Components of the Cardiovascular SystemGenerating & Measuring heart impulses

To transport oxygen and carbon dioxide around the body

To distribute nutrients and transport waste

To maintain body temperature

To circulate hormones

• With its massive infrastructure within our body, thecardiovascular system is our very own transportation system.

• As such, it has four (4) main functions:

“Closed” system “Open” system

Our circulatory system is a “closed” system

complete, single

Oxygenated blood

incomplete, double

De-oxygenatedblood

complete, double

Mixed blood

Our circulatory system is a “complete, double” system

STRUCTURE and FUNCTION

The circulatory system is made upof 3 components:

a) The heart (a pump) – that pushesblood through the vessels

b) Blood vesselsc) A fluid in which materials are

transported (i.e. blood)

heart

blood vessels

blood

heart

blood vessels

blood

Two (2) main circuits:

a) The Pulmonary circuit – bloodvessels that carry blood to the lungswhere it picks up oxygen and thenback to the heart.

b) The Systemic circuit – blood vesselsthat carry oxygen rich blood to thebody tissues and deoxygenatedblood back to the heart.

A third minor circuit:

c) The Coronary circuit – blood vesselssurround the heart to provide itwith oxygen

site of gas exchange

pulmonary

systemic

site of gas exchange

septum

right lung

neck and head

trunk and legs

1. The heart is really a double pump separated inthe middle by a wall called a septum.

2. The heart consists of 4 chambers.two (2) top chambers = atriums,two (2) bottom = ventricles.

left lung 3. The left side of the heart receivesoxygen-rich blood from the lungs &pumps it to the body.

4. The right side of the heart receivesdeoxygenated blood back from thebody and pumps it to the lungs topick up more oxygen.

Vena cava

Vena cava

Vein Artery

Arteriole

Venule

Capillary

blood exchange inthe capillaries

Blood from heartO2

blood going to heartCO2

a) Arteries: blood vessels that carry blood away from the heart. thick walls of muscular layers largest is the aorta that carry oxygenated blood to the body

b) Veins: blood vessels that carry blood towards the heart. veins have thinner walls than arteries and contain valves to preventback flow of blood (i.e. so blood can be pumped against gravity).

major veins are the vena cavas that carry deoxygenated blood tothe right side of the heart.

c) Capillaries: very small blood vessels, red blood cells must travel single-file,gases exchange across the walls of capillaries and into thesurrounding tissues.

When tending wound, apply ice or cold solutionto constrict blood flow!

Bloodcomponent

Diagram Function

Plasma Allowcellstoeasilytravelthroughvessels

Redbloodcells(erythrocytes)

CarryO2tothecells,andcarryCO2fromthecellstothelungstobeexhaled

Whitebloodcells(leukocytes)

Actasyourimmunesystem,circulatethroughthebodyengulfingharmfulparticles

Platelets Platelets+redbloodcellsjoinandformclots

The average adult has about 5L of blood. Blood is 55% liquid, called plasma and 45% cells (red blood cells, white

blood cells and platelets)

aorta

left pulmonary vein

left pulmonary artery

left atrium

left ventricle

superior vena cava

right pulmonary vein

right pulmonary artery

right atrium

Coronary circuit

right ventricle

inferior vena cava

http://www.sciencehelpdesk.com/unit/bg3/2

Sinoatrial (S.A.) Node: the pace maker of the heart. beats are regulated at about 72 beats/min. its activity is triggered by the swelling ofthe atrial walls.

once activated, it triggers the A.V. node.

Atriaventricle (A.V.) Node: is another pace maker it prepares the fibres in the septum to

contract the Right and Left Ventricles.

Valves: there are two (2) types of valves

1. Atrioventricular valves:

located between the atria and ventricles. has three or two flaps these valves open when the atria contract, once the ventricles have filled, the AV valvessnap shut to prevents the backflow of bloodto the atria.

2. Semi-lunar valves:

has three (2) flaps these open when the ventricles contract. on the right, blood is pumped to the

pulmonary artery, and simultaneously on theleft, blood is pumped into the aorta)

once completed, these valves snap shut toprevents the backflow of blood into theventricles.

Electrocardiography:

Time (s)

ECG shows three (3) recognizable waves:

• P wave – small wave immediately before atria contraction• QRS complex – complicated wave before ventricle contraction• T wave – when the ventricle relaxes and preparing for the next contraction event

“Lubb-dubb”: Heart sound ‘lubb dubb’ is the

Two (2) types of blood pressure:

a) Systolic pressure: when blood is pumped out of the left ventricle

b) Diastolic pressure: the pressure in the artery walls in a relaxation state

Q. What is happening in the heart during Diastolic Pressure?The atria + ventriclesare filling with blood.

dshutting of the two sets of valves respectively.

Blood pressure: your pulse (feel as a surge ofblood passes through your arteries.)

Blood pressure is measured in mm of Hg,

Blood pressure is written as:systolic pressurediastolic pressure

Normal blood pressure is 120/80.

Sphygmomanometer