1. The Heart

2. The Heart Muscular pump, about the size of a clenched fist
Approximately 12cm long
9cm wide
6cm thick
Weighs approx 11 ounces
The average adult heart beats –
72 times a minute;
100,000 times a day;
3,600,000 times a year;
2.5 billion times during a lifetime.

3. Because the heart has its own electrical impulse, it can continue to beat even when separated from the body, as long as it has an adequate supply of oxygen
When the body is at rest, it takes only 6 seconds for the blood to go from the heart to the lungs and back, only 8 seconds for it to go the brain and back, and only 16 seconds for it to reach the toes and travel all the way back to the heart
5% of blood supplies the heart, % goes to the brain and central nervous system, and 22% goes to the kidneys.

4. The Heart continued
Made up of a special muscle called Myocardium
This can contract continuously without getting tired
Main purpose is to drive blood through the arteries
This delivers blood to the working muscles and other tissues.
The heart is located in the chest cavity - posterior to the breastbone, between the lungs and superior to the diaphragm
The Heart sits in a twin layered sac known as the Pericardium
Filled with pericardial fluid
Prevents friction as your heart beats.

5. The heart is split into 4 sections- Right & Left side – separated by the septum Upper & Lower chambers – the atria & ventricles

6. Atria Latin for “entrance hall,” The upper chambers of the heart
They receive blood.
Right Atrium – receives deoxygenated blood from the body (Via the Vena Cava)
Left Atrium – receives oxygenated blood from the lungs (Via the pulmonary Vein)

7. Latin for “little belly.”
Ventricles
Latin for “little belly.”
The lower chambers of the heart
They have thicker walls and are stronger
Job is to pump the blood
Right Ventricle pumps blood to the lungs (pulmonary circulation)
Left ventricle pumps blood to the body (systemic circulation)

8. Valves
The “thump-thump” of a heartbeat is the sound made by the four valves of the heart closing
All valves make sure that the blood flows in one direction, and there is no back flow
Chordae Tendineae
Cord like tendons that connect to the tricuspid and bicuspid valves
Ensure the valves stay the right way round and keep the blood flowing in the same direction.
Pulmonary Valve
Aortic Valve
Bicuspid Valve (mitral valve)
Tricuspid Valve

9. Aorta and Vena Cava The largest Artery is the Aorta
The largest vein is the Vena Cava
Carries blood directly into the right atrium from the body
- Superior vena cava
brings blood from the upper body
Inferior Vena Cava
Brings blood from the lower body.
The largest Artery is the Aorta
Carries oxygenated blood directly out of the left ventricle to the body tissues

10. Pulmonary Circulation
Pulmonary Vein
Carries oxygenated blood from the lungs to the left atrium
It is the only vein that carries oxygenated blood.
Pulmonary Artery
Carries deoxygenated blood from the right ventricle to the lungs.
It is the only artery that carries deoxygenated blood

11. The Heart = Double pump
To describe the flow of blood around the heart and the body, you will need to mention that the heart is made up of two pumps
Pulmonary circulation
Pumps blood to and from the lungs
Systemic circulation
Pumps blood around the body

12. The right side of the heart
Blood enters the heart from the body via the vena cavae,
It goes into the right atrium
The right atrium contracts and the blood goes through the tricuspid valve and into the right ventricle
The right ventricle contracts and the blood is pushed out of the heart through the semi lunar or pulmonary valve and into the pulmonary artery
The pulmonary artery carries the blood to the lungs
The heart relaxes and the valves close to stop back flow of the blood
In the lungs, the blood becomes oxygenated, and begins it’s journey back to the heart through the pulmonary vein

13. The Left side of the heart
The heart is relaxed, and this allows blood to enter the left atrium from the pulmonary vein
The left atrium contracts and pushes blood through the bicuspid valve and into the left ventricle
The left ventricle has a very strong muscular wall and contracts very strongly.
This closes the bicuspid valve to prevent backflow, and pushes the blood through the aortic valve and into the aorta. This is the largest artery and splits taking the blood to different areas of the body
The heart contracts and the aortic valve closes, preventing back flow of the blood.

14. Cardiac Conduction
Cardiac conduction is the rate at which the heart conducts electrical impulses.
Cardiac muscle cells contract spontaneously and are coordinated by the sinoatrial node (the pacemaker) located in the right atrium
Other factors that influence heart rate include endocrine hormones, body temperature and exercise.

15. Cardiac Cycle
The cardiac cycle is the sequence of events that occur when the heart beats.
There are two phases of this cycle which are the diastole and systole phases.
During the diastole phase, the atria and ventricles are relaxed and blood flows into the atria and ventricles.
In the systole phase, the ventricles contract sending blood to the rest of the body.

16. Terminology Heart rate (H.R.) Stroke Volume (S.V.) Cardiac Output
The amount of times the heart beats in a minute.
Usually measured in beats per minute (b.p.m.)
Stroke Volume (S.V.)
The amount of blood leaving the left ventricle in one beat.
Normally measure in mililitres
Cardiac Output
The amount of blood leaving the heart in one minute
Normally measured in litres/minute
Cardiac Output = Stroke Volume x Heart Rate

17. Aorta
Superior
Vena cava
Pulmonary Artery
Pulmonary Valve
Pulmonary
Vein
Right Atrium
Left Atrium
Tricuspid
Valve
Left Ventricle
Bicuspid
Valve
Right Ventricle
Inferior
Vena cava
Septum