GCSE Biology - 8 - Exchange and Transport in Animals

Explain how the heart causes the blood to move to the lungs?

Blood flows into the right atrium, into the right ventricle. The heart contracts and the blood pressure increases by heat. The blood then moves into the pulmonary artery.

Describe how blood in the aorta is different from the vena cava?

The blood is deoxygenated in the vena cava and it is more darker. It has a greater concentration of carbon dioxide and it has low pressured blood.

Why does the left ventricle have a thicker wall compared to the right ventricle?

The blood in the left ventricle is under high pressure and it needs to be pushed through the body. Therefore it is more muscular.

How do you calculate cardiac output?

Cardiac output = heart rate * stroke volume

Explain why would a fit person would have a different recovery period than an unfit person?

The fit person has greater blood flow and they have no anaerobic respiration. So there is less build up of lactic acid and lactic acid is removed faster.

Name the part of the blood that transports most of the carbon dioxide to the lungs

Plasma

Explain why it is important that the cardiac output of an athlete increases during exercise?

Muscles contract faster, aerobic respiration occurs and it delivers more oxygen and more glucose to the body. There is also a faster removal of carbon dioxide.

Describe how the circulatory system transports substances in the body?

The aorta transports blood away from the heart, the vena cava transports blood to the heart. Capillaries exchange substances. The plasma carries carbon dioxide and the red blood cell carries oxygen.

What would happen if the bicuspid valve in the heart would not function effectively?

Blood would backwards to the atrium and less oxygenated blood would be transported to the body.

Explain the affects that a reduced cardiac output would have on muscle cells of an athlete?

There would be less blood flow to muscles and less blood would leave the heart. Less oxygen and glucose would reach the muscles . There is a reduced rate of aerobic respiration and less energy is produced. There is less removal of co2. There is a higher rate of anaerobic respiration and build up of lactic acid. It reduces muscle contraction leading to cramps.

What is the word equation for anaerobic respiration?

Glucose ---> Lactic acid

Explain why oxygen uptake increases as an athlete runs at faster speeds?

Muscles contract faster so there is more anaerobic respiration

Explain how the higher cardiac output increased the rate of anaerobic respiration?

Faster blood flow means that there is more oxygen and glucose transported to the muscle cells.

What is the function of a white blood cell?

They are involved in defending the immune system against diseases, they produce antibodies to do this.

Why does the concentration of lactic acid in the blood change while resting?

Concentration of lactic acid decreases as lactic acid is broken down using oxygen into carbon dioxide and water.

How does temperature affect the rate of diffusion?

The greater the temperature, the greater the movement of particles. So they're are more collisions, resulting in a more faster rate of diffusion.

When may anaerobic respiration take place in human cells?

During vigorous exercise

Why may aerobic respiration eventually stop in muscle cells?

Lactic acid build up inhibits the anaerobic respiration

How do red blood cells transport oxygen to body cells?

Haemoglobin in red blood cells bind to form oxyhaemoglobin. Oxyhaemoglobin breaks down to form haemoglobin and oxygen which diffuses into cells.

How are red blood cells adapted to their function?

They have a biconcave shape to increase surface area:volume ratio increases diffusion rate. They have no nucleus so they have more space for carrying oxygen. They can fir through capillaries as they are small and flexible. They are thin which gives a short diffusion distance.

What are phagocytes?

They engulf pathogens and digest them in phagocytosis

What are lymphocytes?

They produce antibodies specific to an antigen to kill them.

What do platelets do?

They help blood clot and prevent infections.

What is plasma?

It is the liquid part of the blood that contains dissolved substances e.g co2

What do the arteries do and how are they specialised for their function?

They carry blood away from the heart under high pressure. They have a narrow lumen and thick wall to withstand the pressure. They are lots of elastic fibres and muscle to provide strength.

What do veins do and how are they specialised?

They carry blood to the heart under low pressure. A large lumen and small wall eases blood flow. They have less muscle and elastic fibre. The valves prevent backflow of blood.

What do capillaries do and how are they specialised?

They allow the exchange of materials. They have a great surface area for diffusion. The walls are one cell are 1 cell thick, so it reduces the diffusion distance. The walls are permeable allowing the exchange of substances. A narrow lumen also decreases diffusion distance.

Describe the pathway of blood around the body?

Pulmonary vein to left atrium to left ventricle to aorta to the body to the vena cava to right atrium to right ventricle to pulmonary artery to lungs

Why is the left ventricle thicker than the right ventricle?

It carries blood that is under high pressure and it needs to be pumped all around the body

What is cardiac output?

The volume of blood pumped out of a ventricle every minute. Calculated in cm3/min

What is stroke volume?

The volume of blood pumped out of a ventricle in a contraction. Calculated in cm3

What is heart rate?

The number of times the heart contracts in one minute. Calculated in bpm

How does oxygen enter and co2 leave the bloodstream?

Oxygen diffuses from the air in the alveoli into the blood. Co2 diffuses from the blood in capillaries into the air in the alveoli

How is the lungs adapted to its function?

They have millions of alveoli which creates a large surface area to volume ratio for diffusion of gases. They have capillaries surrounding them and their walls are 1 cell thick, minimising the diffusion distance. Continual blood flow through capillaries maintains the concentration gradient

Describe the role of the aorta

Transports blood away from the heart to the body

Describe the role of the vena cava

Transports blood to the heart from the body

Describe the role of capillaries

Involved in exchange of material

What substance carries carbon dioxide in the blood?

Plasma

What substance carries oxygen in the blood

Red blood Cells