TEAS 7 muscular system

Anatomy

Function

Allow body to move, support & stabalize the body, provide protection, & produce heat

• Composed of muscle cells & tissues that bring about movement of organs or body parts

Muscles

Fibrous tissue with the ability to contract to move body parts

Cardiac muscle

Involuntary control - controlled by autonomic nervous system

• Strong

• HEART tissue that pumpd blood throughout the body

• Has banded striations caused by protein fibers

• Has branched structure and intercalated discs that allow electrical impulse conduction (Allows heart to beat)

Smooth muscle

Involuntary control - controlled by autonomic nervous system

• Weakest muscle type

• Narrow, spindle shaped cells w. a single centrally located nucleus

• Found in digestive system, veins, arteries, bladder, & eyes

Skeletal muscle

Voluntary control - Controlled by somatic nervous system

• Highly organized tissues that attach to bones or skin to produce movements

• Found in tounge, diapragm, upper esophogus

• Striated, strong muscle cells

• Fibers are long, straight, & multinucleated

Key characteristic of all muscle types

Extensibility

• Muscle can be stretched or extended

Elasticity

• Muscle can return to original length when relaxed

Excitability

• Muscle can respond to stimulus from a motor neuron or hormone

Contractability

• Muscle can shrink or contract

Sacromeres

The basic unit of striated muscle (skeletal and cardiac muscle)

• microscopic segment that allows muscles to generate force and contract

• Thin & thick filaments don’t shorten, they slide

• bordered by Z discs and contains overlapping protein filaments: thin actin and thick myosi

Process of muscle contraction

1. Nuerons signal originates in the CNS (the brain or spinal cord)

2. Travels outward via motor neurons (a part of the Peripheral Nervous System) to the muscles.

3. A sarcomere is bordered by Z discs and contains overlapping protein filaments: thin actin and thick myosin. Muscles contract when these filaments slide past each other, pulling the Z discs closer and shortening the sarcomere

• Actina nd myosin stay the same length

Actin

Thin filaments

• Protein that forms the contractile filaments of muscle cells

Myosin

Thick filament

• Fibrous globulin of muscles that can split ATP & react to actin in muscle contraction

Muscular system disorders

Muscular dystrophy- Gentic disorder

• Abnormal genes interfere with protein production needed to form healthy muscles

• Muscles progressively degenerate and weaken

• Compromises both voluntary and involuntary movement

Muscle strain- Injury

• Stretching/ tearing of muscles

Muscle sprain- Injury

• Injury to supporting tendons & ligaments of a msucle

Tendonitis-

• Inflammation of tendon

Amyotrophic lateral sclerosis (ALS)- Lou Gehrig’s disease

• Motor nuerons degenerate and die, causes loss of voluntary movement.

• Spinal cord injuries, Viral infections (polio), & bacterial infections (Tetanus & botulism) can also affect muscles