Muscles

Question 1

Name and describe the three types of muscle

Answer 1

-Smooth: involuntary, no striations, lines hollow organs
-Cardiac: involuntary, striated
-Skeletal: Voluntary, striated. Attached to Skeleton

Question 2

What is the fascia

Answer 2

sheet of thick connective tissue surrounding a muscle

Question 3

What is the epimysium

Answer 3

surrounds all fascicles. wraps entire muscle

Question 4

What is the perimysium

Answer 4

coarse membrane surrounding fascicles

Question 5

What is the endomysium

Answer 5

delicate connective tissue sheath around each muscle fiber

Question 6

Where are myofibrils found? What is their main function?

Answer 6

Found inside muscle fibers; contraction/ relaxation

Question 7

Name and describe the 2 kinds of protein filaments

Answer 7

Thick: made of protein myosin. Found in dark bands
Thin: made of contractile actin. Found in dark and light bands

Question 8

What is a sarcomere?

Answer 8

smallest contractile unit of myofibrils

Question 9

What is the I band

Answer 9

Thin filament

Question 10

What is the A band?

Answer 10

Thick filament

Question 11

What is responsible for causing striations in the skeletal muscle?

Answer 11

The light/ dark bands (thick/thin filament pattern)

Question 12

State the sliding filament theory

Answer 12

Thick filament slide past thin filaments during muscle contraction, while the filaments stay at relatively constant lengths

Question 13

What enzyme breaks down ATP into ADP releasing energy

Answer 13

ATPase

Question 14

Neurotransmitters cause skeletal muscle fiber to contract, what is the name of the specific neurotransmitter

Answer 14

Acetylcholine (ACh) found in synaptic vesicles of neuromuscular junctions

Question 15

What occurs when there is a high concentration of calcium ions present in the sarcoplasm

Answer 15

A cross bridge forms (sliding filament theory)

Question 16

What are the functions of creatine phosphate and ATP in muscle fibers?

Answer 16

ATP: releases needed energy
Creatine phosphate: transfers a P group to ADP to regenerate ATP

Question 17

What is myoglobin? Why is it important?

Answer 17

iron and oxygen; binding protein

Question 18

How does lactic acid affect muscles?

Answer 18

-A lot of glucose used to make only a little ATP
-leads to muscle soreness

Question 19

Describe rigor mortis

Answer 19

Contraction of muscles a few hours after death due to the release of Ca+ ions

Question 20

How and why is heat transported throughout the body

Answer 20

muscles generate body heat as a by product of contraction to maintain internal temp

Question 21

How are muscles named throughout the body (7 ways)

Answer 21

Shape, # of origins, location, size, direction of muscle fibers, action of muscle, origin/ insertion

Question 22

Define origin

Answer 22

Attachment that remains immobile

Question 23

Define Insertion

Answer 23

attachment where movement occurs

Question 24

Define action

Answer 24

type of movement the muscle allows for

Question 25

What is an all-or-none response? Can skeletal muscles contract partially?

Answer 25

When exposed to a stimulus, muscle fibers will contract to its fullest extent, never partially
-No, but can be a graded response

Question 26

Define muscle twitch.

Answer 26

Brief contraction followed by relaxation

Question 27

Describe the three phases recorded during a muscle twitch

Answer 27

-Latent period: time between stimulus and response
-Period of contraction: muscle pulls attachments
-Period of relaxation: muscle returns to former length

Question 28

What is a tetanic contraction?

Answer 28

When the stimulus increases, there is no relaxation between contractions

Question 29

Name the 2 processes that produce a sustained contraction

Answer 29

Summation: next twitch occurs before previous twitch relaxes

Recruitment of motor neurons: increase in # of motor units activated as stimulation intensity increases

Question 30

What is peristalsis? Where does this occur in the body?

Answer 30

Wavelike motion in certain tubular organs and helps force the contents of these organs along their lengths
Ex: intestines, esophagus