3.2 Transport in animals Flashcards
What is a double circulatory system?
A circulatory system in which the blood flows through the heart twice for each circuit of the body.
What is a single circulatory system?
A circulatory system in which blood flows through the heart once for each circuit of the body.
Why dont small organisms need a transport system?
All their cells are surrounded (or are very close to) their environments so that they can rely diffusion to supply them with enough oxygen and to nutrients survive.
What factors cause larger organisms to require a transport system?
- Size
- Surface area
- Level of metabolic activity
Why does the size of an organism affect its need for a transport system?
For bigger animals:
- Diffusion pathway is increased
- Diffusion rate is reduced so the diffusion is too slow to supply all the requirements.
- Outer layers of cells use up all the supplies, less will reach the cells inside.
How does an animals level of metabolic activity affect the need for a transport system?
A more active animal that moves about a lot and those that keep themselves warm, require a lot of energy from aerobic respiration. This means all the its cells need a good supply and nutrients and oxygen for the energy of movement.
What features will a good transport system include?
- A fluid to carry nutrients, oxygen and wastes around the body.
- A pump to create pressure that will push the fluid around the body.
- Exchange surfaces that enable substances to enter the blood and leave again where they are needed.
- Tubes or vessels to carry blood by mass flow.
- Two circuits- one to pick up oxygen and the other to deliver it.
What sort of circulatory system does a fish have?
A single closed circulatory system.
What sort o0f circulatory system does a mammal have?
A double closed system.
Compare a single and double circulatory system.
The blood pressure in a single circulatory system in lower than the blood pressure in a double circulatory system. This means that the flow of blood is lower in a single circulation system compared to that of a double circulation system.
Why do fish have single circulation systems if they’re not as efficient as double circulation systems?
They’re not as metabolically active as mammals as they do not need to maintain their body temperature. Therefore their single circulatory system delivers efficient oxygen and nutrients for their needs.
Define arteries.
Blood vessels that carry blood away from the heart.
Define arterioles.
Small blood vessels that distribute blood from an artery to the capillaries.
Define capillaries.
Very small vessels with very then walls.
What is a closed circulatory system?
A circulatory system in which the blood is held in vessels.
What is an open circulatory system?
One in which the blood is not held in vessels.
What are veins?
Vessels that carry blood back to the heart.
What are venules?
Small blood vessels that collect blood from capillaries and lead into the veins.
Where is the blood in an open circulatory system?
The blood circulates through the body cavity, so that the tissues and cells are bathed directly in blood.
How does blood circulate in insects?
Insects have a muscular pumping organ, like the heart, that lies just under the upper surface of the body. Blood from the body enters the heart through pores called ostia. The heart then pumps the blood towards the head by peristalsis. At the forward end of the heart, near the head, the blood simply pours out into the body cavity. This circulation continues when the insect is at rest however, is aided by body movements.
What is an ostia?
Pores in an insect the allows blood to enter it’s heart.
What is peristalsis?
The way an insect pimps blood towards the heart.
What are 2 disadvantages of an open circulation system?
- Blood pressure is low so blood flow is low.
- Circulation of blood may be affected by body movements or lack of body movements.
What advantages does a closed circulation system have compared to an open circulation system?
- Higher pressure, so that the blood flows quicker.
- More rapid delivery of oxygen and nutrients.
- More rapid removal of carbon dioxide and other waste.
- Transport is independent of body movements.
What characteristic does all blood vessels have?
All blood vessels have an inner lining made of a single layer of cells, called the endothelium. This is a thin layer made of squamous epithelium cells that are smooth which reduces friction of blood.
What are the characteristics of an artery?
- Artery wall is thick to withstand pressure.
- Lumen is relatively small in order to maintain high pressure.
- Inner wall is folded to allow the lumen to expand as blood flow increases.
What does an artery wall consist of?
- Inner layer consists of a thin layer of elastic tissue which allows the wall to stretch and then recoil to help maintain blood pressure.
- Middle layer consists of a thick layer of smooth muscle.
- Outer layer is relatively thick layer of collagen and elastic tissue. This provides strength to withstand the high pressure, and recoil to maintain the pressure.
Why may arterioles constrict?
When arterioles constrict, it increases the resistance to the flow and reduces the rate of flow of blood. Constriction of the arteriole walls can be used to divert the flow of blood to regions of the body that are demanding more oxygen.
Describe the structure of a capillary.
- Capillaries have very thin walls.
- Their lumen is very narrow- similar to the diameter of a red blood cell, helping to transfer oxygen as it reduces the diffusion path to the tissues.
- The wall consist of a single layer of flattened endothelial cells- reducing the distance for the materials being exchanged.
- The walls are leaky, they allow blood plasma the dissolved substances to leave the blood.
What do the venules do?
They collect the blood from the capillary bed and lead into the veins.
What does the structure on a venule consist of?
Thin layers of muscle and elastic tissue outside the endothelium, and a thin layer of collagen.
What is the structure of a vein like?
- The lumen is relatively large, in order to ease the flow of blood.
- The walls have thinner layers of collagen, smooth muscle and elastic tissue than in artery walls. They no not need to stretch and recoil, and are not actively constrict is order to reduce blood flow.
