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AS Level Biology - 8) Transport in Mammals
- 1. 8. Transport inMammal And the Circulatory System
- 3. Why do weneed a mammalian transport System Animals – far more active than plants Need energy for – contraction of muscles, brain power, mobility (have to find their own food), nervous system Evolved transport system Diffusion – too slow, the surface area is not enough
- 4. Pulmonary Circulation Deoxygenatedblood moving out from the right ventricles through the pulmonary arteries to the lung. The now oxygenated blood then travels back into the left atrium from the pulmonary vein.
- 5. Systemic Circulation Oxygenatedblood moving out of the left ventricle through the aorta to the rest of the body. Deoxygenated blood travelling back through the vena cava into the right atrium
- 7. The Blood vessels Artery Capillaries Vein
- 8. Arteries Vessels thattransport blood at high pressure to the tissue away from the heart Inner endothelium: Tunica intima – layer of flat squamous epithelium cells – REDUCE FRICTION Middle layer: Tunica media – smooth muscle, collagen, elastic fiber Outer layer: Tunica externa – Elastic fiber/ collagen fibers
- 9. Arteries Strong andelastic To withstand high pressure of blood leaving the heart (120mmhg) Elastic fibers: Wall can stretch Allows the heart to moderate the pressure of the blood by recoiling or stretching
- 10. Arterioles Arteries branchinto smaller vessels – Arterioles Arterioles’ wall have more smooth muscle The muscle can contract – controlling the volume of blood moving in and out of a certain body part Vasoconstriction and vasodilation occurs with arterioles Blood pressure drops here from 120 to 85 as arteries branch out
- 11. Capillaries Arterioles furtherbranch out into capillaries where cell will receive oxygen and give out waste One-cell thick wall (endothelium) – 7 micrometer – just enough for Red blood Cell Blood brought to 1 micrometer from the cell Blood pressure drops enough for slower flow with exchange of thing Allow diffusion to occur
- 12. Venules Capillaries graduallyjoin up to form Venules Venules join to form veins – function: return blood to the heart
- 13. Veins Blood pressureis low – no need for elastic muscles or thick wall Larger lumen Blood flow because the contraction of muscle around the veins Backflow prevented by semilunar valves
- 15. THE LYMPHATIC SYSTEM BLOOD PLASMA,TISSUE FLUID, LYMPH
- 17. Blood Plasma Paleyellow liquid composing of 55% of the blood Content: 90% water – 10% : Ions, Glucose, Urea, Plasma proteins (amino acids, hormones, enzymes, antibodies etc.)
- 18. Blood plasma -Importance Contains hormones and other useful substances Maintains pH and osmotic balance
- 19. Tissue Fluid Whenpassing through capillaries – plasma leaks into the spaces between cells forming tissue fluid Proteins cannot pass through White blood cells can squeeze through
- 20. Tissue Fluid Theprocess is as such: The high blood pressure at arterial end of capillary bed – causes blood plasma to flow out of capillaries High protein concentration in plasma = lower water potential, osmotic pressure causes plasma to flow back into capillaries at venule ends of the capillary bed Hence tissue fluid maintains the osmotic balance of the cell If blood pressure too high – at arterial ends too much of the plasma flow into tissue fluid and accumulates – swelling in the form of oedema
- 22. Lymph 90% offluid that leaks out of capillary – seeps back Another 10% is returned by the lymphatic system Lymphatic systems: made up of lymph vessels The lymphatic will allow tissue fluid to leak in Lymph vessels have valves large enough for proteins Lymph nodes: contain antibodies https://www.youtube.com/watch?v=I7orwMgTQ5I
- 23. The Lymphatic system The lymphatic system’s main job is to return blood plasma to the blood and also to maintain the osmotic balance by allowing protein to leak in from the tissue fluid The system is also where a lot of of the white blood cells reside
- 24. Content of Blood 5 dm3 blood = 5 kg 5 x 1013 Red Blood Cells/ Erythrocytes 6 x 1012 Platelets 2.5 x 1011 White Blood Cells/ Leukocytes
- 25. Red Blood Cells Small size = 7 micrometers Biconcave shape Small amount of organelles High flexibility in membrane
- 26. Hemoglobin The Dissociation curve,Transport of Carbon dioxide and the Bohr Shift
- 27. Haemoglobin Proteins foundinside the red blood cells They combine with oxygen to form Oxyhaemoglobin They are tools Red blood cell uses for transporting oxygen Each haemoglobin has 4 haem groups with each one containing an iron prosthetic group This iron allows the molecule to combine with oxygen and hence give a red color to blood
- 28. The Dissociation Curve This is a curve used to show how haemoglobin combine with oxygen at different partial pressure It is important to show how haemoglobin pick up oxygen but also how it releases those oxygen molecules
- 30. The Dissociation Curve At low partial pressure of oxygen – percentage saturation is very low – haemoglobin combines with very little, in this case 1 oxygen molecule As partial pressure increases, it gets easier Plus haemoglobin changes shape after first combination to make it easier for the other 3 https://www.youtube.com/watch?v=HYbvwMSzqdY
- 31. The S-Curve Wemust also take in account the changes of partial pressure of Carbon Dioxide Where there are high CO2 concentration (high partial pressure) eg. Muscle cells – usually respiring cells that actually do need oxygen Oxygen will be released more readily How so?
