Circulatory System

Question 1

What is the circulatory system?

Answer 1

The heart pumps blood around the body, enabling the transport of oxygen, carbon dioxide, nutrients and waste.
- Makes up the network that delivers blood to the body’s tissue.

Question 2

What is the role of the circulatory system?

Answer 2

The circulatory system (cardiovascular system) is an organ system that moves substances to and from cells; it can also help stabilise body temperature and pH (part of homeostasis).

Blood passes from arteries to veins through capillaries, which are the thinnest and most numerous of the blood vessels and these capillaries help to join tissue with arterioles for transportation of nutrients to the cells.

Question 3

What are the main components of the circulatory system?

Answer 3

Heart, blood (arteries, veins, capillaries), and blood vessels (red + white blood cells, plasma).

Question 4

What is the role of the heart?

Answer 4

• Key organ in the circulatory system
• The main function is to propel blood throughout the body

Question 5

What is the role of blood vessels?

Answer 5

• Different types of blood vessels carry blood to and from the heart.

Question 6

What is the role of arteries?

Answer 6

• Blood vessels that carry blood away from the heart.
• Thickest blood vessels with muscular walls that contract to keep the blood moving away from the heart and throughout the body.

Question 7

What is the role of veins?

Answer 7

• Blood vessels that carry blood back to the heart.
• Not as muscular as arteries but contain valves that prevent blood from flowing backwards

Question 8

What is the role of capillaries?

Answer 8

• Connects arteries and veins.
• Extremely tiny but one of the most important parts of the circulatory system because they deliver oxygen and nutrients to the cells.
• Also remove waste products such as carbon dioxide.

Question 9

What is the role of platelets?

Answer 9

• Small cells with no nucleus that help the blood to clot to prevent blood loss.

Question 10

What is the role of red blood cells?

Answer 10

• Carry oxygen throughout the body.

Question 11

What is the role of white blood cells?

Answer 11

• Fights infections.

Question 12

What is the role of plasma?

Answer 12

• Yellowish liquid that carries nutrients, hormones and proteins throughout the body.
• Drops off oxygen and glucose and picks up cellular waste products.

Question 13

What is the heart?

Answer 13

The heart is a hollow sack of cardiac muscle that fills with blood, and contracts, forcing the blood out to the body between 60-80 times per minute at rest. The action of the heart starts the blood circulating around the body. The blood carries oxygen and dissolved nutrients on its way to the cells, and carbon dioxide and waste products on the return journey.

Question 14

Valves prevent the blood from flowing in the wrong direction. The tricuspid valve prevents the blood flowing from the _____________ to the _____________. The bicuspid valve prevents the blood flowing from the ___________ to the _____________. There are 2 semilunar valves. One prevents the blood flowing from the _______________ to the ____________. The other prevents the blood flowing from the ___________ to the _____________.

Answer 14

Valves prevent the blood from flowing in the wrong direction. The tricuspid valve prevents the blood from flowing from the right ventricle to the right atrium. The bicuspid valve prevents the blood from flowing from the left ventricle to the left atrium. There are 2 semilunar valves. One prevents the blood from flowing from the pulmonary artery to the right ventricle. The other prevents the blood from flowing from the aorta to the left ventricle.

Question 15

What happens when blood is forced out of the heart during a contraction?

Answer 15

It moves along the arteries as a wave. This wave can be felt at various places in the body where the artery is located close to the surface. The wrist, or radial pulse, and neck, or carotid pulse, are the easiest to locate.

Question 16

What is the cardiovascular system’s job?

Answer 16

To ensure blood is continually supplied, as nearly every cell in the human body requires a blood supply.

Question 17

How does the cardiovascular system control body temperature?

Answer 17

Directs blood to the skin when it is hot and draws blood back towards the core of the body when it is cold.
- When blood is being directed to the skin to lose heat, the skin becomes red in appearance.
- In cold conditions, blood is shunted away from the extremities to protect vital organs. When this occurs, the extremities (like the nose and fingers) turn white and frostbite may occur.

Question 18

How many circuits is the circulatory system made up of?

Answer 18

2

Question 19

What are the 2 types of circuits?

Answer 19

1. Systemic circuit
2. Pulmonary circuit

Question 20

What does the systemic circuit do?

Answer 20

Carries blood around the body to deliver oxygen and return de-oxygenated blood to the heart.
- Blood also carries nutrients and waste.

Question 21

What does the pulmonary circuit do?

Answer 21

Carries blood to the lungs to be oxygenated and then back to the heart. In the lungs, carbon dioxide is removed from the blood, and oxygen is taken up by the haemoglobin in red blood cells.

