Crackin’ Cardiovascular System

The Happy Heart  Size of your fist  Less than 1 pound  Covered by pericardium  Coronary arteries (blood vessels) – give heart blood  4 chambers –2 atria (atrium) – receive blood, top of heart –2 ventricles – discharge blood, bottom of heart

Path of Blood Through the Heart 1. Inferior/Superior Vena Cava (bring blood from body to heart) 2. Right Atrium 3. Tricuspid Valve 4. Right Ventricle 5. Pulmonary Semilunar Valve 6. Pulmonary arteries Lungs – Release CO 2 and picks up O 2

Path of Blood Through the Heart 7. Pulmonary Veins 8. Left Atrium 9. Bicuspid Valve 10. Left Ventricle (biggest part) 11. Aortic Semilunar Valve 12. Aorta 13. Arteries 14. Capillaries (release O 2 to cells, pick up CO 2 ) 15. Veins – Back to Heart AGAIN AGAIN

IV. Hip, Hip Hooray – Heart Physiology  Atria collect blood  Ventricles Discharge blood  Soooo…. Ventricles are the actual pump. When they contract, blood moves.

A. Double Pump System  Right Side  Pulmonary Circuit  Receives oxygen poor blood from body  Pumps to Lungs to pick up Oxygen and release carbon dioxide

A. Double Pump System  Left Side  Systemic Circuit  Receives Oxygen rich blood from lungs  Pumps blood to body cells to supply them with oxygen and pick up carbon dioxide

B. Valves  1. Prevent Backwash  2. Heartbeat

B. Valves (cont)  “lub”-AV valve closing; longer and louder sound  “dub”-Semilunars closing; shorter and sharper

Cardiac Cycle  Diastole  Complete relaxation  AV valves (bi and tricuspid) open  Semilunar valves closed  Atria empty blood into ventricles  Pressure in heart is low

Cardiac Cycle  Systole  Ventricles contract Bi/Tricuspid close,  Semilunar valves open  Blood rushes out of heart  Pressure in heart is high  Atria are filling

Arteries  Take blood away from the heart  No Valves  High Pressure

C. Veins  Take blood toward the heart  Valves to prevent backflow because...  Low pressure, Thin Walls, Far from the heart and change in pressure

D. Capillaries  Connect arteries to veins  Very thin  Transparent, one-cell layer thick  GAS EXCHANGE TAKES PLACE HERE

Flow of blood through vessels  Aorta  Capillary  Vein  Heart

E. Blood Vessel Physiology  Arterial Pulse Pressure wave created by the expansion and recoil of an artery that occurs with each beat of the left ventricle. Average is beats per minute Average is beats per minute Pulse points are listed in book. Take a look and try to find them on your body. Pulse points are listed in book. Take a look and try to find them on your body.

2. Blood Pressure Pressure the blood exerts against the inner walls of blood vessels. Pressure the blood exerts against the inner walls of blood vessels. Force that keeps blood circulating between beats Force that keeps blood circulating between beats Pressure in arteries near the heart Pressure in arteries near the heart Systolic: Pressure in arteries at peak of ventricular contraction Systolic: Pressure in arteries at peak of ventricular contraction Diastolic: Pressure when ventricles are relaxing Diastolic: Pressure when ventricles are relaxing

Procedure for taking blood pressure 1. Pump up to about 150 (exceed systolic). Stops blood flow. 2. Reduce pressure in cuff while listening carefully. 3. When first soft tapping sounds are heard, SYSTOLIC 4. As pressure is reduced, sounds get louder. When no sounds, record DIASTOLIC

3. What messes up blood pressure? Friction in Blood Vessel (viscosity, atherosclerosis) Friction in Blood Vessel (viscosity, atherosclerosis)

3. What messes up blood pressure? Nervous System (narrows vessels)-fear, exercise, blood loss Nervous System (narrows vessels)-fear, exercise, blood loss

3. What messes up blood pressure? Kidneys (alter blood volume) Kidneys (alter blood volume)

3. What messes up blood pressure? Temperature (cold restricts vessels, hot dilates vessels) Temperature (cold restricts vessels, hot dilates vessels)

3. What messes up blood pressure? Chemicals (alcohol & histamines dilate, nicotine constricts) Chemicals (alcohol & histamines dilate, nicotine constricts)