Transport in Animals- Biology OCR A
What is a double circulatory system? - Answer one in which the blood flows through the
heart twice for each circuit of the body
What is a single circulatory system? - Answer one in which the blood flows through the
heart once for each circuit
Define transport - Answer the movement of substances such as oxygen, nutrients,
hormones, waste and heat around the body
What are the three main factors that influence the need for a transport system? -
Answer -size
-surface area to volume ratio
-level of metabolic activity
Size - Answer -If the organisms are large and further from the surface then the diffusion
pathway is increased.
-The diffusion rate is reduced and diffusion id too slow to supply all the requirements.
-The shorter the diffusion pathway the faster the diffusion rate.
surface area to volume ratio - Answer -having a large surface area to volume ratio is
optimum for diffusing oxygen quickly into the body.
-if the surface area to volume ratio is small then diffusion distance is too slow and not
efficient.
Level of metabolic activity - Answer -animals need energy from food so they can move
around.
-releasing energy from food by aerobic requires oxygen.
-if an animal is very active, its cells need good supplies of nutrients and oxygen to
supply the energy for movement.
-animal that keep themselves warm (e.g. mammals) need even more energy.
Features of a good transport system - Answer -A fluid/medium to carry nutrients,
oxygen and wastes around the body - BLOOD.
-A pump to create pressure to push fluid around the body - HEART.
-Exchange surfaces that allow entrance/exit of substances from the blood -
CAPILLARIES.
-Tubes or vessels to carry blood by mass flow.
-Two circuit's, one to pick up oxygen and the other to deliver oxygen to the tissues
Single circulatory system - Answer Blood passes through the heart once only in a
complete circuit of the body e.g. in a fish -
heart->gills->body->heart
Double circulatory system - Answer one circuit passes blood to the lungs to pick up
oxygen (pulmonary circulation) the other carries the oxygen and nutrients around the
body to the tissues e.g. in mammals-
, Transport in Animals- Biology OCR A
heart->body->heart->lungs->heart
Advantages of a circulatory system - Answer -delivers O2 and nutrients quickly to parts
of the body
-blood flows more quickly by increasing the blood pressure created by the heart
Advantages of a circulatory system
-in fish (single) - Answer Fish (single)
-the blood pressure drops as blood passes through the tiny capillaries of the gills
-blood has a low pressure as it flows towards the body, and will not flow very quickly
-the rate at which oxygen and nutrients are delivered to respiring tissues, and carbon
dioxide and urea re removed, is limited
-fish are less metabolically active, so they do not need to maintain their temperature
therefore they need less energy and the single system delivers sufficient O2 and
nutrients for their needs
Advantages of a circulatory system
-in mammals(double) - Answer -the blood pressure must not be too high in the
pulmonary circulation, otherwise it may damage the delicate capillaries in the lungs
- the heart can increase the pressure of the blood after it has passed through the lungs,
so the blood is under higher pressure at it flows to the body and flows more quickly
-the systemic circulation can carry blood at a higher pressure than the pulmonary
circulation
-Mammals are active animals and maintain their body temp, supplying the energy for
activity and heat needed to keep the body warm requires energy from food. the energy
is released from food in the process of respiration. to release lots of energy the cells
need a good supply of both O2 and nutrients, as well as the removal of waste products.
Define arteries - Answer Blood vessels that carry blood away from the heart
Features of arteries - Answer 1. Arteries carry blood from the heart to the rest of the
body.
2. Blood is carried under high pressure.
2. Thick, muscular walls (smooth muscle) with elastic tissue = expand and recoil
3. Narrow lumen - maintain high pressure
4. Folded endothelium allowing expansion to cope with high pressure and expand.
5. All arteries carry oxygenated blood except for the pulmonary arteries, which take
deoxygenated blood to the lungs.
