Chapter 6: Transport in Humans Flashcards
What does the circulatory system consist of?
- Blood vessels
- Blood
- Heart
What is the function of blood?
It transports substances around the human body and defends it against diseases.
What does plasma contain?
- Water (mostly)
- Substances: Glucose, proteins, amino acids, fats, salts, vitamins, hormones and excretory products.
- Red blood cells
- White blood cells
What do the different adaptations of RBC do? (Haemoglobin)
- RBC contains haemoglobin that can combine reversibly with oxygen.
- In the lungs where oxygen concentration is high, haemoglobin binds to oxygen to form oxyhaemoglobin, which is bright red.
- In tissues where oxygen concentration is low, oxyhaemoglobin releases its oxygen to the tissue cells, and it becomes haemoglobin (purplish-red)
What are the components of blood?
- Plasma
- Red blood cells
- White blood cells
- Platelets
What is plasma?
It is the yellowish liquid in blood.
What is the red blood cell’s main function?
To transport oxygen from the lungs to the other parts of the body.
What do the different adaptations of RBC do? (Circular, biconcave shape)
It increases the surface area-to-volume ratio, increasing the rate of absorption and release of oxygen.
What does plasma transport?
- Blood cells to all parts of the body.
- Nutrients from the small intestine to other parts of the body.
- Excretory products from organs where they are produced to excretory organs for removal.
- Hormones from endocrine
- Glands to target organs
What are the features of a red blood cell?
- Circular, biconcave in shape.
- No nucleus
- Contains haemoglobin
- Flexible
What do the different adaptations of RBC do? (No nucleus)
It allows the RBC to have more space to store more haemoglobin, so that it can bind to more oxygen, thus being able to transport more oxygen around the body.
What do the different adaptations of RBC do? (Flexible)
- Since they are flexible, they are able to change into a bell-shaped structure.
- This allows them to flow easily through narrow blood capillaries.
What are the 2 main types of white blood cells?
- Phagocytes
- Lymphocytes
What is the function of phagocytes?
To perform phagocytosis.
What are the features of white blood cells?
- They are irregular in shape
- They each contain a nucleus.
What is phagocytosis?
It is the process where a white blood cell engulfs and destroys foreign particles such as bacteria.
What do lymphocytes produce?
Antibodies.
What kind of antibodies do lymphocytes produce?
- Antibodies that recognise foreign particles.
- Antibodies that destroy disease-causing organisms such as bacteria and viruses.
- Antibodies that cause bacteria to clump together for easy ingestion by phagocytes.
- Antibodies that neutralise the toxins produced by bacteria.
What are platelets?
They are fragments of cytoplasm.
What do platelets contain?
They contain an enzyme that catalyses the conversion of fibrinogen to fibrin threads.
What do fibrin threads do?
These threads form a network that entangles red blood cells to form a clot, preventing excessive blood loss and entry of harmful organisms into the bloodstream.
What happens to blood exposed to air?
It will soon coagulate.
What is the benefit of blood coagulating when exposed to air?
- The clot it forms seals the wound, preventing excessive loss of blood.
- It also prevents foreign particles from entering the bloodstream.
What may happen to people suffering from haemophilia (blood clotting impaired disorder)?
Slight injuries may cause them to bleed to death or die of internal bleeding if the injury is not treated immediately.
What should people with haemophilia avoid?
Sports
What is a possible explanation as to why people have haemophilia?
Platelets don’t have the enzyme that catalyzes the conversion of fibrinogen to fibrin threads.
What is the process of blood clotting?
- Platelets convert fibrinogen to fibrin threads through the enzymes it contains that catalyzes this conversion.
- Fibrin threads then entangle the blood cells and the whole mass forms a clot.
- The clot seals the wound, preventing the entry of harmful organisms into the bloodstream and excessive blood loss.
What is the condition needed for an organ transplant to be successful?
Transplanted organ must not be rejected by recipient’s immune system.
How does organ rejection happen?
- The organ may be treated like a foreign body by the recipient’s immune system.
- The recipient’s white blood cells may respond by producing antibodies to destroy the transplanted organ.
What is the condition needed for a tissue transplant to be successful?
There must be a tissue match to prevent tissue rejection.
How does tissue rejection happen?
- The recipient’s white blood cells recognize the transplanted tissue as a foreign body.
- They respond by producing antibodies to destroy the foreign tissue, leading to tissue rejection
When will tissue rejection definitely not happen?
When the tissue transplanted comes from the same person.
How to reduce the risk of tissue rejection?
