CHAPTER 15
HOMEOSTASIS
EXERCISE
SECTION 1: Multiple
Choice Questions
Select the correct answer from the following choices
1. Excretion of hypotonic urine in humans is associated best with the:
(a) glomerular capsule
(b) the proximal
convoluted tubule
(d) distal convoluted tubule
(c) loop of the Henle
are
2. The walls of the
made more or less
permeable to water,
depending on the need
to conserve water:
(a) ureter
(b)urethra
(c) fibrous capsule
(d) collecting duct
, 3. Which of the following will cause a decrease in ADH production?
(a) dehydration
(b) an increase in osmotic pressure of blood
(c) drinking water
(d) abnormally low blood pressure
4. The function of glomerulus and Bowmen's Capsule of the nephron is
to:
(a) reabsorb water into the blood.
(b) eliminate ammonia from the body.
(c) reabsorb salts and amino acids.
(d) filter the blood and capture the filtrate
5. In man, glucose is present in blood plasma but not in urine. This is
because glucose molecules are:
(a) actively transported from the proximal convoluted tubule to blood capillaries (b)
oxidised to supply energy for ultrafiltration
(c) stored in the kidney
(d) too large to enter Bowmen's Capsule
6. Evidence for glomerular filtration in the kidney could be obtained by
comparing the sizes of the molecules present in Bowmen's Capsule with
those in the:
(a) afferent blood vessel
(c) loop of Henle
(b) collecting duct.
(d) proximal tubule
7. The site and principal mechanism for the passage of glucose into the
blood stream in the human kidney is the:
(a) collecting duct, by active secretion
(b) glomerulus, by selective reabsorption
(c) glomerulus, by ultrafiltration
(d) proximal concoluted tubule, by selective reabsorption
8. A drug reduces mitochondrial activity in kidney nephrons. Which
, chemical will be present in increased amounts in the urine?
(a) ammonia
(b) glucose
(c) uric acid (d) urea
9. The main difference between endotherms and ectotherms is:
(a) how they conserve water
(b) where from they get most of their body heat.
(c) whether they are warm or cold blooded
(d) whether they live on land or in the water.
10. The water content of human blood is regulated by ADH. In which part
of the nephron does regulation occur?
(a) ascending limb of loop of Henle
(c) Bowmen's Capsule
(b) descending limb of loop of Henle (d) proximal convoluted tubule
Answer
I
(c)
2
(d)
3
(c)
4
(d)
5
(a)
6
(a)
7
(d)
8
(b)
9
(b)
10
(b)
SECTION II: Short Questions
, Give short answers of the following questions.
Q1. Define the term homeostasis, variable and set points.
Answer
a) Homeostasis.
Homeostasis is the tendency of an organism or cell to regulate its internal
environmental conditions, such as the chemical composition of its body fluids, so as to maintain
health and functioning regardless of outside conditions.
OR
It is the ability of an organism to maintain the internal environment constant or near to
constant level against the harms of external fluctuations (temperature, water, heat etc.).
b) Variable
The internal factors which are influenced by external environment are called variables. e.g
body temperature, water and solute concentrations etc..
c) Set point
Set point is the ideal or normal value of variable that is previously set or stored in
memory.
Q2. Differentiate between osmoconformers and osmoregulators
Answer
Animals cells require more critical balance of water and solutes in body as they cannot.
survive a net water gain or loss. Water continuously leaves and enters the cells; however,
the quantity of the water and the solutes is kept in balance. There are two approaches in
maintaing this balance.
1) Osmoconformers
Animal body fluids are kept isotonic to the external environment even for marine saltwater
environment. These animals thus do not require actively to adjust their internal osmotic
state, so are known as osmoconformers.
2) Osmoregulators
In the animals whose body fluid concentration differs noticeably with outside
environment actively regulate to discharge excess water and excrete salts in hypotonic and
hypertonic conditions respectively, therefore are called as osmoregulators.
