g622 monitoring the activity of the human body date: 19 th march 2014 uses of physiological...

G622 Monitoring the activity of the human body

DATE: 19th March 2014Uses of physiological measurements cont.

LO: to understand why we use physiological indicators to assess health and fitness – temperature, blood pressure, heart and lung activityLesson 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 temperaturesSome 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 12.03.14) and swap papers ready to mark

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

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.

Temperature

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 of 26 © Boardworks Ltd 2011

Why control temperature?

Environmental temperature is constantly changing. One minute it can be very hot, the next very cold.

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.

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.


What is core body temperature?

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.

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.


Measuring body temperature


Finding the right balance


Too hot…or too cold?


How is temperature controlled?

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.

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.


Maintaining the core temperature


Why do we shiver?

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.


The structure of the skin


Vasoconstriction and warming up

Why do people go pale when they are cold?

Vasoconstriction is caused by contraction of the muscular wall of the blood vessels.

When core body temperature falls, blood vessels in the skin get narrower. This is called vasoconstriction.

This reduces the volume of blood flowing near the skin surface, and reduces the amount of heat lost from the body.


Vasodilation and cooling down

Why do people turn red when they are hot?

Additional cooling occurs with the production of sweat from sweat glands.

Vasodilation allows a larger volume of blood to flow near the skin surface, transferring heat to the environment. This cools the body down.

When core body temperature rises, blood vessels in the skin get wider. This is called vasodilation.

As the sweat evaporates it transfers heat away from the body.


Responding to change


Negative feedback in the body


Thermoregulation: true or false?

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.

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 60-80 beats per minute.

It will tell if heart is beating too fast or slow or if it is an irregular beat.

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.

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.

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)

Normal

Atrial fibrillation

Ventricular fibrillation

Ventricular tachycardia

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

“LUB”

“DUB”

Atrial Systole

Ventricular Systole

Diastole

Pressures changes in the aorta, left ventricle and left atrium during one

heartbeat

© Pearson Education Ltd 2008This document may have been altered from the original

A normal ECG trace compared with others indicating an unhealthy heart

(.wav)

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

Blood pressure

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

Measuring blood pressure

• bp animation

http://www.sumanasinc.com/webcontent/animations/biology.html

• 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

Disposal of syringes and hypodermic needlesSharps 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 hazardsPathology 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.

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.

g622 monitoring the activity of the human body date: 19 th march 2014 uses of physiological...

Documents