- Contraction of the surrounding skeletal muscle applies pressure of the blood, forcing the blood to move along in a direction determined the valves.
What is hydrostatic pressure?
The pressure that a fluid exerts when pushing against the sides of a vessel or container.
What is lymph?
The fluid held in the lymphatic system, which is a system of the tubes that returns excess tissue fluid to the blood system.
What is oncotic pressure?
The pressure created by the osmotic effects of the solutes.
What is plasma?
The fluid portion of the blood.
What is tissue fluid?
The fluid surrounding the cells and tissues.
What does plasma contain?
many dissolved substances, including, oxygen, carbon dioxide, glucose, amino acids, hormones, plasma proteins and many blood cells including, erythrocytes, leucocytes and platelets.
What is another word for red blood cells?
Erythrocytes.
What is another word for white blood cells?
Leucocytes.
How is tissue fluid and blood plasma similar?
Tissue fluid and blood plasma are similar, however, tissue fluid does not contain most of the cells found in the blood, and plasma proteins.
How is tissue fluid formed?
Tissue fluid is formed by plasma leaking from the capillaries.
Where is tissue fluid found?
It surrounds the cells in the tissue.
What does tissue fluid do?
It supplies tissues with the oxygen and nutrients that they require. AS blood plasma leaks from the capillary, it carries all the dissolved substances into the tissue fluid.
What is it called when the blood plasma leaks into the tissue fluid?
This movement is called mass flow. NOT DIFFUSION.
What happens to waste products and tissue fluid?
Waste products from cell metabolism will be carried back into the capillary as some of the tissue fluid returns back to the capillary.
What occurs at the arterial end of a capillary in the formation of tissue fluid?
At the arterial end of the capillary, the blood is at relatively high hydrostatic pressure, therefore, this pushes the blood fluid out of the capillary through the capillary wall through tiny gaps between cells in the capillary wall.
What remains in the blood when tissue fluid is formed?
All the reds blood cells. platelets,the plasma proteins and most the white blood cells remain in the blood. This is because they’re too large to be pushed through the gaps in the capillary wall.
How does the uptake of gases and nutrients occur from the tissue fluid to the tissues?
The tissue fluid surrounds the body cells, so the exchange of gases and nutrients occurs across the plasma membrane occurs by diffusion, facilitated diffusion and active transport.
What does the pressure being lower at the venous end of the capillary allow?
This allows some (NOT ALL) of the tissue fluid to return to the capillary carrying carbon dioxide and other waste substances into the blood.
If not all the tissue fluid re-enters the blood, what happens to it?
- Some tissue is directed into the lymphatic system.
- This drains excess tissue fluid out of the tissues and returns it to the blood system in the subclavian vein in the chest.
What is lymph?
The fluid in the lymphatic system is called lymph and is similar in composition to the tissue fluid. It will contain more lymphocytes, as these are produced in the lymph nodes.
What has influence which causes movement of fluid into and out if the capillary?
Hydrostatic pressure of the blood and oncotic pressure on the tissue fluid.
How does tissue fluid flow in and out of a capillary?
- The hydrostatic pressure of the blood tends to push fluid out into the tissues.
- The hydrostatic pressure of the tissue tends to push fluid into the capillaries.
- The oncotic pressure of the blood tend to pull water back into the blood.
- The oncotic pressure of the tissue fluid pulls water into the tissue fluid.
What are the atrio-ventricular valves?
Valves between the atria and ventricles, which ensure that the blood flows in the correct direction.
What are cardiac muscles?
specialised muscle found in the walls of the heart chambers.
What are ventricular valves?
Valves that prevent blood re-entering the heart from the arteries.
What is the blood like on the right side of the heart and where is the blood being pumped to?
The right side pumps deoxygenated blood to the lungs to be oxygenated.
What is the blood like on the left side of the heart and where is the blood being pumped to?
The left side pumps oxygenated blood to the rest of the body.
What does the heart consist of?
The main part of the heart is made of the cardiac muscle. There’s 2 main pumping chambers- the ventricles. Above the ventricles, are two thin walled chambers- the atria. Lying over the surface of the heart are the coronary arteries, that supply blood to the heart.
What can happen if the coronary artery becomes constricted or blocked?
It restricts the blood flow to the heart, reducing the delivery of oxygen and nutrients like fatty acids and glucose. This can cause angina or a heart attack.
What are the two upper chambers of the heart called?
The atria.
Label a graph of pressure changes in the heart.
What does a graph showing pressure changes at different parts of the blood system look like?
Draw and label a normal electrocardiogram.
- Wave P shows the excitation of the atria.
- QRS indicates the excitation of the ventricles.
- T shows diastole.
What condition does this person have?
Brachycardia
What condition does this person have?
Trachycardia.
What condition does this person have?
Atrial fibrillation: the atria beating more frequently than the ventricles- no clear P waves.
What condition does this person have?
Ectopic heartbeat- the patient often feels like a heartbeat has ben lost.
What does a haemoglobin dissociation curve look like?
What is the Bohr shift?
When more carbon dioxide, haemoglobin becomes less saturated with oxygen. This is reflected in a change the the haemoglobin dissociation curve , which shifts downwards and to the right- the Bohr shift.
