Muscle Physiology Structure and Function Part 1

Question 1

what does muscle do?

Answer 1

holds our bones together. helps us move. beats our heart.

Question 2

muscle health can be divided into what two groups?

Answer 2

function: sport, occupation, daily living
and
energy expenditure: obesity, diabetes

Question 3

what happens if we have unhealthy muscle?

Answer 3

reduced performance, reduced independence reduced productivity.

Question 4

3 types of muscle in our human body

Answer 4

cardiac, smooth, skeletal

Question 5

what is skeletal muscle?

Answer 5

• majority of muscle in humans
• attached to bones
• striped appearance
• we tell it what to do
• multinucleated

Question 6

what is cardiac muscle?

Answer 6

• muscle of our heart
• fully automatic process
• single nucleus
• intercalated disks

Question 7

what is smooth muscle?

Answer 7

• narrow at end and widens in middle shape
• twisted arrangement
• located in walls of various organs and blood vessels
• single nucleus
• involuntary
• contractions are weak and slow

Question 8

what do muscles do?

Answer 8

Move our bodies through contraction to enable certain movements. key to function of organs

Question 9

what are the main types of muscle contraction?

Answer 9

• isotonic (movement because of change in length of the muscle) ex. bicep curl
• isometric (generating force, no change in muscle length) ex. plank

Question 10

what are the two phases of isotonic?

Answer 10

concentric (shorter) and eccentric (longer)

Question 11

what is epimysium?

Answer 11

• the outer muscle sheath
• a “bundle of fascicles(bundles)”

Question 12

How do muscles move our body in different ways?

Answer 12

Different contractions happen based off of where muscles are attached to our skeleton. Therefore, the location of muscle will dictate the function or movement.

Question 13

attaches muscle to bone

Answer 13

tendon

Question 14

what is perimysium

Answer 14

• surrounds fascicles

Question 15

what is a fascicle?

Answer 15

bundle of muscle fibers

Question 16

what surrounds the individual muscle fibers?

Answer 16

endomysium

Question 17

what is the myofibril?

Answer 17

arrangement of protein filaments (think and thick filaments)
- basic unit of contraction
- overlap to form sacromeres

Question 18

what are the components of the muscle fibers?

Answer 18

• nucleus (multiple nuclei for a single muscle fiber)
• sarcolemma (inside endomysium)
• sarcoplasm (cytoplasm in a muscle cell; holds organelles)
• sarcoplasmic reticulum (holds and releases calcium which is required in muscle contraction)

Question 19

what is a sarcolemma?

Answer 19

• cell membrane of a muscle fiber
• membrane surrounds muscle fiber

Question 20

what is a t-tubule?

Answer 20

• an organelle within muscle fiber
• transverse tubule that is in the sarcolemme and tubes that surround the sarcoplasmic reticulum
• they allow signals from nervous system to penetrate deep into the muscle fiber

Question 21

a single muscle cell has _____ myofibril(s) within it

Answer 21

many

Question 22

what is a thin filament in a myofibril called?

Answer 22

actin

Question 23

what is a thick filament in a myofibril called?

Answer 23

myosin

Question 24

the way that myosin and actin interact together allow what?

Answer 24

allows the muscle to generate force and change shape or shorten or lengthen

Question 25

what is the “Z Line” in the sarcomere?

Answer 25

• separates sarcomeres

Question 26

what is the “H zone” in the sarcomere?

Answer 26

• area that widens and shrinks in the middle of the sarcomere

Question 27

what are the A and I bands in the sarcomere?

Answer 27

• A are the dArk bands (prodomenantly myosin (sometimes actin and mysin overlap))
• I is the lIght band (actin)