Biology Topic 5

What are the four main components of the blood?
Plasma, platelets, red blood cells and white blood cells.
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What is the role of the plasma?
It transports nearly everything around the body. Red and white blood cells and platelets, digested food products, carbon dioxide, urea, hormones, heat energy.
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What are the platelets?
Small fragments of cells that help blood clot. When you damage a blood vessel platelets clump together to protect the damaged area (blood clotting). In a clot the platlets are held together by a mesh of protein called fibrin.
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What is the role of red blood cells?
Transport oxygen from the lungs to all the cells in the body.
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How are red blood cells adapted?
Small, biconcave shape, large surface area for absorbing and releasing oxygen. Haemoglobin- colour, contains iron. In the lungs haemoglobin reacts with oxygen to become oxyhaemoglobin. Release oxygen to cells. No nucleus, free up space.
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What are the two types of white blood cells?
Phagocytes and lymphocytes.
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What is a pathogen?
A microorganism that causes disease. Once they have entered the body they reproduce rapidly unless they're destroyed.
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What do phagocytes do?
Ingest pathogens. They detect foreign bodies and engulf them to digest them. They are non-specific and attack anything that's not meant to be there.
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What do lymphocytes do?
Produce antibodies. Every pathogen has an antigen on its surface, lymphocytes come across a foreign antigen, and produce proteins called antibodies.Lock onto the invading pathogen, specific for each. Antibodies produced rapidly, kill disease.
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What is the role of a vaccination?
To protect from future infections. Inject a dead or inactive pathogen into the body. They carry antigens, triggering an immune system response. Lymphocytes produce antibodies to attack them. Remain in memory cells, so can kill any live pathogens.
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How are blood vessels designed for their function?
Arteries- carry blood away from the heart. Capillaries- involved in the exchange of materials at the tissues. Veins- carry the blood to the heart.
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Describe the function of arteries.
They carry blood under pressure. The heart pumps blood out at high pressure so the artery walls are strong and elastic. The walls are thick compared to the size of the lumen, contain thick layers of muscle to make them strong. Largest artery-aorta.
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Describe the function of capillaries.
Arteries branch into capillaries. They are too small to see, they carry blood really close to every cell in the body to exchange substances with them. Permeable walls-diffusion. Supply food and oxygen, take away wastes like CO2. One cell thick.
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Describe the function of veins.
Capillaries eventually join up to form the veins. Blood is at lower pressure, don't need to be as thick as artery walls. Bigger lumen (than arteries), help the blood flow. Valves to keep flowing in the right direction. Largest vein- vena cava.
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Diagram of the heart with labels. (picture)
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How does the hormonal system help to control heart rate?
When an organism is threatened the adrenal glands release adrenaline. Adrenaline binds to specific receptors in the heart, causing cardiac muscles to contract more frequently and with more force, heart race increases, more blood pumps. Inc. of oxygen
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Structure of the circulation system. (picture)
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What are the three main roles of the kidneys?
Removal of urea from the blood- urea is produced in the liver from excess amino acids. Adjustment of salt levels in the blood. Adjustment of water content of the blood.
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Describe ultrafiltration.
Blood from the renal artery flows through the glomerulus. A high pressure is built up which squeezes water, urea, salts and glucose out of the blood and into Bowman's capsule. Membranes between BV's, G., B.C. act like filters- big molecules kept.
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Describe reabsorption.
As the filtrate flows along the nephron, useful substances are selectively reabsorbed back into the blood. All glucose reabsorbed from proximal convoluted tubule, active transport. Sufficient salt and water reabsorbed, collecting duct into the blood.
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Describe the release of wastes.
Remaining substances form urine (water, salts, urea). Nephron through the ureter and down to the bladder, stored before being released via the urethra.
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How do the kidneys adjust the body's water control?
Osmoregulation. Adjusting the amount of water excreted by the kidney's in urine.
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How does ADH help to control water content?
Anti-diuretic hormone. Makes the nephrons more permeable, more water reabsorbed. Brain monitors the water content of the blood, instructs the pituitary gland to release ADH into the blood.
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Other cards in this set

Card 2


What is the role of the plasma?


It transports nearly everything around the body. Red and white blood cells and platelets, digested food products, carbon dioxide, urea, hormones, heat energy.

Card 3


What are the platelets?


Preview of the front of card 3

Card 4


What is the role of red blood cells?


Preview of the front of card 4

Card 5


How are red blood cells adapted?


Preview of the front of card 5
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