Question 22

What is the pathway that blood travels through the heart?

Answer 22

1. Right Atrium (deoxygenated blood)
2. Tricuspid Valve
3. Right Ventricle
4. Pulmonary Valve
5. Pulmonary Artery
6. Lungs
7. Left Atrium (oxygenated blood)
8. Left Ventricle
9. Aortic Valve
10. Aorta
11. Travels through the rest of the body

Question 23

Blood is the third component of the circulatory system, the ________ that flows through the vessels, that is pumped by the heart. Blood accounts for about ____ of total body weight. Blood consists of ____ plasma. Plasma is mostly ______ (90%), but also includes dissolved nutrients, proteins, salts, glucose, _________, gases and waste products. The function of plasma is to ______ these substances as well as the blood cells and their contents around the body.
Blood cells make up _____ of blood volume, and 95% of these are red blood cells (____). The red blood cell’s main function is to carry ________ and it does this through the presence of a protein called _____________. Red blood cells are made in the marrow of bones.
White blood cells (____) or ____________ come in five different forms, but they all have a similar function, which is to ________ the body from disease. White blood cells are also made in the bone marrow.
____________ are also formed in the bone marrow, and they are small cells that have the important function of _________ the blood. If a person cuts themself or gets a nosebleed, a protein in the plasma called fibrinogen constructs long fibres that form a mesh across the hole. The platelets block this mesh and form a ______. If this clot is exposed to the air it will form a _______. This is the body’s way of protecting itself from losing blood, but also preventing ________ from entering the body.

Answer 23

Blood is the third component of the circulatory system, the fluid that flows through the vessels, that is pumped by the heart. Blood accounts for about 8% of total body weight. Blood consists of 55% plasma. Plasma is mostly water (90%) but also includes dissolved nutrients, proteins, salts, glucose, hormones, gases and waste products. The function of plasma is to transport these substances as well as the blood cells and their contents around the body.
Blood cells make up 45% of blood volume, and 95% of these are red blood cells (RBCs). The red blood cell’s main function is to carry oxygen and it does this through the presence of a protein called haemoglobin. Red blood cells are made in the marrow of bones.
White blood cells (WBCs) or leukocytes come in five different forms, but they all have a similar function, which is to protect the body from disease. White blood cells are also made in the bone marrow.
Platelets are also formed in the bone marrow, and they are small cells that have the important function of clotting the blood. If a person cuts themself or gets a nosebleed, a protein in the plasma called fibrinogen constructs long fibres that form a mesh across the hole. The platelets block this mesh and form a clot. If this clot is exposed to the air it will form a scab. This is the body’s way of protecting itself from losing blood, but also preventing germs from entering the body.

Question 24

Approximately how much blood does an average adult have?

Answer 24

10% of adults weight —— 1.2-1.5 gallons (10 units).

Question 25

What substance does the blood transport towards a muscle cell, and in what parts of the blood is each of these carried?

Answer 25

Oxygen, transported by RBCs, supplies nutrients such as glucose and fatty acids transported by plasma.

Question 26

What 2 substances does the blood transport away from a muscle cell, and in what part of the blood is each of these carried?

Answer 26

Carbon dioxide + lactic acid —– cellular waste products, done via. plasma.

Question 27

What are the different types of blood groups and rhesus factors of blood?

Answer 27

Rh positive or Rh negative —— A, B, O

Question 28

How much blood is generally given during blood donation? How does the body recover?

Answer 28

470mL (8% of average adult blood volume)
- The body replaces this volume within 24-48 hours + replenishes RBCs in 10-12 weeks in the bone marrow.

Question 29

What is stroke volume?

Answer 29

Amount of blood pumped out of the left ventricle during a contraction.

Question 30

What happens to stroke volume when training?

Answer 30

Stroke volume increases gradually as the heart rate increases. As the body requires more oxygen, the heart rate continues to rise and beats more strongly. This is due to an increased amount of blood being pumped with each contraction of the heart.

Question 31

What is cardiac output?

Answer 31

The total amount of blood pumped out of the heart each minute.

Question 32

What is the average cardiac output at rest?

Answer 32

5-6 litres per minute.

Question 33

What is the formula for calculating cardiac output?

Answer 33

Cardiac output = stroke volume x heart rate
- This is expressed in litres per minute.

Question 34

What happens to cardiac output when training?

Answer 34

Cardiac output increases as the heart rate increases.

Question 35

What happens to the cardiac output of an untrained individual, when training?

Answer 35

Untrained people are able to increase their cardiac output to approximately 21 litres per minute when exercising while elite endurance athletes can increase their cardiac output to approximately 35 litres per minute.