Unit 15: Muscle Anatomy & Movement

Question 1

muscle is?

Answer 1

• one of the four primary types of tissues in the body
• there are three types of muscle tissue: skeletal, cardiac, and smooth muscle

Question 2

what do the muscle tissues have in common?

Answer 2

• excitability as their plasma membrane can change their states from polarized to depolarized and can send an electrical wave called an action potential along the length of the membrane

Question 3

skeletal muscle completely depends on?

Answer 3

signaling from the nervous system to move properly.

Question 4

what does elasticity do?

Answer 4

when the muscle can return to its original length when relaxed due to elastic fibers.

Question 5

what is extensibility?

Answer 5

it can stretch or extend

Question 6

what is contractility?

Answer 6

allows muscle tissue to pull on attachment force.

Question 7

what are the differences among the three muscle types?

Answer 7

actin and myosin proteins
- in the cytoplasm of the muscle cells in skeletal and cardiac muscle, the actin and myosin creates a pattern called striations.
smooth muscle does not have striations

Question 8

how many nuclei does each muscle type have?

Answer 8

skeletal muscle: multinucleated
smooth muscle: mononucleated
cardiac muscle: one to two but i would put mononucleated

Question 9

what is the best known feature of the skeletal muscle?

Answer 9

to contract and cause movement. they can produce movement and also stop movement

Question 10

swallowing, urinating, and defecting are all?

Answer 10

voluntary control by skeletal muscles.

Question 11

how do skeletal muscles contribute to homeostasis?

Answer 11

by generating heat.
- muscle contration requires energy and when atp is broken down, heat it produced.
- shivering produces random skeletal muscle contractions to generate heat.

Question 12

each skeletal muscle contains?

Answer 12

skeletal muscle fibers, blood vessels, nerve fibers, and connective tissue.

Question 13

what are the 3 layers of connective tissue in skeletal muscle?

Answer 13

connective tissue layers in skeletal muscle aka mysia
1. epimysium
2. perimysium
3. endomysium

Question 14

what is the epimysium?

Answer 14

each muscle is wrapped in connective tissue called epimysium which allows the muscle to contract.
- the epimysium also separates muscle from other tissues and organs so that it can move independently.

Question 15

in each skeletal muscle, muscle fibres are organized into individual bundles called?

Answer 15

fasicle and it it surrounded by the perimysium. it contains the blood vessels and nerves.

Question 16

endomysium?

Answer 16

endomysium is the innermost layer surrounding each individual muscle fibre. the endomysium contains the extracellular fluid and nutrients to support it.

Question 17

in muscles that work with tendons to pull on bones?

Answer 17

the collagen in the 3 tissue layers intertwines with the collagen of a tendon. at the other end of the tendon, it fuses with the periosteum coating the bone.

Question 18

muscle fibre in skeletal muscle is also?

Answer 18

supplied by the axon of a somatic motor neuron which signals the fibre to contract.

Question 19

unlike the cardiac or smooth muscle, the only way to contract a skeletal muscle is through?

Answer 19

signalling from the nervous system.

Question 20

the plasma membrane of muscle fibers is called the

Answer 20

sarcolemma

Question 21

what is the cytoplasm of the muscle fibers called?

Answer 21

sarcoplasm

Question 22

what is the endoplasmic reticulum of the muscle fibers called?

Answer 22

sarcoplasmic reticulum which stores and releases calcium ions.

Question 23

the muscle fibers surrounded by the endomysium are wrapped in a cell membrane called?

Answer 23

sarcolemma

Question 24

inside each muscle fiber there are? surrounded by?

Answer 24

tiny rods called myofibrils which are surrounded by the sarcoplasm

Question 25

the myofibrils/fibrils consist of?

Answer 25

repeating segments called sarcomeres: tiny units responsible for skeletal muscle contraction

Question 26

myofibrils are made up of? and they are?

Answer 26

myofibrils are made up of sarcomeres and sarcomeres are where the contraction of muscle occurs through actin myosin filament interactions

Question 27

zigzag sections that mark the end of each sarcomere are called?

