Circulatory System

What are some functions of the circulatory system? Heat Regulation Protection Antibodies White blood cells Repair – clotting Hormone transport O2 and CO2 transport Transport of nutrients and wastes

Hematology – the study of blood

Characteristics of Blood Blood = plasma + cells Plasma = liquid portion of blood 90% water Contains dissolved substances (proteins, gases, salts, nutrients) Cells

Red Blood Cells Contain hemoglobin for oxygen transport Biconcave disk shape (↑surface area) Made in red bone marrow 25 trillion in adult male 90-120 day life span Broken down in liver Iron recycled Protein turned into biliruben and excreted

Section 37.2 Summary – pages 975-984 Red blood cells: Oxygen carriers Side view 2.0 micrometers The round, disk-shaped cells in blood are red blood cells. Top view 7.5 micrometers Red blood cells carry oxygen to body cells. Section 37.2 Summary – pages 975-984

White blood cells Fight infection Formed in lymph tissue, spleen and bone marrow Different kinds

Platelets Clot blood with help of proteins in blood Fragments of large cells in bone marrow

Blood Types ABO system 4 types (A, B, AB, O) Indicates presence/absence of antigen A and antigen B (on surface of RBC) Clumping is caused by RBC with their antigen mixed with matching antibody in plasma Only worry about donor’s cells and recipient’s antibodies

Type A Type B Type O Type AB

A patient with type A needs a blood transfusion, what type(s) of blood can he receive? Explain your answer. He can receive from Type A (same as his type) Type O : the patient has antibodies against B and type O has no B antigens.

The Heart Structure 4 Chambers 4 immediate blood vessels R and L atria – collect blood R and L ventricles – pump blood 4 immediate blood vessels Arteries – away from the heart Pulmonary artery – to lungs Aorta – to body Veins blood to heart Pulmonary vein – from lungs Vena cavae (inferior and superior) – from body

4 valves – keep blood from backflow Tissue layers Pericardium: fibrous sack around heart. Contains fluid for protection Epicardium: outermost layer, contains vessels Myocardium: muscle layer, thickest in left ventricle (why?)

II. Pathway of Blood Flow

III. Cardiac Cycle: repeated pattern of contraction and relaxation Systole = Contraction (highest pressure) Diastole = Relaxation (lowest pressure) Normal blood pressure value: 120/80 Contraction triggered by SA node “the pacemaker”