Skin, Bones, Muscles Test Next Block Days Wednesday April 13th or Thursday April 14th
Levels of Organization Organ System Tissue Organ Organism Cell • Cell: smallest unit of structure and function in living things. • Tissue: a group of similar cells working together. • Organ: a group of different tissues working together to do a specific job. • Organ System: a group of different organs working together to do a specific job. • Organism: a living thing that carries out its own life activities.
Four Body Tissues The small intestine seen here is an example of an organ of the body that contains all four types of tissues. Most organs are made up of the four types of tissues, but they are organized in different ways to perform different tasks. The Small Intestine (an organ) Epitheial Nervous Muscle Connective Tissue
Skeletal System • A. Functions: • There are 5 main functions of the skeletal system: • 1.provide support and shape for the body • . allow for movement • . store minerals (like Ca and P) • . protect internal organs (cranium - brain) • . make blood cells (in the bone marrow) • B. Types of Bone: • . Compact bone – strong, dense, tightly packed bone that is covered by nerves and blood vessels. • . Spongy bone – less dense type of bone filled with holes (like Swiss cheese). These holes allow for cushioning; thus, spongy bone is usually found at the ends of bones where a lot of stress occurs.
Skeletal System • C. Bone Structure: • . Bone marrow – fills the hollow parts of bones.Red marrow makes blood cells, whereas Yellowmarrow stores fat. • . Cartilage – covers the ends of the bones at joints so that bones can rub smoothly past each other. • . Ligament – connective tissue that connects bone to bone at a joint • . Tendon – connective tissue that connects bone to muscle • D. Bone Problems: • Osteoporosis – a disease caused by loss of bone mass. Bones become weak, break easily, and are hard to heal. It usually affects older people, especially women. New bone stops forming in early twenties! • Rheumatoid arthritis – an • Auto-immune disease in which the cartilage that cushions joints breaks down, causing pain and stiffness.
Skeletal System Periosteum Spongy Bone/Red Marrow Cartilage Cartilage Yellow Marrow FYI… There are 206 bones in the human body! The smallest are the incus, malleus, and stapes in the inner ear. The longest is the femur in your thigh.
A. Three Types of Muscle: Skeletal, Smooth & Cardiac • 1. Skeletal muscle – under voluntary control. • - It is has thick bands with striations. (filaments for contraction) • -It is found attached to bone; allowing for movement (arms, legs..) • 2. Smooth muscle – under involuntary control. • -There are no striations. • - It is found in walls of blood vessels and digestive organs; inside eye (iris). • 3. Cardiac muscle – under involuntary control. • -It has striations. • -Can only be found in the heart Muscular System
B. Muscle Contraction: • Things to know: • . Tendonsconnect muscle to bone. • . When a muscle contracts, it shortens, pulling on the bones it is attached to. When it relaxes, it gets longer. • . When one muscle contracts, the opposite muscle relaxes. (bicep contracts / tricep relaxes) D. Nerves and Muscles Working Together: Nerves communicate with the muscle fibers, causing them to contract and do work when the brain wants them to. Muscular System
Ingetumentary System(“Skin”) The Integumentary System consists of: skin, hair & nails. • Functions: • 1. outer covering that provides skin from infectious agents and sun’s UV rays • 2. helps prevent water loss (dehydration) • 3. helps regulate body temperature (maintains homeostasis) • B. Structure: • 1. Epidermis – outermost; made of a living layer and dead layer of epithelial cells. New epithelial cells are produced each day pushing up old ones to form a dead layer filled with a durable protein called keratin. The epidermis also contains dark-brown pigments, called melanin, giving the skin its color and protecting us from UV light. • 2. Dermis – The dermis supports the epidermis and contains nerve endings, blood vessels, smooth muscles, touch receptors, sweat glands, and oil glands (called sebaceous glands). • 3. Hair and nails are also a part of the integumentary system, and are made from a protein called keratin.
Ingetumentary System(“Skin”) Skin Cancer Excessive exposure to the sun’s UV radiation can produce skin cancer. The most sever and fatal type of skin cancer is calledmalignant melanoma. Signs: