Homeostasis — Paper 4 · IGCSE Sciences - Co-ordinated (Double) 0654

10 Fig. 10.1 is a graph to show the blood glucose concentration of a person’s blood measured every hour over a period of 15 hours. 280 260 240 220 blood glucose 200 concentration / mol per dm3 180 160 140 120 100 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 time / hours Fig. 10.1 (a) (i) Suggest a reason for the change in the blood glucose concentration immediately after 3 hours. … [1] (ii) State how many hours it takes for the blood glucose concentration to return to its starting concentration after its peak at 260 mol per dm3. … hours [1] (iii) Explain why the blood glucose concentration decreases after its peak at 5 hours. … … … [2] (b) Suggest one situation when the blood glucose concentration falls dramatically below normal. … … [1] (c) (i) Control of blood glucose concentration is an example of negative feedback. Explain the term negative feedback. … … … [2] (ii) Name one other example of negative feedback in the human body. … [1] Please turn over for Question 11.

8 marks

Mark scheme: 10(a)(i) eaten a meal ; 1 10(a)(ii) 6 (hours) ; 1 10(a)(iii) pancreas detects rise in blood glucose concentration ; (pancreas) produces insulin ; (causing liver) to convert glucose to glycogen ; max 2 10(b) exercise ; starvation ; max 1 10(c)(i) a change from, normal / set point ; (causes) response that, cancels out the change / returns system to normal / returns system to a set point ; 2 10(c)(ii) temperature control ; 1

This question in 0654/41 Oct/Nov 2017

7 (a) Fig. 7.1 shows the blood glucose concentration of a person during a period of exercise and recovery. 140 130 120 110 blood glucose concentration / 100 mg per 100 cm3 of blood 90 80 exercise recovery 70 60 0 10 20 30 40 50 60 time / minutes Fig. 7.1 (i) Explain why blood glucose concentration decreases during the period of exercise. … … … [2] (ii) Explain why blood glucose concentration increases during the period of recovery. … … … … [3] (b) (i) Explain why the control of blood glucose concentration is an example of negative feedback. … … … … [2] (ii) State one other example of negative feedback in the human body. … [1] Please turn over for Question 8.

8 marks

Mark scheme: 7(a)(i) glucose used in respiration ; glucose used to release energy (for exercise) ; AVP ; max 2 7(a)(ii) low blood glucose concentration detected ; glucagon released by the pancreas ; glycogen converted to glucose by the liver ; 3 7(b)(i) if blood glucose concentration, varies / increases / decreases, from normal ; cause steps to be taken to return blood glucose concentration to normal ; 2 7(b)(ii) temperature control ; 1

This question in 0654/42 Oct/Nov 2018

10 (a) Fig. 10.1 shows the circulatory system of a fish and a human. lung capillaries gill capillaries 1 ventricle 2 heart atria 1 atrium heart 2 ventricles body capillaries body capillaries fish circulatory system human circulatory system Fig. 10.1 (i) Use Fig. 10.1 to describe three ways the circulatory system of a human is different from the circulatory system of a fish. 1 … … 2 … … 3 … … [3] (ii) State the name of the structure in the human heart that separates the left ventricle from the right ventricle. … [1] (b) Gills are the gas exchange surface in fish. Suggest two features that gills have that allow efficient gas exchange. 1 … 2 … [2] (c) The human circulatory system contains arterioles. Arterioles are used in the regulation of body temperature. Describe the role of arterioles in reducing body temperature. … … … … … [3] [Total: 9]

9 marks

Mark scheme: 10(a)(i) in humans: blood travels through the heart twice in one circuit of the body / double circulation / circulation to the lungs and to the body ; heart has two atria / ventricles ; oxygenated and deoxygenated blood in the heart / (only) deoxygenated in fish heart ; lungs instead of gills ; max 3 10(a)(ii) septum ; 1 10(b) large surface area ; thin surface ; good blood supply ; max 2 10(c) correct ref to vasodilation / arterioles widen ; arterioles supply more blood to the capillaries in the skin surface ; (vasodilation) increases rate of thermal energy / heat loss from the skin; ; 3

