HAP Muscular System Quiz

The smallest unit of contraction of muscle (from one z line to the next z line) is the

Sarcomere

a muscle cell is also known as?

fiber

the structure(s) responsible for giving skeletal muscle a striated appearance

actin and myosin

In a muscle cell "I" bands are

light
made up of actin only
shortens after contraction

In a muscle cell "A" bands are

dark
made up of thin and thick filaments
stays the same after contraction

h zone

thick filaments only
shortens with contraction

z lines

The ends of a sarcomere.
Move closer together after contraction

Calcium

released by sarcoplasmic reticulum and binds troponin

Acetylcholine

the neurotransmitter release at the neuromuscular junction signaling a muscle contraction

Tropomyosin

covers binding sites on actin when a muscle is relaxed

rotator cuff injury

Tears in tendon and/or muscle due to repeated overhead motion or by acute injury of the shoulder

muscle spasm/cramp

Myosin heads do not detach from binding sites on actin sudden involuntary contraction

sprain

Overstretching of a ligament in a synovial joint

Tendinosis/Tendinitis

Degeneration of the tendon's collagen in response to chronic overuse

Muscle strain

Stretching or tearing a muscle or tendon

mitochondrial myopathy

Damage to organelles necessary to sustain aerobic production of ATP results in exercise intolerance.

cerebral palsy

A brain injury during fetal development. lack of muscle coordination, tone and balance.

poliomyelitis

virus causing skeletal muscle paralysis.

muscular dystrophy

Mutation in the DMD gene that encodes a protein that helps stabilize and protect muscle fibers. The disease is characterized by very weak muscles that can not sustain weight.

Amylotrophic Lateral Sclerosis

a progressive disease that affects motor neurons, which are specialized nerve cells that control muscle movement. Over time motor neurons die, leading to muscle weakness, a loss of muscle mass, and an inability to control movement.

Tetanus

Infection by a toxin producing bacteria. toxin interferes with the normal function of the neuromuscular junction causing spastic paralysis of skeletal muscles

Myesthenia Gravis

autoimmune disorder where antibodies attach acetylcholine receptors on the sarcolemma of muscle cells resulting in skeletal muscle weakness.

Fibromyalgia

Chronic pain, stiffness, and tenderness of muscles, tendons, and joints, without detectable inflammation.

Parkinson's disease

Degenerative movement disorder due to loss of dopamine in areas of the brain involved in the planning and execution of movement.

The origin of a muscle is considered to be?

where it attaches to the immovable bone

The insertion of the muscle is considered to be?

Where the muscle attaches to the movable bone

When a muscle contracts what happens?

insertion moves toward origin
the muscle shortens

What are the antagonistic pairs to know

Platysma and masseter
Deltoid and Latissimus dorsi
Biceps femoris and Rectus femoris
Biceps brachii and Triceps brachii

flexion

Decreases the angle of a joint

abduction

movement away from the midline

adduction

Movement toward the midline

extension

increases the angle of a joint

plantarflexion

Ankle movement pointing the foot downward

Triceps brachii function?

extension at the elbow

Latissimus dorsi function?

adducts the humerus

Rectus femoris function

extension at the knee

Orbicularis oris function?

closes and protrudes lips

Biceps brachii function?

flexion at the elbow

Masseter function?

elevates the mandible

Deltoid function?

abducts the humerus

Orbicularis oculi function

closes the eye

Soleus function?

plantarflexion at the ankle

Biceps femoris function?

flexion of the knee

Platysma function?

depresses the mandible

Sliding Filament Mechanism of Muscle contraction

states that skeletal muscle shortens as the thick and thin filaments slide past one another. During a muscle contraction, myosin heads pull on the thin filaments, causing them to slide inwards towards the H zone. The filaments slide past one another. In muscle contractions, sarcomeres actually shorten.