Muscle

Question 1

Three types of muscles

Answer 1

• skeletal
• cardiac
• smooth

Question 2

Step 1 of muscular contraction

Answer 2

-nerve stimulation

Question 3

Step 2 of muscular contraction

Answer 3

-action potential

Question 4

Action potential

Answer 4

an electrical current that must be generated in the sarcolemma

Question 5

Step 3

Answer 5

Action must be propegated along sarcolemma

Question 6

Step 4

Answer 6

intracellular Ca2+ levels must rise briefly

Question 7

What ACH

Answer 7

-acetycholine, which is the neurotransmitter at neuromuscular junction

Question 8

Four main characteristics of muscle

Answer 8

• elasticity
• excitability
• elasticity
• contractility

Question 9

Excitability

Answer 9

ability to receive and respond to a stimuli

Question 10

Extensability

Answer 10

Ability to be stretched

Question 11

Elasticity

Answer 11

ability to recoil after stretched

Question 12

Contractility

Answer 12

ability to shorten forcibly when stimulated

Question 13

Four movement functions of muscle

Answer 13

• produce movement
• stabalize joints
• generate heat
• maintain posture

Question 14

Three features of skeletal muscle

Answer 14

• nerve and blood supply
• connective tissue sheaths
• attachments

Question 15

Sarcolemma

Answer 15

muscle fiber plasma membrane

Question 16

Sarcoplasm

Answer 16

muscle fiber cytoplasm

Question 17

Modified organelles

Answer 17

• myofibrils
• sarcoplasm
• t tubules

Question 18

Myofibrils

Answer 18

• densely packed rod like elements

- account for 80% of the muscle cell volume

Question 19

Myofibril features

Answer 19

• stirations
• sarcomeres
• myofilaments
• molecular composition of myofilaments

Question 20

Sarcomere

Answer 20

• smallest contractile unit

- individual sarcomere align end to end and along myofibril, like boxcars of a train

Question 21

Myofilaments

Answer 21

orderly arrangment of myosin and actin myofilaments within sarcomere

Question 22

Actin myofilaments

Answer 22

-thin filaments

Question 23

Myosin filaments

Answer 23

-thick filaments

Question 24

Molecular composition of thick filaments

Answer 24

• composed of the protein myosin

- during contraction, heads link thin and thick filaments together forming crossbridge

Question 25

Molecular composition of thin filaments

Answer 25

-composed of protein actin

Question 26

Troponin and tropomyosin

Answer 26

-regulatory proteins bound to actin

Question 27

Elastic filament

Answer 27

composed of protein called titin

Question 28

Titin

Answer 28

- holds thick filaments in place | - helps recoil after stretch

Question 29

Sarcoplasmic reticulum

Answer 29

- network of smooth endoplasmic reticulum - functions in regulation of intracellular Ca2+ - stores and releases Ca2+

Question 30

T-tubules

Answer 30

- tube formed by protusion of sarcolemma deep into cell interior - increases muscle fiber surface area - allows electrical signal to reach deep into cell interior of each muscle finer

Question 31

Sliding filament model of contraction

Answer 31

states that during contraction, thin filaments slide past thick filaments, causing actin and myosin to overlap more

Question 32

contraction

Answer 32

the activation of cross bridges generate force

Question 33

How are bridges made possible?

Answer 33

because of calcium release in the sarcoplasmic retiulum

Question 34

depolarization

Answer 34

reduction of negative membrane potential

Question 35

Polarization

Answer 35

movement of the membrane potential to the initial resting state

Question 36

Excitation contraction coupling E-C

Answer 36

-events that transmit AP along sarcolemma (excitation) are coupled to sliding of myofilaments (contraction)

Question 37

Step 1 of crossbridge cycle

Answer 37

- cross bridge formation | - high energy

Question 38

Step 2 of crossbridge cycle

Answer 38

Working (power) stroke: myosin head pivots and pulls thin filament towards m line

Question 39

Step 3 of cross bridge cycle

Answer 39

cross bridge development: ATP attaches yo myosin head, causing cross bridge detach

Question 40

Step 4 of cross bridge cycle

Answer 40

cocking of myosin head, energy from hydrolysis of ATP "cocks" myosin head into high energy state

Question 41

Creatine phosphate

Answer 41

Ca2+ re entry into SR-tension declines to zero

Question 42

Glycolysis

Answer 42

first step in breakdown of glucose

Question 43

3 factors of glycolysis

Answer 43

- does not require oxygen - glucose is broken down into 2 pyruvic acid molecules - 2 ATP's are generated for each glucose