Muscles

Question 0

Cardiac muscle

Answer 0

Striated. Short branched cells. Single nucleus. Involuntary. Heart only myocardium.

Question 1

Skeletal muscle

Answer 1

Striated, long parallel, multi nucleated, voluntary, attached to bone

Question 2

Smooth muscle.

Answer 2

Non striated. Involuntary. Walls of internal structures.

Question 3

Muscle cells are called

Answer 3

Myofibers

Question 4

Muscle cells are surrounded

Answer 4

by fascia endomysium

Question 5

Muscle cells are separated into fascicles by

Answer 5

Perimysium fascia

Question 6

Surrounds and separates muscles

Answer 6

Epimysium

Question 7

Fascia has

Answer 7

Poor blood supply. Inelastic

Question 8

Orign

Answer 8

Least movable part. Often proximal

Question 9

Insertion

Answer 9

More movable. Often distal

Question 10

Between origin and insertion is

Answer 10

Belly

Question 11

Agonist

Answer 11

Prime mover

Question 12

Antagonist

Answer 12

Relaxed and stretches over joint

Question 13

Steady’s action of agonist and antagonist

Answer 13

Synergists

Question 14

Skeletal muscle cell surrounded by

Answer 14

Sarcolemma (cell membrane)

Question 15

Skeletal muscle cell structure

Answer 15

Multi nucleated. Many mitochondria. Sarcoplasm (contains glycogen and myoglobin. Myofibrils(bundles of myofilaments). Sarcoplasmic reticulum (store calcium). T-tubules(sarcolemma extension into cell interior, depolarises cell)

Question 16

Myofilaments are

Answer 16

2 different protein strands
Myosin bundles make thick filament.
Actin is thin and surrounded by troponin and tropomyosin.
Provide power of muscle contraction.

Question 18

Primary motor cortex is

Answer 18

Precentral gyrus in the frontal lobe

Question 19

Muscle contraction step 1

Answer 19

A thought in the precentral gyrus travels down nerve cells thru spinal cord

Question 20

Muscle contraction step 2, arrival

Answer 20

Nerve cell triggers motor unit

Question 21

Muscle contraction step 3

Answer 21

Calcium is released from sarcoplasmic reticulum into sarcoplasm

Question 22

Muscle contraction step 4

Answer 22

calcium ions bind to troponin, troponin changes shape, removing the blocking action of tropomyosin, actin active sites exposed.

Question 23

Muscle contraction step 5

Answer 23

Myosin heads attach to actin

Question 24

Muscle contraction step 6

Answer 24

Myosin head swivel, pulling actin towards its tail

Question 25

Muscle contraction step 7

Answer 25

Myosin releases and attaches to next actin binding site (like rowing)

Question 26

Muscle contraction (Sliding filament theory) continues until

Answer 26

Muscle cell and muscle shortens and thickens by up to 50% OR neurons stop stimulating muscle

Question 27

Muscle contraction uses

Answer 27

Energy ATP

Question 28

What informs the brain of the amount of contraction occurring?

Answer 28

Proprioceptors (muscle spindles)

Question 29

Why does the body go stiff after death

Answer 29

Calcium is release into myofibre. Calcium bonds to troponin which changes shape removing blocking action of tropomyosin so actin active sites are exposed and myosin heads all attach. This happens all over the body causing all the muscles to contract

Question 30

Why does the body eventually go limp after death?

Answer 30

Because after a prolonged attachment of myosin heads to actin the heads tear off