Biology B - Topic 4 (Part 1)
- Created by: patiw2004
- Created on: 21-06-21 18:13
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- Biology B: Topic 4
- The Heart
- Tricuspid Valve separates the right atrium and ventricle
- Semilunar Valve separates the ventricles from the pulmonary artery/vein
- Bicuspid Valve separates the left atrium and ventricle
- Circulation
- Single Circulation
- Two-chambered heart
- deoxygenated blood is pumped from the heart to the gills
- oxygen is given to body cells before returning to the heart
- Blood becomes oxygenated in the gills
- Double Circulation
- Involves two circulatory systems: systematic and pulmonary
- Systematic: oxygenated blood from heart to body cells, deoxygenated blood back to heart
- Pulmonary: deoxygenated blood from heart to lungs,, carries back oxygenated blood to the heart
- Four chamber heart: right atrium, right ventricle, left atrium, left ventricle (separated by valves to prevent backflow)
- Mammals must maintain high body temperature and move without support of water
- more oxygen and glucose is used up as it requires more energy
- Single Circulation
- Roles of Blood
- Erythrocytes
- Contain Hb which binds to oxygen
- small in size and have a biconcave shape
- large SA:V to aid oxygen diffusion
- lack nucleus
- Leucocytes
- white blood cells
- involved in defence against infection
- Plasma
- carries water-soluble materials
- carries digested food molecules, excretory products & hormones
- maintains body temperature by transferring heat energy
- buffer to pH change
- contains platelets (involved in blood clotting)
- Neutrophils and Monocytes
- Engulf and digest pathogens by phagocytosis
- Eosinophils
- allergic responses & protection against viruses and parasitic worms
- Lymphocytes
- natural killer cells, include formation of antibodies
- Erythrocytes
- Blood Circulation
- Arteries
- Carry oxygenated blood from heart around body
- Veins
- Carry deoxygenated blood back toward the heart
- Capillaries
- Narrow vessels link arteries and veins
- pass very close to cells
- arterioles feed into networks of capillaries
- walls allow rapid diffusion
- Valves
- Prevent backflow, one way blood flow to heart
- needed as there is low pressure in veins
- Arteries
- Transporting o2 and co2
- Oxygen Dissociation Curve of Hb
- Hb is ideally suited to pick up o2 at the lung and drop it off at the tissues
- shows percentage saturation of Hb with o2 in relation to how much o2 is available in the environment
- The Bohr Effect
- Effect of co2 on the o2 dissociation curve of Hb
- high co2 = reduced affinity, Hb binds with o2 less well
- Hb needs higher levels of o2 to become saturated
- low co2 = increased affinity, Hb binds with o2more easily
- Oxygen Dissociation Curve of pH
- pH decrease = graph shift right, drop in affinity
- H+ makes solution acidic, near muscles and cells
- Curve Shift to the LEFT: Low levels of co2, low temp. High pH, high affinity of Hb
- Curve Shift to the RIGHT: High levels of co2, high temp. Low pH, low affinity of Hb
- Oxygen Dissociation Curve of Hb
- Blood Clotting Cascade
- prothrombin -> thrombin by thrombo-plastin
- soluble fibrinogen-> fibrin by thrombin
- Valves Opening and Closing
- Semi-lunar Valve
- Open: ventricles > aorta & pulmonary artery
- Close: aorta & pulmonary artery > ventricles
- Atrio-ventricular Valve
- Open: atria > ventricles
- Close: ventricles > atria
- ECG Graph
- A: AV Valves close, B: SL Valves open, C: SL Valves close, D: AV Valves open
- Semi-lunar Valve
- Cardiac Cycle
- Atrial Systole, Ventricular Systole, Diastole
- Controlling the Heart
- If there is no P-Wave, no contraction, no electrical impulse, no depolarising
- The Heart
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