The Nervous System

1. The Nervous System The BOSSof the human body because it issues the orders and controls and regulates everything the organism does. Composed of the brain,spinalcord,nerves and ganglia or masses of gray tissue found in inner organs of the body.

2. Nerve cell or neuron – fundamental unit of the nervous system which is found in all various parts of the nervous system. Three kinds of neurons: 1. sensory 2. motor 3. Intermediate neurons Brain– a vital part of the nervous system and found within the cranial cavity and weighs approximately fifty ounces.

3. The Excretory System Is a passive biological system that removes excess, unnecessary materials from an organism, so as to help maintain homeostasiswithin the organism and prevent damage to the body. It is responsible for the elimination of the waste products of metabolismas well as other liquid and gaseous wastes, as urine and as a component of sweat and exhalation.

4. Four widely separated organs: 1.Lungs – eliminate the carbon dioxide. 2. Perspiration glands – eliminate water,salts,small amounts of other wastes. 3. Kidneys – extract water, salts and urea, which is the waste produced from the use of certain foods by the cells 4. Liver – helps in the process of removing wastes from the bloodstream.

5. The Endocrine System Is the system of glands, each of which secretesdifferent types of hormones directly into the bloodstream (some of which are transported along nerve tracts to maintain homeostasis. The endocrine system is in contrast to the exocrine system, which secretes its chemicals using ducts.

6. Hormones – is a chemical released by a cell, a gland, or an organ in one part of the body that affects cells in other parts of the organism. Major Parts of Endocrine System: 1. Thyroid gland - controls how quickly the body uses energy, makes proteins, and controls how sensitive the body is to other hormones. 2. Pituitary gland- called master gland that manufactures several hormones of great importance in physical growth and development. 3. Gonads – which are responsible for the bodily changes in boys and girls at adolescence.

7. The Integumentary System This refers to the skin and membrane of the body with the major task of protecting the underlying tissues. The skin covers the surface of the body and provides a tough layer of protection from bacteria , dirt,mechanical injury and temperature.

8. The Reproductive System Is a system of organs within an organism which work together for the purpose of reproduction. The organs of male are the testes which produce sperm. In the female they are called ovaries and produce eggs or ova.

9. A human being is the result of the union of a male germ cell (sperm) with a female germ cell ( ovum) to form a single cell or fertilized egg. Over approximately a nine –month period, the fertilized egg divides and subdivides and grows in size until a human being is formed. Chromosomes – tiny structures that can be found in each of the male and female germ cells. It is an organized structure of DNA, protein, and RNAfound in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Genes – which determine the characteristics that are inherited by human beings.

10. The Digestive System The human digestive system is a complex series of organs and glands that processes food. In order to use the food we eat, our body has to break the food down into smaller molecules that it can process; it also has to excrete waste.

11. Three stages in the digestive process: 1. Digestion in the Mouth - the teeth grind food into small particles as it is mixed by mastication with the alkaline saliva. 2.Digestion in the Stomach – Food is passed from the mouth to the stomach by the perestaltic movements of the esophagus. 3. Digestion in the Intestine – Now a semi fluid product , the food is moved by peristaltic movements into the small intestine where it mixed with intestinal juice.

12. Characteristics of Growth 2. 1. Growth is Change A person goes through stages of development: infancy, childhood, adolescence and adulthood. Within each stage changes occur. 2. Growth Takes time,is Orderly and Uneven Growth does not happen overnight. It is very clear that evidence of growth can not be expected in a day or two. Physical growth, or any kind of growth, whatsoever, is a developmental process, and it is orderly because it follows a pattern as infancy,childhood,aadolescence , and adulthood.

13. Differences in Boys and Girls

14. Other Sex Differences: 1. Girls mature earlier than boys. 2. Boys are superior to girls in motor capacity. 3. Girls have better memory. 4. Boys do better in tests of originality. 5. Boys do better in reasoning test,arithmeticcomputations and mechanical tests. 6. Girls are superior in aesthetic comparisons,drawing designs for memory and in linguistic ability. Body Types

16. Posture Posture – refers to the habitual or assumed alignment and balance of the body segments over the base of support.