BIO 245 FULL LECTURE EXAM

A

Z Discs

B

I band

C

A band

D

H zone

E

M line

Skeletal Muscle Histology

Cells long and linear, 100s of nuclei per cell, Striated, Many mitochondria, somatic NS

Cardiac Muscle Histology

Cells short and branch, 1-2 nuclei per cell, Striated, Many mitochondria, Intercalated discs= gap junctions, autorhythmic= Starts its own contractions, Autonomic NS

Smooth Muscle Histology

Fusiform shaped, No transverse tubules, Little sarcoplasmic reticulum and Rely on calcium that is outside, Non-striated

can respond to stimulus by changing electrical membrane potential

Excitability

can send electrical charge down the length of the muscle fiber membrane

Conductivity

muscles can shorten and cause movement

Contractility

can stretch

Extensibility

can return to original length after it lengthens or shortens

Elasticity

Epimysium

wraps whole muscle

Perimysium

wraps a fascicle

Endomysium

wraps individual fiber

cords of dense regular ct, muscle to bone

tendons

thin flat sheet of dense irregular tissue

Aponeurosis

deep fascia

superficial to the epimysium, separates individual muscles, binds muscles with similar functions

superficial fascia

superficial to the deep fascia, Separates muscles from skin

triad

2 terminal cisternae + 1 T-tubule

Connectin

From Z disc to M line, Springlike structure with passive tension

Dystrophin

Anchors some of the myofibrils

Motor End Plate

Region of sarcolemma with many ACh receptors, ACh binds, opens the channel for

Na+ to enter and K+ to exit

myokinase

ADP + ADP = ATP + AMP, transfers 1 phospahte from 1 adp to make atp, few secs

creatine phosphate

high energy bond btween creatine & phosphate, phosphate can be transferred to ADP to form atp, 10-15 sec

glycolysis

anaerobic, glucose to pyruvate make 2 atp, cytosol, 30 sec

aerobic cellular respiration

req oxygen, mitochondria, makes 30 net ATP, takes longer

lactate formation

from pyruvate when no O2, lactate be used for fuel, sent to liver converted to glucose lactate build up bad, cause fatigue

rigor mortis

dead no atp made, calcium leaks bc membrane breakdown and muscle contracts, once atp all used up muscle stay contracted, stiff

fiber contraction power

power depends on diameter, thicker= stronger

oxidative fiber

aerobic respiration, fatigue resistant, capillaries oxygen supply, red meat

glycolytic fiber

anaerobic respiration, fatigable, build up lactic, few capillaries/ mitochondria, white meat

slow oxidative fiber

type 1, slower, less powerful contraction, high endurance, fatigue resistant, red, half diamater as other

fast oxidative fibers

type 2a, intermediate, fast, powerful contraction, intermediate size, light red

fast glycolytic fibers

type 2x, fast anaerobic, fast powerful contraction brief, fatigue, largest, white

long distance runner fiber

slow oxidative fiber

sprint runner fiber

fast glycolytic fiber

wave summation

temporal summation, cannot relax btwn twitches, higher tension produced

incomplete tetanus

freq incrs beyond wave summation, get partial fusion of twitches

complete tetanus

freq incr even further, tension fuses, no relaxation

isometric contractions

length no change, tension gen but cannot overcome resistance

isotonic contractions

muscle tension overcome resistance, muscle length changes

concentric

muscle shortens, isotonic

eccentric

muscle lenghtens, isotonic

length tension relationship

resting length has optimal overlap of think and thick filaments and generate maximum force

endurance exercise

cardio, lead to better ATP production, have more mitochondria

resistance exercises

weight lifting, lead to hypertrophy, incr size

lack of exercise

muscle atrophy

aging

lose muscle w age, less ability to recover w injury

motor unit order

small motor unit recruited before large motor unit

small motor unit

less than 5 muscle fibers, precise

large motor unit

thousands of muscle fibers, large force production

thick filaments

myosin

thin filaments

actin, has myosin binding sites, has tropomyosin & troponin proteins