Muscles

Question 1

What are the types of muscle

Answer 1

1. Smooth muscle: causes peristalsis
2. Skeletal muscle: helps us move and breathe
3. cardiac: contracts our heart

Question 2

What are characteristics of muscle

Answer 2

1. contractile: causes movement of the body and changes in size/shape of internal organs.
2. conductive
3. skeletal muscle is a major source of body heat (by product of cellular respiration)

Question 3

What are characteristics of skeletal muscle

Answer 3

1. somatic (voluntary)
2. striated
3. multinucleated

Question 4

what are characteristics of cardiac muscle

Answer 4

1. heart
2. autonomic
3. striated
4. single nucleus; centrally placed
5. intercalated discs

Question 5

what are characteristics of smooth vessel

Answer 5

1. walls of viscera, blood vessels, skin
2. autonomic
3. not striated

Question 6

diff between smooth muscle and dense irregular CT:

Answer 6

You see a lot of nuclei (fusiform or corkscrew) and not a lot of extracellular space. Collagen in ECM stains more darkly with eosin in dense irregular CT

Question 7

What is organization of a skeletal muscle

Answer 7

muscle –> muscle fascicle –> muscle fiber –> myofibrils –>myofilaments

Question 8

reticular fibers is what type of collagen

Answer 8

type 3

Question 9

describe endomyseum

Answer 9

1. reticular fibers

2. surr ind muscle fibers

Question 10

describe perimysyium

Answer 10

1. thicker CT
2. surr muscle fascicles
3. blood vessel and nerves withim

Question 11

what are myofibrils

Answer 11

contain contractile element of the cell

-extend the entire length of the muscle fiber

Question 12

myofilaments are arranged in:

Answer 12

sarcomores which is a contractile unit; sarcomere shortens with contraction

Question 13

Sarcomeres:

Answer 13

Thin filaments only present in the I band.
A band is in the center.
M line is where other proteins are that anchor the thick filaments together.

Question 14

A band never changes in ___but the amount they overlap changes

Answer 14

length

Question 15

____bands shorten during contraction

Answer 15

I

Question 16

What are the thin filaments

Answer 16

1. actin
2. tropomyosin
3. troponin

Question 17

what is the thick filaments

Answer 17

1. myosin
2. 2 heavy chains (rod and heavy)
3. 4 light chains (regulatory)

Question 18

ONly possible with the prescense of calcium

Answer 18

1. Myosin heads bound to thin filament
2. ATP binds to mysoin head causeing conformation change which releases actin
3. ATP gets hydrolyzed to ADP and phophate; which causes head to get cocked back
4. Powerstroke: head reaches up and binds actin which releases inorganic phosphate and ADP; myosin head comes forward again and pulls actin chain
5. Back to step 1

Question 19

I band =

Answer 19

light band

Question 20

A band =

Answer 20

dark band

Question 21

H band is the light band witin the

Answer 21

A band.

Question 22

During contraction only I band and H band

Answer 22

decrease in size; A band is constant

Question 23

What is SR

Answer 23

Specialized smooth ER involved in sequesteration of calcium

Question 24

What is T tubule

Answer 24

bring depolarization from sarcolemma along SR within skeletal muscle fiber; leads to release of calcium from SR allowing contraction; lined up at interface of I band and A band.

Question 25

What is sarcolemma

Answer 25

plasma membrane of muscle fiber which travel all the way down to center of cell

Question 26

where is mitochondria located

Answer 26

in periphery and between myofibrils

Question 27

What forms myotubes

Answer 27

myoblasts which are made from progenitor cells.

Question 28

Each motor end plate of formed from;

Answer 28

presynaptic membrane

Question 29

describe features of muscle spindles

Answer 29

Proprioceptive elements to the muscles. They consist of spindle fibers within double capsule. Muscle spindle fibers involved with gamma motor neurons