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G622 Monitoring the activity of the human body

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1 G622 Monitoring the activity of the human body
DATE: 19th March 2014 Uses of physiological measurements cont. LO: to understand why we use physiological indicators to assess health and fitness – temperature, blood pressure, heart and lung activity Lesson outcomes: All D= state that a sphygmomanometer can be used to monitor blood pressure and that an electrocardiograph (ECG), spirometer and peak-flow meter can be used to monitor the activity of the heart and lungs Most C = describe normal and abnormal ECG traces and discuss recognised values for; breathing instruments and different temperatures Some B = explain how the body maintains normal body temperature and what the measurements taken from the above instruments say about the probable physiological status of people Starter - get out exam questions, Q4 May 12, Q2 Jun 11 (set ) and swap papers ready to mark

2 Starter - get out exam question
May 2012 Q4 p12-13 (blood tests inc ELISA) part b should read cell not cells (15) (HW 12.03) Jun 2011 Q2 p5-7 (diabetes) (20) (HW 12.03) Swap papers ready to mark ..\G622 exam papers\2012 June\2012 jun MS unit-g622-monitoring-the-activity-of-the-human-body-specimen-june.pdf ..\G622 exam papers\2011 June\2011 jun MS-unit-g622-monitoring-the-activity-of-the-human-body-june.pdf

3 Monitoring Physiological changes:
There are many ways in which doctors, nurses and other health care specialists monitor the working of the human body. This is necessary to ensure that everything is working as it should. Some examples are temperature, pulse and breathing rate, BP and ECG. Often they are concerned with a major organs function because any problem will have a major affect on the well being of the individual i.e. heart or lungs. In this lesson we will look at temperature, pulse rate and ECG. The normal values are those that the OCR will use in the exam, so learn them.

4 Temperature

5 Temperature: We measure body temperature using a clinical thermometer - either mercury or electronic. The reason body temperature is measured is that our body is controlled within a relatively narrow temperature range and a range of diseases (notable infections) can alter that balance.


7 Why control temperature?
Boardworks GCSE Science: Biology Homeostasis Environmental temperature is constantly changing. One minute it can be very hot, the next very cold. Despite this, the body must be kept at a constant temperature of 37 °C. Why? This is the optimum temperature for the body’s enzymes. Even slight changes in body temperature can have a life-threatening effect on health. If body temperature falls too low, reactions become too slow for cells to survive: too high, and the body’s enzymes are at risk of denaturing. This content is higher tier for OCR Gateway Science. 7

8 What is core body temperature?
Boardworks GCSE Science: Biology Homeostasis The vital organs located deep within the body, such as the heart, liver and kidneys, are maintained at 37 °C. This is the core body temperature. Skin temperature at the body's extremities, such as the fingers and toes, is usually lower than the core body temperature. This reduces the energy lost. Teacher notes Temperatures in the ear, mouth and rectum most closely mirror core body temperature. On a warm day, skin temperature may be just 1 °C lower than the core body temperature, but on a very cold day it could be up to 9 °C lower. 8

9 Measuring body temperature
Boardworks GCSE Science: Biology Homeostasis The worksheet ‘Homeostasis’ accompanies this slide. 9

10 Finding the right balance
Boardworks GCSE Science: Biology Homeostasis Teacher notes This two-stage animation introduces the physiological and behavioural mechanisms of thermoregulation. 10

11 Boardworks GCSE Science: Biology
Too hot…or too cold? Boardworks GCSE Science: Biology Homeostasis Teacher notes This five-stage animation illustrates what would happen to a boy and girl in extreme environmental conditions who are unable to thermoregulate. The girl is unable to vasodilate or produce sweat to help cool her down, which speeds up the rate at which she develops heatstroke. People who have anhidrosis – an absence or severe reduction of sweating – have a dangerously high risk of heatstroke in hot weather, which can rapidly be fatal if untreated. In a person who can thermoregulate, sweating will lead to dehydration in extreme heat, which results in additional heatstroke symptoms to the ones shown in the animation. 11

