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