- 32. The Bohr Shift When Carbon Dioxide enters the Red Blood cell, carbonic anhydrase allows it to combine with water to form Carbonic acid The Carbonic acid dissociates into Hydrogen bicarbonate and hydrogen ions The hydrogen ion is actually taken up by the haemoglobin And hence the oxygen has to be released THIS IS PERFECT, BECAUSE NOW OXYGEN IS RELEASED WHERE IT IS NEEDED MOST
- 33. Transport of Carbon dioxide Because of the Bohr shift – 85% of the CO2 is now transported in the form of hydrogen bicarbonate ions Another 10% of CO2 directly combines with haemoglobin to form Carbaminohaemoglobin The other 5% is transported in solution
- 35. Problems with Oxygen Transport HighAltitude, Carbon Mooxide
- 36. Effects of Carbon Monoxide Haemoglobin combines very readily with Carbon monoxide – even more so than oxygen (250 times more) To form Carboxyhaemoglobin – a very stable molecule Now the body cannot transport oxygen Carbon monoxide quickly diffuse through alveoli Even 0.1% in the air may cause death by asphyxiation They are found in cigarette smokes – hence most smokers actually have 5% of their blood permanently combined with carbon monoxide
- 37. Effects of HighAltitude Partial pressure of oxygen in normal air is higher than in air at high altitude Haemoglobin becomes less saturated Less oxygen carried around the body Causing breathlessness and illness
- 38. Altitude Sickness Whenthe body doesn’t have enough time to adjust to the change in altitude Increase in rate/ depth of breath Dizziness and weakness Arterials dilate for more oxygen transport – blood flow into the capillary bed more – oedema Oedema in brains can lead to disorientation The way to cure is simple – come down
- 40. Adaptations If thebody is allowed to acclimatized – number of Red Blood Cells increases – usually takes 2 -3 weeks Permanent adaptations for those living at high altitudes Broader chest – for more lung capacity Larger right side of heart – to pump blood to the lung More haemoglobin
- 41. The Heart Heart beatsand how they work
- 44. The Heart Structure Mass: 300 g Size: fist A bag of muscle filled with blood Muscles – cardiac muscles – interconnecting cells with membranes tightly joined for electrical excitation to pass through
- 45. Aorta The largestartery Arch shape Branches leading to the head Main flow double back down toward the body High pressure blood flow here Connected to the left ventricle
- 46. Venae Cavae 2large veins running vertically on the right side of the heart, Connected to the right atrium 1 vessel (superior vena cava) brings blood from rest of the body Another brings blood from the head
- 47. Pulmonary Arteries/ Veins P Artery: takes blood out of the heart to the lung – connected to the right ventricle P Veins: Takes blood from the lung into the hear – connected to the left atrium The revers of the rest of the body – if veins at the rest of the body carry deoxygenated blood, pulmonary veins carries oxygenated blood. Same goes for pulmonary arteries Pulmonary artery branches off immediately to the right and left lung Pulmonary vein returns first into then combine into one
- 48. Coronary arteries Branchoff from aorta Deliver oxygen to the heart itself
- 49. The Cardiac Cycle The sequence of events which make up one heartbeat 3 stages Atrial systole Ventricular systole Ventricular diastole
- 50. Atrial Systole Heartis filled with blood – muscle ready to contract Muscular wall of atrial are thin – contraction do not produce much pressure Pressure still forces Atrioventricular valves (tricuspid/ bicuspid) open Blood flows from the atria into the ventricles Valves in the veins prevent backflow
- 51. Ventricular Systole 0.1seconds after the atria contract Ventricles contract Atrioventricular valves pulled shut due to the pressure in the ventricles exceeding the atria Semi lunar valves forced open Blood rushes into the arteries This lasts for 0.3 seconds
- 52. Ventricular Diastole Thewhole heart muscle relaxes Semilunar valve shuts Blood from veins flow into the atria – at low pressure – but thin wall of atria gives not much resistance Blood just begins flowing into the ventricles when the atria contracts again
- 53. Control of heartbeat The muscles in the heart are myogenic They naturally contract/ relaxes The heart still has its own natural pacemaker Sinoatrial node (SAN) - in the right atrium wall – it can still respond to the brain SAN works a little faster than the heart It sends excitation waves across the atrial walls – causing atrial systole
- 54. Control of heartbeat Muscles of the ventricle contracts 0.1 second after – this is because of the AVN The AVN (Atrioventricular node) receives excitation wave which it withholds until the atria contracts, then it sends down to the ventricles so that they can follow in contraction Between atria and ventricle – a band of fiber that does not conduct electrical impulse is there The AVN send the impulse down through the purkyne tissues in the septum which travels to the rest of the ventricles