Muscles

Question 1

detail traits of smooth muscle cells

Answer 1

single nucleus
spindle shaped
not striated
simple
around blood vessels and intestines
involved in blood flow, emptying bladder, and digestion

Question 2

detail traits of cardiac muscles

Answer 2

branches
striated
only in heart
connected via gap junctions
can self depolarize/beat spont

Question 3

detail traits of skeletal muscles

Answer 3

striated
control voluntary movements
large, multinucleated
can’t extend muscles…can only relax or contract
a muscle fiber equates to a cell
each fiber is packed w/ bundles of myofibrils
each myofibril has sarcomeres

Question 4

functions of diff sarcomere things

Answer 4

Z lines are the boundaries; anchor actin
A band is band of myosin in the middle (w. overlapping actin)
M band has proteins that support myosin filaments
H, I bands are non overlapping actin and myosin
H band is just myosin
I band is just actin

Question 5

how are bundles of myosin held together?

Answer 5

in register by titin that runs all along through sarcomere, Z line to Z line though myosin

Question 6

which bands elongate or narrow in contraction

Answer 6

A band elongates….eh kinda

I band narrows

Question 7

anatomy of myosin molecule

Answer 7

2 polypep chains coiled together, each w a globular head

Question 8

what properties do the mysosin heads exhibit

Answer 8

ATPase. hydrolyzing

Question 9

anatomy of actin molecule

Answer 9

2 chains of f actin twisted
troponin- a 3 subunit molecule that binds to Ca+2, tropomyosin, and actin; sim to calmodulin
tropomyosin wraps around actin and masks myosin binding sites

Question 10

what energy conformatin does myosin bind to actin w

Answer 10

high energy, releases at low energy

Question 11

what constitutes a motor unit

Answer 11

a motor neuron and all the muscle fibers it branches to and synapses w

Question 12

function of SR?

Answer 12

Ca+2 store, intracellular

Question 13

T/F: muscle cells are excitable

Answer 13

T

Question 14

detail muscle contraction

Answer 14

AP down axon that releases ACh in neuromuscular junction…AP propagated down muscle fiber and T tubule which are next to SR…conformational change of Ca+2 channels–> open –> influx into cytoplasm–> binds to troponin which pushes tropomyosin off myosin binding sites–> When myosin bound to ATP, low energy–> hydrolyze and high energy, bind to actin–> release hydrolyzed ATP and slides–> ATP binds and releases actin–> start all voer

Question 15

Explain rigor mortis

Answer 15

dec ATP = Ca+2 pumps not working, so excess Ca+2 in cytoplasm–> cross bridges form, can’t unform–> muscle rigidity due to contraction of muscles on both sides of joints

Question 16

3 major factors for determining TOD for forensics

Answer 16

body temp, rigor mortis, blood settling

Question 17

what happens after rigor mortis?

Answer 17

proteases chew up actin and myosin, no more cross bridges so limp

Question 18

What is tetanus? and how is it diff from RM

Answer 18

max muscle contraction

doesnt occur n both sides of joint

Question 19

what are the 2 major groups of muscle fibers

Answer 19

oxidative (Type I red) and glycolytic (Type IIb white)

Question 20

what are the traits of oxidative muscle fibers

Answer 20

many mito and myoglobin; long term aerobics like swimming and running

Question 21

what are the traits of glycolytic fibers

Answer 21

fewer mito and myoglobin, myosin has high ATPase but can’t replenish aTP fast enough to sustain; sudden and max strength, sprinting

Question 22

effect of weightlifting on myosin and actin?

Answer 22

increases number, DOESNT inc number of muscle cells

Question 23

effect of aerobic exercise?

Answer 23

inc capillary density in muscles, inc myoglobin and mito

if occurs in fast twitch fibers, can convert from glycolytic fast twitch type IIb to oxidative fast type IIa

Question 24

what are the 2 types of oxidative fibers

Answer 24

Type 1 Red: slow oxidative, lots of myoglobin, slow contraction, fatigue resistant, many mito, split ATP slowly
Type IIa Red: fast oxidative, lots of myoglobin, faster contraction, fatigue resistant, many mito, split ATP quickly

Question 25

what is the glycolytic muscle fiber

Answer 25

Type IIb White: fast glycolytic, low myoglobin, few mito, fatigue easy, lots of glycogen, splits ATP quickly

Question 26

what does curare do

Answer 26

paralyses muscles by blocking ACh from reaching receptors
an antagonist to ACh
asphyxiation from paralysis of diaphragm muscles

Question 27

botulism

Answer 27

7 toxins, A-G
blocks ACh release
botox tradename for Botulism A
Botulism A affects SNAP-25
not permanent