CIRCULATORY SYSTEM

FUNCTIONS Transports oxygen and nutrients to the cells Transports carbon dioxide and other waste for elimination from the body Maintains homeostasis of the body cells

3 MAIN PARTS 1. Heart 2. Blood 3. Blood vessels – arteries and veins*** Veins: carry blood back to the heart Arteries: carry blood from heart to body tissues (when you take your pulse, you are checking one of these sights) Capillaries: smallest blood vessels that connect the veins and arteries

SIMPLE VS. COMPLEX ANIMALS Simple animals do NOT have a circulatory system. The exchange of materials and waste occur by diffusion across the main body cavity and cells. Example: Cnidarians Complex Animals have either an open or closed circulatory system.

OPEN CIRCULATORY SYSTEM The heart pumps blood into open-ended blood vessels. The blood is pumped from the heart, through the vessels, and it “bathes” the tissues Example: Grasshopper (Insects)

CLOSED CIRCULATORY SYSTEM The hearts pumps the blood only through blood vessels which carry the blood to all the body tissues and then back to the heart. Examples: Annelids, Mammals

Insect: Open Circulatory System Annelid: Closed Circulatory System Heartlike structures Blood vessels Heartlike structure Small vessels in tissues Blood vessels Hearts Heart Sinuses and organs Open & Closed Circulatory Systems

Fish has a 2 chambered heart Amphibian has a 3 chambered heart Mammal has a 4 chambered heart SINGLE LOOP VS. DOUBLE LOOP SYSTEM

2 CIRCUITS THAT BLOOD TRAVELS (DOUBLE LOOP SYSTEM ) 1. PULMONARY CIRUIT: A short loop where blood is carried between your heart and lungs. In your lungs the blood absorbs oxygen and releases carbon dioxide. Then the oxygenated blood returns to the heart.*** 2. SYSTEMIC CIRCUIT: Carries oxygenated blood to all other body cells then the blood releases oxygen to the cells and picks up carbon dioxide and other wastes and returns to the heart. Your heart is basically 2 pumps, one for each circuit.

Fish has a 2 chambered heart Amphibian has a 3 chambered heart Mammal has a 4 chambered heart

CHARACTERISTICS OF YOUR HEART It is about the size of your fist. It is located beneath the sternum and near the center of your chest. It is a hollow organ with thick walls made of cardiac muscle. It is surrounded by a double walled sac called the pericardium. It has 2 sides separated by a thick wall called a septum. It has 4 chambers.

Figure 42.5 The mammalian heart: a closer look Superior Pulmonary Tricuspid Inferior Aortic Mitral Septum

PARTS OF THE HEART AND THEIR FUNCTIONS The atria (right atrium and left atrium) are at the top of the heart and the RECEIVE blood. The Ventricles (right ventricle and left ventricle) are at the bottom of the heart and the PUMP BLOOD OUT. Valves keep the blood moving in the correct direction. The right side of the heart carries the deoxygenated blood. The left side of the heart carries the oxygenated blood.

Figure 42.4 The mammalian cardiovascular system: an overview Flow of blood through the heart: Deoxygenated blood  right atrium  right ventricle  pulmonary artery  pulmonary vein  left atrium  left ventricle  aorta  body

BLOOD PRESSURE Caused by the force with which the ventricles contract. Measured with a sphygmomanometer (blood pressure cuff) A healthy adult should have a blood pressure of 120/80 Top number is systolic pressure, the force felt in the arteries when the ventricles contract Bottom number is diastolic pressure, the force felt in the arteries when the ventricles relax.

BLOOD COMPONENTS 55% PLASMA (a straw colored fluid) 45% Blood Cells Plasma 90% water 10% dissolved minerals Blood cells Red blood cells- transport oxygen and get their color from hemoglobin (an iron containing protein)*** White blood cells- fight disease Platelets- help in blood clotting

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Figure The composition of mammalian blood