Microscopic Muscle fiber

Question 1

What is a cell at rest, where is more negative

Answer 1

on the inside

Question 2

what does the sarcolemma do

Answer 2

it is a cell membrane that separates charges

Question 3

what are transverse tubules

Answer 3

regions of sarcolemma that dip into muscle cell, they transmit APs deep into the cell

Question 4

what transmit ap deep into cell

Answer 4

transverse tubules

Question 5

what are the 4 things in sarcoplasm

Answer 5

myofibrils
sarcoplasmic reticulum
mitochondria
glycogen granules

Question 6

what are myofibirls

Answer 6

bundels of myofilaments, like actin and myosin
they run the length of the cell and anchor to cell membrane location of contraction

Question 7

what does the sarcoplasmic reticulum do

Answer 7

sequesters Ca ++ and keeps cytoplamic Ca++ low at rest

Question 8

what are the 2 things in sarcoplasmic reticulum

Answer 8

terminal cisternae
triad

Question 9

what are terminal cisternaes

Answer 9

part of the sarcoplasmic reticulum that are bloated areas of SR, located adjacent to t. tubules.

Question 10

what do mitochondria benefit in the sarcoplasm

Answer 10

the breakdown of glucose

Question 11

rank groupings from largest to smallest

Answer 11

faascicle, fiber, myofibril, myofilament

Question 12

what is the sarcomere

Answer 12

myofilaments organized into repeating functional units

Question 13

what is the h zone

Answer 13

part of the a band that is only myosin

Question 14

what is the a band

Answer 14

region that contains the entire myosin molecule

Question 15

what cuases striations

Answer 15

arrangement of contractile proteins,
differences in size, density, and distribution of actin and myosin

Question 16

what is the thin filament

Answer 16

actin

Question 17

what is the active site of actin

Answer 17

the myosin binding site

Question 18

nebulin def

Answer 18

holds g actin together

Question 19

what is tropmyosin

Answer 19

a linear filament protein that at rest, covers all active sites (2 strands of it )

Question 20

troponin info

Answer 20

a globular protein

Question 21

what does troponin do

Answer 21

binds ca++ and causes a conformational change.
its task is to pull tropomyosin away from the active site

Question 22

what is the thick filament

Answer 22

myosin

Question 23

what are the 3 parts of myosing

Answer 23

tail
head
hinge

Question 24

tail of myosin vs head and hinge

Answer 24

tail is the linear part, where myosin molecules anchored together
head binds actin if active site is uncovered and forms cross bridge
the hinge is the ability to shift

Question 25

what binds actin if the active site is uncovered

Answer 25

the myosin head

Question 26

what is titin

Answer 26

a protein that anchors myosin to z line

Question 27

what is the fxns of titin

Answer 27

maintains proper alignment between actin and myosin prevents extrememe stretching recoil after stretching

Question 28

what is the sliding filament theory

Answer 28

individual myofilaments do not change length, and the fact that contraction is due to myofilaments sliding past one another.

Question 29

can filaments pass the z or m line

Answer 29

no

Question 30

what are the 3 components of the neuromuscular junction

Answer 30

synaptic knob synaptic cleft motor end plate

Question 31

what is the synaptic knob

Answer 31

wider portion of axon that comes up to muscle fiber

Question 32

what do synaptic vessicles contain

Answer 32

neurotransmitters

Question 33

what is the synaptic cleft

Answer 33

the physical gap between neuron and muscle fiber where neurotransmitters diffuse to muscle fiber

Question 34

what is the motor end plate

Answer 34

region of muscle fiber that has neurotransmitter receptors (folded appearance