Option H Study Guide (H1-H3) – Further Human Physiology
Topic 6.5.7- 6.5.12/Option H1: Hormones, Homeostasis, Hormonal Control
For questions 1 – 3, state whether the following physiological situation will directly lead to an increase or decrease in internal body temperature.
1. The hypothalamus signals shivering muscles to activate
2. The hypothalamus signals skin arterioles to constrict
3. The hypothalamus and anterior pituitary signal thyroid gland to secrete thyroxine.
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For questions 4, arrange the following events associated with conserving water within body tissues in the proper sequential order.
a. ADH is stored in the posterior pituitary gland
b. Kidney collecting duct cells become permeable to water
c. Osmoreceptors in hypothalamus detect low water potential in the blood
d. Water moves by osmosis from collecting duct to nephron peritubular capillaries
e. ADH moves down the axon of a neurosecretory cell
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For questions 5 & 6, state whether each of these events would be expected to raise or lower blood glucose levels.
5. Hepatocytes hydrolyze glycogen
6. Insulin fits into gated channels receptors on cell membranes of body cells.
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7. Compare the transport mechanisms of steroid hormone and protein hormone across the plasma membrane.
8. Explain the mechanism of negative feedback in maintaining homeostasis.
9. Where are ‘releasing hormones’ produced? What is the purpose of these releasing hormones?
10. What is the major difference between Type I and Type II diabetes?
Topic 6.1/Option H2 & H3: Digestion
11. a. Compare the digestion of carbohydrates, proteins, and lipids.
b. Outline the role of the lymphatic system in the transport of the products of digestion
12. What is the main advantage of having some of the enzymes involved in the digestive process attached to epithelial cells of the villi as opposed to free floating enzymes?
13. a. Describe, with the aid of diagrams, the anatomical (structural) adaptations that make the small intestine of humans suitable for absorption.
b. Describe the mechanisms involved with the absorption of named substances
in the small intestine.
14. What enzyme is lacking in humans (and most other organisms) that is necessary to hydrolyze the cell wall of plants?
15. What is the name of the liver phagocytic cells that are responsible for destroying “old” erythrocytes?
16. What is the name of the specific pigment, found within bile, that gives a characteristic color to human feces?
17. What category of protease enzymes hydrolyze the terminal amino acids from a polypeptide chain during the digestive process?
18. Epithelial cells of villi are not surrounded by interstitial fluid as is the case with most cells. The cells are ‘sealed’ to prevent nutrients from leaching between cells and thus nutrients can be selectively absorbed. What do you call these ‘seals’ between epithelial cells?
19. The main components of bile are water, bicarbonate ions, bile salts, and bile pigments. Which of these components acts as the emulsifying agent of lipids?
IB Exam Questions
1. (a) Distinguish between exopeptidases and endopeptidases. (1)
(b) Explain why pepsin is initially synthesized as an inactive precursor and how it is subsequently activated. (3)
(Total 4 marks)
2. Explain the mechanisms used by the ileum to absorb food.
(Total 6 marks)
3. The diagram below shows a transverse section of the ileum.
[Source: P H Raven and G B Johnson, Biology, (2002), 6th edition, McGraw-Hill, page 1024]
(a) (i) State the name and function of the structures labelled 1 and 2. (2)
(ii) Distinguish between the muscles labelled 3 and 4. (1)
(Total 3 marks)
4. (a) Explain the control of ADH secretion. (5)
(b) Explain how structural features of an epithelium cell in a villus are related to its function. (5)
(Total 10 marks)
5. (a) State a hormone which is a
(i) steroid; (1)
(ii) peptide. (1)
(b) List three structural features of exocrine glands. (3)
(Total 5 marks)
6. (a) Identify the parts of the human digestive system indicated below.
(2)
(b) In the space below draw the structure of an amino acid.
(2)
(c) The enzyme pepsin, involved in protein digestion in the stomach, requires an acid pH to work properly. Explain the effect of pH on enzyme activity. (2)
(d) Explain how three structures of the villus are related to the role of the villus in absorption. (3)
(Total 9 marks)
8. (a) Draw a labelled diagram of the structural features of exocrine glands. (3)
(b) Explain the control of thyroxine by negative feedback. (7)
(Total 10 marks)