6.2 The Transport System

Topic 6 Human Health and Physiology

6.2.1 Draw and label a diagram of the heart showing the four chambers, associated blood vessels, valves and the route of blood through the heart.(Care should be taken to show the relative wall thickness of the four chambers. Neither the coronary vessels nor the conductive system are required)

6.2.2 State that the coronary arteries supply heart muscle with oxygen and nutrients.

6.2.3 Explain the action of the heart in terms of collecting blood, pumping blood, and opening and closing of valves.

(A basic understanding is required, limited to the collection of blood by the atria, which is then pumped out by the ventricles into the arteries. The direction of flow is controlled by atrio-ventricularand semilunar valves)

6.2.4 Outline the control of the heartbeat in terms of myogenicmuscle contraction, the role of the pacemaker, nerves, the medulla of the brain and epinephrine (adrenaline).

(Histology of the heart muscle, names of nerves or transmitter substances are not required)

Aim 7: Simulation and data logging involving heart rate monitors, or data logging involving an EKG sensor to measure electrical signals produced during muscle contractions, can be used.

6.2.5 Explain the relationship between the structure and function of arteries, capillaries and veins.

6.2.6 State that blood is composed of plasma, erythrocytes, leucocytes (phagocytes and lymphocytes) and platelets.

6.2.7 State that the following are transported by the blood: nutrients, oxygen, carbon dioxide, hormones, antibodies, urea and heat.

(No chemical details are required)

The Heart

The mammalian heart is a muscular pump. The mammalian heart is a closed system. It has a double circulation system (passes through the heart

twice). The mammalian heart has two sides separated by a

muscular septum. The mammalian heart has 4 chambers:

Left and right atria (singular - atrium) Left and right ventricles

The Heart

Handout: The Heart

The Heart

The walls of the atria are thinner than the walls of the ventricles

Coronary arteries around the heart supply the heart with blood.

The heart consist of cardiac muscle which can contract without nervous or hormonal impulses.

Path of blood through the heart

The path blood follows through the heart is: Blood returns to the heart via the vena cava (superior and inferior) Blood enters the right atrium and then passes through the

atrioventricular (tricuspid) valve to the right ventricle. Blood is then pumped out of the heart through the semi-lunar

valves to the lungs via the pulmonary arteries. Oxygenated blood returns to the heart from the lungs via the

pulmonary veins and enters the left atrium. Blood then passes through the atrioventricular (bicuspid) valve to

the left ventricle. Blood is then pumped out of the heart and to the body via the

largest artery in the body, the aorta.

The Heart Beat

The heart beat is myogenic, meaning that the contraction originates in the heart itself.

There is no need for nervous impulses from the brain. Contraction of the heart is known as systole and relaxation is known as diastole.

The heart beat starts in the sinoatrial node, a small patch of tissue sometimes called the pacemaker and passes to the atrioventricular node.

The heart beat rate can be altered by nervous messages from the brain or from hormones eg: adrenaline

Handout: The Heart Beat

Blood Vessels

There are 3 main types of blood vessels; Arteries Veins Capillaries

Arteries carry blood away from the heart and generally carry oxygenated blood. Arteries are thicker to handle the higher pressure of the blood travelling through them.

Veins carry blood back to the heart and generally carry deoxygenated blood. Veins have valves (semi-lunar valves) to prevent back flow of blood.

Capillaries connect arteries and veins and are a network of tiny blood vessels, with walls that are one cell thick. No cell in the body is very far from a capillary.

Blood Vessels

Handout: Blood Vessels

Blood Blood is composed of:

Plasma (55%) Plasma is mainly water Carries absorbed nutrients, hormones ,antibodies, urea and carbon

dioxide . Erythrocytes (red blood cells)

Carry respiratory gases; oxygen and a little carbon dioxide Produced in the red bone marrow and destroyed in the liver and

spleen. Leucocytes (white blood cells)

Larger than erythrocytes Responsible for fighting infection Numerous types; phagocytes(neutrophils, macrophages),

lymphocytes (B cells and T cells) Platelets

Cause blood clotting, smaller than erthrocytes

6.2.1 Draw and label a diagram of the heart showing the four chambers, associated blood vessels, valves and the route of blood through the heart.(Care should be taken to show the relative wall thickness of the four chambers. Neither the coronary vessels nor the conductive system are required)

6.2.2 State that the coronary arteries supply heart muscle with oxygen and nutrients.

6.2.3 Explain the action of the heart in terms of collecting blood, pumping blood, and opening and closing of valves.

(A basic understanding is required, limited to the collection of blood by the atria, which is then pumped out by the ventricles into the arteries. The direction of flow is controlled by atrio-ventricularand semilunar valves)

6.2.4 Outline the control of the heartbeat in terms of myogenicmuscle contraction, the role of the pacemaker, nerves, the medulla of the brain and epinephrine (adrenaline).

(Histology of the heart muscle, names of nerves or transmitter substances are not required)

Aim 7: Simulation and data logging involving heart rate monitors, or data logging involving an EKG sensor to measure electrical signals produced during muscle contractions, can be used.

6.2.5 Explain the relationship between the structure and function of arteries, capillaries and veins.

6.2.6 State that blood is composed of plasma, erythrocytes, leucocytes (phagocytes and lymphocytes) and platelets.

6.2.7 State that the following are transported by the blood: nutrients, oxygen, carbon dioxide, hormones, antibodies, urea and heat.

(No chemical details are required)