Biology 3 Flashcards
Name the four chambers of the heart
Right atrium
Left atrium
Right ventricle
Left ventricle
Why does the heart have valves?
To make sure the blood flows in the right direction.
Name the four main blood vessels leading into and out of the heart
Vena cava
Pulmonary vein
Pulmonary artery
Aorta
How does blood flow through a heart?
1) Blood flows from the left and right atrium from the pulmonary vein and the vena cava.
2) The atria contract which pushes the blood into the ventricles.
3) The ventricles contract which forces blood into the pulmonary artery and the aorta.
4) Blood flows out of the heart, through the arteries and comes back through the veins.
Arteries
They carry blood away from the heart. The heart pumps blood at high pressures so the walls of arteries are strong and elastic. So they can spring back, they are made out of elastic fibres. So they are strong, they have thick walls made out of muscle. They have a small lumen.
Capillaries
The walls are permeable so that substances can be exchanged with cells. The rate of diffusion is increased because the walls are very thin (about one cell thick). They are also narrow and have a large surface area to volume ratio so that diffusion can occur quickly.
What blood vessel has valves?
Veins
Which blood vessel has the smallest and largest lumen?
Artery has the smallest lumen.
Vein has the largest lumen.
Veins
Veins carry blood towards the heart. As the blood is at a low pressure the walls aren’t as thick as they would be in an artery. Veins have a large lumen.
What is blood?
A tissue.
What is blood made out of?
Red blood cells
White blood cells
Platelets
What are the components of the blood suspended in?
Plasma.
What do red blood cells do?
Transport oxygen around the body.
What shape do red blood cells have?
Biconcave
Why does a red blood cell have a biconcave shape?
Gives a larger surface area for absorbing oxygen. They contain haemoglobin which carries oxygen.
What makes red blood cells different from most cells?
It doesn’t have a nucleus.
What happens to oxygen and haemoglobin in the lungs?
Oxygen diffuses into the blood and combines with haemoglobin to become oxyhaemoglobin.
What happens to oxygen and haemoglobin in the body tissues?
Oxyhaemoglobin becomes oxygen and haemoglobin.
What is the function of white blood cells?
To protect the body against microorganisms that cause disease.
How can white blood cells protect the body?
Produce antibodies.
Produce antitoxins.
Engulf and digest microorganisms.
True or false.
White blood cells have a nucleus.
True.
What are platelets?
Small fragments of cells.
What are the function of platelets?
They help blood to clot at the wound.
True or false.
Platelets have a nucleus.
False.
What is plasma?
A liquid which carries everything in the blood.
What does the plasma carry?
Red blood cells White blood cells Platelets Carbon dioxide Hormones Antibodies Antitoxins Urea
What are the advantages of artificial hearts?
Help a person live for longer.
Less likely to be rejected than donor hearts.
What are the disadvantages of artificial hearts?
Surgery can cause infections. Electric motor could fail. Can cause blood clots. Have to take immunosuppressants. Can be uncomfortable.
What are artificial heart valves?
Make sure blood flows in the right direction. It can cause blood clots and infections.
What are stents?
They are placed inside of arteries so that blood can pass through.
What are the advantages of stents?
Reduce the risk of a heart attack.
What are the disadvantages of stents?
They can irritate the artery.
Make scare tissue grow.
Blood clotting can occur.
What are the phloem tubes made of?
Living cells.
What are the xylem tubes made of?
Dead cells.
What do phloem tubes transport?
Food.
What do the xylem tubes transport?
Water and mineral ions.
What is the transpiration stream?
The movement of water through a plant.
What are the stages of the transpiration stream?
1) Water from the leaf evaporates.
2) This creates a shortage of water so more is taken from the rest of the plant by the xylem.
3) Now more water is drawn up through the roots.
What is homeostasis?
The maintenance of a constant internal environment?
What two products have to be removed by the body?
Carbon dioxide
Urea
What are the three roles of kidneys?
To remove urea.
Adjust ion content.
Adjust water content.
How is urine produced?
1)Ultrafiltration-
Blood from the renal artery enters the kidney.
A high pressure is built up the blood vessels so water, urea, ions and sugar is squeezed out of the blood and into a capsule at the start of the nephron.
The membranes between the blood vessel and the capsule don’t allow big molecules to be squeezed out so they stay in the blood.
2)Reabsorption-
The liquid flows along the nephron and all useful substances such as all the glucose (by active transport), sufficient water and sufficient ions are reabsorbed.
3)Release of waste products-
The urea, excess ions and excess water go out of the nephron, into the ureter and into the bladder as urine.
How does kidney dialysis work?
Someone’s blood flows along a partially permeable membrane. This allows smaller molecules to pass through. The dialysis fluid has the same concentrations of dissolved substances as normal blood which means that the useful substances are not lost. Instead waste products will diffuse across the membrane.
What are the disadvantages of dialysis?
Have to go to a hospital a lot. Expensive to run the machines. Can lead to infections. Can cause blood clots. Have to be careful about what they eat. They have to be careful about how much fluid they consume.
What are the disadvantages of kidney transplants?
Rejection
Long waiting list
Big operation
Immunosuppressants can cause infections
How can the risk of rejection be reduced?
Get a donor with the same tissue type.
They person has to have immunosuppressants.
What part of the brain receives information about the body temperature from receptors?
Thermoregulatory centre in the brain.