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Respiration
Aerobic – With Air/Sufficient Oxygen
C6H12O6 + 6O2  6CO2 + 6H2O
This is a chemical reaction. Glucose is broken down, in the presence of oxygen. This takes place in the mitochondria of cells to
produce energy. The energy can be broken down to release energy for muscle contraction.
Anaerobic – Without air/insufficient Oxygen
Less O2 is taken in. There is not sufficient O2 in the blood to allow for enough energy to be produced for muscles to use immediately.
There is a lag in O2 supply to the muscles - O2 deficit. Glucose is respired anaerobically to provide energy.
Glucose  pyruvate  lactate (lactic acid)
Respirometer can be used to measure respiratory rate.
Respiratory quotient = volume CO2 given off/volume of oxygen taken up
Lungs and Breathing
Breathing In: External
Intercostal muscles contract.
Ribcage pivots up and out.
Diaphragm contracts and
moves down.
Lung volume increases 
pressure falls  air rushes in
to fill space and equalise
pressure
Breathing Out: Internal
Intercostal muscles contract.
Ribcage moves down and in.
Diaphragm relaxes and moves
up.
Lung volume decreases 
pressure increases  air
forced out
Features of Alveoli: Large Surface area, moist, well supplied with attached blood vessels, single cell thick – thin walls
Diffusion (Gas Exchange): from an area of high concentration to low concentration. Aided by: short diffusion path for O 2 (thin cell
walls, attached blood vessels). Blood vessels carry blood away and this maintains the diffusion gradient.
Cartilage: supports the trachea – keeps it open, stops collapse C shaped rings – this allows breathing/prevents suffocation. Glands:
secrete mucous, moistens air, traps dust and other particles. Cilia: wave like motions, push mucus (removes dust), stops it getting
into lungs.
Emphysema: Broken alveoli walls/fewer alveoli  less surface area  less O2  less O2 for respiration  LESS ENERGY released
and available
Aorta/Arteries: Elastic tissue allows flexibility, (stretches
during ventricular systole, recoils during ventricular
diastole)and thick muscle tissue allows it to withstand the
high pressure of blood
Blood flows back to heart because: as skeletal muscles move
in inhalation, this causes a pressure change, and expansion of
the vena cava. Blood can only flow in one direction due to the
valves in the veins that prevent backflow (ensure that blood
flows in one direction only)
Blood pressure altered by arterioles because: stimulation of the sympathetic nerves cause vasoconstriction. When the sympathetic
nerve stops, vasodilation occurs. This is controlled by the vasomotor centre in the medulla oblongata of the brain
Haemoglobin in blood is oxidised to oxyhaemoglobin (highest concentration found in lungs/pulmonary vein)
Arteries usually carry oxygenated blood away from the heart except for pulomonary artery which carries a high level of
carbon dioxide
Heart is an example of double circulation: During each cardiac cycle blood travels through the heart twice
Heart  Lungs via pulmonary circulation Heart  Body via systemic circulation
Heart controlled by electrical impulses (sent by cardiovascular centre of the brain along nerves to the sympathetic nerves):
1)
2)
3)
4)
Sinoatrial node (in right atrium of heart) sends electrical impulses to the atria, these contract (atrial systole) and pump
blood to the ventricles.
The electrical impulses continue through the atrioventricular node, ventricles contract (ventricular systole) and force blood
through the pulmonary artery to the lungs and through the atria to the rest of the body
The atria relax (atrial diastole). Blood enters the atria from the pulmonary veins or vena cava
The ventricles relax (ventricular diastole), the bicuspid and tricuspid valves open and the next pumpful of blood enters the
ventricles form the atria.
When the chemo receptors in the carotid artery detect increased levels of CO 2 the frequency of nerve impulses is increased
Resting pulse = pulse before exercise. The fitter you are, the faster your pulse will return to normal/resting rate after exercise
Hypertension: high blood pressure – can cause blood vessels to burst. Can be avoided by losing weight, healthy lifestyle, reducing
salt. Can be caused by arteriosclerosis (hardening of the arteries)
Temperature and Homeostasis
Too Hot: detected by thermo receptors in the skin. sweat glands produce
sweat, vasodilation in skin: blood diverted to skin capillaries. Evaporation of
water/sweat cools body. Cooling mechanisms are inhibited, and temperature
returns to normal.
Too cold: detected by thermo receptors in the skin. This stimulates the
thermoregulatory centre in the hypothalamus of the brain: causes shivering,
hairs on skin to become erect. Air is trapped in hairs and acts as an insulator.
Vasoconstriction: arterioles near skin divert blood away from skin to vital
organs
Homeostasis is process where body tries to keep conditions
normal.
Fever: Rise in body temperature: kills/denature bacteria
responsible for infection. This reduces the number of
bacteria, lessening infection and reducing fever. Symptoms
of Hypothermia: Pale skin, extremities turn blue, slow pulse
rate, shivering, reduced consciousness, lack of coordination,
confusion/tiredness/apathy Dehydration: reduces blood
volume, muscles have to work harder, so more heat is
generated. If blood volume is reduced, then blood pressure
falls. Less water available for perspiration, so body can not be
cooled through evaporation of sweat. Less blood flow to the
surface of skin (vasoconstriction occurs) so skin is cooler,
paler and heat can not be lost through radiation. Small
amounts of heat also lost through: expired air, urine, faeces
Blood Pressure: sphygmomanometer
•Cuff wrapped around the upper arm level with the heart.
