Cardiovascular System

I. System Anatomy  Heart  Pumps Blood  Blood Vessels  Deliver blood to cells

II. System Physiology  Transports oxygen, nutrients, hormones, carbon dioxide, waste products and other substances

III. Heart  Size of your fist  Weighs less than 1 pound  Made of Cardiac Muscle Tissue  Has 4 chambers  Right Atrium – receives blood from body  Right Ventricle – pumps blood to lungs  Left Atrium – receives blood from lungs  Left Ventricle – pumps blood to body (most muscular part)

Superior Vena Cava Right Pulmonary Artery Right Atrium Tricuspid Valve Right Pulmonary Veins Right Ventricle Inferior Vena Cava Aorta Left Pulmonary Artery Left Atrium Bicuspid/Mitral Valve Left Ventricle Septum Pulmonary Valve Aortic Valve Left Pulmonary veins

Path of Blood  1. Superior and Inferior Vena Cava  2. Right Atrium  3. Tricuspid Valve  4. Right Ventricle  5. Pulmonary Valve  6. Right/Left Pulmonary Arteries  7. Lungs – get rid of Carbon Dioxide, Pick up Oxygen  8. Pulmonary Veins

Path of Blood (cont)  9. Left Atrium  10. Bicuspid/Mitral Valve  11. Left Ventricle  12. Aortic Valve  13. Aorta  14. Arteries  15. Capillaries – give oxygen to cells, pick up carbon dioxide  16. Veins  Again!!

IV. Heart Physiology  Heart pumps entire volume of blood 1000 times per day around the body  Double Pump System  Right Side – Pulmonary Circuit – pumps blood to lungs to pick up oxygen and get rid of carbon dioxide  Left Side – Systemic Circuit – pumps blood to body – brings oxygen to cells and picks up carbon dioxide

Heart Physiology (cont)  Valves  Let blood flow in one direction only (prevent backflow) 1. AV valves – Tricuspid and Bicuspid – between atrium and ventricle Make first sound of heart beat (lub) 2. Pulmonary and Aortic Valves Make second sound of heart beat (dup)

Heart Physiology (cont)  Cardiac muscle is involuntary  Must have a control system to coordinate the heart beat  Pacemaker – sets the pace for the heart and coordinates the beats  Also called the Sinoatrial node  Approximate average heart rate is 75 bpm (beats per minute)

Cardiac Cycle  Diastole  Heart relaxation  Pressure in heart is low  Bicuspid/Tricuspid are open  Pulmonary and Aortic Valves are Closed  Blood flowing from atrium to ventricle

Cardiac Cycle (cont)  Systole  Heart Contraction (pumping)  Pressure in heart is high  Bicuspid/Tricuspid valves are closed  Aortic and Pulmonary valves are open  Blood is being pumped to lungs and body

Blood Vessels  Transport blood from heart throughout the body  Can have up to three layers  Tunica intima – inner layer – made of squamous epithelial tissue  Tunica media – middle layer – made of smooth muscle tissue  Tunica externa – outer layer – made of fibrous connective tissue

Arteries  Carry blood AWAY from the heart  Have Thick walls due to high pressure of blood  Have all three layers  Expand as blood is pumped  You can feel a pulse in your arteries

Veins  Carry blood TOWARDS the heart  Pressure is lower than in arteries  Have thinner walls  Have VALVES to prevent backflow of blood  Usually blood tests are done with blood from the veins

Capillaries  Very thin  One have inner layer (tunica intima)  Come into contact with cells  Link between arteries and veins  Site of gas (oxygen and carbon dioxide) and nutrient exchange with cells

Atrial Pulse  Expanding and recoil of arteries that occur with each beat of heart  Average 70 to 76 bpm  Don’t use your thumb when taking pulse measurements – you’re thumb has its own pulse

Blood Pressure  Pressure the blood exerts on inner walls of blood vessels  Keeps blood circulating in between heartbeats  Arteries closest to heart have highest pressure

Measuring Blood pressure  Systolic pressure  Number when you first hear sounds  Ventricle is contracting  Diastolic pressure  Number when sounds stop  When ventricles are relaxing

Measuring Blood Pressure  Put cuff with stethoscope over the brachial artery  Close valve and inflate cuff to 160 mmHg – DO NOT GO HIGHER THAN 160 (you are cutting off the circulation to the artery)  Slowly release air and listen for a sound like a heart beat  Record the number at the first soft tapping sound  Sounds will get louder and then decrease  Record the number when the sound stops (blood is flowing freely)

Factors that Affect blood pressure  Normal range: Systolic 110 – 130mmHg; Diastolic 70-80mmHg  Many factors affect blood pressure  Age  Temperature  Cold – constricts blood vessels = increase in bp  Warm – dilates blood vessels = decrease in bp  Diet  Clogged arteries  Physical Activity

Factors that Affect blood pressure  Chemicals  Epinephrine (Adrenaline) increases blood pressure  Nicotine increases due to constricting of veins  Alcohol and histamine decrease due to dilation of veins