- The tissues of both the donor and recipient must be as genetically similar as possible.
- Use drugs that inhibit the resposnes of recipient’s immune system.
What are the possible side effects of using immunosuppressants?
More prone to falling sick
What do the surfaces of red blood cells contain?
Special proteins called antigens
What happens if the antibodies in our blood react with the antigens of someone elses blood? (Incompatible blood types)
This causes agglutination of the red blood cells, which causes the red blood cells to clump together and restrict blood flow and will eventually lead to death.
What are the different blood groups and what antibodies and antigens do they contain?
- A: Antigen A, Antibody b
- B: Antigen B, Antibody a
- AB: Antigen A and B, no antibodies
- O: No antigens, Antibodies a and b
What part of our blood is transfused when we donate blood?
Red blood cells.
What are the parts of the circulatory system?
- Heart
- Arteries
- Arterioles
- Blood capillaries
- Veins
- Venules
What are the basic movements of the heart?
- When the heart relaxes, it fills up with blood.
- When it contracts, the blood is squeezed out with great force and pressure.
What kind of blood vessels are arteries?
Blood vessels that carry blood away from the heart.
What is the large artery that leaves the left side of the heart?
Aorta
How are arterioles formed and what do they form?
- The arteries branch to form arterioles.
- They divide and ultimately, they become blood capillaries.
Why are blood capillaries important?
They ensure exchange of substances to different parts of the body.
What are capillaries?
Microscopic blood vessels that are found between the cells of almost all the tissues.
What are the features of capillaires?
- Their walls are made up of only a single layer of flattened cells.
- Their walls are partially permeable.
- They are have a lot of branches.
What is the use of the capillary walls being made up of only a single layer of flattened cells?
It decreases the diffusion distance between the substances in the blood and the cell so that exchange of substances can take place more efficiently.
What is the use of capillaries’ walls being partially permeable?
Allows certain substances to diffuse through them quickly.
What is use of capillaries having many branches?
- The numerous branches provide a large surface area for the exchange of substances between blood and tissue cells.
- It also increases the total cross-sectional area of the blood vessels, lowering the blood pressure in the capillaries as the flow of blood is slowed down giving more time for the exchange of substances.
What are venules?
Small blood vessel formed when capillaries unite after leaving an organ or tissue.
What are veins?
Blood vessels that carry blood back to heart.
What are the characteristics of arteries?
- Thick, muscular elastic walls.
- They carry oxygenated blood
What is the special artery in our bodies and why is it special?
Pulmonary artery. It carries deoxygenated blood, from the heart to the lungs, but arteries usually carry oxygenated blood.
What do arteries need to be able to do?
As they receive blood directly from the heart, they need to be able to withstand the high pressure of fast-moving blood being forced out of the heart.
What adaptation do arteries have to withstand the high pressure of blood being pumped out of the heart?
Thick, muscular and elastic walls.
Why do arteries that are located nearest to the heart have a much thicker elastic layer of the wall?
It receives the highest pressure of blood, thus it needs to be the most thick, muscular and elastic wall to withstand the highest pressure of blood.
What is the use of the artery walls being elastic?
- Enables artery wall to stretch and recoil
- Helps to push blood in spurts along artery
- Causes the pulse of heart
Why do artery walls need to recoil?
- Without this recoil, the artery wall will become stretched out and will be unable to come back to its original shape
- There will not be enough blood pressure, blood cannot be pushed forward, causing no blood flow in the body.
- No exchange of substances, body will eventually shut down and you will die due to no exchange of substances.
What happens when an artery constricts?
- Lumen becomes narrower
- Less blood flows through it per unit time.
What happens when an artery dilates?
- Lumen becomes wider
- More blood flows through it per unit time.
Why does your face turn red when running?
- Face turns red as more blood is flowing through arteries in face.
- Artery dilates, lumen becomes wider to allow more blood to flow through it per unit time.
- Blood closer to skin surface, absorbs heat from when running and carries it away so that body won’t overheat.
What are the characteristics of veins?
- Thinner and less muscular walls as comapred to walls of arteries of the same size
- Less elastic tissue in walls
- Contains valves
What is the special vein in our bodies and why is it special?
Pulmonary vein. It carries oxygenated blood from the lungs to the heart.
Why don’t the walls of the veins need not be as thick and muscular as arteries of the same size?
- As veins transport blood towards the heart, the blood pressure in the veins is much lower than the blood pressure in the arteries.
- Thus, blood flows slower and smoother in the veins, don’t need thick muscular walls.
What do valves help the vein to do?
