Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and...

22
Where Is Your Heart?

Transcript of Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and...

Page 1: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

Where Is Your Heart?

Page 2: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

Circulation of blood

Pulmonary circulation - Blood from heart to lungs and back again

Systemic circulation – blood from heart to the rest of the body and back again

In mammals there is double circulation because of lungs. Blood passes the heart twice in a complete circuit: Double Circulation

Page 3: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

Advantages of double circulation

• Blood entering lungs is at low pressure compared to blood leaving. This ensures that blood flows slowly in lungs allowing more time for blood to be well oxygenated.

• Heart pumps blood at high pressure to rest of body so that oxygenated blood can be distributed more quickly to tissue cells.

Page 4: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

Structure of heart• The whole heart is surrounded by a ‘bag’ called pericardium. • Pericardium made up of 2 layers of membrane with inner layer in contact

with heart.• Between the 2 membranes is a fluid that reduces friction when heart is

beating.

pericardium

Page 5: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

Heart Chambers4 chambers:- 2 smaller upper chambers (atria)

- 2 bigger lower chambers (ventricles)

The right side of heart is completely separated from the left by a muscular wall called median septum.

This is to avoid mixing of blood which when occur, will reduce the amount of oxygen carried to tissue cells.

Median septum

Why does the left ventricle has a much thicker wall than the right ventricle?

Page 6: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

Did you know?

• The walls of the ventricles of the heart are more muscular than those of the atria

because the ventricles have to force blood out of the heart, higher pressure is needed whereas the atria only force blood into the ventricles. (does not require high pressure)

• The right ventricle has thinner walls than the left ventricle

as it pumps blood to lungs which is a short distance away. Left ventricle needs thick wall to withstand high pressure as it pumps blood to aorta and round the body.

Page 7: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

Pathway of blood

(Cord-like tendons that help attach valves to walls)

Page 8: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

Label the structure of the heart

What is the purpose of valves in the heart?Valves – Maintain 1 way flow of blood (prevent backflow)

Anterior (Superior) vena cava

Right atrium

Posterior (Inferior) vena cava

Tricuspid valve

Right ventricle

Left ventricle

Bicuspid valve (mitral valve)

Aortic valve (semi-lunar valve)

Left atrium

Pulmonary veins

Pulmonary artery

Aortic arch/AortaPulmonary valve (semi-lunar valve)

Pulmonary arch

Page 9: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

Did you know?

• The walls of the ventricles of the heart are more muscular than those of the atria because the ventricles have to force blood out of the heart, higher pressure is needed whereas the atria only force blood into the ventricles. (does not require high pressure)

• The right ventricle has thinner walls than the left ventricle as it pumps blood to lungs which is a short distance away. Left ventricle needs thick wall to withstand high pressure as it pumps blood to aorta and round the body.

Page 10: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

Pathway of blood (explained)

1. Deoxygenated blood from various parts of the body return to the right atrium of heart via the anterior (superior) vena cava (head, neck and arms) and posterior (inferior) vena cava (other parts of body).

2. Right atrium contracts allowing blood to flow into right ventricle. Tricuspid valve opens when the pressure in right atrium is higher than that in right ventricle to allow blood to flow through. The tricuspid valve consists of 3 flaps that are attached to walls via chordae tendineae and point downwards to allow easy flow of blood.

Page 11: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

Pathway of blood (explained)

3. Right ventricle contracts and high blood pressure closes tricuspid valve preventing backflow of blood into right atrium. Blood leaves the right ventricle via the pulmonary arch which divides into 2 pulmonary arteries, one to each lung. Semi-lunar valves in the pulmonary arch prevents the backflow of blood into right ventricle.

4. Blood in pulmonary arteries is at low pressure, thus rate of blood flow is slow which gives more time for gaseous exchange in lungs.

Page 12: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

Pathway of blood (explained)

5. Oxygenated blood from lungs is brought back to left atrium via pulmonary veins. Left atrium contracts causing blood pressure in left atrium to be higher than that in left ventricles. Bicuspid valve (mitral valve) with two flaps opens to allow blood to enter left ventricle. When left ventricle contracts, blood leaves through the aortic arch.

6. From aortic arch, blood is distributed to all parts of body except lungs. The aortic arch possess a semi-lunar valve to prevent backflow of blood into left ventricle. Blood entering aortic arch is at a high pressure. 2 coronary arteries, which originate from the aortic arch bring food and oxygen to heart muscles.

Page 13: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

The cardiac cycle

• Sequence of events that take place during the completion of one heartbeat.

• Involves repeated contraction (systole) and relaxation (diastole)

Page 14: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

The Cardiac cycle

1. Both atria and ventricles are relaxed.

• Blood returns to both atria.

Page 15: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

2. Atria contracts, forcing blood into relaxed ventricles.(Atrial systole)

semilunar valves closed

Page 16: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

What happens during

During Ventricular systole…

Tricuspid and Bicuspid valves closed to prevent flow of blood into atrium

Semi-lunar valve opened for blood to flow into aorta and pulmonary arteries

Blood flow from ventricle into aorta and pulmonary artery

Page 17: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

3. After a short pause, ventricles contract (ventricular systole), atria relax.

• Increase in blood pressure in ventricles closes bicuspid and tricuspid valves. (prevent backflow of blood into atria) This produces a loud ‘lub’ sound.

• When pressure in ventricles are higher than in aorta and pulmonary artery, semi-lunar valves open to allow blood to flow into aortic arch and pulmonary arch.

Page 18: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

What happens during

During Ventricular diastole…

Tricuspid and Bicuspid valves open if atrial contraction had taken place OR closed if atrial relaxation.

Semi-lunar valves closed to prevent backflow of blood in aorta and pulmonary artery.

Blood flow from superior vena cavae into right atrium and pulmonary vein into left atrium.

Page 19: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

4. Ventricles relax (ventricular diastole)

• Drop in pressure in ventricles (increase pressure in pulmonary artery and aorta) closes semi lunar valves in both arches to produce a soft ‘dub’ sound (prevent backflow of blood)

• Blood returns to relaxed atria and whole cycle repeats.

Page 20: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

RightAtrium

Tricuspid valve

Superior& inferior vena cava

Pulmonary arteries

RightVentricle

Aorta

Bicuspid valve

Pulmonary veinsLeft

VentricleLeft

Atrium

Semilunar valve /

Aortic valve

PulmonarySemilunar

valve

Lung tissue(pulmonary circulation)

Body tissue(Systemic

circulation)

Route taken by blood flow

through the heart

Page 21: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

How do we identify the side of the heart that contains oxygenated blood?

The side with a thicker muscular wall.

Does that mean that the whole half of the heart will be thicker than the other?

There is NO difference in thickness between the left and right atria.

Questions...

Page 22: Where Is Your Heart?. Circulation of blood Pulmonary circulation - Blood from heart to lungs and back again Systemic circulation – blood from heart to.

Why do you think the separation of deoxygenated and oxygenated blood is important?

What happens if the septum is broken or removed?

Hole in the heart or septal defecthttp://www.webmd.com/video/helex-heart-patch

Septum