Topic 2 - Organisation - Organising Animals

Question 1

What are the four main things in your blood?

Answer 1

1. Red blood cells
2. White blood cells
3. Platelets
4. Plasma

Question 2

Red blood cells function?

Answer 2

1. Red blood cells carry oxygen from the lungs to all the cells in the body.
2. Their shape is a biconcave disc to give them a larger surface area for absorbing oxygen.
3. They don’t have a nucleus which allows for more room to carry oxygen.
4. They contain a red pigment called haemoglobin.

Question 3

What does haemoglobin do?

Answer 3

1. In the lungs, haemoglobin binds to oxygen to become oxyhaemoglobin.
2. In body tissues, the reverse happens- oxyhaemoglobin splits up into haemoglobin and oxygen to release oxygen into the cells.

Question 4

White blood cells function?

Answer 4

1. White blood cells defend against infection.
2. Some produce antibodies to fight pathogens, as well as antitoxins to neutralise any toxins produced by the pathogen.
3. Unlike red blood cells, they do have a nucleus.

Question 5

Platelets function?

Answer 5

1. Platelets are small fragments of cells. They have no nucleus.
2. They help the blood to clot at a wound, to stop blood from pouring out and to prevent pathogens getting in.
3. A lack of platelets can cause excessive bleeding and bruising.

Question 6

Plasma function?

Answer 6

1. Plasma is the pale straw-coloured liquid that carries everything in the blood:
   - Red and white blood cells and platelets
   - Nutrients like glucose and amino acids
   - Carbon dioxide from the organs to the lungs
   - Urea from the liver to the kidneys
   - Hormones
   - Proteins
   -Antibodies and antitoxins

Question 7

Where do arteries carry blood to?

Answer 7

1. Away from the heart

Question 8

Where do veins carry blood to?

Answer 8

1. To the heart

Question 9

Arteries function and adaptions?

Answer 9

1. The heart pumps the blood out at high pressure so the artery walls are strong and elastic.
2. The walls are thick compared to the size of the lumen.
3. They contain thick layers of muscle to make them strong, and elastic fibres to allow them to stretch and spring back.

Question 10

Capillaries function and adaptions?

Answer 10

1. Arteries branch into capillaries.
2. Capillaries are tiny, too small to see.
3. They carry the blood really close to every cell in the body to exchange substances with them.
4. They have permeable walls so that substances can diffuse in and out.
5. They supply food and oxygen, and take away waste like CO2.
6. Their walls are only one cell thick. This increases the rate of diffusion by decreasing the distance over which it occurs.

Question 11

Veins function and adaptions?

Answer 11

1. Capillaries eventually join up to form veins.
2. The blood is at lower pressure in the veins so the walls don’t have to be as thick as artery walls.
3. They have a bigger lumen than arteries to help the blood flow despite the lower pressure.
4. They also have valves to help keep the blood flowing in the right direction.

Question 12

Circulatory system function?

Answer 12

1. Carries food and oxygen to every cell in the body.
2. Carries waste products to wh ere they can be removed from the body.

Question 13

How does the double circulatory system work?

Answer 13

1. Humans have a double circulatory system, two circuits joined together.
2. In the first one, the right ventricles pump deoxygenated blood to the lungs to take in oxygen. The blood then returns to the heart.
3. In the second one, the left ventricle pumps oxygenated blood around all the other organs of the body. The blood gives up its oxygen at the body cells and the deoxygenated blood returns to the heart to be pumped out to the lungs again.

Question 14

How does the heart use its chambers to pump blood to the lungs to become oxygenated?

Answer 14

1. Deoxygenated blood flows into the right atrium from the vena cava.
2. The right atrium contracts, pushing the blood into the right ventricle.
3. The right ventricle contracts, pushing blood into the pulmonary artery where it is taken to the lungs and is oxygenated.

Question 15

How does the heart use its chambers to pump blood to the rest of the body after being oxygenated?

Answer 15

1. Oxygenated blood flows into the left atrium from the pulmonary vein.
2. The left atrium contracts, pushing blood into the left ventricle.
3. The left ventricle contracts, pushing blood into the aorta where the oxygenated blood is taken to all the other organs in the body.

Question 16

What is a pacemaker?

Answer 16

1. Your resting heart rate is controlled by a group of cells in the right atrium wall that act as a pacemaker
2. These cells produce a small electric impulse which spreads to the surrounding muscle cells, causing them to contract

Question 17

What is an artificial pacemaker?

Answer 17

1. An artificial pacemaker is used to control heartbeat if the natural pacemaker doesn’t work properly for example an irregular heartbeat
2. It is a little device that is implanted under the skin and has a wire going to the heart
3. It produces an electric current to keep the heart beating regularly

Question 18

Where are the lungs?

Answer 18

Thorax

Question 19

What path does air take when you breathe it in?

Answer 19

1. The air that you breathe in goes through the trachea. This splits into two tubes called bronchi, one going to each lung
2. The bronchi split into progressively smaller tubes called bronchioles
3. The bronchioles finally end at small bags called alveoli where gas exchange occurs

Question 20

What are alveoli?

Answer 20

1. The lungs contain millions and millions of little air sacs called alveoli surrounded by a network of blood capillaries
2. This is where gas exchange happens

Question 21

How do the blood, alveoli and the lungs link?

Answer 21

1. The blood passing next to the alveoli has just returned to the lungs from the rest of the body, so it contains lots of carbion dioxide and very little oxygen
2. Oxygen diffuses out of the alveolus and into the blood. Carbon dioxide diffuses out of the blood and into the alveolus to be breathed out
3. When the blood reaches body cells oxygen is released from the red blood cells and diffuses into the body cells
4. At the same time, CO2 diffuses out of the body cells and into the blood. It is then carried back to the lungs

Question 22

How are the lungs adapted for gas exchange?

Answer 22

1. Large surface area. The lungs contain millions of tiny air sacs called alveoli. This creates a huge surface area for gas exchange
2. Thin walls. The walls of the alveoli and surrounding capllaries are only one cell thick, this increases the rate of diffusion by decreasing the distance over which it has to occur
3. The lungs have a rich blood supply from a network of capillaries. This maintans a steep concentration gradient for oxygen and carbon dioxide
4. Moist lining. The alveoli are coated with a thin layer of moisture, which helps dissolve gases and allows them to diffuse more easily