- Since veins contain lesser elastic tissue, vein walls are unable to stretch and recoil, making it unable push the blood received in spurts.
- To help prevent backflow of blood, the veins have internal valves along their length to prevent backflow of blood.
Where is tissue fluid located?
In the tiny spaces between tissue cells.
What is the function of tissue fluid
It transports dissolved substances between the tissue cells and the blood capillaries.
How does tissue fluid carry out its function?
- Dissolved food substances and oxygen diffuse from the blood in the capillaries into the tissue fluid, where they then move into the cells.
- Excretory waste products diffuse from the cells into the tissue fluid.
- They are then transferred through the blood capillary walls into the blood.
- The blood then transports these waste products to the excretory organs for removal.
What are the parts of the heart?
- Right atrium
- Right ventricle
- Left atrium
- Left ventricle
What is the flow of blood in the circulatory system?
Lungs-Pulmonary vein-Left atrium-Left ventricle-Aorta-All parts of body- Vena cava-Right atrium-Right ventricle-pulmonary artery
Which side of the heart carries the different types of blood?
Left side carries oxygenated blood, right side carries deoxygenated blood
What are the rules of blood circulation?
- All blood returning to heart must return to atrium
- Blood in atrium always go to heart.
- Blood flows from higher to lower pressure
How does blood become deoxygenated?
When oxygenated blood is transported to all parts of the body, body cells use all the oxygen in blood, causing the blood to become deoxygenated.
Describe blood circulation in humans.
- From the heart, pulmonary arteries carry blood to the lungs
- Oxygen enters the blood at the lungs and the oxygenated blood is returned to the heart by the pulmonary veins.
- Oxygenated blood leaves the left side of the heart and is distributed by arteries to all parts of the body, except the lungs.
- The veins then carry blood from all parts of the body back to the right side of the heart.
What are the characteristics of the atria?
- They recieve blood from the veins
- They have comparitively thin muscular walls.
Why does the atria have compartively thin muscular walls?
They only force blood into the ventricles that lie directly below them, and this does not require high pressure, thus they do not need thick walls.
What are the characteristics of ventricles?
- They have comparitively thick muscular walls
- The right ventricle has thinner walls than the left ventricle.
Why do the ventricles have comparitively thick muscular walls?
They pump blood around the whole body, which is a longer distance that they need to pump as comapred to the atria, and this requires high pressure to generate more force to pump the blood to a further distance.
Why is the right ventricle wall thinner than the left ventricle wall?
It only pumps blood to the lungs, which is close to heart.
What is the median septum?
It is a muscular wall that separates the right and lefts sides of the heart and runs down the middle of the heart.
What is the function of the median septum?
It prevents the mixing of deoxygenated blood in the right side with oxygenated blood in the left side.
What will happen if deoxygenated blood and oxygenated blood mix?
This results in the reduction of amount of oxygen carried to the rest of the body.
What is the flow of oxygenated and deoxygenated blood through the heart controlled by?
The opening and closing of the valves.
What are the different valves?
- Tricuspid valve
- Bicuspid valve
- Aortic valve
- Pulmonary valve
What is the function of the tricuspid valve?
It prevents backflow of blood from the right ventricle to the right atrium.
What are the characteristics of the tricuspid valve?
- Located between right atrium and right ventricle.
- It consists of three flaps that point downwards into the ventricle, and these flaps are attached to the walls of the right ventricle by chordae tendineae
What is the function of biscupid valves?
It prevents backflow of blood from the left ventricle to the left atrium.
What are the characteristics of the bicuspid valves?
- Located between left atrium and left ventricle
- It has two flaps that point downwards into the left ventricle, and they are attached to the walls of the left ventricle by chordae tendineae.
How do the valves prevent backflow of blood?
The chordae tendineae prevent the flaps from being reverted into the atrium when the ventricular muscles contract.
Describe the path that blood takes through the heart.
- Deoxygenated blood from the body is returned to the right atrium by the venae cavae. The upper vena cava transports blood from the head, neck and arms back to the heart. The lower vena cava transports blood from the rest of the body back to the heart.
- From the RA, blood passes through the tricuspid valve into the right ventricle.
- From the RV, blood leaves the heart by the pulmonary arteries to the lungs.
- Pulmonary veins transport oxygenated blood from the lungs to the LA
- Blood passes from the LA through the bicuspid valve into the LV
- From the LV, blood leaves the heart and enters the aorta to be distributed around the body through different arteries. Two small coronary arteries emerge from the aorta. They bring oxygen and nutrients to the heart muscles.
