Muscles

What type of control are skeletal muscles

What type of control are skeletal muscles

voluntary

Shape description of a skeletal muscle cell

long, multinucleate with striations

where is skeletal muscle found

attached to bones and sometimes skin

where is smooth muscle found

in the walls of hollow organs such as the intestine and esophagus

what type of control is smooth muscle

involuntary

description of smooth muscle

uninucleate with no striations

where is cardiac muscle found

in the heart

what kind of control is cardiac muscle

involuntary

description of cardiac muscle cell

branching chains, uninucleate, striated and has intercalated discs

what is the endomysium

connective tissue that surrounds a single muscle fiber

what is the perimysium

connective tissue that surrounds a fascicle (bundle) of muscle fibers

what is the epimysium

connective tissue that covers the entire muscle

what is a sarcolemma

specialized plasma membrane for the muscle fiber

What is the I band

contains thin filaments, also called the light band

what is found in the light band

actin

what is the midline called in the light band

Z disc

What is the A band

contains thick filaments, also called the dark band

what is found in the dark band

myosin

what is the central area of the dark band called

H zone

what is the center of the H zone called

M line

what is a sarcomere

the structural and functional unit of the muscle fiber

what is sliding filament theory

how a muscle contracts

states that myosin hooks onto the actin and pulls it inwards towards the M line during muscle contraction

Characteristics of muscle fibers

irritability, contractability, extensibility, elasticity

One motor neuron can stimulate…

very few or very many muscle fibers

what is a motor unit

a motor neuron and all of the skeletal muscles that it stimulates

the axon terminal of a neuron connects to…

the sarcolemma of the muscle

the junction between the axon terminal and the sarcolemma is called

the neuromuscular junction

a neurotransmitter is

a chemical released by a nerve upon the arrival of a nerve impulse

what is the synaptic cleft

the space between the axon and the sarcolemma

what happens when the nerve impulse reaches the axon terminal

calcium channels open and calcium enters the axon.

what happens when calcium enters the axon terminal

the vesicles release neurotransmitters

what is the fastest way to provide energy for muscle contraction

direct phosphorylation of creatine phosphate

what is direct phosphorylation of creatine phosphate

creatine phosphate transfers a phosphate group to a molecule of ADP to convert it back into ATP

how much more creatine phosphate do muscle fibers store compared to ATP

5x more

how fast is the creatine phosphate storage exhausted

< 15 seconds

how many molecules of ATP is produced per molecule of creatine phosphate

1

what is the aerobic pathway to provide muscles with energy

oxidative phosphorylation

what is oxidative phosphorylation

glucose is broken down into pyruvic acid which causes aerobic respiration which leaves a product of CO2 and water

how much ATP does oxidative phosphorylation produce

32

why is oxidative phosphorylation slower than direct phosphorylation of creatine phosphate

because it requires a constant supply of nutrients and oxygen

what is a anaerobic pathway to supply muscles with energy

glycolysis and lactic acid formation

how does glycolysis and lactic acid formation occur

glucose is broken down into pyruvic acid without the use of oxygen which results in 2 ATP. The pyruvic acid is turned into lactic acid and then released into the blood

what are isotonic muscle contractions

myofilaments are able to slide past each other during muscle contraction

muscle shortening and movement occurs

what are isometric muscle contractions

myofilaments are unable to slide past each other

muscles do not shorten but tension is present

aerobic exercise results in

stronger, more flexible muscles that have a greater resistance to fatigue

aerobic exercise improves

metabolism, digestion and coordination

resistance exercise results in

increased muscle size and strength

what is muscular dystrophy

lack of protein in muscle fibers leads to the inability to maintain the sarcomere. progressive weakness and muscle degeneration results

what is myasthenia gravis

a deficiency in acetylcholine receptors due to having an antibody against Acetylcholine

can lead to respiratory failure