HOMEOSTASIS
EXERCISE
SECTION 1: Multiple
Choice Questions
Select the correct answer from the following choices
1. Excretion of hypotonic urine in humans is associated best with the:
(a) glomerular capsule
(b) the proximal
convoluted tubule
(d) distal convoluted tubule
(c) loop of the Henle
are
2. The walls of the
made more or less
permeable to water,
depending on the need
to conserve water:
(a) ureter
(b)urethra
(c) fibrous capsule
(d) collecting duct
, 3. Which of the following will cause a decrease in ADH production?
(a) dehydration
(b) an increase in osmotic pressure of blood
(c) drinking water
(d) abnormally low blood pressure
4. The function of glomerulus and Bowmen's Capsule of the nephron is
to:
(a) reabsorb water into the blood.
(b) eliminate ammonia from the body.
(c) reabsorb salts and amino acids.
(d) filter the blood and capture the filtrate
5. In man, glucose is present in blood plasma but not in urine. This is
because glucose molecules are:
(a) actively transported from the proximal convoluted tubule to blood capillaries (b)
oxidised to supply energy for ultrafiltration
(c) stored in the kidney
(d) too large to enter Bowmen's Capsule
6. Evidence for glomerular filtration in the kidney could be obtained by
comparing the sizes of the molecules present in Bowmen's Capsule with
those in the:
(a) afferent blood vessel
(c) loop of Henle
(b) collecting duct.
(d) proximal tubule
7. The site and principal mechanism for the passage of glucose into the
blood stream in the human kidney is the:
(a) collecting duct, by active secretion
(b) glomerulus, by selective reabsorption
(c) glomerulus, by ultrafiltration
(d) proximal concoluted tubule, by selective reabsorption
8. A drug reduces mitochondrial activity in kidney nephrons. Which
, chemical will be present in increased amounts in the urine?
(a) ammonia
(b) glucose
(c) uric acid (d) urea
9. The main difference between endotherms and ectotherms is:
(a) how they conserve water
(b) where from they get most of their body heat.
(c) whether they are warm or cold blooded
(d) whether they live on land or in the water.
10. The water content of human blood is regulated by ADH. In which part
of the nephron does regulation occur?
(a) ascending limb of loop of Henle
(c) Bowmen's Capsule
(b) descending limb of loop of Henle (d) proximal convoluted tubule
Answer
I
(c)
2
(d)
3
(c)
4
(d)
5
(a)
6
(a)
7
(d)
8
(b)
9
(b)
10
(b)
SECTION II: Short Questions
, Give short answers of the following questions.
Q1. Define the term homeostasis, variable and set points.
Answer
a) Homeostasis.
Homeostasis is the tendency of an organism or cell to regulate its internal
environmental conditions, such as the chemical composition of its body fluids, so as to maintain
health and functioning regardless of outside conditions.
OR
It is the ability of an organism to maintain the internal environment constant or near to
constant level against the harms of external fluctuations (temperature, water, heat etc.).
b) Variable
The internal factors which are influenced by external environment are called variables. e.g
body temperature, water and solute concentrations etc..
c) Set point
Set point is the ideal or normal value of variable that is previously set or stored in
memory.
Q2. Differentiate between osmoconformers and osmoregulators
Answer
Animals cells require more critical balance of water and solutes in body as they cannot.
survive a net water gain or loss. Water continuously leaves and enters the cells; however,
the quantity of the water and the solutes is kept in balance. There are two approaches in
maintaing this balance.
1) Osmoconformers
Animal body fluids are kept isotonic to the external environment even for marine saltwater
environment. These animals thus do not require actively to adjust their internal osmotic
state, so are known as osmoconformers.
2) Osmoregulators
In the animals whose body fluid concentration differs noticeably with outside
environment actively regulate to discharge excess water and excrete salts in hypotonic and
hypertonic conditions respectively, therefore are called as osmoregulators.
