Biology 2 muscle system

Myology

Study of muscles

Voluntary movement

Movement we choose to perform

Involuntary movement

Reflexes and organ activities that occur without conscious control

Cardiac beat

The involuntary contraction of the heart muscle

Digestive tract peristalsis

Involuntary muscle contractions that move food through the digestive system

Flexor

Muscle that bends a joint

Extensor

Muscle that straightens a joint

Kinetic Energy

Energy of motion produced by muscles

Carbohydrates

The first source of energy for muscles, burning cleanest

Muscle functions

Muscles help maintain posture, adjust to temperature changes, and facilitate movement

Antagonist muscles

Muscles that work in opposition to each other

Neuromuscular junction

The site where a motor neuron connects with a muscle fiber

Effects of exercise on muscles

Exercise influences muscle strength, endurance, and overall health

Muscle structure

The physical composition and arrangement of muscle tissue

Skeletal muscles

Striated muscles that are under voluntary control

Muscle disorders

Conditions affecting muscle function and health

epimysium

fibrous connective tissue surrounding a muscle

fasciculi

bundles of nerve or muscles fibers bound together by connective tissues

perimysium

connective tissue enveloping bundles of muscle fibers

fibers

individual cells that make up fasciculus surrounding each muscle cell

endomysium

thin connective tissue surrounding each muscle cell

myofibrils

rod like bundle of contractile filaments (myofilaments) found in muscle cells

myofibillae

cells that make up the myofibril

actin

thin protein filament

myosin

thick protein filament

actinmyosin

compound formed during a contraction caused by sliding-filament theory

sarcoplasm

muscle cytoplasm

sarcoplasmic reticulum

specialized network of canals that feeds the muscle (muscle version of endoplasmic reticulum)

sarcomere

functional unit of contraction

Irritability

react to stimuli (varies)

Contractibility

muscles get shorter, 'pull' (how they work)

Extensibility

reverse of a contraction; conditions for flexibility

Elasticity

stretch and return to normal without damage to the muscles (like a rubber band)

Red muscles

extensors (type 1) that contain muscle myoglobin (muscle hemoglobin) which carries O2 to the mitochondria

Slow twitch

muscle fibers that are more resistant to fatigue and are used for endurance activities

Hemoglobin

Iron pigment in red blood cells that carries O2/CO2.

Myoglobin

Muscle hemoglobin that carries O2 to the mitochondria.

Pale muscles

Muscles that are less red in color due to a mixture of red and white fibers, tire quickly, and are deficient in myoglobin.

Type 2 muscles

Fast twitch muscles that react quickly but tire easily due to great demand for oxygen.

Neuromuscular junction (NMJ)

The synapse between a motor neuron and a muscle fiber.

Motor Unit

A nerve and all the muscle fibers it controls.

Acetylcholine (ACH)

A neurotransmitter that bridges the neuromuscular junction.

Cholinesterase

An enzyme that neutralizes acetylcholine.

Motor end plate

The end of a motor neuron within a muscle that triggers action.

Energy for muscle contraction

Energy obtained from sources in order of use: Creatine Phosphate, Aerobic Cellular Respiration, Anaerobic Glycolysis, Ketones.

Creatine Phosphate (CP)

A compound that can release energy during times of great demand.

Glycolysis

A process that can release energy from the breakdown of glycogen, which can occur with or without oxygen.

Oxygen debt

A condition that builds up lactic acid due to insufficient oxygen.

Kymograph

A device used to record changes over time, such as muscle contractions.

Myogram

A device used to measure the force of a muscle contraction.

Latent period

The time between the application of a stimulus and the beginning of muscle contraction.

Contraction

The actual muscle response where fibers contract (actin + myosin = actinmyosin).

Recovery

The process of a muscle returning to its normal position and being supplied with oxygen to produce energy.

All or none principle

Muscles cannot partially contract.

Liminal (threshold) stimulus

The weakest stimuli needed for a contraction.

Subliminal (sub threshold)

Stimuli that are not strong enough to cause a response.

Summation of Twitches

The process where each stimulus adds to the previous one, increasing the strength of contraction.

Hypertrophy

The enlarging of muscle diameter by adding more volume to cells.

Atrophy

The shrinking of muscles, making them almost useless due to lack of use.

Isotonic exercise

Weight resistance training that tones muscles.

Isometric exercise

Tightening of muscles without changing their length.

Myasthenia gravis

A disorder characterized by weakness in the skeletal muscles.

Muscular dystrophy

A group of genetic diseases that cause progressive weakness and loss of muscle mass.

Tetanus

A bacterial infection that causes muscle stiffness and spasms.

Cerebral palsy

A group of disorders that affect movement and muscle tone, often caused by damage to the brain.

Paralysis

The loss of the ability to move one or more muscles.

Myositis

An inflammation of the muscles.

Spasms and cramps

Involuntary muscle contractions that can cause pain.