Transport in Animals PDF

9- TRANSPORT IN ANIMALS The main transport system of human is the circulatory system, a system of tubes (blood vessels) with a pump (the heart) and valves to ensure one-way flow of blood. Its functions: To transport nutrients and oxygen to the cells. To remove waste and carbon dioxide...

9- TRANSPORT IN ANIMALS The main transport system of human is the circulatory system, a system of tubes (blood vessels) with a pump (the heart) and valves to ensure one-way flow of blood. Its functions: To transport nutrients and oxygen to the cells. To remove waste and carbon dioxide from the cells. To provide for efficient gas exchange. Mammalian circulatory system is a closed double circulation (closed- blood is inside vessels)(double circulation- blood passes through heart twice for one complete circuit of the body)  Single circulation of a fish Fish have a two-chambered heart and a single circulation Deoxygenated The blood passes through the heart once in a blood is pumped by complete circulation of the body the heart to the gills for Dorsal Aorta(upper side of fish) oxygenation, after which the oxygenated blood flows to the rest of the body and back to the heart. Ventral Aorta(lower side of fish) Heart/ Cardiac muscle Pulmonary Artery(to lungs) Aorta Superior Pulmonary veins vena cava Right Atrium Left Atrium Semilunar valve Right atrioventricular valve(Tricuspid valve Right atrioventricular valve(Bicuspid valve) Inferior vena cava Right Left Ventricle Ventricle Septum Systemic circulation: Pulmonary circulation: It transports oxygen-rich blood from The pulmonary artery the left ventricle is in charge of through aorta to the delivering deoxygenated blood body from the right ventricle Vena cava transport to the lungs. deoxygenated blood from the body to the RA LA Blood is oxygenated and heart. cleansed before being RV LV returned to the left atrium The right atrium then through the pulmonary vein delivers and then to the left ventricle. deoxygenated blood to the right ventricle. RA-Right Atrium RV-Right ventricle LA-Left Atrium LV-Left ventricle Advantages of Double Circulation 1 oxygenated and deoxygenated blood, are kept separate(separated by septum) 2 ensures efficient supply of oxygen and nutrients(like glucose, iron, calcium, protein, vitamins to body 3 causes lower pressure in pulmonary artery circulation to prevents damage to capillaries in the lungs 4 allows higher pressure distribution of blood (from Aorta) in body to ensure efficient, blood supply to (rest of) body 5 allows filtration in kidneys (for excretion) 6 maintains a high rate of respiration The septum helps keep oxygenated Systole- contracting/pumping blood from the lungs from mixing Diastole- Relaxation/filling with deoxygenated blood from the body. It also prevents blood from flowing back into the heart chambers after pumping it out. Differences in the thickness of the walls of the: atria and ventricles In human heart, the walls of the ventricle are much thicker than the atrium because the ventricles have to generate a higher pressure, so that deoxygenated blood reaches the lungs (from right ventricle) and oxygenated blood reaches to all the body parts (travelling greater distances) from left ventricle. Thus walls of ventricles are more muscular than the walls of atria, as ventricles have to generate greater force. The walls of atria are relatively thin, as they are the upper chambers and they just have to pump blood below into the ventricles of the heart which require much lesser force. Differences in the thickness of the walls of the: left ventricle and right ventricle Because the left ventricle needs to pump the blood further to the rest of the body(long distance) it needs to generate more force, hence more pressure during contraction in order to do this. This extra force is generated due to the thicker walls(additional muscle) found in the left ventricle wall Additionally, the blood being pumped to the lungs from the right ventricle needs to be at a lower pressure in order to prevent damage to the many thin capillaries the blood goes through in the lungs. Hence the wall of the right ventricle is thinner. Deoxygenated blood Oxygenated blood enters enters through vena the left atrium through cava into the right pulmonary vein atrium Left atrium contracts Right atrium contracts and blood is and blood is pumped pumped through the through right left atrioventricular atrioventricular valve valve to the left to the right ventricle ventricle Blood is then pumped As the left ventricle through the