This question in 0654/43 May/June 2019

13 (a) Adrenaline is a hormone. Describe how adrenaline is transported around the body. … … [1] (b) When a person is scared, adrenaline is released causing the concentration of glucose in the blood to increase. (i) Suggest why an increase in blood glucose concentration might be needed when someone is scared. … … [2] (ii) Describe two other effects of adrenaline on the body. 1 … … 2 … … [2] (c) The body tries to maintain blood glucose concentration within certain limits. If the blood glucose concentration exceeds these limits, the body responds to return the blood glucose concentration to normal. (i) Name the term used to describe this mechanism. … [1] (ii) Describe how the liver and pancreas work to reduce the blood glucose concentration if it gets too high. … … … … … [3] [Total: 9]

9 marks

Mark scheme: 13(a) in the, blood / plasma ; 1 13(b)(i) (glucose needed) for respiration / to release energy ; for, flight / fight / AW ; 2 13(b)(ii) any two from pupil dilation ; increase in pulse rate ; increase in breathing rate ; avp ; max 2 2 13(c)(i) negative feedback ; 1 13(c)(ii) pancreas produces insulin ; glucose converted to glycogen ; glycogen stored in the liver ; 3

This question in 0654/42 Oct/Nov 2019

13 (a) The blood glucose concentration of a person is monitored for 180 minutes after eating a meal. Fig. 13.1 shows the results. 1.6 1.4 1.2 1.0 blood glucose concentration / 0.8 g per cm3 0.6 0.4 0.2 0.0 0 20 40 60 80 100 120 140 160 180 200 time after eating / minutes Fig. 13.1 (i) State the name of the hormone that causes the change between 60–120 minutes. … [1] (ii) Suggest one other way to cause a similar change to blood glucose concentration as shown between 60–120 minutes. … [1] (iii) Describe how the liver and pancreas work together to cause the changes shown between 120–150 minutes. … … … … … [3] (b) State a term that can be used to describe the control of blood glucose concentration. … [1] (c) The blood glucose concentration is controlled by hormones. Some of the body’s responses are controlled by the nervous system. Table 13.1 compares some of the features of the hormonal and nervous control systems. Table 13.1 type of control system hormonal nervous method of information … chemical hormones transfer … speed of information … … transfer … … … longevity of action short-lived … Complete Table 13.1 to compare the hormonal and nervous control systems. [2] [Total: 8]

8 marks

Mark scheme: 13(a)(i) insulin ; 1 13(a)(ii) exercise ; 1 13(a)(iii) pancreas releases glucagon ; glycogen (stored) in liver ; glycogen converted to glucose ; 3 13(b) negative feedback ; 1 13(c) type of control system hormonal nervous method of information transfer chemical hormones electrical impulse speed of information transfer slow fast longevity of action long-lasting / AW short-lived 2

This question in 0654/43 Oct/Nov 2019

10 (a) The temperature of a person’s skin is recorded in different environmental temperatures. Fig. 10.1 shows the two parts of the skin where the readings are taken. A B Fig. 10.1 Table 10.1 shows the results. Table 10.1 temperature of the skin / °C part of body cold environment warm environment hot environment (15 °C) (27 °C) (47 °C) A 30.1 34.4 35.8 B 23.7 33.8 36.7 (i) Describe how the skin responds to cold temperatures in order to maintain a constant internal body temperature. … … … … … … [3] (ii) Suggest why the temperature range of the skin on part A is less than on part B. … … … … [2] (b) Body temperature is controlled to keep it within set limits. Name the term used to describe this. … [1] (c) Temperature control of the body shows that humans have sensitivity to their environment. Define sensitivity. … … … … [2] [Total: 8]

