CAIE IGCSE Biology 14.4 Homeostasis Questions
Practise homeostasis questions on stable internal conditions, blood glucose control and temperature regulation through skin responses.
- Syllabus
- 2026–2028
- Course
- Biology 0610
Practise homeostasis questions on stable internal conditions, blood glucose control and temperature regulation through skin responses.
The kidneys filter blood, separate useful molecules from excretory wastes and control the water content of the blood.
Fig. 2.1 is a diagram of a kidney tubule and associated blood vessels. The arrows show the direction of blood flow.
Fig. 2.2 is a drawing of a vertical section through a cell from the lining of region 2 of the tubule.
Fig. 2.1
Fig. 2.2
The kidneys are examples of organs that help the body to maintain a constant internal environment.
State the term for maintaining a constant internal environment by negative feedback.
homeostasis ;
Explain how negative feedback controls the blood glucose concentration of a person who has not eaten for a day.
any three from:
1 (blood) glucose concentration, is low / decreases ;
2 (causing) glucagon, secretion / production ;
3 glucagon, released from / produced in, pancreas ;
4 (glucagon stimulates) breakdown of glycogen / release of glucose (into the blood) ;
5 from liver / muscle ;
6 (blood) glucose concentration, goes (back) up / returns to normal / stays within limits ;
Glucose is absorbed into the blood in the small intestine. Fig. 6.1 shows the human circulatory system and the pathway taken by molecules, such as glucose, when they travel in the blood.
Fig. 6.1
Insulin is a hormone that is secreted by the pancreas.
Describe the role of insulin in the body.
1 controls blood, glucose / sugar, concentration / level ;
2 increased, uptake / respiration, of glucose ;
3 (simulates cells to) convert glucose to glycogen ;
4 idea that target organs are, muscle / liver ;
5 (so) decreases blood glucose concentration ;
6 ref to, negative feedback / homeostasis ;
Explain how blood flow in the skin helps to maintain a constant body temperature in very hot conditions.
1 shunt vessels, constrict / close / AW ;
2 less blood flow through shunt vessels ;
3 arterioles, widen / dilate / relax ;
4 vasodilation (in context of arteries and arterioles) ;
5 more blood flow (through capillaries) near the surface of the skin / AW ;
6 (more) heat loss from blood (by radiation) ;
R if in context of capillaries / veins
A 'blood vessels'
Fig. 6.1 is a flow chart of some of the events that occur to maintain a constant body temperature.
Fig. 6.1
State the name of one effector shown in Fig. 6.1.
sweat glands ;
blood vessels ;
hair erector muscles ;
State the name of the mechanism that controls homeostasis which is represented by the flowchart in Fig. 6.1.
negative feedback ;
Describe how shunt vessels in the skin function to help cool the body when the body temperature is high.
shunt vessels, constrict / close / AW ;
more / redirect, blood flow to skin (capillaries) ;
heat from blood, lost / radiates ;
vasodilation (of arterioles) ;
A vasoconstriction
A heat loss from blood vessels
Describe how the sweat glands and the hair erector muscles function in mammals when the external environment is hot.
sweat, secreted / made (by sweat glands) ;
evaporative (cooling) ;
hair erector muscles relax ;
(hairs lie flat) so that less (air) insulation / allows more air movement (across skin) ;
A less air trapped
List two hormones that are involved in homeostasis.
1
2
insulin ;
glucagon ;
ADH ;
AVP ;