Cardiovascular System

Functions of the Cardiovascular System Transport nutrients and O2 to body Transport waste from cells to kidneys for excretion Distribute hormones & antibodies Help control body temp Help maintain homeostasis

Types of Circulation Pulmonary: Right side of heart pumps O2 poor blood to lungs where CO2 exchanged for O2 Systemic: Left side of heart pumps O2 rich blood to body Hepatic: blood from intestines, gallbladder, pancreas, stomach, spleen through liver to remove toxins from blood

Heart Structures Heart: hollow muscular organ 4 chambers In thoracic cavity between lungs Tilted slightly to left Contains own blood supply

Heart Structures Atria Two upper chambers of the heart R atrium receives low oxygenated blood from body L atrium receives oxygenated blood from lungs

Heart Structures Ventricles Lower chambers of heart Pumping chambers Pump under high pressure

Heart Structures Myocardial Septum Separating wall or partition of heart chambers in right and left halves

Heart Valves Atrioventricular Tricuspid valve Mitral or bicuspid valve between right atrium and right ventricle Mitral or bicuspid valve between left atrium and left ventricle

Heart Valves Semilunar Pulmonary valve Aortic valve Between right ventricle and the pulmonary artery Aortic valve Between left ventricle and aorta

Heart Structures Pericardium Double membrane covering heart Outer fibrous layer Inner watery layer-epicardium Provides protection

Heart Structures Myocardium Endocardium Muscular Pumps blood Smooth inner layer Prevents damage to blood cells

Path of Blood Through Heart Low O2 blood from body to superior & inferior vena cava Right atrium Tricuspid valve Right ventricle Pulmonary valve Pulmonary arteries Lungs O2 blood from lungs Pulmonary veins Left atrium Mitral valve Left ventricle Aortic valve Aorta Body

How the Heart Contracts Sinoatrial nodes (SA node) Natural pacemaker Atrioventricular node (AV node) Bundle of His Purkinje fibers Surround ventricles Causes contractions Normal heart rate: 60-90 beats per minute (bpm)

Main Blood Vessels Arteries Veins Capillaries

Circulation Arteries Carry blood AWAY from the heart Largest artery: Aorta Carry O2 blood except for pulmonary arteries Muscular layers withstand high pressure Divide into smaller branches called arterioles which connect to capillaries

Circulation Capillaries Connect arterioles and venules Smallest vessels-one cell thick Allows exchange of gases, nutrients, and waste products

Circulation Veins Carry blood to heart Largest: superior & inferior vena cava Carry low oxygenated blood except for pulmonary veins Branch into smaller venules Have one way valves to prevent back flow of blood

Assessment Techniques Measuring pulse and blood pressure Listening to heart sounds Determining cardiac output Measuring muscle activity with electrocardiography Inserting a cardiac catheter Using echocardiography

Pulse The pressure of the blood pushing against the wall of an artery as the heart beats and rests More easily felt in arteries that lie close to skin and pressed against bone

Pulse Points Temporal-temple Carotid-neck-emergencies Brachial-inner aspect of elbow-B/P Radial-wrist-most common site for pulse Femoral-groin Popliteal-knee Pedal-top of foot

Pulse Rates Noted as number beats per minute Varies due to age, sex, body size Adult: 60-90 Men: 60-70 Women: 70-80 Children >7: 72-90 1-7: 80-120 Infants: 90-140

Factors Affecting Pulse Rate Increased rates: Exercise/excitement Stimulant drugs Shock Nervous tension Decreased rates: Sleep Depressant drugs Heart disease Coma

Blood Pressure Force of blood against walls of arteries Systolic pressure: When heart contracts Normal range: 90-140 Diastolic pressure: When heart relaxed Normal range: <100 Written as fraction: Systolic over diastolic Normal: <120/80 mmHg

Individual Factors Influencing B/P Increase: Excitement, anxiety, nervous tension Stimulant drugs Exercise and eating Decrease: Rest or sleep Depressant drugs Excessive blood loss