8 marks

Mark scheme: 10(a)(i) ref to vasoconstriction ; arterioles narrow ; blood flow to, surface capillaries / skin surface, reduced ; less heat lost by radiation ; hair stands on end ; AVP ; max 3 10(a)(ii) part A covers vital organs ; a suitable temperature is required for body / AW to function ; ref to enzymes ; AVP ; 2 10(b) homeostasis ; 1 10(c) ability to detect, stimuli / changes to the environment / surroundings ; and respond ; 2

This question in 0654/42 Oct/Nov 2020

4 (a) A person monitored the concentration of glucose in their blood for 12 hours. The results are shown in Fig. 4.1. 10 8 6 concentration of glucose 4 in the blood / mmol per dm3 2 0 0 1 2 3 4 5 6 7 8 9 10 11 12 time / hours Fig. 4.1 (i) The concentration of glucose in the blood increases rapidly after a meal is eaten. Suggest the number of meals the person had during the 12 hours. … [1] (ii) Complete the sentences to explain the results between 2 and 3 hours. The brain detects an increase in the concentration of glucose in the blood. The … releases insulin. The insulin stimulates the … to convert glucose to … and store it. This lowers the concentration of glucose in the blood. [3] (b) Name two hormones that increase blood glucose concentration. 1 … 2 … [2] (c) Name the term used to describe the mechanism that is used to return blood glucose concentrations to a normal level. … [1] (d) Glucose is absorbed in the small intestine. (i) Define the term absorption. … … … [2] (ii) Describe how the small intestine is adapted for efficient absorption. … … … … [2] [Total: 11]

11 marks

Mark scheme: 4(a)(i) 3 ; 1 4(a)(ii) pancreas ; liver ; glycogen ; 3 4(b) adrenaline ; glucagon ; 2 4(c) negative feedback ; 1 4(d)(i) movement of digested food molecules ; across the (wall of the) small intestine / into the blood ; 2 4(d)(ii) presence of villi ; large surface area for absorption ; AVP 2

This question in 0654/42 Feb/March 2021

7 Fig. 7.1 is a diagram of a cross-section through human skin. A B C D Fig. 7.1 (a) The boxes on the left show the letters in Fig. 7.1. The boxes on the right show the names of some of the parts of the skin. Draw lines to link each letter in Fig. 7.1 to its correct name. letter in Fig. 7.1 name A fatty tissue B hair erector muscle C receptor D sweat gland [3] (b) Fig. 7.2 shows blood vessels in the skin during warm conditions. skin surface capillary arteriole Fig. 7.2 (i) Describe the role of arterioles and capillaries in temperature control when the body gets too hot. Include the name of the process in your answer. … … … … … … [3] (ii) State one response by the body to a decrease in internal body temperature. … [1] (iii) Name the term used to describe the mechanism used to return internal body temperature to a normal level. … [1] (c) Adrenaline is a hormone that can also affect the skin and blood flow. Describe two ways that adrenaline affects the blood. 1 … … 2 … … [2] [Total: 10]

10 marks

Mark scheme: 7(a) A fatty tissue B hair erector muscle C receptor D sweat gland ;;; 7(b)(i) ref to vasodilation ; arterioles, widen / dilate / AW ; more blood flows through capillaries ; 3 7(b)(ii) shivering / hair stands on end / vasoconstriction ; 1 7(b)(iii) negative feedback ; 1 Question Answer Marks 7(c) increase blood flow / pulse rate ; increase the (blood) glucose (concentration) ; avp ; 2

This question in 0654/43 May/June 2021

10 Hormones control blood glucose concentration. (a) State the name of the part of the blood that transports hormones. … [1] (b) Fig. 10.1 is a flowchart showing the control of blood glucose concentration. Complete the flowchart in Fig. 10.1. increase in blood normal blood glucose glucose is … glucose concentration converted into is released concentration detected by the … … decrease in blood this causes normal blood glucose glucagon … glucose concentration is released to be converted concentration detected by the to glucose in the … … Fig. 10.1 [4] (c) State the term that is used to describe this type of control. … [1] (d) Name one other hormone that increases the glucose concentration of the blood. … [1] (e) Table 10.1 compares nervous and hormonal control. Complete Table 10.1. Table 10.1 hormonal control nervous control transmission method in the blood speed of transmission length of effect [3] [Total: 10]

