Applied science: monitoring the activity of the human body

  • Created by: Aman
  • Created on: 08-05-14 17:20

imaging using ultrasound & ionising radiation

X-ray photography; radiation imaging of which shows denser material

+ relatively cheap & easy; gives a good quality bone image; can be interpreted by anyone

- cannot be used to identify soft tissue; ionising radiation harmful; high-voltage use hazardous

CAT scan; rotating image (cannon-like machine)

+ more readily available(than MRI) in the UK; more detailled(especially for soft tissue)

- much greater radiation doses; very expensive; requires co-operative/sedated patient 

MRI scan; protons give out energy to the surrounding to provide an image

+ does not involve ionising radiation; no side effects; non-invasive; 3D image

- very expensive; cannot be used with metallic implanted patients; unsuitable for claustrophic or obese patients

Ultrasound; sound waves that reflect from the internal organs and picked up by the transducer 

+ does not involve ionising radiation; no side effects; good for soft tissue; non-invasive; equipment relatively cheap

- nothing can be seen beyond the bone

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Vital signs

blood glucose levels;

fasting -> 3.5-7.5 mmol dm-3 Glucose in urine -> 9 mmol dm-3


typical rate -> 15-18 per min Tidal volume -> 0.4-0.5 dm3

peak flow 400-600dm3 min-1         vital capacity(male) -> 6; women -> 4.25

Blood pressure;

18yr old adult -> 120/80

20yr old male -> 125/80 20yr old female -> 123/80

40yr old male -> 135/80 40yr old female -> 133/80

pulse rate -> 60-80bpm 

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vital signs; body temperature

Body temperature

Normal -> 36.5 - 37.2 Death -> 25 Hypothermia -> 32                                 Fever -> Above 37.2 Hypothermia/heat stroke -> above 38                           High temperature leading to death -> above 43


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The heart rate

cardiac cycle involves the natural muscular activity in the heart:

Systole; contraction

Diastoyle; relaxation

the cardiac cycle is controlled by the SAN: sinalatrialnode 

The SAN acts as the pacemaker in the heart and works by...

1)Generating impulses at each contraction(systole)

2)Exitement caused by impulse spreads to both atria -> both atria contract

3)Septum fibre between ventricle and atrium constricts exitement passing down to ventricules

4)The AVN fibres pick up the impulse after 0.1 seconds 

5)The exitement wave travels through the ventricular wall, causing the muscle cells to contract and push the blood around the body/to the lungs(systole)

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Controlling the heart rate

During periods of increased physical activity, the muscles involved require a faster and greater amount of oxygen & glucose for respiration -> the blood flow needs to increase. ALSO, the extra carbon dioxide and lactic acid(if undergoing anerobic respiration) being produced needs to be oxidised and removed from the body. 

The Vagus nerve is a parasympathetic nerve that slows down heart rate & stroke volume

The sympathetic nerve increases the heart rate & stroke volume 

Adreneline is a hormone produced by the adrenal glands, and affects the heart in a similar way to sympathetic nerves -> increasing heart rate & stroke volume

The cardiovascular centre is located in the brain, and is used to regulate the heart activity and breathing by the use of...

1)Chemoceptors; chemical receptors measuring concentrations of oxygen, carbon dioxide and hydrogen ions

2)Baroceptors; pressure receptors measuring the pressure of the blood vessels -> baroceptors would detect high pressure blood vessels and would induce vagus nerve to reduce stroke volume and pressure

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Pressure changes in the heart

During a cardiac cycle, there are diastole and systole moments

In systolic moments the...

Aortic pressure increases -> pushing blood through the body 

Ventricule pressure increases -> pushing blood through to the aorta 

Atrial pressure decreases -> atrial is being filled up at this stage 

At diastolic moment the...

Aortic pressure decreases -> aorta relaxes, waiting for blood to collect at the ventricules

Ventricular pressure decreases -> ventricules receive blood from atrium

Atrial pressure increases -> atrium pushes blood into ventricules 

Pressure is greatest V.S Pressure is lowest

Arteries Arteriols Veins Capillaries

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human ventilation

In inhalation...

Air passes through the nose/nose-> trechea -> bronchia -> bronchioles; then reaches alveoli; gas exchange allowes the CO2 of the deoxygenated blood to 'swap' with the oxygen in the alveoli

The intercoastal muscles(ribs) contract 

The diaphram relaxes 

The pressure of the lungs decreases, allowing air to fill and spead out in the lungs 

In exhalation...