12 How is temperature controlled?
Boardworks GCSE Science: Biology Homeostasis Body temperature is monitored and controlled by temperature receptors in the skin and brain. hypothalamus These receptors detect changes in the temperature of blood flowing through those areas. The thermoregulatory centre in the brain is called the hypothalamus. This content is higher tier for OCR Gateway Science. If body temperature deviates from 37 °C, the hypothalamus and skin receptors send out electrical signals that trigger actions or behaviours that increase or decrease heat loss. 12

13 Maintaining the core temperature
Boardworks GCSE Science: Biology Homeostasis 13

14 Boardworks GCSE Science: Biology
Why do we shiver? Boardworks GCSE Science: Biology Homeostasis When core body temperature drops, muscles begin to twitch. This rapid contraction and relaxation of the muscles is called shivering. Shivering generates heat, which raises body temperature. Goosebumps involuntarily appear when a person becomes cold. Goosebumps are caused by the tiny muscles at the base of body hairs pulling the hairs erect. The upright hairs trap an insulating layer of air, which helps reduce heat loss. 14

15 The structure of the skin
Boardworks GCSE Science: Biology Homeostasis This content is higher tier for OCR Gateway Science and Edexcel Science. 15

16 Vasoconstriction and warming up
Boardworks GCSE Science: Biology Homeostasis Why do people go pale when they are cold? When core body temperature falls, blood vessels in the skin get narrower. This is called vasoconstriction. Vasoconstriction is caused by contraction of the muscular wall of the blood vessels. This reduces the volume of blood flowing near the skin surface, and reduces the amount of heat lost from the body. This content is higher tier for OCR Gateway Science and Edexcel Science. 16

17 Vasodilation and cooling down
Boardworks GCSE Science: Biology Homeostasis Why do people turn red when they are hot? When core body temperature rises, blood vessels in the skin get wider. This is called vasodilation. Vasodilation allows a larger volume of blood to flow near the skin surface, transferring heat to the environment. This cools the body down. Additional cooling occurs with the production of sweat from sweat glands. This content is higher tier for OCR Gateway Science and Edexcel Science. As the sweat evaporates it transfers heat away from the body. 17

18 Boardworks GCSE Science: Biology
Responding to change Boardworks GCSE Science: Biology Homeostasis Teacher notes This activity could be used to check students’ understanding of how the skin responds to temperature changes. This content is higher tier for OCR Gateway Science and Edexcel Science. 18

19 Negative feedback in the body
Boardworks GCSE Science: Biology Homeostasis Teacher notes This five-stage animation can be used to illustrate how the body uses the principle of negative feedback to control body temperature. Students could be asked if they know of other examples of negative feedback in homeostasis. 19

20 Thermoregulation: true or false?
Boardworks GCSE Science: Biology Homeostasis Teacher notes This true-or-false activity could be used as a plenary or revision exercise on thermoregulation, or at the start of the lesson to gauge students’ existing knowledge of the subject matter. Coloured traffic light cards (red = false, yellow = don’t know, green = true) could be used to make this a whole-class exercise. 20

21 Heart

22 Direct measurements: Heart sounds: The beat of the heart produces a sound: the heartbeat. It has two sounds - lub-dup - which is the blood hitting the heart valves. The lub sound is made when blood is forced back against the bi and tri-cuspid valves as the ventricles contract. The dup comes from the back flow of blood as it hits the semi-lunar valves of the pulmonary artery and aorta as the ventricles relax Can be heard using a stethoscope. This magnifies and isolates the heart sounds. It will pick up unusually sounds or murmurs in the heart which may indicate a valve is leaking or that the chambers are not working together.

23 Monitoring heart function:
Monitoring the heart can by direct or indirect measurement. Indirect measurement: is the monitoring the pulse. Each time the ventricles contract, blood is forced out into the aorta under high pressure, and then onto the arteries,. This pressure surge is felt as a pulse. Simple to measure on any of the arteries lying close to the skin in the wrist or neck. Usual to count it for 15 seconds and then multiply by 4 to give number of beats per minute. Alternatively can be measured by a pulse meter. Normal adult rate is beats per minute. It will tell if heart is beating too fast or slow or if it is an irregular beat.

