BIOS 1300 unit 4 exam

Twitch

single contraction of one muscle fiber produced by single stimulus

• 7-100ms

Twitch sequence

stimulus

contraction

relaxation

Muscle fiber types

Fast glycolytic

Fast oxidative-glycolytic

Slow oxidative

Fast glycolytic

Fastest twitch

fastest myosin 

glycolysis for ATP

quick bursts

fatigues quickly 

Fast oxidative glycolytic

Both aerobic respiration and glycolysis

fast myosin

fatigues less quickly

Slow oxidative

Aerobic respiration

slow myosin

low fatigue

Twitch 3 phases

Latent

contraction

relaxation

Latent period

Between stimulus and contraction

AP propagates

Ca released

Contraction

Cross bridge cycle

Relaxation

Ca pumped back into SR

Cross bridge detach

Treppe

next stimulus comes at end of previous

increase max tension to over 30-50 stimuli

Wave summation

next stimulus comes before previous relaxation is over

Incomplete tetanus

sustained high frequency of stimulation

wave summation

reaches plateau

quick periods of partial relaxation

Complete tetanus

Very high frequency of stimulation

no relaxation

rapid APs

sustained high Ca in sarcoplasm

Muscle contraction

tension generated by muscle

= the sum of tensions generated by its fibers

Variation in tension of muscle 

frequency of stimulation 

number of fiber contractions at once

Motor units

1 motor neuron and all the fibers it controls

small MU

4-6 fibers

Ex) eye muscle

large MU

1000-2000 fibers

Ex) rectus femoris

MU intermingled

distribute force on tendon

Isometric

muscle generates tension

does NOT shorten

Isotonic

muscle generates tension

muscle changes length

Concentric

shortens

Eccentric

lengthens

Functions of the nervous system

Sensory

integration

motor

Sensory

recognize changes in environment

Integration

analysis of sensory info

info storage

decisions

Motor

signals to effectors (muscles or glands)

Organization of the Nervous system

Central

Peripheral

cranial nerves 

Sensory division

input into CNS

somatic

special

Somatic senses

touch

nociception

proprioception

special senses

sight

hearing 

taste

smell

motor division of PNS

motor output from CNS

somatic- voluntary

autonomic- involuntary

Autonomic

Sympathetic- fight or flight

Parasympathetic- rest and digest

smooth and cardiac muscle and glands

Enteric

controls digestive system

smooth muscle and glands of GI tract

Nerves

bundles of axons

• from multiple neurons

Nerves made of

axons

schwann cells

CT

blood vessels

no neurosomas

Neurosomes in:

ganglia

spinal cord

brain

Nerves inside brain?

no

Cell bdy 

neurosoma;soma