Introduction to Body Systems Levels of Organization Circulatory System Excretory System

Levels of Organization Cell The basic unit of structure and function of living things Tissue Cells that work together to carry out a specialized task Epithelial, Muscle, Connective, Nervous Organ Tissues that function together Organ System Two or more organs that coordinate to perform a specific function

Interacts with every other system of the body Transports gases, nutrients, wastes Helps regulate temperature and fight infection Consists of blood, blood vessels, and the heart Circulatory System

Blood is connective tissue that is composed of cells, cell fragments called platelets, and fluid called plasma Plasma makes up about 55% of the total blood volume Plasma is 90% water and 10% protein, salts, lipids, and glucose Cells are produced in the bone marrow in the center of bones Bone marrow consists of young blood cells, fat, and stem cells Blood

RBC are the most abundant cell type found in blood RBC lose their nucleus and organelles as they mature No nucleus = RBC cannot reproduce RBC life span is 120 days Red Blood Cells

Fight infection and remove dead cells Five types each with a specific function Lymphocytes = make antibodies Have a nucleus and irregular cytoplasm For engulfing pathogens Life span is 1-2 days White Blood Cells

Form sticky webbing to trap blood cells which stop bleeding and form a clot Platelets

Blood Type

Rh Factor Surface protein found on some RBC = Rhesus factor (Rh) Either inherit the protein (+) or not (-)

Blood Vessles Three types of vessels that transport blood A rteries Carry blood away from the heart Thick/muscular walls Veins Carry blood to the heart Contain valves to prevent backwards flow of blood Capillaries Diffusion of gasses and nutrients into and out of the blood (exchange) Thin walls

The Heart Made of cardiac muscle About the size of the fist Four chambers that fill with blood Right & Left Atria Right & Left Ventricles Right side pumps blood to the lungs (pulmonary circulation) Drop of CO2 Pick up O2 Left side pumps blood to the body (systemic circulation) Drop of O2 Pick up CO2 and waste

Blood Pressure Blood pressure is the force with which blood pushes against the wall of an artery Systolic Pressure Heart contracts Diastolic Pressure Heart relaxes

Excretory System Cells produce waste in the form of CO2, salts, and urea Kidneys Ureters Urinary Bladder Urethra Skin Lungs

Kidneys Kidneys = most important organ of the excretory system 1. Remove metabolic waste products 2. Regulate water content of the blood 3. Help maintain pH balance

Kidneys filter blood and produce urine by filtration Each filtering unit in the kidney is call a nephron Your kidney each contain over a million nephrons Nephron