The Muscular system

Question 1

Skeletal Muscle

Answer 1

locomotion of breathing
maintain posture
heat production
form smooth contours of body
vary in shape
under voluntary control
striated
cells are multinucleated
attached to bones

Question 2

Cardiac Muscles

Answer 2

pumping mass of heart
under involuntary control
arranged in a spiral shape
cells behave as one unit
striated

Question 3

Smooth Muscle

Answer 3

no striations
single nucleus
found mainly in the walls of hallow organs
slow contraction
under involuntary control

Question 4

Function of Muscles

Answer 4

Produce movement
maintain posture
generate heat
stabilize joints
propel substances

Question 5

Endomysium

Answer 5

located around a single muscle fiber(a connective tissue)

Question 6

Perimysium

Answer 6

surrounds multiple fibers

Question 7

Fasicle

Answer 7

bundle of fibers

Question 8

Epimysium

Answer 8

covers the entire skeletal muscle

Question 9

Sarcolemma

Answer 9

specialized plasma membrane
helps in synaptic transmission

Question 10

Sarcoplasmic recticulum

Answer 10

specialized smooth endoplasmic reticulum which stores and pumps calcium ions

Question 11

Myofibril

Answer 11

Bundles of muscle cells in a fascicle

Question 11

I- Band

Answer 11

a band of myofilament that is made of actin(light band)

Question 12

A-Band

Answer 12

a band of myofilament that is made of myosin(dark band)

Question 13

Sarcomere

Answer 13

Contractile unit of a muscle fiber
contains thin and thick filaments

Question 14

Myosin filaments

Answer 14

Thick filaments composed of the protein myosin
have heads(extensions or cross bridges)
has ATPase enzymes

Question 15

Actin Filaments

Answer 15

filaments composed of the protein actin
overlap somewhat
have the proteins:troponin and tropomyosin attached to it

Question 16

The Sliding filament theory of muscle contraction

Answer 16

Activation by nerves causes myosin heads to attach to binding cites on the thin filaments(only when the calcium ions bind with the proteins on the thin filaments)
myosin heads then bind to the next site of the thin filament and pull then towards the center of the sarcomere
results in a muscle that is shortened

Question 17

Neuromuscular Junction

Answer 17

Association site of nerve and muscle

Question 18

Neurotransmitter

Answer 18

chemicals released by nerve upon arrival of nerve impulse

Question 19

Synaptic cleft

Answer 19

a gap between nerve and muscle

Question 20

Motor unit

Answer 20

consists of a single motor neuron and all the muscle fibers it innervates.

Question 21

Events that take place in the neuromuscular junction

Answer 21

Action potential reaches the motor end plate of the neuron.
Voltage-gated calcium channels open, and calcium enters the neuron.
Vesicles are stimulated to migrate to the end plate and release acetylcholine into the neuromuscular junction.