Answer 27

z disc or z line: allow for attachment of thin actin filaments and elastic protein called titin

Question 28

each sarcomere contains?

Answer 28

thin actin filaments and thick myosin filaments

Question 29

the thick myosin filaments attach to?

Answer 29

the elastic protein called titin which then attaches to the z disc

Question 30

the __ and __ engage during muscle contraction.

Answer 30

the actin and myosin filaments engage during muscle contraction.

Question 31

m line or m band anchor to the?

Answer 31

center of the myosin filaments holding them together acting as a shock absorber

Question 32

what causes striations in skeletal muscle?

Answer 32

filament arrangement of sarcomere causes the striated appearance: both cardiac and muscle tissue have it

Question 33

a band?

Answer 33

the section of the sarcomere that contains the entire length of the thick myosin filament and some of the thin actin filament

Question 34

i band?

Answer 34

section of the sarcomere that surrounds the z disc and contains only thin actin filaments

Question 35

h zone?

Answer 35

section in the a band that consists of the thick myosin filaments and its embedded m lines

Question 36

synovial joints allow the body?

Answer 36

a wide range of movements

Question 37

orientation of the muscles?

Answer 37

each muscle is attached at an ORIGIN and INSERTION. the origin is the part that remains stable when the muscle contracts. the insertion is the attachment to the bone which will move when the muscle contracts.

Question 38

what is flexion?

Answer 38

flexion decreases the angle between the two structures: when the ulna moves closer to the humerus

Question 39

what is extension?

Answer 39

increases the angle between the two structures: ulna moves away from the humerus

Question 40

hyperextension?

Answer 40

moved beyond normal range of motion by that joint

Question 41

is flexion/extension at which plane?

Answer 41

sagittal plane

Question 42

abduction/adduction at what plane?

Answer 42

coronal/frontal place

Question 43

abduction?

Answer 43

movement of structure away from midline point: moving arms sideways away from the body

Question 44

adduction?

Answer 44

occurs as the structure is added back toward the midline reference point: bringing the arm back to the midline

Question 45

what is circumduction?

Answer 45

circular movement of a limb combining flexion, extension, adduction, abduction.

Question 46

rotation?

Answer 46

body movement describing movement around an axis.

Question 47

supination?

Answer 47

turning the palm or foot upwards.

Question 48

pronation?

Answer 48

turning the palm or foot downward.

Question 49

dorsiflexion?

Answer 49

when the top of the foot moves towards the foot

Question 50

plantar flexion?

Answer 50

when the foot point downwards increasing the angle between the foot and leg

Question 51

two requirements for skeletal muscle contraction to occur?

Answer 51

neuromuscular junction and excitation-contraction coupling

Question 52

what is neuromuscular junction?

Answer 52

refers to the synpase between a motor neuron and a skeletal muscle fibre.

Question 53

every skeletal muscle fibre must be?

Answer 53

activated or stimulated by the nerve ending at the neuromuscular joint so that a change in membrane potential occurs

Question 54

the signals from the neuron are the only way to?

Answer 54

activate the fibre to contract

Question 55

they generate a ?

Answer 55

electrical current called an action potential in the sarcolemma which is the plasma membrane of the muscle fibre

Question 56

the second requirement is?

Answer 56

excitation contraction coupling

Question 57

what is the cells resting membrane potential?

Answer 57

-70mV

Question 58

neurons and muscle cells use their membrane potential to generate?

Answer 58

electrical signals

Question 59

how do neurons and muscle cells use their membrane potential to generate electrical signals?

Answer 59

they do this by controlling the movement of ions across the membrane.

Question 60

both neurons and muscle cells are? meaning what?

Answer 60

electrically excitable meaning they are able to generate action potentials.

Question 61

what is an action potential?

Answer 61

an action potential is a electrical signal that can travel along a cell membrane

Question 62

what exactly does excitation contraction coupling even mean?

Answer 62

for a skeletal muscle fibre to contract, the membrane must first be excited or stimulated to fire an action potential. THEN the muscle fibre action potential across the sarcolemma as a wave is "coupled" to the actual contraction through the release of calcium ions from the sarcoplasmic reticulum.