RespirationAerobic – 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

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 O2 (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

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

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) Sinoatrial node (in right atrium of heart) sends electrical impulses to the atria, these contract (atrial systole) and pump blood to the ventricles.

2) 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

3) The atria relax (atrial diastole). Blood enters the atria from the pulmonary veins or vena cava4) 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 CO2 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

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

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

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

ECGSinus 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

Xrays Cat Scans Ultrasound MRI Radioactive tracers

Features: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

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

Advantages:Widely availableQuick and straightforward to useGood bone resolution

Can image soft tissues like the brainCan show slices or 3D images

no known hazards, non invasive, relatively inexpensive, no hazards for operators, no discomfort (besides cold). No ionising radiation

Good contrast between healthy/unhealthy tissues. No ionising radiation. Produces a 3D image, various views possible without moving machine or patient

Can study metabolic processes and tumour activity

Disadvantages:Uses ionising radiationRisk to operator/patient on exposurePoor images of soft tissue/low density difference

Xrays harmful (Ionising radiation) Might not be able to distinguish scar tissue from cancer tissue

Sonographer has to be trained, image needs skilful interpretation, bone absorbs ultrasound so images of brain hard to get

Cant use with patients that have metal objects such as pacemakers, stressful/claustrophobic, takes a long time, expensive

Gamma rays harmful, doesn’t show growing cancers well, PET scans are expensive, can’t be used if breast feeding

Used for:Bone fractures, dental decay

Cancer detection, brain examination

Examining foetuses, liver and kidney illnesses (abscess/cysts/tumours), detecting circulatory illnesses (weakend/blocked vessels)

Examine internal organs like brain/heart/spinal cord. (e.g after stroke/heart attack). Sports injuries, cancer detection and reproductive organ examination

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