The liver (Answer of the quiz)
1. Which of the following terms are spelt correctly ? (2)
A. homeostasis
B. homeostatic
C. homoiotherm
D. homogeneous Answer: All are correct (also homogenous)
2. Briefly explain why intercellular fluid can return to venule ?
(in less than 3-4 lines) (3)
At the venule end, hydrostatic (blood) pressure is low and the osmotic
pressure * of blood is relatively high, hence intercellular fluid (= tissue fluid) is
drawn back into capillary by osmosis. (* Notice that in animal physiology, the term
osmotic pressure is used by convention, its algebraic value is exactly opposite to
that of osmotic potential, thus a fluid of high osmotic pressure refers to one with
more dissolved solutes, in this example, the solutes are colloidal plasma proteins
which can not diffuse out of capillary.)
3. What is the similar term of physiological saline ? (1)
Ringer's solution (R is in capital letter)
4. Define gluconeogenesis . (2)
Gluconeogenesis is the synthesis of glucose
from non-carbohydrate sources (e.g. fats and proteins)
in time of starvation or prolonged deficiency.
5. Construct an equation to link up these words: (2)
glycogenesis
glucose-1-phosphate glycogen at liver
glycogenolysis due to glucagon
6. Where is insulin secreted (up to the tissue level) ? (3)
Insulin is secreted from the -cells of Islets of Langerhans in the pancreas.
7. Which word best summarizes the functional relation between insulin and
glucagon ? (1)
antagonistic [hear it] or opposite
8. What is meant by hyperglycaemia ? (1)
Hyperglycaemia is the condition when blood glucose level is abnormally high
( i.e. much higher than the homeostatic set point.)
9. Which of these statements are true for the homeostatic regulation of blood glucose
level ? (2)
A. it is self-adjusting
B. it involves a physiological mechanism
C. it illustrates the principle of positive feedback (should be NEGATIVE)
D. it involves several organs (pancreas, liver/muscle, intestine, blood)
E. it breaks down in patients suffering from diabetes melitus.
Answer: A, B, D, E
10. By citing a specific functional example, explain why liver cell has prominent Golgi
complex and rough endoplasmic reticulum ? (3)
Liver cells manufacture fibrinogen (for blood clotting) and immunoglobulin 免
疫球蛋白 (for body defence), these are complex protein molecules which are
synthesized at the ribosomes of rough endoplasmic reticulum and then
processed at the Golgi complex (body).
11. What is the histological term of liver cell ? (1)
hepatocyte
12. Which blood vessels are found at the portal area among liver lobules ? (3)
13. State one function of the Kupffer cell found along the lining of sinusoid. (1)
These are phagocytic macrophages which destroy old red blood cells and
remove bacteria and foreign particles from the blood flowing through the
liver.
14. Name one hormone, other than glucagon , that may increase blood glucose level . (1)
adrenaline 腎上腺素 (which is secreted in time of emergency)
15. What is meant by fasting ? (1)
fasting = a period of time when no food is eaten
16. Write down the general equation for deamination . (2)
amino acid ammonia + remaining part of amino acid (a keto-acid)
17. Write down the equation to summarize the ornithine cycle . (2)
[For the advanced learner only :
ammonia + carbon dioxide = urea + water ]
18. State two chemicals that can be detoxified 解毒 by the liver. (2)
* Hydrogen peroxide
* alcohol
* ammonia
* certain drugs
19. What is the function of the bile salts ? (1)
Bile salts physically emulsify fats and oils (i.e. break them down into minute
droplets and thereby increase the surface area for subsequent digestion by
lipase)
20. What nutrient, when taken in excess, may lead to the formation of gall stones ? (1)
Cholesterol
21. Name one synthetic and one catabolic function of the liver with reference to the blood-vascular system.
(2)
synthetic : Formation of red blood cells in the foetus (or during the foetal stage)
or the synthesis of fibrinogen (for blood clotting)
catabolic : Destruction of old red blood cells in the adult
22. In terms of their origin, what do fibrinogen, albumen, and globulin have in common ? (1)
They are all synthesized in the liver.
23. Which vitamin(s) is/are abundant in cod-liver oil ? (1)
Vitamin A, D and B12
24. Is the word `bile canaliculi' correctly spelt ? (1)
25. Make a 2 x 2 matrix to accommodate the following words . (1)
centre, periphery ;
intralobular vein, interlobular blood vessels.