Chapter 15 Bones, Muscles, and the Skin

Body Organization and Homeostasis There are five levels to the organization of the body – in order: Cells Tissues Organs Organ systems organism

Tissues There are four types of tissue made of cells: 1.Muscle Tissue: can contract or shorten. This tissue helps the body to move. 2.Connective Tissue: (Blood, bone, and fat) Connects the parts of the body and provides support for the body. 3.Nerve Tissue: Directs and controls the body by carrying messages back and forth between the brain and all other parts of the body. 4.Epithelial Tissue: (Skin) Covers the entire surface of the body.

Muscle Tissue

Epithelial Tissue Skin

Nerve Tissue

Connective Tissue Cartilage

15-1 – Organs and Organ Systems Organs are structures composed of different kinds of tissue. The job of the organ is more complex than that of tissue. (Heart, Liver, Lung, Kidney, stomach, or bladder). Organ System: a group of organs that work together to perform a certain task. For example, the circulatory system consists of the heart and blood vessels working together.

Organ Systems

15-1 Homeostasis Homeostasis is the body’s tendency to maintain an internal balance. The process by which the organism’s internal environment (inside the body) is kept stable in spite of changes in the external environment (outside the body). For example, body temperature regardless of winter or summer.

15-1 Homeostasis - Stress Some stress is good, and some stress is bad. Stress is your body’s reaction to something threatening, challenging, or disturbing. (feeling uncomfortable, butterflies in the stomach, sweating, racing heart, breathing rate increases,etc.).

Stress The stress process upsets your homeostasis : seconds: alarm stage. 2.Chemical (adrenaline) is released into the bloodstream. This causes increase in energy – called “Fight or Flight”.

15-2 The Skeletal System

15-2 Skeletal System There are five major functions performed by the skeletal system: –Shape and support –Protects your internal organs –Enables you to move –Produces red blood cells –Stores certain materials until

15-2 Bones are made from two minerals: Phosphorus and Calcium. New bone tissue forms throughout your life.

Bone Diagram membrane

15-2 Bone Structure Basic Structure: 1.Membrane: covers all the bone except the ends. Blood vessels and nerves enter and leave through the membrane. 2.Compact Bone: hard and dense, but not solid. Small canals run through the compact bones carrying blood vessels and nerves from the bone’s surface to living cells within the bone.

Spongy Bone: has many small spaces within it and is found at the ends of the bone. The spaces contain soft connective tissue – marrow. 4.Marrow: there are two types of marrow: –Yellow marrow: stores fat –Red marrow: produces red blood cells.

Cartilage: connective tissue which is more flexible than bone (ears, nose). At infancy, most of the skeleton structure is cartilage – this helps to move the baby through the birth canal. As the baby matures, the bone becomes dense and hard.

Joints: joints are where two bones come together and allow bones to move in different ways. Moveable joints are held together by strong connective tissue called ligaments (Knees).

Hinge Joint A hinge joint allows extension and retraction of an appendage.

Saddle Joint A saddle joint allows movement back and forth and up and down, but does not allow for rotation like a ball and socket joint.

Ball and Socket Hips and shoulders - moves in any direction

Gliding Joint In a gliding or plane joint bones slide past each other. Metacarpal and metatarsal joints are gliding joints

Pivot Joint Pivot joints allow rotation around an axis. The neck and forearms have pivot joints. In the neck the occipital bone spins over the top of the axis. In the forearms the radius and ulna twist around each other.forearms

15-2 When you look at an elderly lady, and she seems to be shorter then she used to be – shrinking grandmother’s is not a myth. As people (mostly women), become older, their bones begin to lose minerals, which can lead to osteoporosis. Osteoporosis is when the bones shrink and become weak. Beginning and maintaining a rich diet of calcium during the teen years can prevent future osteoporosis – dairy products.

15-3 The Muscular System

15-3 The muscular system contains about 600 different muscles in your body. Muscles that are not under your conscious control are called involuntary muscles: the lungs or the heart. Muscles that you do control are called voluntary muscles – such as smiling.

Voluntary Muscle

15-3 There are three types of muscle: –Skeletal Muscle: attached to bones of your skeleton. These are voluntary muscles, and react quickly, causing the muscle to tire faster. At the end of skeletal muscle are tendons. Tendons are strong connective tissue that attaches bone to muscle. –Smooth Muscle is involuntary. The digestive system is made of smooth muscle – reacts slowly and tire slowly. –Cardiac Muscle: Involuntary and found only in the heart. Cardiac muscle does not tire.

15-3 Muscles Muscles work by: 1.Contracting and expanding 2.Becoming shorter and thicker. –Skeletal muscle works in pairs –while one muscle contracts, the other muscle in the pair returns to its normal length. –Exercise makes individual muscles grow thicker, wider, and stronger. –You can prevent muscle injuries by warming muscles up before exercise.

Muscle Animation ractswf/index.htmlhttp://entochem.tamu.edu/MuscleStrucCont ractswf/index.html

15-4 The Skin

15-4 – The Skin Draw and label diagram (Skin Structure)

15-4 Functions of the Skin 1.Covers the body and prevents the loss of water. 2.It protects the body from infection or injury. 3.Helps to regulate body temperature. 4.Eliminates waste – salt, water, etc. 5.Produces vitamin D 6.Gathers information about the environment.

Skin layers

15-4 Skin Layers There are two main layers: –Epidermis: The epidermis is the outer layer and does not contain nerve cells or blood cells. Cells in the epidermis have a life cycle and new cells form deep in the epidermis and move upward. These cells become the surface layer and when they die – they shed. –Cells deep in the epidermis produce melanin. Melanin is a pigment that gives skin its color. The more melanin you have, the darker you are. Melanin protects the skin from burning.

15-4 Skin Layers Dermis: the lower layer of the skin is called the dermis. This layer contains nerves, blood vessels, sweat glands, hair and oil glands. –Sweat glands produce perspiration and is then released through the pores. Strands of hair grow in structures called follicles. Oil produces in glands around hair follicles waterproofs hair and keeps the skin moist.

15-4 – Keeping Skin Healthy Eat properly. Nutrition has a lot to do with the health of your skin. Drink plenty of water – hydrates the skin as well as the body. Clean skin twice a day with warm water and a mild soap. Never scrub the face or use abrasive soaps that dry the skin. Always pat the skin dry after washing. When using a moisturizer, use a gel instead of cream – cream moisturizers block pores and cause blackheads. Avoid exposure to the sun – USE SUNSCREEN!

15-4 – Diseases of the Skin Skin Cancer: body cells divide uncontrollably. Repeated exposure to the sunlight without the use of sunscreen can damage skin and cause cancer. Acne: When oil glands become clogged with oil, bacterial infections occur. Some acne is hormonal. Do not pop and squeeze skin – see a dermatologist if you suffer from repeated and bad acne – hormonal acne can be treated. Fungi: fungus infects the skin, especially on the feet (planters warts). Bacteria between the toes – athlete’s foot.

Acne

Skin Cancer UV-B