Muscular SystemUnit F

1H06.01

Describe the structure of the muscles.

Muscular System Nearly half our

weight comes from muscle tissue.

There are 650 different muscles in the human body.

Muscles give us shape, posture, movement and form.

Muscles produce most of our body heat.

Types of MusclesSkeletal muscle Attached to bone. Striated (striped)

appearance. Voluntary. Multinucleated muscle cell

bundles (muscle cells = muscle fibers).

Sarcolemma = cell membrane.

Contract quickly, fatigue easily, can’t maintain contraction or long period of time.

Types of Muscles Cont.Smooth muscle. Visceral (organ) muscle. Found in walls of digestive

system, uterus and blood vessels.

Cells small and spindle-shaped.

Involuntary. Controlled by autonomic

nervous system. Act slowly, do not tire easily,

can remain contracted for long time.

Types of Muscle Cont.Cardiac muscle. Found only in the

heart. Striated and

branched. Involuntary. Cells are fused-

when one contracts, they all contract.

Muscle Anatomy

1H06.02 Analyze the function of the

muscular system

Characteristics of Muscles When a

muscle becomes shorter, thicker & causes movement, it is said to have?

CONTRACTIBILITY

Excitability (irritability)- the ability to respond to certain stimuli by producing impulses.

Extensibility- the ability to be stretched.

Elasticity- ability of muscle to return to its original length when relaxing.

Movement

As a muscle contracts, it pulls the insertion bone closer to the origin bone. Movement occurs at the joint between the origin and the insertion.Rule: A muscle’s insertion bone moves toward its origin bone.

1.Muscles move bones by pulling on them.

2. Groups of muscles usually contract to produce a single movement.

Movement Cont. Motor unit- a motor neuron

plus all the muscle fibers it stimulates.

Muscle Fatigue Muscle fatigue-

caused by the accumulation of lactic acid in the muscles.

Neuromuscular Junction Neuromuscular junction- the junction

between the motor neuron’s fiber which transmits the impulse-and the muscle cell membrane.

AcetylcholineIs a chemical neurotransmitter, diffuses across

the synaptic cleft

(carries impulse across synaptic cleft).

If a muscle cell is stimulated repeatedly without rest it

losses its ability to contract! This is called?

What thoracic muscle aids in breathing?

Muscles that are partially contracted at all times are

said to be in a constant state of what?

1H06.03 Identify characteristics &

treatment of common muscle disorders.

Disorders and Related Terminology

Atrophy- wasting away of

muscles.Massaging the muscle

helps atrophy.Failing to exercise can

makemuscles weak, flaccid

& cause them to

atrophy.

Myalgia- muscle pain.

Tendonitis- inflammation of a tendon.

Strain- tear in the muscle resulting

from excessive use. Bleeding inside

the muscle can result in considerable

amount of pain & swelling. Ice packs

will help stop the bleeding and

reduce swelling.

Sprain-stretched ligament

Hypertrophy- an increase in the size of the muscle cell.

A person who lifts weights &

overuses his muscles will

enlarge their size.

Muscle spasm (cramp)- sustained

contraction of the muscle, usually

because of overuse. Severe calf pain at

night is caused by muscle spasms.

Sphincter Special circular

muscles in openings of esophagus and stomach, stomach and small intestine, anus, urethra and mouth.

What muscle is found in the neck?

Major muscle that lies over the upper ribs?

Muscle that abducts the upper arm at the shoulder

joint?

Medical name for the calf muscle?

Circular muscles in the openings between the

esophagus & stomach are?

The main muscle in the lower back is the?

The main muscle of the upper back is the?

What muscle is found in the arm?

What muscle is considered VOLUNTARY?

Which kind of muscle forms the walls of the heart?

Joanie is experiencing oxygen dept. What has he

been doing?Oxygen debt- after exercise,

the amount of oxygen needed

by the muscle to change lactic

acid back to glucose.

If you want to improve your extensibility you should do

what every morning?