10 marks

Mark scheme: 10(a) plasma ; 1 10(b) pancreas in boxes 2 and 6 ; insulin in box 3 ; glycogen in box 4 and 8 ; liver in box 8 ; 4 10(c) negative feedback ; 1 10(d) adrenaline ; 1 10(e) hormonal control nervous control transmission method in the blood by neurones / electrical impulses ; relative speed of transmission slow fast ; relative length of effect long lasting short-lived ; 3

This question in 0654/41 Oct/Nov 2021

7 (a) The effect of an injection of adrenaline on pulse rate is recorded. The adrenaline is injected at 1 minute. Fig. 7.1 shows a graph of the results. 110 100 90 80 pulse rate / beats per minute 70 60 50 40 0 2 4 6 8 10 time / minutes Fig. 7.1 (i) Identify in Fig. 7.1 the pulse rate before the adrenaline injection. … beats per minute [1] (ii) Describe the immediate effect of the adrenaline injection on pulse rate shown in Fig. 7.1. Use data from the graph to support your answer. … … … [2] (b) (i) State one effect adrenaline has on the eye. … [1] (ii) Name the nerve that carries impulses from the eye to the brain. … [1] (c) A hormone decreases blood glucose concentration by causing the glucose to be stored. (i) State the name of the hormone that decreases blood glucose concentration. … [1] (ii) State the name of the organ that produces this hormone. … [1] (iii) State the name of the organ that stores the excess glucose. … [1] (d) Describe two ways the actions of the hormonal system are different from the nervous system. 1 … … 2 … … [2] [Total: 10]

10 marks

Mark scheme: 7(a)(i) 65 (beats per minute) ; 1 7(a)(ii) (steep) increase ; to 98 beats per minute / by 33 beats per minute ; 2 7(b)(i) pupils widen ; 1 7(b)(ii) optic (nerve) ; 1 7(c)(i) insulin ; 1 7(c)(ii) pancreas ; 1 7(c)(iii) liver ; 1 7(d) hormonal actions are slower to act ; hormonal actions last longer ; 2

This question in 0654/43 May/June 2022

10 (a) Fig. 10.1 is a diagram of a cross-section through skin. A B C D Fig. 10.1 Table 10.1 shows the names and functions of some of the parts labelled A–D in Fig. 10.1. Complete Table 10.1. Table 10.1 letter in name of part function Fig. 10.1 provide insulation hair erector muscle B [3] (b) Describe the role of arterioles in reducing body temperature when the body gets too hot. … … … … … [3] (c) The control of internal body temperature is an example of negative feedback. (i) Explain what is meant by the term negative feedback. … … … [2] (ii) State one other example of negative feedback. … [1] [Total: 9]

9 marks

Mark scheme: 10(a) 3 name of part letter in function Fig. 10.1 fatty tissue / fat C provide insulation hair erector D (contract to) raise hair muscle sweat gland B produce sweat ;;; 10(b) ref to vasodilation / arterioles widen / dilate ; 3 increase in blood flow to, skin surface / capillaries ; (more) heat loss from skin (by radiation) ; 10(c)(i) ref to a, set point / normal level ; 2 any change results in an opposing action / AW ; 10(c)(ii) control of blood glucose concentration / AVP ; 1

This question in 0654/41 Oct/Nov 2022

1 (a) Fig. 1.1 is a diagram of a cross‑section of skin. C A B D E arteriole capillary Fig. 1.1 (i) State the letter in Fig. 1.1 that identifies a part: of the peripheral nervous system … that produces sweat … that requires energy for contraction. … [3] (ii) Describe how the blood vessels labelled in Fig. 1.1 try to maintain a constant internal body temperature if internal body temperature increases. … … … … … … … [3] (iii) State the term used to describe the homeostatic mechanism used to control internal body temperature. … [1] (b) The control of glucose concentration in the blood is an example of homeostasis. (i) State the name of the hormone that reduces the concentration of glucose in the blood. … [1] (ii) State the type of organs that produce hormones. … [1] (c) Stimuli cause the body to make responses. (i) State the name of the organ that detects the change in temperature of the blood. … [1] (ii) State the name of the characteristic of living organisms that describes the detection and response to stimuli. … [1] [Total: 11]

