Composed of the heart and all the blood vessels of the body.
HEART Muscular organ – size of fist Made of muscle called myocardium Average heart rate = 70-80 beats/minute
HEART Contains four chambers Small upper chambers are called the left and right atrium Larger lower chambers are called the left and right ventricles A wall of tissue called the septum separates the right side from the left side Valves between the atria and the ventricles allow blood to flow. These valves are one-way valves. A
HEART At the top of the right atrium is the area that acts as a pacemaker for the heart. This area is called the SA Node
BLOOD Delivers oxygen, hormones, and nutrients to the cells and carries away waste that the cells produce.
PLASMA The fluid in which other parts of the blood are suspended. Plasma is mostly water
RED BLOOD CELLS Transport oxygen to the cells and tissue Red blood cells are formed in bone marrow and contain hemoglobin Hemoglobin is the oxygen-carrying protein in blood. It contains iron that binds with oxygen in the lungs.
WHITE BLOOD CELLS (see also lymphocytes under part IV) Main role is to protect the body against infection. Produced in the bone marrow Production of cells increases when infection is present.
PLATELETS Cells that prevent the body’s loss of blood Release sticky substance that causes clumping at site of an injury Stimulate blood to produce small thread-like fibers called fibrin These fibers trap platelets and red/white blood cells to form a clot
HEMOPHILIA The condition that occurs as a result of a deficient or abnormal clotting factor
BLOOD TYPES Four types of blood A B AB O Universal Donor = O Universal Recipient = AB
Rh Factor A protein substance found in the red blood cells of most people (+) If not present the blood is considered negative (-) Normally has no impact on health unless blood is mixed The blood will agglutinate (clump together)
BLOOD VESSELS Network of more than 60,000 miles of blood vessels Enough length to circle the earth approx. 2.5 times!
ARTERIES Carry blood away from the heart Thick, elastic walls Coronary arteries – carry blood to the heart itself
ARTERIOLES Smaller arteries as they move away from the heart Connect with the capillaries
CAPILLARIES Smallest blood vessels Connect the arterioles to the venules Exchange oxygen, carbon dioxide, nutrients and waste Play a role in temperature regulation by dilating during heat, and constricting during cold.
VENULES Smaller veins as they move toward the heart Connect the capillaries to the veins
VEINS Carry blood to the heart Thinner, less elastic walls Contain valves to prevent backflow
Lymph Circulation The lymphatic system is a network of vessels and tissues that move and filter lymph. Lymph – the clear fluid that fills the spaces around body cells Contains water, proteins, fat and lymphocytes Lymphocytes are specialized white blood cells that protect the body against pathogens (microorganisms that cause disease)
Lymphocytes Two Types Lymph is filtered by lymph nodes – small bean shaped organs found in lymph vessels B CellsT Cells (Killer and Helper) Produce antibodies to fight pathogens Killer T cells release toxins that prevent infection from spreading Create immune response by preventing a second attack of the same disease Helper T cells activate the B cells and the killer T cells
BLOOD PRESSURE Measure of the amount of force that the blood places on the walls of the blood vessels, particularly large arteries, as it is pumped through the body.
SPHYGMOMANOMETER Blood pressure cuff – measures blood pressure along with a stethoscope.
BLOOD PRESSURE Average blood pressure for an adult is 120/80 Systolic pressure – maximum pressure on the artery walls (during a contraction) Top number in the fraction Diastolic pressure – pressure at its lowest point (ventricles relax) Bottom number in the fraction
Cardiovascular System Problems Congenital Heart Defects – heart conditions that are present at birth. (Septal defect is a hole in the septum) Heart Murmurs – hole in heart OR a leaking/malfunctioning valve. Varicose veins – valves in vein do not close tightly, allowing back flow of blood
Cardiovascular System Problems Anemia – ability of blood to carry oxygen is reduced. Often caused by iron deficiency. Hemophilia – inherited disorder- blood does not clot properly. Leukemia – form of cancer in which too many white blood cells are produced.