24 ECG or electrocardiogram;
The wave of excitation through the Purkinje tissue of the heart is measured by an electrocardiograph and this produces a graphical display called an electrocardiogram or ECG.

25 Each part of the ECG curve represents a particular electrical event in the heart:
P wave is caused by the excitation spreading from the sinoatrial node (SAN) to the atrioventricular node (AVN) causing atrial systole (contraction) QRS complex is the spread of excitation through the Purkinje tissue causing ventricular systole T wave is the recovery or depolarization of the ventricles after contraction Flat area of the heart is caused by diastole, when there is no excitation of the heart.

26 An ECG is able to identify a number of heart problems:
sinus tachycardia (abnormally rapid fast heartbeat) usually higher than 100 beats/min bradycardia (abnormally slow heartbeat) usually less than 60 beats/min sinus arrhythmia (irregular heartbeat) ventricular fibrillation (irregular and uncoordinated contractions of the ventricles) atrial fibrillation (irregular contractions of the atria)


28 Normal Atrial fibrillation Ventricular fibrillation Ventricular tachycardia

29 A Atrioventricular valves close (1st louder heart sound “LUB”)
Atrial Systole Ventricular Systole Diastole “DUB” “LUB” A Atrioventricular valves close (1st louder heart sound “LUB”) B Semilunaris valves open C Semilunaris valves close (2nd softer heart sound “DUB”) D Atrioventricular valves open

30 Pressures changes in the aorta, left ventricle and left atrium during one
heartbeat © Pearson Education Ltd 2008 This document may have been altered from the original 30

31 A normal ECG trace compared with others indicating an unhealthy heart


33 Health and safety Student activities:
find out and make notes on the health and safety requirements for the following: 1. Regulations for disposal of hazardous biological waste e.g. sharps and hypodermic needles used in obtaining blood for testing 2. Procedures for the treatment of materials that may be contaminated with microbiological hazards e.g. used petri dishes, materials from antibody testing 3. How to carry out a risk assessment for a blood test, state hazards and explain how to minimse the risks to the person carrying out blood test

34 Blood pressure

35 Blood pressure values typical 18-year-old adult 120/80 mmHg
male aged 20 years, 125/80 mmHg female, aged 20 years, 123/80 mmHg male, aged 40 years, 135/85 mmHg female, aged 40 years, 133/85 mmHg

36 BWks

37 Measuring blood pressure
bp animation

38 Lungs

39 breathing rate, 15 – 18 breaths per min
tidal volume, 0.4 – 0.5 dm3 vital capacity (male), 6.00 dm3 vital capacity (female), 4.25 dm3 Peak flow, 400 – 600 dm3

40 Disposal of syringes and hypodermic needles
Sharps and hypodermic needles are disposed of in special containers to avoid contact. Specialist waste disposal companies provide a service to collect and dispose of the waste material in the sharp boxes. Similar services exist for disposal of clinical waste that might be contaminated with blood borne viruses ,such as swabs and other soiled waste. The clinical waste is finally disposed of in special incinerators. Disposal of microbiological hazards Pathology laboratories produce large volumes of clinical waste. This will include microbiological cultures, antibody testing kits, including ELISA plates, contaminated plastic tubes and even radioactive waste. All of this is potentially infected waste. High hazard waste, like microbiological cultures are autoclaved before disposing as clinical waste and then incinerated. Non disposable apparatus is sterilised by being autoclaved, washed before being reused.

41 Risk assessment for a blood test:
The volume of blood my differ depending on the type of analysis required. The details of a general blood test i.e. the method used is always designed to minimise the risks involved with that hazard. Techniques may alter in some way to take the blood but the hazards, risks and precautions will be similar. The risk assessment on the next slide might be used for a blood test but it is only one example of how the assessment might appear.


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