Lecture 4 Skeletal Muscle and Nerve tissue

Question 1

Muscle cell

Answer 1

Made up of myofibrils

Myofiber/Myocyte/Muscle fiber

Question 2

Fascicle

Answer 2

group of myofibers

Question 3

Muscle

Answer 3

group of fascicles

Question 4

nebulin

Answer 4

“ruler” for determining

length of actin filament

Question 5

M-line:

Answer 5

attachment site for myosin

Question 6

Z-disk:

Answer 6

separates sarcomeres; attachment site for actin and titin

Question 7

H band:

Answer 7

space on either side of M-line where there is no actin

Question 8

A band:

Answer 8

distance from the end of one myosin head to the head of the
opposite myosin (overlap of actin + myosin and H band)

Question 9

I band:

Answer 9

space on either side of the Z-disk where there is no myosin

Question 10

Sliding Filament Mechanism

Answer 10

Thin filaments slide past
thick filaments
• This brings Z-disk’s closer
together
• All myofibrils in a muscle
contract at the same time
making the entire muscle
shorten
• *Actin and myosin DO NOT
change in length, they
simply overlap each other

Question 11

Sarcolemma:

Answer 11

membrane around

each muscle cell

Question 12

Transverse (T) tubules:

Answer 12

membrane
system penetrating the muscle cell
to convey electrical impulses from
sarcolemma into cell

Question 13

Sarcoplasm:

Answer 13

cytoplasm of muscle

cell

Question 14

Sarcoplasmic Reticulum:

Answer 14

tubular

system acting like the smooth-ER

Question 15

Terminal Cisternae =

Answer 15

flattened sac of
SR on either side of a Transverse T
Tubule
-store Ca2+

Question 16

Triad

Answer 16

T tubule + 2 Terminal

cisternae (1 on either side)

Question 17

End Feet:

Answer 17

connect T tubules with

SR to allow Ca release

Question 18

Neuromuscular Junction (NMJ)

Answer 18

Skeletal muscle
innervated by peripheral
a-motor neurons from
the anterior horn of the
spinal cord

Question 19

Neuromuscular Spindle Apparatus Action

Answer 19

reflexive response to
prevent overstretching of a
muscle

Question 20

Extrafusal muscle fibers:

Answer 20

contract

the muscle

Question 21

Intrafusal muscle fibers:

Answer 21

sense length

and rate of change of the muscle

Question 22

Type Ia sensory nerve fibers:

Answer 22

afferent innervation of intrafusal fibers

sense stretch and rate of change of intrafusal fibers

Question 23

a-motor nerve fibers:

Answer 23

efferent
innervation of extrafusal muscle fibers
-receive signal from type Ia fibers

Question 24

g-motor nerve fibers:

Answer 24

efferent
innervation of intrafusal muscle fibers
-receive signal from type Ia fibers

Question 25

soma/body

Answer 25

contains all organelles of neuron

Question 26

nissle substance

Answer 26

abundant RER w/in the cytoplasm of soma

Question 27

dendrite

Answer 27

receives signals from other neurons

Question 28

axon hillock

Answer 28

connection between soma and axon

Question 29

axon

Answer 29

conveys electrical impulse to synapse

Question 30

synapse

Answer 30

transfers electrical impulse from neuron to target tissue

Question 31

Multipolar:

Answer 31

multiple

dendrites and one axon

Question 32

Bipolar:

Answer 32

single dendrite
(multiple extensions) and
one axon

Question 33

Pseudounipolar:

Answer 33

one
cell process with a single
dendrite branch and axon
branch

Question 34

Schwann cell:

Answer 34

surround axon and create myelin sheath in PNS

– Wrap around one part of one axon

Question 35

Oligodendrocyte:

Answer 35

surround axon and create myelin sheath in CNS

– Wrap around a part of many axons

Question 36

Myelin Sheath:

Answer 36

circumferential layers of myelin allowing for faster

signal conduction velocity