Muscle Tissue

Question 1

3 types of muscle

Answer 1

skeletal, cardiac, and smooth

Question 2

Sarcomere

Answer 2

contractile unit of striated muscle. Expands from one Z disc to the next Z disc

Question 3

G-actin

Answer 3

globular actin monomer. assembles to form a polymer that kinda looks like a string of beads

Question 4

Filamentous actin

Answer 4

two polymers twisted together

Question 5

Thin filaments

Answer 5

made up of actin and troponin

Question 6

Tnt

Answer 6

attaches to tropomyosin

Question 7

TnC

Answer 7

binds calcium ions during muscle contraction

Question 8

TnI

Answer 8

attaches to actin monomer to block actin/myosin interation

Question 9

Tropomyosin

Answer 9

consists of two polypeptide chains that come together to form an alpha helix.

Question 10

Myofibril

Answer 10

sacromeres attached to one another to form a large cylindrical series

Question 11

Vesiculus

Answer 11

msucel fibers come together to form these

Question 12

A-band

Answer 12

Dark band. contains thick and thin filaments. bisected by H band

Question 13

I band

Answer 13

contains only thin filaments

bisected by Z disc

Question 14

H band

Answer 14

contains only thick filaments

Question 15

Sarcomere accessory proteins

Answer 15

attach, space, and align myofilaments for an even, prcise and orderly arrangment. HOld think and thick filaments in place

Question 16

Nebulin

Answer 16

nonelastic protein. 2 molecules hold thin filament in place

Question 17

Titin

Answer 17

elastic protein. HOlds thick filament in place. Acts like an ianchor

Question 18

Myomesin and c prtein

Answer 18

hold thick filaments in place

Question 19

Endomysium (reticular fibers)

Answer 19

delicate layer of connective tissue. surrounds each muscle cell/fiber

Question 20

Perimysium Icollagenous CT)

Answer 20

surround each bunch/bundle of muscle cells

Question 21

Epimysium (collagenous CT, deep fascia)

Answer 21

surrounds many bundels

Question 22

Skeletal muscle

Answer 22

voluntary control.

Question 23

T-tubules

Answer 23

run peripendicular to longitudinal acis of cell. Open into extraceullular space. Lumen is continuous.

Question 24

Triad - at A-I of sarcomere

Answer 24

two terminal cisternae with a T-tubule. Contain calcium in lumen for muscle contraction

Question 25

Axon terminal branches

Answer 25

nerve branch has dilated structure closely attached to skeletal muscle cells/fibers

Question 26

Myoneural junction

Answer 26

point of contact between terminal and cell

Question 27

Presynaptic terminal

Answer 27

contains synaptic vesciles.

Question 28

Moto unit

Answer 28

nerve cell and all the muscle fibers it innervates

Question 29

Myasthenia Gravis

Answer 29

autoimmune disease. Autoantibodies inferfere with muscle contraction. Specifically fucks with actylcholine

Question 30

Duchenne Muscular Dystrophy

Answer 30

affect striated muscle. Most common and most severe form.

Question 31

Purkinje Gibers

Answer 31

specialized cardiac muscle fibers. Relay electrical impulses to regular cardiac muscles to cause contractino. Located in endocardium

Question 32

Smooth muscle

Answer 32

No sacromere. No alternating light and dark bands. Cells packed very tightly, without extracellular space. Has euchromatic nucleus located in wider part of cell

Question 33

Smooth muscle cells

Answer 33

Has caveolae on interior surface of cell membrane to release Ca++ into cell fo rtraction. Pinocytotic vesciles located all along inner surface of smooth muscle membrane.

Question 34

Dense bodies

Answer 34

found in smooth muscle cells. Can either be anchored to inner surface of cell membrane or locacted at point of contact of myofilament bundles imbedded within the cytoplasm.

Question 35

What happens to nucleus when smooth muscle contracts

Answer 35

It curls

Question 36

How does nerve impulse spread in skeletal muscle

Answer 36

Sweep oer entire sarcolemma, comes to openings of T-tubules along sacrolemma surface. Spread deep into muscle. Changes permeability of sarcoplasmic reticulum

Question 37

Myofibrils

Answer 37

found in cytoplasm. Made of sarcomeres

Question 38

How is Ca++ released

Answer 38

by terminal cisternae on myofibril surface

Question 39

What does Ca++ do

Answer 39

binds to TC subunit, changes confirmation of troponin. TnT bound to tropomyosin pushes tropmyosin filament deeper into groove on actin filament. Myosin biding site of actin monomer on the actin filament is exposed. This whole process requires ATP

Question 40

What happens during muscle contraction

Answer 40

- Thick filaments pull on thin filaments and slide over them - Globular heads attach to thin filament actin sites and drag them to midline - Z-discs get closer to each other and closer to midline - The length of the thick and thin filaments stay the same.