Human Systems

Digestive System Saliva contains amylase to begin digestion of sugars; begins in mouth. Esophagus tube carries out peristalsis to push food into stomach. Stomach mixes food with water, hydrochloric acid and gastric juices making it a soup mixture. Small intestines complete digestion. Lipids, proteins and sugars are completely broken down; leaves out small intestines and enter bloodstream by absorption.

No digestion takes place in the large intestines No digestion takes place in the large intestines. Undigested food enters large intestines where excess water is removed and will be recycled in body. Gall bladder helps digestion by storage of bile. Liver produces bile which will be used to digest fats. Appendix is a vestigial organ. (no known purpose) Pancreas produces insulin to digest sugar.

Respiratory System Air enters nose and mouth. Air travels down trachea. (wind pipe) Trachea splits into bronchial tubes- one tube goes to the right lung and one tube goes to the left lung. Air enters lungs and is carried into alveoli: (air sacs where gas exchange occurs) CO2 leaves out of blood by diffusion and O2 enters into the bloodstream by diffusion. Epiglottis- flap over trachea so choking does not happen. Pathway of airflow: nose → trachea → bronchial tubes → lungs (bronchioles- small tubes into lungs) → alveoli

Structures of a Nerve 3 Kinds of Nerve Cells Sensory Neurons- pick up impulses from the environment and carry them to the brain. Interneurons- receive impulse (located in the brain and spinal cord) and determine what response needs to occur. Motor Neurons- carry impulses from brain or spinal cord to an effector (muscle or organ) that needs to carry out the response. Automatic response in a reflex which has been sent to the spinal cord for a quick reaction, then the brain translates what has happened.

Circulatory System Blood Circulation = Flow Blood is returned to the heart by vena cava and enters the right atrium (RA) and the RA sends the blood into the right ventricle (RV). The RV pumps blood into the pulmonary artery which leads to the lungs to pick up O2 and the pulmonary vein carries blood back to the heart and enters the left atrium (LA) and LA pumps blood into the left ventricle (LV) which will pump the blood up into the aorta (largest artery) which breaks into 3 branches. Veins return blood to heart (deoxygenated) except for pulmonary vein (oxygenated).

3. Arteries carry blood from heart (oxygenated) except for pulmonary artery (deoxygenated).

Endocrine System Production of hormones are to maintain homeostasis. Pituitary Gland- master gland- its hormone triggers other glands to produce hormones needed in the body- located at the base of the brain. Thyroid gland- needs iodine to function properly. Its hormone controls your metabolism and growth. Parathyroid Gland- (neck) controls mineral regulation- controls calcium, magnesium, and phosphate levels inside the body. Adrenal Gland- (Top of kidneys) works during stress; releases steroids, adrenalin.

Pancreas- produces insulin (hormone) that controls sugar levels Pancreas- produces insulin (hormone) that controls sugar levels. Helps digest sugar and control sugar levels in the body. Cells are islets of langerhan. Ovaries- (female only) Production of egg and hormone estrogen which causes breast to increase in size, hips to widen and trigger the onset of the menstrual cycle. Testes- (male only) production of sperm. Produce the hormone testosterone which causes the voice to deepen and hair to grow on face and chest.

(Lymphatic) Immune System *** AIDS is a pathogen (disease germ) that destroys the T-Cells. Pathogens enter tissues through a wound. They are attacked by macrophages at the infection site. Antigens of the pathogens are displayed on the surface of the of the macrophage. Helper T-cells have receptor sites that recognize and bind to the antigens on the macrophage.

B-cells can bind to antigens directly. Helper T-cells bind to antigens on B-cells. T-cells release chemicals that cause B-cells to produce clones of plasma cells.