MUSCLES!

After this powerpoint…

• You can:• Define what muscle is made of• Explain where they are found• Classify the three types of muscle

Vocabulary:• Contractile – To become reduced in size

by or as if by being drawn together

• Fascia – connective tissues that surrounds muscles, groups of muscles, blood vessels, and nerves, like cling-wrap to a bunch of sandwiches

• Tendon – A tough band of fibrous connective tissue that usually connects muscle to bone.

Vocabulary• Epi- (prefix): on top of• Peri- (prefix): about or around• Endo- (Prefix): within or inside• Myo- (Prefix): muscle• Sarco- (Prefix): flesh

Muscle

• Muscle is a contractile tissue of animals (including humans)

Why are muscles important? (remember MPH!)

Function 1: Movement

• Movement is the contractile ability of muscle tissues.

• Example• One bone stays

stationary while the other is drawn closer

• It also allows for movement of tissues for important functions like:• Blood flow• Swallowing food• Breathing• Digestion & excretion

Function 2: Posture

• Poor posture may lead to:• Limited breathing• Stress/pain in

back, knees, hips, shoulders

• Stress on internal organs such as • Heart• Intestines• Liver• lungs

Function 3: Heat

• Muscle provides a layer of insulation, helping the body to regulate temperature

• Also, when the core body temperature drops, muscles ‘shiver’ to make heat for the body.

MuscleWhat is it made of?

Muscle Fibers

• Muscles are made of muscle cells called muscle fibers.

• Muscle fibers are• Long• Cylindrical• Have more than one nucleus• Have striations (stripes)

Muscle Fibers

• Muscle fibers contain myofibrils, which contain either actin or myosin.

• These two act as the ‘motor’ of a muscle’s contraction

Muscle Fibers

• A layered section of these actins and myosins is called a sarcomere

• Myosin is thick and actin is thin, so these appear striped, or striated

• (sarco = muscle)• In the presence of

calcium, actin slides past myosin, causing the muscle fiber to contract

Muscle Fibers

• A group of muscle fibers is called a fascicle

• A group of fascicles is called a muscle

• Every layer is individually wrapped in perimysium

Types of muscle

• There are three types of muscle in the body

• SKELETAL

• SMOOTH

• CARDIAC

Skeletal

• Skeletal muscle is also called voluntary muscle

• It is attached to bones for movement

• These are muscles you can control!

Smooth

• Smooth muscle is also called involuntary muscle

• It is found at or in soft tissues and organs to provide movement• Peristalsis in

esophagus• Diaphragm for

breathing

Cardiac Muscle

• Cardiac Muscle is different because:• The cells have one

nucleus• It is resistant to

fatigue• Its both striated

and involuntary

• The cells in cardiac muscle are interconnected, allowing for better transfer of signals

Muscle Naming

•Muscles can be named based on 4 categories•Location (Tibialis anterior)

•Function (Levator scapulae)

•Appearance (trapezius, rhomboids)

•Attachment Sites (Sternocleidomastoid)