Air consisting of carbon dioxide passes outwards from the alveoli-> bronchioles-> bronchi-> trachea-> and exits the body from the nose/mouth

The intercoastal muscles relax 

The diaphram pushes upwards 

The pressure of the lungs increases, rushing the air outwards to a place of reduced pressure


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Eliza testing

Elisa testing is a identification test to identify whether the person has contracted a disease(e.g. AIDS) 

1)Antibodies specific to the antigen of identification (e.g. AIDS) are added to bind the bottom the wells 

2)The wells are washed to remove any excess antibodies

3)An agent is added to bind those areas of the walls that are not occupied by the antibody 

4)The wells are washed to remove any excess agent 

5)The patient's blood sample is added to the wells; Any of the antigen present in the blood will bind to the antibodies fixed on the bottom of the wells 

6)The wells are washed to remove any excess blood sample 

7)An antibody-enzyme complex is added to the wells; this complex binds to any antigen trapped in the wells 

8)If the antibody is present, the enzyme will react with the sample 

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sphygmomanometer's are used to moniter blood pressure. there are electrical and manual versions. The electrical version is easier to use, but not as accurate as the manual stethoscope used to measure blood pressure. 


techycardia; abnormally high heart rate 

barcycardia; abnormally low heart rate

arrhythmia; any change from the normal heart rate

ventricular fibrillation; irregular and inconsistent 

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Measuring ventilation

A spirometer & peak flow meter are used to moniter the activity of the lungs 

A spirometer measures the...

Tidal volume; the volume of air that is ventilated during either the inspirotory or expirotory phase of the breathing cycle 

Inspitory reserve volume; the volume of extra air that can be inspired after the end of tidal inspiration

Expitory reserve volume; the volume of extra air that can be expired after the end of tidal expiration 

Vital capacity; maximum volume of air that can be expired after a maximum inspiration 

Residual volume; the volume of gas left in the lungs after maximum expiration 

If lung volumes are low -> lung cancer pulmonary fibrosis

Astmha has normal lung volumes BUT with a reduced flow rate

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How to take pulse and measure cardiovascular fitne

To measure the pulse rate, the following steps should be adhered to...

1)Ensure patient is calm

2)Press two foremost fingers onto cartoid artery in the neck 

3)Count the number of pulses that occur over a 1 minuete period -> counting for 20 seconds and multipling the value will lead to innacuracies -> the patient may have an irregular pulse rate

There are three main methods to measure cardiovascular fitness...

I)Step test

II)Cycle ergonometer 


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Measuring ventilation

A spirometer is used to measure the lung volumes and capacities discussed. 

The procedure of using a spirometer:

1)The spirometer is pre-filled with medical grade oxygen to ensure the safety of the patient 

2)The spirometer is left full with the taps close (to allow oxygen to spread through the spirometer)

3)The patient should sit down next to the spirometer while maintaining a state of relaxation

4)The mouth-piece of the spirometer is rinsed in antiseptic solution/new mouth-piece is used

5)A mouthpiece is placed in the patients mouth, with a nose clip being adhered 

6)The patient undergoes the following tests required to identify the different measurements 

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X-rays have benefits and backdraws...

+Relatively cheap/easy to use/can be interpreted by non-radiologists 

-Poor soft tissue imagery/ionising radiation harmful

Valid points:

X-rays pass through body /soft tissue

Radiation / X-ray produces an image / picture

X-ray film / image / picture acts as a record

image dark where most gets through / shadow image / bones white or light grey / bones give better resolution

different tissues absorb different amounts of X-rays  bones/denser material, absorbs more radiation

soft tissues absorb less radiation 

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similar processes of x-ray imagery, but CAT scan uses many detectors that rotate around the patients head to give a 3D image of hard and soft tissue.

There are benefits and backdraws towards this screening method...

+More readily available (than MRI) in the UK/More detailled in soft tissue imagery

-Much more radiation dose received than X-rays/Very expensive/claustriphoibiac issues

MRI; magnetic resonance imagery provides a detailled image of soft and hard tissue using strong magnetic forces:

+Does not involve ionising radiation/No known side effects/Non invasive/3D image/Better soft tissue image than CAT

-Very high cost/Cannot scan patients with metallic implants/claustriphobiac issues

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The use of sound waves allows instantaneous images to be produced...

1)Ultrasound frequency waves at 2-20MHz 

2)Ultrasound is transmitted & received via the use of a probe

3)A gel is applied on the surface of the area being scanned-> to prevent the reflected waves escaping 

4)The waves reflect off soft tissue/organs(heart e.g.) towards the surface; the waves are picked up by the transducer. 

5)The transducer converts the sound waves into a real-life image on a moniter

+Does not involve ionising radiation/No known harmful side effects/Good soft tissue resolution/Non invasive/Equipment is relatively cheap

-Nothing can be seen beyond bone 

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