11 marks

Mark scheme: 1(a)(i) A ; D ; B ; 3 1(a)(ii) any three from: ref to vasodilation ; arterioles widen / dilate ; increase in blood flow to, skin surface / capillaries ; AVP ; 3 1(a)(iii) negative feedback ; 1 1(b)(i) insulin ; 1 1(b)(ii) glands ; 1 1(c)(i) brain ; 1 1(c)(ii) sensitivity ; 1

This question in 0654/41 May/June 2023

10 (a) Fig. 10.1 shows the effect of adrenaline on blood glucose concentration. 2000 1800 1600 blood glucose concentration 1400 g / m3 1200 1000 800 0 10 20 30 40 50 time / minutes time of adrenaline release Fig. 10.1 (i) Calculate the percentage increase in blood glucose concentration between 0 and 10 minutes in Fig. 10.1. blood glucose concentration at 0 minutes … g / m3 blood glucose concentration at 10 minutes … g / m3 percentage increase = … % [2] (ii) Explain the changes to blood glucose concentration shown between 10 and 30 minutes in Fig. 10.1. … … … … … [3] (b) State the name of one hormone, apart from adrenaline, that increases the blood glucose concentration. … [1] (c) Table 10.1 contains some definitions of processes that occur in the alimentary canal. Complete Table 10.1 with the terms of each definition. Table 10.1 term definition breakdown of food into smaller pieces without chemical change to the food molecules movement of digested food molecules into the cells of the body where they are used, becoming part of the cells movement of digested food molecules through the wall of the intestine into the blood [3] (d) Fig. 10.2 is a diagram of a structure found lining the small intestine. X Fig. 10.2 (i) State the name of the structure shown in Fig. 10.2. … [1] (ii) State the name and function of the part labelled X in Fig. 10.2. name … function … [2] [Total: 12]

12 marks

Mark scheme: 10(a)(i) 1050( 10) and 1900(10) ; 2 (((1900–1050) / 1050)  100) = 81 (%) ; 10(a)(ii) any three from: 3 increase in blood glucose concentration detected by pancreas ; insulin released (by pancreas) ; conversion of glucose to glycogen ; glycogen stored in liver ; 10(b) glucagon ; 1 10(c) 3 mechanical digestion ; assimilation ; absorption ; 10(d)(i) villus ; 1 10(d)(ii) lacteal ; 2 fat / lipid absorption ;

This question in 0654/43 Oct/Nov 2023

4 (a) Blood glucose concentration is controlled so that it remains within set limits. State the name given to this type of control. … [1] (b) Fig. 4.1 shows the blood glucose concentration of a person after they have eaten a meal. 9 8 7 blood glucose concentration 6 mmol / dm3 5 4 3 0 10 20 30 40 50 60 70 80 90 100 time / minutes Fig. 4.1 Complete the sentences to describe and explain the changes seen in Fig. 4.1. Carbohydrates such as starch are broken down by the enzyme … to form simpler sugars. These simpler sugars are absorbed into the blood. After 30 minutes, the blood glucose concentration reaches a maximum of … mmol / dm3. The increase in blood glucose concentration is detected and the hormone insulin is released from the … . Insulin causes glucose to be converted to … . This is then stored in the … reducing the blood glucose concentration to its previous level. [5] (c) State the names of two hormones that increase blood glucose concentration. 1 … 2 … [2] (d) State the name of the component of blood that transports hormones. … [1] (e) Table 4.1 compares nervous and hormonal control. Complete Table 4.1. Table 4.1 nervous control hormonal control form of transmission chemical hormones relative speed of action relative longevity of action [3] [Total: 12]