semilunar contracts it pumps valve to the pulmonary oxygenated blood artery through the AORTA to the rest of the body Remember! Blood is pumped away from the heart in arteries and returns to the heart in veins The activity of the heart may be monitored by: ECG(electrocardiogram), pulse rate and listening to sounds of valves closing (contraction) Veins Contains elastic fibres and muscle fibres Capillaries Diameter of capillary- 5-10µm; Diameter of RBC- 7µm High surface area- network of capillaries forms capillary bed, allows more exchange of oxygen, glucose etc. Blood flowing through the capillaries is brought close to the cells of the body to allow efficient exchange of materials (particularly the diffusion of oxygen) The wall of the capillaries is only one-cell thick, decreasing the diffusion distance, which ensures that substances can diffuse easily between the capillary and neighbouring cells The walls are also “leaky” – there are small gaps between individual epithelial cells that form the wall to allow small substances( water, ions, glucose)to leak out of the blood into the fluid surrounding the cells of the body forming tissue fluid Small lumen diameter to slow down flow of blood, bring RBC close to the body tissue  Coronary arteries supply blood to the cardiac muscle which also needs oxygen and nutrient rich blood to function and remove waste If a coronary artery becomes partially or completely blocked by fatty deposits called ‘plaques’ (mainly formed from cholesterol), the arteries are not as elastic as they should be and therefore cannot stretch to accommodate the blood which is being forced through them - leading to coronary heart disease Partial blockage of the coronary arteries creates a restricted blood flow to the cardiac muscle cells and results in severe chest pains called angina Risk factors-> Unhealthy diet, lack of Complete blockage means cells in that area of the exercise, stress, smoking, genetic heart will not be able to respire and can no longer predisposition, contract, leading to a heart attack age and sex(male more prone to CHD) https://dynamicpapers.com/wp-cont ent/uploads/2015/09/0610_w17_qp _43.pdf  Components of Blood: Function Plasma is important for the transport of carbon dioxide, digested food (nutrients), urea, mineral ions, hormones and heat energy Red blood cells transport oxygen around the body from the lungs to cells which require it for aerobic respiration ○ They carry the oxygen in the form of oxyhaemoglobin White blood cells defend the body against infection by pathogens by carrying out phagocytosis and antibody production Platelets are involved in clotting of blood  Blood Red blood cell: biconcave (disc shape, no nucleus , plasma smaller than white blood platelets cells like lymphocyte; function: transports oxygen lymphocyte: little cytoplasm ,large nucleus / nucleus fills most of the cell WBCs ,function: responds to, antigens or vaccine(s) ,produces antibodies WBCs Phagocyte: appearance: lobed & ir nucleus function: engulf pathogens by phagocytosis  STEPS: Blood clotting is important for preventing blood loss and Injury to the epithelial lining of a the entry of pathogens blood vessel, rupturing the blood vessel platelet get activated and bind tightly to the extracellular matrix to anchor them to the site of the wound(break in the blood vessel) Fibrinogen is a complex glycoprotein present in high concentrations in plasma. Platelets release chemicals that cause soluble fibrinogen proteins to convert into insoluble fibrin and form an insoluble mesh across the wound, trapping red blood cells and therefore forming a clot preventing blood loss The clot eventually dries and develops into a scab to protect the wound from bacteria entering  Phagocytes carry out phagocytosis by engulfing and digesting pathogens ○ Phagocytes have a sensitive cell surface membrane that can detect chemicals(ANTIGENS) produced by pathogenic cells ○ Once they encounter the pathogenic cell, they will engulf it and release digestive enzymes to digest it ○ This is a ‘non-specific’ immune response  Lymphocytes: B lymphocytes, also called B cells, create a type of protein called an antibody. These antibodies bind to pathogens or to foreign substances, such as toxins, to neutralize them. Antibodies are Y-shaped proteins with a shape that is specific (complementary) to https://youtu.be/lrYlZJiuf18?si=fYdc r4FPYnYtMBfd the antigens on the surface of the pathogen This is a ‘specific’ type of immune response as the antibodies produced will only fit one type of antigen on a pathogen