Cardiovascular System Blood Vessels Heart Organization and Functions

Allows blood to reach tissues Blood Vessels Allows blood to reach tissues Contains smooth muscle and elastic tissue Carries blood away from the heart Returns blood to the heart

Capillary Exchange Balance of blood pressure and osmotic pressure controls flow of materials Water, Oxygen and Nutrients leave capillary at arterial end Diffusion of small molecules continues through middle of capillary Water, Carbon Dioxide and Wastes enter capillary at venous end

Blood Return Through Veins Skeletal muscles help return blood to the heart (skeletal muscle pump) Valves prevent back-flow Pressure changes in respiration also assist in moving blood through veins (respiratory pump)

Heart Chambers and Valves Left Atrium Semilunar Valves Atrioventricular Valve Right Atrium Left Ventricle Atrioventricular Valve Right Ventricle

Tissues of the Heart Endocardium- lining Myocardium- muscle Fibrous pericardium Endocardium- lining Myocardium- muscle Pericardium- outside Layers of Heart Tissue Visceral pericardium

Cellular Structures of Cardiac Muscle Cardiac Muscle cell Mitochondrion Intercalated disk: double membrane structure where cardiac muscle fibers are joined Gap junctions of intercalated disks allow simultaneous contraction of adjacent cells

The Cardiac Cycle Oxygenated blood from lungs Deoxygenated blood to lungs Heart Relaxes; atria fill passively Oxygenated blood to body Deoxygenated blood from body Atria Contract Ventricles Contract

Connecting Vessels Superior Vena Cava (from upper body) Aorta Inferior Vena Cava (from lower body) Superior Vena Cava (from upper body) Aorta Pulmonary Artery (to right lung) Pulmonary Artery (to left lung) Pulmonary Veins (from right lung) Pulmonary Veins (from left lung) Descending Aorta (to lower body)

Pulmonary and Systemic Circuits Circulates blood through body tissues Circulates blood through the lungs

Blood Vessels of the Heart Coronary arteries (red) and cardiac veins (blue) serve heart muscle Imaging methods can detect blockages in coronary arteries

Atrioventricular (AV) Node Control of Heartbeat Sinoatrial (SA) Node Atrioventricular (AV) Node SA Node = pacemaker, initiates atrial contraction AV Node receives signals from SA node, sends signal through Purkinje fibers for ventricles to contract simultaneously Purkinje Fibers

Heart Function Heartbeat visualized with ECG Irregular heart rhythm Semilunar Valves Close “dup” sound Atrioventricular Valves Close “lubb” sound Ventricular fibrillation Atria Contract Ventricles Relax Atria Relax Ventricles Contract Irregular heart rhythm

Blood Pressure Blood pressure = Systolic pressure Diastolic pressure Systolic: pressure during ventricular contraction Diastolic: pressure during ventricular relaxation Normal blood pressure Is below 120/80.

Disorders of the Cardiovascular System Hypertension: high blood pressure Atherosclerosis: buildup of plaque deposits in blood vessels Stroke: loss of blood flow to brain tissue due to blockage or bursting of blood vessel Heart Attack: damage to heart tissue due to lack of blood flow

Applying Your Knowledge Left Ventricle Semilunar Valve Right Atrium Left Atrium Atrioventricular valve Which structure receives blood returning from the lungs? Which structure prevents blood from flowing back into the ventricles? Which structure pumps blood to the body (systemic) circuit?

1. Transport of gases, nutrients, hormones Functions of Blood 1. Transport of gases, nutrients, hormones Red blood cells transport oxygen and assist in carbon dioxide transport Red blood cells usually have a concave shape Red blood cell from patient with sickle-cell anemia

2. Defense: protection against invaders Functions of Blood 2. Defense: protection against invaders White blood cells engulf invaders or produce substances to fight against them Macrophages engulf invaders Monocytes give rise to macrophages

2. Defense: protection against invaders Functions of Blood 2. Defense: protection against invaders White blood cells engulf invaders or produce substances to fight against them Lymphocytes target specific invaders or infected cells B lymphocytes produce antibodies against an invader Antibodies mark the invader for destruction T lymphocytes destroy body cells that are infected with the invader

Platelets initiate the process Clotting factors produce fibrin threads Functions of Blood 3. Blood Clotting Platelets initiate the process Clotting factors produce fibrin threads 1. Blood vessel is punctured. 2. Platelets congregate and form a plug. Prothrombin activator 3. Platelets and damaged tissue cells release prothrombin activator, which initiates a cascade of enzymatic reactions. Ca 2+ Prothrombin Thrombin Ca 2+ Fibrinogen Fibrin threads 4. Fibrin threads form and trap red blood cells. fibrin threads red blood cell

Functions of Blood 4. Regulation of body temperature plasma 55% cells, platelets 45% Percent by Volume Water, 91% Percent by Weight Proteins, 7% Solutes, 2% (ions, nutrients, waste products, gases, hormones, vitamins) 4. Regulation of body temperature water/salt balance pH Plasma is responsible for these functions.

Applying Your Knowledge Plasma Red blood cells White blood cells Which one regulates blood pH? Which one fights foreign invaders? Which one transports gases?