Integumentary, Skeletal,
Muscular, and Nervous Systems

• Function:- The electrical system of the body.
- Control/coordinate body functions and respond to external stimuli
Neurons:- Cells that carry electrical signals throughout the body.
3 Types:
1)Sensory carry signal from sense organs to spinal cord/brain.
2)2) Motor carry signal from brain/spinal cord to muscles and glands.
3)3) Interneurons connect sensory and motor neurons.

Central Nervous System (CNS):
• Brain has three parts to it.
• 1) Cerebrum receives sensory impulses and coordinates muscle response and thinking impulses.
• 2) Cerebellum coordinates voluntary muscle movements and balance.
• 3) Brain Stem controls involuntary functions, such as breathing, swallowing, blood pressure, etc.
• Spinal Cord links the brain with parts of the body and controls reflexes.

Peripheral Nervous System
(PNS):
• All other nerves except the brain & spinal cord.
• Sensory division transmits signals from sensory organs to CNS.
• Motor division transmits signals from CNS to muscles or glands.

Integumentary System:
• Function:protection and temperature regulation of the body.
• Structure:skin has layers called epidermis and dermis.melanin gives color.
• sweat glands cool body.
• oil glands condition and waterproof skin.
• hair and nails are also a part of this system.

Function:
1. Support of the body
2. Protection of internal organs
3. Provides movement
4. Stores minerals
5. Site of blood cell formation

Structure:
Axial skeleton: skull, vertebral column and ribs.
Appendicular skeleton: pectoral/pelvic girdles and appendages (arms & legs
Periosteum: Connective tissue layer on outside of bone.
Outer Layer: "Compact bone" contains blood vessels that run through Haversian canals
Core: "Spongy bone" provides strength.206 bones: red marrow (where blood is made) yellow marrow (fat cells)
Cartilage: strong & flexible cushion between bones for protection.

Axial
Skeleton
(Green)

Appendicular
Skeleton(Yellow
)

• Ligaments: Connects bone to bone.
• Tendons: Connects bone to muscle.
• Synovial fluid: Lubricates joints.

Joints: Where two bones meet.

Function: movement and protection of some internal organs.
Skeletal muscles: Attached to bones for movement (Tendons)
Have many nuclei
Striated

Smooth muscles:
Found in involuntary organs
Aid in digestion & reproduction
Contraction is called peristalsis
One nucleus
No striations

Is your heart
One or two nuclei
Involuntary
Striated

How Muscle & Bones Interact
• ONLY skeletal muscles attach to bones.
• Attached with tendons.
• When a muscle contracts, it shortens.
• When a muscle relaxes, it lengthens.
• One muscle is attached to TWO bones.
• When the muscle contracts, it pulls the bones closer together