week 4 study guide

Question 1

describe cardiac muscle

Answer 1

only in the heart.

Question 2

is cardiac muscle striated

Answer 2

yes

Question 3

does the cardiac muscle need nervous system stimulation of contract

Answer 3

no

Question 4

is cardiac muscle voluntary or involuntary

Answer 4

involuntary

Question 5

where is skeletal muscle found

Answer 5

organs attached to the bones and skin

Question 6

what are the fibers of skeltal muscles called

Answer 6

muscle fibers

Question 7

are skeletal muscles striated

Answer 7

yes

Question 8

are skeletal muscles under conscous control

Answer 8

yes, they are voluntary

Question 9

do skeletal muscles require nervous system stimulation

Answer 9

yes

Question 10

where is smooth muscle found

Answer 10

in the walls of hollow organs like the stomach urinary bladder and airways

Question 11

is smooth muscle striated

Answer 11

no

Question 12

does smooth muscle require nervous system stimulation

Answer 12

no

Question 13

is smooth muscle voluntary

Answer 13

no , it is involuntary

Question 14

what is excitablity

Answer 14

ability to recieve and respond to stimuli

Question 15

what is contractability

Answer 15

ability to shorten forceably when stimulated

Question 16

what is extensibility

Answer 16

ability to be stretched

Question 17

what is elasticity

Answer 17

ability to recoil to resting length

Question 18

list the 4 important functions of muscles

Answer 18

movement of bones or fluid
maintaining posture and body position
stabilizing joints
heat generation

Question 19

list the 3 connective tissue sheaths that protect muscles

Answer 19

epimysium- surrounds entire muscle
perimysium-surrounds fasicles
endomysium-surrounds each muscle fiber

Question 20

name the 2 kinds of muscle attachments

Answer 20

insertion

origin

Question 21

what kind of attachment is an insertion

Answer 21

moveable bone

Question 22

what kind of attachment is an origin

Answer 22

immovable bone

Question 23

explain sliding filament model

Answer 23

the sliding filament model in contraction- the filaments overlap only at the ends of the A band. Essentially when a muscle is contracting the filaments slide past each other (the thin filament will slide past the thick filament) this causes more overlap because there is more overlap we know that it will have contracted. When there is contraction, the myocin heads connect to the actin and they pull, this causes the sarcomere to contract and shorten. The distance between 2 zdisks will shorten.

Question 24

what are troponin and trophomyosin

Answer 24

they are regulatory proteins that are bound to the actin. When a muscle fiber is stiumlates, it sets of a whole series of reactions and it removes the trophpmyocen out of the way so that they attachment.

Question 25

why do we see muscle striations

Answer 25

striations are there because myofibals are lined up in a certain pattern that causes them

Question 26

describe myacin

Answer 26

myacin filaments -are the thick ones, they extend the length of the a band and connected and the end line. the myacin molecule has heads and tails. each one has a tail made up of interwoven polypeptide chains. it has 2 heads. the heads act as a cross bridge where the muscles contract. when stimulated it uses atp to bind to the binding site on the actin filament. when it binds it creates a cross bridge. myocin is located int he middle and actin is on either side

Question 27

describe actin

Answer 27

ACTIN- twisted there are subunits have active cites where the myocin can bind . The active site is a place where the myocin can bind to . Only myocin would be able to bind there. Myocin will only be able to get there if it is not blocked by troponen and trophomyocin. when a muscle is relaxed, the active site is blocked by those to . if an action potential is generated, a chemical reaction will take place and move trophomin and tophoomyocin out of the way and myosin will be able to bind to the actin.