1Y: The Circulatory System

Question 1

Why do we need a circulatory system? (2)

Answer 1

The circulatory system is a system of organs that;

1. Allows blood to transport substances likle oxygen and nutrients to the cells of the body.
2. It also transports wastes away like carbon dioxide from the cells.

Question 2

What are the 5 functions of blood?

Answer 2

1. To transport oxygen to the cells
2. To transport food to the cells
3. To transport waste materials away from cells
4. To help fight infection
5. To help keep the body at the correct temperature

Question 3

What is a tissue?

Answer 3

A tissue is a group of cells with a similar structure and function.​

Blood is a type of tissue, because it is made up of similar cells that work together.

Question 4

What is the straw-coloured liquid blood is made up of?

Answer 4

Blood is made up of a straw-coloured liquid called plasma.

Question 5

Name the three types of blood cells and their functions?

Answer 5

There are three types of blood cells floating in the plasma:

1. Red blood cells: Carry oxygen to the body cells
2. White blood cells: Fight infection
3. Platelets: Clot blood when blood vessels are damaged

Question 6

What is Plasma made up of?

What is carried along in the Plasma? (3)

Answer 6

What is Plasma made up of?

• Plasma is made up of mostly water and proteins.

What is carried along in the Plasma? (3)

1. Blood cells are carried along the blood vessels floating in the plasma.
2. Foods such as glucose, vitamins and minerals are also carried in the plasma.
3. Heat from hard-working organs such as the liver and muscles is transferred throughout the body by the plasma.

Question 7

How do the Red Blood Cells carry oxygen to the cells?

Answer 7

1. Red blood cells have a red pigment (colour) called haemoglobin.
2. When oxygen enters the blood, it enters the red blood cells and attaches to the haemoglobin.
3. It then travels in the blood attached to the haemoglobin.
4. When the blood arrives at the cells, the oxygen gets released into the cells.

Question 8

How do White Blood Cells fight infection?

Answer 8

• Some white blood cells can surround bacteria and other foreign organisms that enter the body.
• The white cells then take the organism into itself (engulfs) and digests it.

Question 9

How do Platelets help blood clot?

Answer 9

• Platelets play an important role in helping to clot blood wherever a blood vessel gets damaged.
• This clot prevents blood from escaping and it also prevents microorganisms from entering the body.

Question 10

Where are blood cells made?

Answer 10

• Most types of blood cell are made in the bone marrow – the soft substance found in the centre of bone.
• In adults it is the long bones of the body along with the ribs and vertebrae that make blood.
• In children all the bones make blood.

Question 11

Name the 3 tyes of blood vessels?

Answer 11

(1) Arteries
(2) Veins
(3) Capillaries

Question 12

What are the function of the Arteries?

Answer 12

• Arteries have thick walls that are very strong.
• They are usually deeper in the body than veins.
• Arteries always carry blood away from the heart.

Question 13

What are the function of the Veins?

Answer 13

• Veins have thinner walls and are easier to damage.
• Veins always carry blood towards the heart.

Question 14

What are the function of the Capillaries?

Answer 14

• Capillaries have walls that are only one cell thick.
• Capillaries are extremely narrow because they need to weave in through the organs of the body in order to deliver substances to its cells.
• They also need to take away waste matter.
• Each cell in the body has a capillary very close to it.

Question 15

What type of muscle is the heart made from?

Answer 15

• The heart is an organ made of a unique type of muscle known as cardiac muscle.
• Unlike the muscles on the skeleton (skeletal muscle) it never tires.
• Cardiac means something to do with the heart.

Question 16

What is the function of the heart?

Answer 16

• The hearts function is to pump oxygenated blood all around the body.
• It also sends deoxygenated blood to the lungs to remove carbon dioxide and collect oxygen.

Question 17

Label the Human Heart below?

Answer 17

Human Heart

Question 18

How does the heart work?

Answer 18

• Blood enters the right atrium through the vena cava and the left atrium through the pulmonary vein, at the same time.
• The right atrium and the left atrium contract at the same time to squeeze the blood into the right and left ventricles.
• The right ventricle contracts to force blood into the pulmonary artery to the lungs.
• At the same time, the left ventricle contracts to force blood into the aorta.
• Both of these blood vessels (the pulmonary artery and the aorta) have valves to prevent blood back flow into the chambers of the heart.

Question 19

Why does exercise increase heart rate?

Answer 19

• Exercise requires energy.
• We get energy from respiration.
• Respiration needs oxygen.
• The more exercise done, the more energy required. Therefore, a greater rate of respiration needs more oxygen to the cells.
• Blood delivers oxygen to cells so it needs to move faster in order to deliver enough oxygen for the increased level of respiration

Question 19

How do the organs of the circulatory system work with each other?

Answer 19

1. Heart and arteries: Arteries are the blood vessels that carry blood away from the heart and carry it towards the organs of the body.
2. Heart and veins: Veins are the blood vessels that carry blood away from the organs of the body and deliver it back to the heart.
3. Arteries and capillaries: Arteries are larger blood vessels, too big to get near individual cells in the body. The arteries break up into smaller blood vessels called capillaries which can get very close to the cells.
4. Veins and capillaries: When capillaries coming away from an organ join back together again, they join up as a vein.