•Cuff is inflated by squeezing the hand pump.
•Pressure in the bag is raised to 200mmHg which is enough to flatten the brachial artery in the arm.
•Blood flow into the arm is stopped.
•Microphone of a stethoscope is placed over the brachial artery close to the cuff.
•Air is let out using a valve so the pressure slowly reduces.
•When the pressure is reached that the blood can just flow through the artery, the artery makes a tapping sound.
•This pressure corresponds to the systolic pressure.
•The cuff pressure reduced until blood can flow
•the tapping sounds become muffled and stop • this pressure corresponds to the diastolic pressure.
•Recordings are made of systolic over diastolic
• units are mmHg
ECG
Sinus Tachycardia: faster than 100 bpm. Rhythm is similar to normal but RR interval is shorter. Symptoms: extreme tiredness,
dizziness, fainting, shortness of breath, difficult or painful breathing.
Bradycardia: slower than 60bpm, RR interval longer.
Symptoms: little or now blood so patient will lose
consciousness and go into cardiac arrest.
Sinus arrhythmia: RR and PP intervals nor regularly spaced. Symptoms vary (can be a response to exercise, stress, anger or indicate
blood flow is restricted e.g. after a heart attack)
Ventricular Fibrillation: parts of ventricles depolarize
repeatedly in an erratic, uncoordinated way. Can cause
cardiac arrest/death. Other symptoms milder e.g palpitations
or even completely benign
Normal is 60-100 beats per minute
Spirometer
11.5 peaks in 60s = 12 breaths per minute.
Tidal volume (height of small peaks) = 0.5 dm3
Vital Capacity = maximum peak = 5dm3
•Vital Capacity (E): Maximum amount of air which a person
can breath out after maximum inspiration (from full lungs)
•Residual Air (D): air that remains in alveoli/lungs after
breathing out as hard as you can
• Expiratory reserve volume (C): extra air that can be forced
out of lungs after normal expiration
Tidal air/Tidal Volume (F): volume of air which a person
(normally) breathes in or out in one ventilation cycle
Lung function affected by asthma, fitness, age
Features:
Advantages:
Disadvantages:
Used for:
Xrays
Cat Scans
Ultrasound
MRI
Radioactive
tracers
Short wavelength
electromagnetic waves.
Computer axial
tomography uses
rotating xrays – patient
put inside machine.
Computer builds up
image
High frequency sound
waves
Magnetic resonance
imaging – magnet lines
up atoms, radio waves
excite hydrogen atoms,
as this decays they give
back out radiowaves
which are detected
Widely available
Quick and straightforward
to use
Good bone resolution
Can image soft tissues
like the brain
Can show slices or 3D
images
Uses ionising radiation
Risk to operator/patient on
exposure
Poor images of soft
tissue/low density
difference
Bone fractures, dental
decay
Xrays harmful (Ionising
radiation)
Might not be able to
distinguish scar tissue
from cancer tissue
no known hazards, non
invasive, relatively
inexpensive, no hazards
for operators, no
discomfort (besides
cold). No ionising
radiation
Sonographer has to be
trained, image needs
skilful interpretation,
bone absorbs ultrasound
so images of brain hard
to get
Examining foetuses, liver
and kidney illnesses
(abscess/cysts/tumours),
detecting circulatory
illnesses
(weakend/blocked
vessels)
Good contrast between
healthy/unhealthy
tissues. No ionising
radiation. Produces a 3D
image, various views
possible without moving
machine or patient
Cant use with patients
that have metal objects
such as pacemakers,
stressful/claustrophobic,
takes a long time,
expensive
Examine internal organs
like brain/heart/spinal
cord. (e.g after
stroke/heart attack).
Sports injuries, cancer
detection and
reproductive organ
examination
Radioactive dye (e.g
technecium/gallium)
introduced and
detected by a gamma
camera. PET uses an
radioactive sugar that is
taken up quickly by
cancer cells
Can study metabolic
processes and tumour
activity
Cancer detection, brain
examination
Gamma rays harmful,
doesn’t show growing
cancers well, PET scans
are expensive, can’t be
used if breast feeding
Brain activity, tumour
detection, detecting
inflammation or
infection, kidney
disease
Ethics – i.e use common sense!
Examples of some ethical issues you should be aware of are:
• treatment of self-inflicted problems; (NHS could use the money better vs people paid their tax and withholding
treatment is unethical)
• whether the cost of treatment should affect treatment options; (we cant afford everything!)
• turning off life support systems;
• transplants; (e.g religious ideas against pig heart transplants, how long will the replacement last rejection,
immunosuppressant’s)
• withholding distressing information from patients;
• using human beings as subjects for investigations and clinical trials.
All procedures involve an element of risk- is the treatment worth the risk?
Kinetic Energy = ½ MV2
Gravitational Potential Energy = Weight x ∆Height
Weight = mass x acceleration due to gravity
Energy Transferred (Work Done) = Power x Time
Cost = Units x Cost per unit
Units = Power x time
Efficiency = (useful output / useful input) X 100 %
Momentum = mass x velocity
Force = change in momentum/time = rate of change of momentum
Impulse = force x time = change in momentum