 25

gray matter

Answer 25

unmyelinated cell bodies

Question 26

slow axonal transport

Answer 26

anterograde only 1-3 mm/day 'stop and go' cytoskeletal

Question 27

fast axonal transport

Answer 27

anterograde and retrograde 200-400 mm/day vesicles containing substances and membrane bound organelles

Question 28

rabies

Answer 28

uses retrograde transport to infect the CNS

Question 29

multipolar neurons

Answer 29

3+ processes (one axon, many dendrites) most common

Question 30

bipolar neurons

Answer 30

2 processes rare- special sensory neuron

Question 31

unipolar neurons

Answer 31

one process (T shaped) receptive endings instead of dendrites primarily found in ganglia of PNS

Question 32

sensory neurons

Answer 32

transmit impulses from receptors to CNS; mostly unipolar

Question 33

motor neurons

Answer 33

carry impulses away from CNS cell bodies located in the CNS

Question 34

interneurons

Answer 34

connect sensory and motor neurons mostly confined to the CNS primarily multipolar

Question 35

neuroglia

Answer 35

hold neurons together; maintain extracellular fluid, assist neural function, repair damaged tissue

Question 36

CNA neuroglia types

Answer 36

astrocytes oligodendrocytes microglial cells ependymal

Question 37

PNS neuroglia types

Answer 37

schwann cells satellite cells

Question 38

astrocytes

Answer 38

anchor neurons and blood vessels in place, maintain EC environment, assist in blood-brain barrier formation, repair damaged tissue

Question 39

oligodendrocytes

Answer 39

flattened end processes form myelin sheaths around some CNS axons

Question 40

microglia

Answer 40

act like macrophages in CNS tissue

Question 41

ependymal cells

Answer 41

line brain ventricles, produce cerebrospinal fluid, circulates cerebrospinal fluid with cells

Question 42

schwann cells

Answer 42

wrap around some PNS axons to form myelin sheath

Question 43

satellite cells

Answer 43

surround and support cell bodies

Question 44

myelin sheaths

Answer 44

electrical insulators (numerous phospholipid bilayers)

Question 45

myelin sheaths in CNS

Answer 45

oligodendrocytes, no neurolemma, myelination begins after birth

Question 46

myelin sheaths in PNS

Answer 46

schwann cells wrap around part of single axon, outer layer forms neurolemma, myelination begins in early fetal period

Question 47

regeneration of nervous tissue

Answer 47

CNS: nearly non-existent PNS: limited -can regenerate only if cell body remains intact