midterm 2

Question 1

three types of muscle

Answer 1

smooth, cardiac, skeletal

Question 2

striated muscle

Answer 2

skeletal and cardiac

Question 3

unstriated muscle

Answer 3

smooth muscle

Question 4

voluntary muscle

Answer 4

skeletal innervated by somatic NS

Question 5

involuntary muscle

Answer 5

cardiac and smooth, innervated by autonomic NS

Question 6

name for a single skeletal muscle cell

Answer 6

muscle fibre

Question 7

in embryonic development, skeletal muscle fibres are formed by the fusion of ____

Answer 7

myoblasts

Question 8

specialized contractile elements that make up 80% of the muscle fibre volume

Answer 8

myofibrils

Question 9

thick filaments

Answer 9

special assemblies of the protein myosin

Question 10

thin filaments

Answer 10

primarily made of protein actin

Question 11

level of organization in a skeletal muscle

Answer 11

whole muscle, muscle fibre, myofibril, thick and thin filaments, myosin and actin

Question 12

purpose of connective tissue

Answer 12

provides structure to the muscle and allows transfer of force to the bone, providing tension for stabilization/ movement

Question 13

the connective tissue which covers the whole muscle

Answer 13

epimysium

Question 14

connective tissue that divides the muscle fibres into bundles or fascicles

Answer 14

perimysium

Question 15

inner most connective tissue, covers each muscle fibre or cell

Answer 15

endomysium

Question 16

dark bands

Answer 16

a bands

Question 17

light hands

Answer 17

I bands

Question 18

the lighter area within the middle of the A band where the thin filaments do not reach

Answer 18

H zone

Question 19

extends vertically down the middle of the A band within the centre of the H zone, system of supporting proteins holding thick filaments together

Answer 19

M line

Question 20

the area between two Z lines

Answer 20

sarcomere, the functional unit of skeletal muscle

Question 21

a flat cytoskeletal disc that connects the thin filaments of two adjoining sacromeres

Answer 21

Z line

Question 22

largest protein in the body, 30 000 amino acids

Answer 22

titin

Question 23

functions of titin

Answer 23

helps stabilize the position thick filaments in relation to the thin filaments, and greatly augments muscle elasticity
(helps muscle recoil)

Question 24

a motor protein molecule consisting of two identical subunits each shaped somewhat like a golf club

Answer 24

myosin

Question 25

the two important sites on a cross bridge crucial to the contractile process

Answer 25

an actin binding site, and an ATPase (ATP splitting) site

Question 26

three proteins that that make up thin filaments

Answer 26

actin, tropomyosin, troponin

Question 27

are myosin an actin unique to muscle cells?

Answer 27

no, but they are abundant and highly organized in muscle cells

Question 28

what is excitation-contraction coupling?

Answer 28

the series of events linking muscle excitation to muscle contraction

Question 29

skeletal muscles are stimulated to contact by release of _____

Answer 29

acetylcholine (ACh)

Question 30

what do the sarcoplasmic reticulum lateral sacs store?

Answer 30

Ca2+

Question 31

what are ryanodine receptors

Answer 31

foot proteins / bridge the gap and serve as ca2+ release channels because they are locked in the open position but the plant chemical ryanodine

Question 32

how long does a single action potential in a skeletal muscle fibre last

Answer 32

1 to 2msec

Question 33

a single action potential that is too short and weak to be useful

Answer 33

twitch

Question 34

tetanus

Answer 34

if a muscle fibre is stimulated so rapidly that it doesn't have a chance to relax between stimuli, tetanus occurs and is 3-4x stronger than a single switch

Question 35

most common type of lever system in the body

Answer 35

flexion of the elbow joint