3 layers of artery walls - Answer inner layer
-tunica intima-> consists of a thin layer of elastic tissue which allows the wall to stretch
and then recoil to help maintain blood pressure
middle layer
-tunica media-> consists of a thick layer of smooth muscle
What is a double circulatory system? - Answer one in which the blood flows through the
heart twice for each circuit of the body
What is a single circulatory system? - Answer one in which the blood flows through the
heart once for each circuit
Define transport - Answer the movement of substances such as oxygen, nutrients,
hormones, waste and heat around the body
What are the three main factors that influence the need for a transport system? -
Answer -size
-surface area to volume ratio
-level of metabolic activity
Size - Answer -If the organisms are large and further from the surface then the diffusion
pathway is increased.
-The diffusion rate is reduced and diffusion id too slow to supply all the requirements.
-The shorter the diffusion pathway the faster the diffusion rate.
surface area to volume ratio - Answer -having a large surface area to volume ratio is
optimum for diffusing oxygen quickly into the body.
-if the surface area to volume ratio is small then diffusion distance is too slow and not
efficient.
Level of metabolic activity - Answer -animals need energy from food so they can move
around.
-releasing energy from food by aerobic requires oxygen.
-if an animal is very active, its cells need good supplies of nutrients and oxygen to
supply the energy for movement.
-animal that keep themselves warm (e.g. mammals) need even more energy.
Features of a good transport system - Answer -A fluid/medium to carry nutrients,
oxygen and wastes around the body - BLOOD.
-A pump to create pressure to push fluid around the body - HEART.
-Exchange surfaces that allow entrance/exit of substances from the blood -
CAPILLARIES.
-Tubes or vessels to carry blood by mass flow.
-Two circuit's, one to pick up oxygen and the other to deliver oxygen to the tissues
Single circulatory system - Answer Blood passes through the heart once only in a
complete circuit of the body e.g. in a fish -
heart->gills->body->heart
Double circulatory system - Answer one circuit passes blood to the lungs to pick up
oxygen (pulmonary circulation) the other carries the oxygen and nutrients around the
body to the tissues e.g. in mammals-
, Transport in Animals- Biology OCR A
heart->body->heart->lungs->heart
Advantages of a circulatory system - Answer -delivers O2 and nutrients quickly to parts
of the body
-blood flows more quickly by increasing the blood pressure created by the heart
Advantages of a circulatory system
-in fish (single) - Answer Fish (single)
-the blood pressure drops as blood passes through the tiny capillaries of the gills
-blood has a low pressure as it flows towards the body, and will not flow very quickly
-the rate at which oxygen and nutrients are delivered to respiring tissues, and carbon
dioxide and urea re removed, is limited
-fish are less metabolically active, so they do not need to maintain their temperature
therefore they need less energy and the single system delivers sufficient O2 and
nutrients for their needs
Advantages of a circulatory system
-in mammals(double) - Answer -the blood pressure must not be too high in the
pulmonary circulation, otherwise it may damage the delicate capillaries in the lungs
- the heart can increase the pressure of the blood after it has passed through the lungs,
so the blood is under higher pressure at it flows to the body and flows more quickly
-the systemic circulation can carry blood at a higher pressure than the pulmonary
circulation
-Mammals are active animals and maintain their body temp, supplying the energy for
activity and heat needed to keep the body warm requires energy from food. the energy
is released from food in the process of respiration. to release lots of energy the cells
need a good supply of both O2 and nutrients, as well as the removal of waste products.
Define arteries - Answer Blood vessels that carry blood away from the heart
Features of arteries - Answer 1. Arteries carry blood from the heart to the rest of the
body.
2. Blood is carried under high pressure.
2. Thick, muscular walls (smooth muscle) with elastic tissue = expand and recoil
3. Narrow lumen - maintain high pressure
4. Folded endothelium allowing expansion to cope with high pressure and expand.
5. All arteries carry oxygenated blood except for the pulmonary arteries, which take
deoxygenated blood to the lungs.
3 layers of artery walls - Answer inner layer
-tunica intima-> consists of a thin layer of elastic tissue which allows the wall to stretch
and then recoil to help maintain blood pressure
middle layer
-tunica media-> consists of a thick layer of smooth muscle
