Ep - Ch 12 Muscle

Front 1

Structural proteins that anchor myosin during cotraction

Back 1

M Lines

Front 2

Elastic protein attaching myosin to Z disk that contributes to elastic recoil of muscle

Back 2

Titin

Front 3

Where a branch of an axon of a motor neuron meets the sarcolemma of a muscle fiber.

Back 3

Neuromuscular junction

Front 4

Includes the single synaptic ending of the motor neuron innervatin each muscle fiber

Back 4

Neuromuscular junction

Front 5

Number of muscle fibers in motor unit varies according to degree of fine control capability of the muscle

Back 5

Vary from 1:100 to 1:2000

Front 6

Fine control of muscles occurs when motor units are...

Back 6

Small...1 motor neuron innervates small # of fibers.

Front 7

Sliding Filament Theory

Back 7

The length of each filament remains the same...The A bands stay the same length

Front 8

Action potentials in T Tubules cause release of Cc from cisternae via V-gated Ca release channels called...

Back 8

Electromechanical release

Front 9

When Action potentials cease...

Back 9

Muscle relaxes because Ca channels close and Ca is pumped back into SR

Front 10

If muscle is stimulated by an increasing frequency of electrical shocks, its tension will increase to a maximum

Back 10

Incomplete Tetanus

Front 11

If frequency is so fast no relaxation occurs and a smooth sustained contraction occurs.

Back 11

Complete Tetanus

Front 12

Contractions of varying strength obtained by stimulation of varying numbers of muscle fibers (recruitment)

Back 12

Graded Contractions

Front 13

Exerted force does not cause load to move and length of muscle fibers remains constant

Back 13

Isometric Contraction

Front 14

Force (tension) remains constant throughout shortening process

Back 14

Isotonic Contraction

Front 15

Load is greater than exerted force and fibers lengthen

Back 15

Eccentric contraction

Front 16

Strength of muscle fiber contraction is influenced by...

Back 16

Frequency of stimulation, Thickness of each muscle fiber, and Initial length of muscle fiber (the longer the initial length the stronger the contraction)

Front 17

Skeletal muscles respire anaerobically the first _____ seconds of moderate to heavy exercise.

Back 17

45-90 seconds. Cardiopulmonary system requires this time to increase O2 supply to exercising muscle.

Front 18

Aerobic respiration contributes to majority of muscle requirements after the first 2 minutes in what type of exercise

Back 18

Moderate exercise

Front 19

Max O2 uptake is...

Back 19

Aerobic capacity is the max rate of O2 consumption and is determined by age, gender, and size and ranges from 12-84 ml of O2/minute/kg

Front 20

% of max O2 uptake at which there is significant rise in blood lactae levels

Back 20

Lactate (Anaerobic) Threshold

Front 21

50-70% of the Max O2 uptake

Back 21

Lactate Threshold

Front 22

During light exercise most energy is derived from aerobic respiration of ....

Back 22

fatty acids

Front 23

During moderate exercise, energy is derived equally from....

Back 23

fatty acids and glucose

Front 24

During heavy exercise energy supply is from...

Back 24

Glucose supplies 2/3 of energy and liver increases glycogenolysis

Front 25

Type 1 fibers

Back 25

SLow twitch, slow fatigue, aka red slow oxidative. Uses mostly aerobic respiration. Has rich capillary supply. Rich in mitochondria and aerobic enzymes. Has lots of myoglobin. Have small motor neurons with small motor units.

Front 26

Type IIA and IIX fibers

Back 26

Fast Twitch, white fast

Front 27

Type IIX Fibers

Back 27

Aka White fast glycolytic. Adapted to contract fast using Anaerobic metabolism. Have Lg stores of glycogen, few capillaries, and mitochondria, little myoglobin.

Front 28

Type IIA Fibers

Back 28

Aka White Fast oxidative. Adapted to contract fast using aerobic metabolism. Intermediate to Type I and Type IIX. Have Lg motor neurons with Lg motor units.

Front 29

Causes of muscle fatigue

Back 29

Accumulation of extracellular K. Depletion of glycogen stores. Accumulation of Lactic Acid.

Front 30

Occurs as brain is less able to activate muscles even when muscles are not fatigued is called...

Back 30

Central fatigue

Front 31

Adaptations of muscles to exercise training...Aerobic training improves...

Back 31

Aerobic capacity by 20%
Lactate threshold by 30%

Front 32

Weight training increases muscle size by...

Back 32

Increasing # of myofibrils/fiber. and in some cases fibers can split.

Front 33

Motor neuron cell bodies are in ventral horn of spinal cord..axons leave in ventral root and are called...

Back 33

Lower motor neurons.

Front 34

Information of tension is from...

Back 34

Golgi tendon organs

Front 35

Info on length of muscle is from...

Back 35

Muscle spindle apparatus.

Front 36

Muscle spindle apparatus consists of modified thin muscle cells called

Back 36

Intrafusal fibers

Front 37

Regular muscle fibers are called

Back 37

Extrafusal fibers

Front 38

Stimulation of muscle spindle causes

Back 38

Reflex contraction of muscle

Front 39

These innervate extrafusal fibers and cause muscle contraction

Back 39

Fast conducting Alpha motor neurons.

Front 40

These innervate and induce tension in intrafusal fibers (active stretch) - Increases sensitivity of muscle to passive stretch

Back 40

Slower conducting Gamma Motor Neurons

Front 41

Upper motor neurons usually stimulate alpha and gamma motor neurons simultaneously ...called

Back 41

Coactivation

Front 42

Stimulation of alphas results in...

Back 42

muscle contraction and shortening

Front 43

Stimulation of Gammas...

Back 43

helps to maintain normal muscle tone.

Front 44

Monosynaptic-stretch reflex

Back 44

Consists of only one synapse within CNS = Knee jerk reflex
-

Front 45

Involves 2 synapse in the CNS. Sensory axons from golgi tendon organ syapse on interneurons which make inhibitory synapses on motor neurons

Back 45

Golgi Tendon organ reflex or Disynaptic Reflex

Front 46

Prevents excessive muscle contraction or excessive passive muscle stretching

Back 46

Golgi Tendon organ reflex

Front 47

Interneuron inhibits motor neurons of antagonistic muscles...when limb is flexed antagonistic extensors are inhibited from doing stretch reflex

Back 47

Reciprocal innervation

Front 48

Sensory impulses travel to stimulate motor neurons on both sides of the spinal cord

Back 48

Crossed-extensor reflex

Front 49

Means on the same side

Back 49

Ipsilateral

Front 50

On the opposite side

Back 50

Contralateral

Front 51

Pyramidal tracts are formed by

Back 51

Axons of neurons in precentral gyrus

Front 52

Extrapyramidal tracts arise from

Back 52

Neurons in other areas of brain

Front 53

Recieves sensory input from spindles, golgi tendon organs, and areas of cortex devoted to vision, hearing and equilibrium

Back 53

Cerebellum

Front 54

All output from cerebellum is...

Back 54

inhibitory...aids motor coordination.

Front 55

Exert inhibitory effects on activity of lower motor neurons

Back 55

Basal ganglia (nuclei)

Front 56

Characteristics of smooth muscle

Back 56

No sarcomeres, has gap junctions, Contains 16x more actin than myosin (allowing greater stretch and contract) + Actin Filaments are anchored to dense bodies.