Cardiovascular System

I. System Anatomy

Heart Pumps Blood

Blood VesselsDeliver 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 beatsAlso called the Sinoatrial node

Approximate average heart rate is 75 bpm (beats per minute)

Cardiac Cycle

DiastoleHeart relaxationPressure in heart is lowBicuspid/Tricuspid are openPulmonary and Aortic Valves are ClosedBlood flowing from atrium to ventricle

Cardiac Cycle (cont)

SystoleHeart Contraction (pumping)Pressure in heart is highBicuspid/Tricuspid valves are closedAortic and Pulmonary valves are openBlood 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 heartHave Thick walls due to high pressure of

bloodHave all three layersExpand 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 thinOne have inner layer (tunica intima)Come into contact with cellsLink between arteries and veinsSite 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 soundsVentricle is contracting

Diastolic pressureNumber when sounds stopWhen 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 bpWarm – dilates blood vessels = decrease in bp

Diet Clogged arteries Physical Activity

Factors that Affect blood pressure

Chemicals Epinephrine (Adrenaline) increases blood

pressureNicotine increases due to constricting of

veinsAlcohol and histamine decrease due to

dilation of veins