Anatomy & Physiology Muscle Study

Question 1

Three Types of Muscles

Answer 1

• Smooth
• Cardiac
• Skeletal

Question 2

Smooth Muscle

Answer 2

Located- digestive tract, blood vessels, bladder, airways, uterus.
Non-striated
Involuntary (contracts naturally)

Question 3

Cardiac Muscle

Answer 3

Located- Only in the heart
Involuntary (contracts naturally)

Question 4

Skeletal Muscle

Answer 4

Attaches to bone & causes movement in body.
Appears stripped under a microscope.
Voluntary ( contrast at will)

Question 5

Muscle Fibers

Answer 5

• Long, thread-like appearence.
• Muscle cells in these fibers contain MULTIPLE NUCLEI pressed against side of plasma membranes.

Question 6

Muscle Fibers contain ______ Structures:

Answer 6

Sarcolemma - cell membrane

Myofibrils - fundamental role in muscle contraction

Sarcoplasmic Reticulum ( endoplasmic reticulum) - activates muscle contraction mechanism when a muscle fiber is stimulated.

Myofilaments - proteins that for light & dark bands that makes muscle appear striated.

Transverse tubules - opens to the outside of muscle fiber & contain extracellular fluid, activates the muscle contraction mechanism when muscle fiber is stimulated.

Question 7

Muscle Attachment

Answer 7

Skeletal muscle may appear in 1 of 2 ways

Question 8

Direct Attachment

Answer 8

Muscle Fibers merge w/ the periosteum of bone to form a strong attachment.

Question 9

Indirect Attachment

Answer 9

Epimyosium extends past the muscle as a tendon, which merges w/ the periosteum.

Question 10

Muscle Movement

Answer 10

• Prime movement
• Synergists
• Antagonists

Question 11

Prime mover

Answer 11

Main muscle triggering the movement

Question 12

Synergists

Answer 12

Muscles that assist the Prime Mover.

Question 13

Antagonists

Answer 13

Muscles that oppose that action of the Prime Mover. Typically works to moderate speed/ range of movement to prevent injury.

Question 14

How Muscles and Movement Work Together

Answer 14

• When the Prime Mover contracts, the Antagonist must relax to give the Prime Mover control.

-Prime Mover for one movement = Antagonist for opposite movement.

Question 15

Hypertrophy

Answer 15

Enlarging muscles ( ex. weight lifting).

Question 16

Atrophy

Answer 16

Shrinking muscles (from lack of use).

Question 17

Aerobic

Answer 17

Endurance (endurance exercise) stimulates the growth of blood vessels in the muscle. ( increases supply of oxygen & glucose for ATP production)

Question 18

Slow Twitch (Type 1)

Answer 18

a slower reaction to stimuli.
- contains a lot of mitochondria & rich blood supply for efficiency at using oxygen to generate ATP of energy
- responds slower but fires for a longer time before becoming fatigued.

Question 19

Fast Twitch (Type 2)

Answer 19

Better @ generating short bursts of speed/strength.
- Smaller amts of mitochondria & a poorer supply of blood, but can absorb/release calcium quickly.
- fatigues quicker than twitch fibers.

Question 20

Muscle Fatigue

Answer 20

Muscle loses ability to contract during strenuous exercise = fatigue.
- arises usually from electrolyte imbalances & decreased ATP levels
- muscle cramps are due to lack of ATP required to return calcium ions back to the Sarcoplasmic reticulum so muscle fibers can relax.

Question 21

Muscles are named according to:

Answer 21

• Size
• Shape
• Location
• Number of origins
  -Direction of muscle fibers
  -Action/Function

Question 22

Size of Muscles:

Answer 22

MAXIMUS- largest

MINIMUS- smallest

MAJOR- large

MINOR- small

LONGUS- longest

BREVIS- shortest

Question 23

Shape of Muscles

Answer 23

DELTOID- triangular

RHOMBOID- diamond shaped

SERRATUS- sawtoothed

TRAPEZIUS- trapezoidal

Question 24

Pectoralis

Answer 24

Chest

Question 25

Brachio

Answer 25

Upper arm

Question 26

Gluteus

Answer 26

Buttock

Question 27

Fermoris

Answer 27

Femur

Question 28

Sterno

Answer 28

Sternum

Question 29

Cleido

Answer 29

clavicle

Question 30

Mastoid

Answer 30

mastoid process

Question 31

Digiti

Answer 31

finger or toe

Question 32

Pollicis

Answer 32

thumb

Question 33

Number of Origins

Answer 33

Biceps- 2 origins Triceps- 3 origins Quadriceps- 4 origins

Question 34

Direction of Muscles

Answer 34

Rectus- straight Transverse- across Oblique- diagonal

Question 35

Action of Muscles

Answer 35

Adductor- adducts Abductor- abducts Flexor- flexes Extensor- extends Leviator- elevates

Question 36

Muscle Contraction

Answer 36

1) impulse reaches end of motor neuron, causing small vesticles to fuse w/ cell membrane & release a neurotransmitter: ACETYLCHOLINE (ACh) into the synaptic cleft. 2) ACh quickly diffuses across synaptic cleft, stimulating receptors in the sarcolemma, sending an electrical impulse over the sarcolemma & inward along the T-Tubules. - causes the sacs in the sarcoplasmic reticulum to release calcium. 3) Calcuim binds with the tropin on the actin filament to expose attachment points. - in response, the myosin heads of thick filaments grab onto thin filaments and muscle contraction occurs.

Question 37

Muscle Relaxation

Answer 37

1) when nerve impulses stop arriving @ neuromuscular junction, ACh is no longer released. 2) An enzyme breaks down any remaining ACh while calcium ions are pumped back into the sarcoplasmic reticulum. 2) w/ calcium removed, troponin and tropomyosin again prevent the myosin heads from hooking onto thin filaments & muscle fiber relaxes.

Question 38

Calcium & ATP

Answer 38

*calcium in required to prevent tropmyosin & tropin ( 2 protein molecules entwined in actin filament) from blocking the sites where the myosin head attaches. *ATP provides energy which allow myosin heads to release their grip on actin filaments. The ATP splits, giving the myosin fuel to form new cross bridges.

Question 39

Strength of contraction

Answer 39

The nervous system controls strength of a contraction by: Altering the FREQUENCY of the stimulus & altering the INTENSITY of the stimulus.

Question 40

Stimulus Frequency

Answer 40

- When a muscle contracts several times in a row, the last contraction will be stronger than the first. (the sarcoplasmic reticulum doesn't have time to completely reabsorb the calcium) - When the impulse releases the muscle fibers even faster. the fibers don't have a chance to completely relax before the next impulse arrives. ( as a result, each subsequent contraction builds on the previous one.)

Question 41

Stimulus Intensity

Answer 41

A strong stimulus may stimulate all fibers in a motor nerve, causing nerve fibers to call on their accompanying muscle fibers to contract. In contrast, a weak stimulus stimulates only a few nerve fibers, which creates a weaker response.