13. (a)
(i) State a precise location in the human body at which red blood cells are made - Leaving Cert Biology - Question 13 - 2006
Question 13
13.
(a)
(i) State a precise location in the human body at which red blood cells are made.
(ii) State two ways in which red blood cells differ from typical body... show full transcript
Worked Solution & Example Answer:13. (a)
(i) State a precise location in the human body at which red blood cells are made - Leaving Cert Biology - Question 13 - 2006
Step 1
State a precise location in the human body at which red blood cells are made.
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Answer
Red blood cells are primarily made in the bone marrow, specifically within the long bones such as the femur and humerus, as well as the ribs and sternum.
Step 2
State two ways in which red blood cells differ from typical body cells e.g. from the cheek lining.
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Answer
Red blood cells lack a nucleus, which differentiates them from typical body cells that contain a nucleus.
Red blood cells do not have mitochondria; instead, they rely on anaerobic respiration, while most body cells utilize aerobic respiration.
Step 3
Explain the terms, plasma, glomerular filtrate.
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Answer
Plasma is the liquid part of blood that contains water, salts, and organic molecules. Glomerular filtrate refers to the plasma that has entered Bowman's capsule and is essentially plasma without the larger proteins and cells.
Step 4
Explain why red blood cells are normally absent from glomerular filtrate.
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Answer
Red blood cells are normally absent from glomerular filtrate because they are too large to pass through the pores of the glomerulus, which filters blood.
Step 5
The concentration of glucose is the same in plasma and glomerular filtrate. Why is this?
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Glucose is small enough to pass through the filtration barrier of the glomerulus, thus maintaining the same concentration in both plasma and glomerular filtrate.
Step 6
Why is glucose normally absent from urine?
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Answer
Glucose is normally absent from urine because it is reabsorbed in the renal tubules; the body reclaims glucose from the filtrate before it is excreted.
Step 7
Following a period of heavy exercise an athlete may produce only a small volume of concentrated urine. Explain this observation and give an account of the process that concentrates the urine.
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Answer
During heavy exercise, the body experiences dehydration, which leads to a drop in blood volume. This triggers receptors that alert the brain, causing the secretion of antidiuretic hormone (ADH) from the pituitary gland. ADH stimulates reabsorption of water in the collecting ducts of the kidneys, resulting in the production of a smaller volume of concentrated urine.
Step 8
Describe the structure of the lymphatic system.
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Answer
The lymphatic system consists of lymph nodes and lymph vessels. Lymph nodes are small, bean-shaped structures that filter lymph and contain immune cells. Lymph vessels are thin tubes that transport lymph throughout the body.
Step 9
Give an account of three functions of the lymphatic system.
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Transport: The lymphatic system transports excess interstitial fluid back to the circulatory system, thereby maintaining fluid balance.
Defense: It plays a central role in the immune response by filtering pathogens and producing lymphocytes.
Fat absorption: The lymphatic system absorbs fats and fat-soluble vitamins from the digestive system and transports them to the bloodstream.
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