Structure of Skeletal Muscles 2

Question 1

network of membraneous channels

Answer 1

surrounds each myofibril and runs parallel to it

Question 2

transverse tubules (t-tubules)

Answer 2

set of membranous channels extending inward from the fiber’s membrane and passes all the way through the fiber

Question 3

extracellular fluid

Answer 3

denotes all body fluid outside of the cells

Question 4

sarcoplasmic reticulum and transverse tubules

Answer 4

activate the muscle contraction mechanism when the fiber is stimulated

Question 5

neuromuscular junction

Answer 5

connection between the motor neuron and muscle fiber

1. action potential from CNS
2. ach releases into synaptic cleft
3. ach receptor gates open
4. Na+ enters gates
5. enters t-tubules
6. Ca+ is released

Question 6

motor end plate

Answer 6

• formed by muscle fiber

- usually only has 1

Question 7

nuclei and mitochondria

Answer 7

• numerous in muscle fiber

Question 8

sarcolemma

Answer 8

cell membrane

Question 9

mitochondrian

Answer 9

organelle housing enzymes that catalyze (accelerate) reactions of aerobic respiration

aerobic respiration takes place here

Question 10

cytoplasm

Answer 10

contents of a cell including the gel-like cytosol and organelles , enclosed by cell membrane

distal ends of motor neuron fibers

• contains many mitochondria
• contains many synaptic vesicles

Question 11

synaptic vesicles

Answer 11

store neurotransmitters

Question 12

motor neuron

Answer 12

transmits impulses from the central nervous system

• nerve fibers, are densely branched and because of this 1 neuron may connect to many muscle fibers

Question 13

acetylcholine

Answer 13

neurotransmitter, which is a biochemical secreted into the synaptic left at axon ends of neurons

Question 14

synaptic clef

Answer 14

space between two cells forming a synapse

Question 15

synapse

Answer 15

functional connection between the axon of a neuron and the dendrite or cell body of another neuron or the membrane of another cell type

Question 16

muscle fiber

Answer 16

• usually has a single motor end plate

Question 17

all-or-none principle

Answer 17

when a motor neuron transmits an impulse, all of the muscle fibers it links to are stimulated to contract simultaneously

Question 18

motor unit

Answer 18

a motor neuron and all the muscle fibers it innervates, together