Unit 7

Unit 7 Human Body Systems5 Functions of the Skeletal System.

•Gives shape and support to the body

•Protects the internal organs

•Provides an attatchment point for muscles

•Formation of red blood cells in the bone marrow

•Calcium and phosphorus are stored here

Periosteum- tough, tight fitting membrane that contains blood vessels that carry nutrients to the bone.

Spongy bone- contains open spaces that make the bone light weight.

Marrow- a fatty tissue that produces red and white blood cells

Cartilage- a thick, smooth rubbery layer of tissue that reduces friction between bones

Ligament- tough, elastic connective tissue (rubber band rope) that joins bone to bone (ACL tear)

Tendon- connective tissue that that joins muscle to bone

Joints- places where two bones come together

1. Ball and socket joint(EX: Shoulder and hip)

2. Hinge joint(EX: elbow and knee)

3. Gliding joint(EX: Wrist, vertebrae & neck)

4. Pivot joint(EX: forearm)

5. Suture Joint (EX: Skull)

1st 2nd 3rd

Class lever Class Lever Class Lever

Neck Balls of foot ElbowSee saw Easy Hard

Muscles Muscles are organs that contract to perform a task, such as moving body parts.

1.Voluntary Skeletal Muscles (striated)-those that can be consciously controlled and are attached to the skeleton

Ex: arm muscles

2. Involuntary Smooth Muscles cannot usually be controlled; found in skin irises & the digestive tract

3. Cardiac Muscles- heart muscle which is in like other muscles in that it generates it own electrical

Skin

Epidermis- Surface layer of skin made of dead cells

Dermis- livings skin layer; contains blood vessels and nerve endings

Melanin- pigment that gives skin its color protects us from ultraviolet radiation

Circulatory System

Arteries- thick elastic walled blood vessels (tubes) that move oxygen- rich blood away from the heart through the body

Veins- flat blood vessels with one way valves that moves carbon dioxide- rich blood back to the heart

Capillaries- microscopic blood vessels that connect arteries and veins, oxygen, nutrients, and wastes; veins, oxygen, nutrients are exchanged through capillary walls

Plasma- the liquid part of blood; made mostly of water but also containing nutrients, minerals & oxygen; 90% of blood is made from plasma.

Platelet- irregularly shaped cell fragment that forms clots (scabs) when chemicals in torn or cut skin combine with blood. Platelets stick together to form tiny threads of fibrin which clog the wound.

Side view- skin; close up

•Skin torn•Chemical in skin released•Platelets from the threads of fibrin which clots the wound, stopping blood loss

Your skin, hair and nails make up the Integumentery System.

The Lymphatic System

Generally speaking, it is responsible for re-absorbing liquids from your body’s tissues (lymphatic fluids.) These liquids are collected into lymph vessels. Skeletal muscles squeeze fluid through these tubes. Lymph nodes in your neck remove pathogens and dead cells, as many white blood cells, are found there. Purified lymphatic fluid

then drains into your neck veins.The thymus just above the heart releases white blood cells.

The spleen, located in the upper let abdomen, is the “oid fitter” for dead red blood cells.

The tonsils are located at the back of the nasal (avity, and help fight infection.

Hemoglobin- protein that allows red blood cells to carry oxygen.

END OF Unit 7