biology topic 1
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- Created by: sianxxxxxxxxx
- Created on: 15-02-20 14:08
small organisms
diffusion due to large surface area to volume ratio of the body
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why can larger animals not use diffusion
Surface area to volume ratio decreases Diffusion distance increases Metabolic rate increases Diffusion becomes insufficient.
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mass transport system,and what it consists of
consisting of heart and circulation, which moves the substances efficiently over a long distance due to pressure differences and allows exchange of substances to take place.
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water
dipolar-partially positive H and negative O-cohesive,transports substances through body,good solvent
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arteries
Oblood to body, small lumen maintain high bp-Endothelium protects,provides smooth surface-less resistance to blood flow-Thick layer of smooth muscle contract+relax to dilate+constrict bv+elastic fibres stretch+recoil+Collagen fibres-strength+support
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veins
Carry deoxygenated blood to the lungs (except the pulmonary vein) - Large lumen - Endothelium - Thinner layer of muscle and elastic fibres - Collagen fibres - Valves (to prevent backflow)
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capillaries
Lumen - Endothelium (to maintain short diffusion distance and fit between cells)
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4 main blood vessels
• Four main blood vessels - pulmonary vein (from lungs to left atrium), aorta (from left ventricle to body), vena cava (from body to right ventricle), pulmonary artery (from right atrium to lungs)
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valves
Atrioventricular valves - mitral or tricuspid/bicuspid - separate atria from ventricles • Semilunar valves - pulmonary/aortic - separate arteries from ventricles
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septum
• Septum - muscle and connective tissue - prevents oxygenated/deoxygenated blood mixing
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coronary artery
wrapped around the heart to supply blood to cardiac muscle
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atrial systole
during atrial systole the atria contract. This forces the atrioventricular valves open and blood flows into the ventricles.
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ventricular systole
contraction of the ventricles causes the atrioventricular valves to close and semilunar valves to open, thus allowing blood to leave the left ventricle through the aorta and right ventricle through the pulmonary artery.
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carsiac diastole
atria and ventricles relax and pressure inside the heart chambers decreases. The causing semilunar valves in the aorta and pulmonary arteries close, preventing backflow of blood.
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atherosclerosis
narrowing and hardening of arteries
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steps to atherosclerosis
Artery wall damaged,inflammatory response,large WBC enter wall,Cholesterol accumulates,atheroma forms,ca salts and fibrous tissue accumulate,hard plaque forms,wall elasticity reduced,artery narrows,higher bp,vicious cycle.
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lifestyle factors
Diet-high in saturated fat-ATHEROMAS,high in salt HIGH BP-high blood pressure-smoking,carbon monoxide combines with haemoglobin,nicotine makes platelets sticky,decreases antioxidants-inactivity(sedentary lifestyle)
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factors beyond control
Genetics,Age,Gender.
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what can atherosclerosis lead to
stroke, myocardial infarction, CVD
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steps to blood clotting part 1
Damage to endothelium-high bp.,Thrombolastin released from damaged tissue+platelets,serotonin released narrows bv+slows blood flow,platelets stick to form platelet plug,inactive prothrombin to active thrombin in presence of ca and thromboplastin.
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steps to blood clotting part 2
Thrombin catalyses conversion of soluble fibrinogen to insoluble fibrin,fibrin mesh traps cells to form clot.
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cholesterol
synthesised in liver, keeps cell membrane rigid, hormones
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diastole
2/3 relaxing
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blood pressure
hydrostatic force of blood against walls of a blood vessel-skeletal muscle
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circulatory system
closed-double circulatory-heart,blood,blood vessels
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how is blood pressure measured
sphygmomanometer
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leucocyte
white blood cells-immunity
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erythrocyte
oxygen,carbon dioxide
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dissolved substances
plasma-ions,glucose,carbon dioxide,amino acids
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Other cards in this set
Card 2
Front
why can larger animals not use diffusion
Back
Surface area to volume ratio decreases Diffusion distance increases Metabolic rate increases Diffusion becomes insufficient.
Card 3
Front
mass transport system,and what it consists of
Back
Card 4
Front
water
Back
Card 5
Front
arteries
Back
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