12 marks

Mark scheme: 4(a) homeostasis ; 1 4(b) amylase ; 8.0 (mmol per dm3) ; pancreas ; glycogen ; liver / muscles ; 5 4(c) adrenaline ; glucagon ; 2 4(d) plasma ; 1 4(e) nervous control hormonal control form of transmission electrical impulse chemical hormones relative speed of action fast slow relative longevity of action short-lived / AW long-lasting / AW ;;; 3

This question in 0654/42 May/June 2024

10 (a) Fig. 10.1 shows a diagram of human skin. A B C Fig. 10.1 Identify the parts labelled A, B and C in Fig. 10.1. A … B … C … [3] (b) Describe the role of the blood vessels in maintaining a constant internal body temperature when external temperature increases. … … … … … … … [3] (c) State the name of the type of feedback used to maintain a constant internal body temperature. … [1] [Total: 7]

7 marks

Mark scheme: 10(a) A (hair) erector muscle ; 3 B sweat gland ; C fatty tissue ; 10(b) any three from: 3 vasodilation ; (which occurs in) arterioles ; (therefore) more blood flow to capillaries (at skin surface) ; (so) more heat lost from the (capillaries at) surface of the skin ; 10(c) negative ; 1

This question in 0654/42 Oct/Nov 2024

2 A patient has been told by his doctor to exercise to reduce his risk of coronary heart disease. During exercise, the patient notices these effects: • increased heart rate • increased breathing rate and depth • hotter body temperature. (a) (i) Explain the effects of exercise on heart rate and breathing. … … … … … … [3] (ii) Describe how the patient’s body responds to the increase in body temperature. … … … … … … [3] (b) The patient’s doctor also suggests using a type of drug called statins as well as exercise. (i) State what is meant by the term drug. … … … [2] (ii) State one other way the patient may reduce his risk of coronary heart disease. … … [1] [Total: 9]

9 marks

Mark scheme: 2(a)(i) any three from: 3 increased respiration; increased energy requirement; increased muscle contraction; (muscles) need more oxygen / glucose; increase in carbon dioxide concentration (detected by brain); blood pumped faster; 2(a)(ii) any three from: 3 (blood temperature) detected by brain; (increase in) sweat; vasodilation / widening of arterioles; increased blood flow to capillaries / skin surface; relaxation of hair muscles / hair lies flat; 2(b)(i) a substance/chemical taken into the body; 2 that, affects/modifies/changes, chemical reactions; 2(b)(ii) balanced diet / less stress / stop smoking; 1

This question in 0654/43 May/June 2025

1 (a) Hormones are chemical substances produced in the body. (i) Complete the sentences about hormones. Hormones are chemical substances, produced by a type of organ called a … . Hormones are carried by the … . Hormones alter the activity of one or more specific … organs. [3] (ii) Fig. 1.1 is a diagram showing some of the organs of the body that produce hormones. B A Fig. 1.1 Use Fig. 1.1 to complete Table 1.1. Table 1.1 letter name of organ hormone produced A … … B … … [4] (b) The concentration of glucose in the blood must be kept within a very narrow range. Fig. 1.2 shows the control of blood glucose concentration by hormone J and hormone K. pancreas secretes hormone J increases returns to normal blood normal blood glucose glucose concentration concentration decreases returns to pancreas secretes hormone K Fig. 1.2 (i) Use Fig. 1.2 to identify: hormone J … hormone K. … [2] (ii) Identify the type of homeostatic control shown in Fig. 1.2. … [1] [Total: 10]

10 marks

Mark scheme: Question Answer Marks 1(a)(i) gland ; 3 blood / plasma ; target ; 1(a)(ii) 4 letter name of organ hormone produced A testes / testicle(s) ; testosterone ; B adrenal (gland) ; adrenaline ; 1(b)(i) insulin ; 2 glucagon ; 1(b)(ii) negative feedback ; 1

This question in 0654/41 Oct/Nov 2025