PHS - Ch. 9 Body Systems for Support & Movement (Slides 23-29)

PHS - Ch. 9 Body Systems for Support & Movement (Slides 23-29)

1. The Muscular System

The Muscular System

• Functions:

  • Muscles interact with other body systems to enable stability, movement, breathing, body heat, and digestive functions

• Organs:

  • Tendons

  • Ligaments

  • Cardiac Muscle

  • Smooth Muscle

  • Skeletal Muscle

• Collagen:

  • Collagen surrounds muscle fibers and gives them strength

  • Collagen is the main component of tendons, which connect muscles to bones to allow movement

• Professions:

  • Athletic trainers and physical therapists focus on building and maintaining the health and function of the muscular system.

Types of Muscle

• Cardiac muscle pumps blood in the heart

• Smooth, or visceral, muscle is found in the digestive system and blood vessels

• Skeletal muscle connects to bones to enable movement

• Cardiac and smooth muscle control is involuntary; skeletal muscle control is voluntary

• Muscles are described as striated or smooth.

  • Cardiac and skeletal muscles are striated, while smooth muscle is not.

Muscle Attachment

• Muscles have a "belly" in the middle and tendons at the ends.

• The belly is the meaty bulk of muscle tissue that can be felt when muscle contractions occur.

• Muscle Need two points of attachment :

  • Point of origin and point of insertion

• Muscles must cross at least one joint to create movement

Muscle Shape

Different shapes of muscles have different attachments:

• Strap muscles are long and narrow with small attachments

• Sphincters form a circle to close an opening and have many short attachments

• Convergent muscles are fan-shaped with muscle bundles spread over a broad attachment area on one end

• Pennate muscles have parallel fibers and attach to tendons at an angle

Muscle Movements

• Muscles contract when stimulated by electrical impulses from the brain

• Muscles grow stronger the more they are stimulated; unused muscle will shrink, or atrophy

• Muscles work in opposing pairs (agonist/antagonist) or in groups (synergists)

• Types of joint movement:

  • Flexion/extension

  • Hyperflexion/hyperextension  

  • Abduction/adduction

  • Rotation and circumduction

Critical Thinking

Explain how the following muscle names indicate each muscle’s action, structure, location, shape, or size.

• Adductor longus

  • A long muscle that brings the leg toward the body (adduction)

• Extensor digitorum

  • Extends the finger (digit)

• Tibialis anterior

  • Located on the front (anterior) of the tibia

• Triceps brachii

  • Has three (tri-) attachments on the upper arm

• Deltoid

  • Has a triangular shape (delta)

• Gluteus maximus

  • A large muscle

Muscle Diseases and Injuries

• Muscular dystrophy

  • Group of diseases that cause atrophy and weakness in skeletal muscles; may affect cardiac muscle

  • Some forms caused by defective collagen

• Tendinitis

  • Inflamed tendon due to repetitive stress

• Muscle strain

  • moderate damage

• Muscle tears

  • More serious than strain; may require surgery

Technology and Treatments

• Exercise techniques are used to provide therapy treatments to patients with physical disabilities to help strengthen muscles, improve mobility, restore function, and relieve pain.

• Muscle strains result in tenderness and swelling are are treated with:

  • RICE (Rest, Ice, Compression, Elevation)

  • Surgery may be required to repair these injuries if they are severe enough.

Age Related Changes

Control of skeletal muscles develops in an organized pattern:

• As children develop, they first learn to control their large motor muscles, and then gain fine motor skills.

  • Ex. babies will hold up their head and control the muscles used to eat before they learn to coordinate the muscles used for speech.

  • Babies will also reach with their arms before learning to grasp with their hands.

• After about 30 years of age, the amount, size, and tone of muscle tissue begins to decrease again, resulting in a gradual loss of strength.

Match

Muscle Types:

• A voluntary, striated muscle that connects to bones and is responsible for movement

• An involuntary muscle located in the body's visceral organs (stomach/intestines) and blood vessels

• An involuntary, striated muscle tissue located in the walls of the heart

skeletal muscle

smooth muscle

cardiac muscle

• skeletal muscle

• smooth muscle

• cardiac muscle

Match

Agonist vs. Antagonist (remember they work opposite of each other)

• the muscle actively working during movement

• the relaxed muscle during movement

• where the bone originates or the stationary part that does not move

• where a muscle inserts/attaches to a bone that does move

agonist

antagonist

the point of origin

the point of insertion

• agonist

• antagonist

• the point of origin

• the point of insertion

Match

Muscle movements:

• bending of the arm

• straightening of the arm

• moving a limb away from the midline

• moving a limb toward the midline

flexion

extension

abduction

adduction

• flexion

• extension

• abduction

• adduction