Circulatory System
Functions of Circulatory System Carries oxygen to all cells and removes carbon dioxide Carries waste products of cell activity to kidneys to be removed Transports nutrients from the digestive system to all cells Carries materials that fight infections and heal wounds
Components of Blood Plasma Red Blood Cells White Blood Cells Platelets
Plasma Liquid part of blood Composed of water and nutrients Contains electrolytes Electrolytes: chemicals that allow cells to maintain the correct electrical voltage (ex: nerve impulses)
Red Blood Cells Most numerous blood cells Tiny, flexible cells (allows them to fit through capillaries) No nucleus Contains hemoglobin
Hemoglobin Hemoglobin contains iron & carries oxygen in the blood
White Blood Cells Fight infection
Platelets Small cell fragments that clot the blood when there are cuts and scrapes
3 types of Blood Vessels Arteries Veins capillaries
Arteries Carry blood away from the heart Arteries branch into smaller vessels, known as arterioles Arteries have thick walls because the blood is pumped with strong pressure from the heart
Veins Carry blood from the body tissues back to the heart Smallest veins are venules Deoxygenated blood is not under much pressure, so veins have thinner walls than arteries
Capillaries Smallest blood vessels One cell thick This is the location of exchange of oxygen, carbon dioxide, wastes, and other nutrients Arterioles and venules meet at the capillaries
Heart Made of cardiac muscle Located under the rib cage
Cardiac Muscle Muscle that contracts without nerve stimulation
Pacemakers Special cells in the heart that control the electrical system of the heart Cause the heart to beat by electrical signals 2 areas: Sinoatrial node Atrioventricular node
Heart Chambers The human heart has 4 chambers 2 small atria: right atrium & left atrium 2 large ventricles: right ventricle & left ventricle
Valves Valves allow blood to flow in one direction only
Tricuspid valve separates the right atrium & right ventricle
Mitral valve separates the left atrium & the left ventricle
Aortic valve: between left ventricle & aorta
Pulmonary valve between the right ventricle & pulmonary artery
Pericardium a double walled sac filled with fluid that protects the heart
Vena Cava Superior Vena Cava Inferior Vena Cava The higher vein that brings blood from the head, neck, and arms to return to the heart Inferior Vena Cava The lower vein that brings blood From the rest of the body to the heart
Pulmonary artery This artery carries deoxygenated blood from the heart to the lungs
Pulmonary vein This vein brings oxygenated blood from the lungs to the heart
Aorta This is the largest artery in the body It has strong muscular walls to withstand the high pressure with which the left ventricle pumps the blood
Pulmonary Circulation The circulation system that takes blood from your heart to your lungs and back to your heart
Systemic Circulation The circulation that takes blood from your heart to your body and back to your heart