CIRCULATORY SYSTEM 7 SCIENCE

Review What things that humans need to survive? Food – nutrients! Water Air – oxygen Another name for the circulatory system is cardiovascular system Includes: Heart Blood Blood vessels (veins and arteries)

What is the purpose of the circulatory system? Transports important substances to all parts of your body through your blood Moves oxygen and nutrients to cells Removes carbon dioxide and wastes from the cells

HEART Made of cardiac muscle 2 upper chambers called atria Located between your lungs and protected by bones 2 upper chambers called atria Right atrium Left atrium 2 lower chambers called ventricles Right ventricle Left ventricle

BLOOD VESSELS Veins Arteries Capillaries Returns blood to heart Valves keep blood moving towards the heart Contains blood low in oxygen Arteries A = AWAY from the heart Thick elastic walls Capillaries Connects veins and arteries Only one cell thick! E.g. in your eyes when you are tired

Circulation (movement) of Blood through the Heart To watch an animation of the heart pumping: Click here! You can speed up/slow down the pumping of the heart here.

REVIEW: organs of the circulatory or cardiovascular system Heart Veins Arteries Capillaries Blood

HEART During a heartbeat, both atria contract then both ventricles contract Valves separate the chambers prevents blood from flowing between the atrias or ventricles

BLOOD CIRCULATION Blood continuously moves around your body 3 types: Pulmonary: blood flows away from the heart TO THE LUNGS to get oxygen Systemic: blood flows AWAY from the heart to rest of body Veins Arteries

BLOOD CIRCULATION Coronary: blood that moves only in and around the heart If this circulation stops or is blocked, oxygen cannot get to the heart = heart attack

BLOOD PRESSURE Heart pumps blood through your blood vessels and pressure builds on the inside Like water flowing through a hose Called blood pressure As pressure increases and decreases, this creates your pulse Highest in your arteries: WHY? NORMAL: 65 – 80 beats/minute

CARDIOVASCULAR DISEASE Heart disease is the #1 cause of death in Colombia Stroke and heart attacks count for over 1/3 of adult deaths Atherosclerosis Fat deposits on inside of arteries block blood flow Caused by: eating too much fat and foods high in cholesterol

CARDIOVASCULAR DISEASE Hypertension High blood pressure Atherosclerosis can cause hypertension, i.e. blocked arteries can increase the pressure inside a blood vessel Usually caused by: too much salt and fat SOLUTIONS? Good diet and exercise Regular doctor appointments!