CAIE Biology A-level Transport In Mammals Flashcards PDF

CAIE Biology A-level Topic 8: Transport in Mammals Flashcards PMT Education is licensed under https://bit.ly/pmt-cc This work by https://bit.ly/pmt-edu-cc CC BY-NC-ND 4.0...

CAIE Biology A-level Topic 8: Transport in Mammals Flashcards PMT Education is licensed under https://bit.ly/pmt-cc This work by https://bit.ly/pmt-edu-cc CC BY-NC-ND 4.0 https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Define the term “closed circulatory system”. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Define the term “closed circulatory system”. A circulatory system in which the blood pumped by the heart is contained within blood vessels. The blood does not come into direct contact with the cells. Closed circulatory systems are found in animals, e.g. vertebrates. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc  Describe the journey of blood through the human circulatory system with reference to the 4 major blood vessels of the heart. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Describe the journey of blood through the human circulatory system with reference to the 4 major blood vessels of the heart. heart (r) → pulmonary artery → lungs → pulmonary vein → heart (l) → aorta → body → vena cava → heart (r) https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Define the term “double circulatory system”. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Define the term “double circulatory system”. A circulatory system in which the blood flows through the heart twice in two circuits. Blood is pumped from the heart to the lungs before returning to the heart. It is then pumped around the body, after which it returns to the heart again. Double circulatory systems are found in mammals. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc What are the advantages of a closed system? https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc What are the advantages of a closed system? Lower blood volume required to keep system moving Blood pressure can be controlled and maintained https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc What are the advantages of a double circulatory system? https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc What are the advantages of a double circulatory system? Maintains blood pressure around the whole body Uptake of oxygen is more efficient Delivery of oxygen and nutrients more efficient BP can differ in pulmonary and systemic systems https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Relate the structure of arteries to their function. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Relate the structure of arteries to their function. Thick, muscular walls to withstand high pressure Elastic tissue allows them to stretch and recoil to prevent pressure surges Narrow lumen to maintain pressure Smooth muscle which enables them to vary blood flow Lined with smooth endothelium to reduce friction and ease flow of blood https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Relate the structure of veins to their function. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Relate the structure of veins to their function. Wide lumen eases blood flow Thin walls eases compression by skeletal muscles Require valves to prevent backflow of blood Less muscular and elastic tissue as they don’t have to control blood flow https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Relate the structure of capillaries to their function. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Relate the structure of capillaries to their function. Walls only one cell thick giving a short diffusion pathway Narrow lumen, red blood cells squeeze through, decreasing the diffusion distance Numerous and highly branched, providing a large surface area https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Relate the structure of arterioles and venules to their function. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Relate the structure of arterioles and venules to their function. Branch off arteries and veins in order to feed blood into and take blood away from the capillaries Smaller than arteries and veins so that the change in pressure is more gradual as blood passes through increasingly small vessels https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Draw and describe the structure of an erythrocyte. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Draw and describe the structure of an erythrocyte. Diameter- 6.2-8.2μm Thickness- 2-2.25μm Large surface area to volume ratio Form biconcave discs No nucleus and no large organelles to 1. Cell surface membrane 2. Cytoplasm - appear dark at maximise O2 carrying ability edges, becoming lighter in the centre (pink gradient stain under light microscope) https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Draw and describe the structure of neutrophils. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Draw and describe the structure of neutrophils. Lobed nucleus for flexibility within blood vessels Granulocyte 1. Cell surface membrane 2. Cytoplasm (appears granular) stains light blue 3. Lobed nucleus- varies from 3-5 lobes- stains deep blue https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Draw & describe the structure of lymphocytes. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Draw & describe the structure of lymphocytes. Very large nucleus Small amount of cytoplasm Agranulocyte 1. Cell surface membrane 2. Cytoplasm- stains pale purple 3. Circular nucleus- stains dark purple https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc What is tissue fluid? https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc What is tissue fluid? A fluid surrounding cells and tissues that contains glucose, amino acids, oxygen and other nutrients. It supplies these to the cells, while also removing any waste materials. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Outline the different pressures involved in the formation of tissue fluid. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Outline the different pressures involved in the formation of tissue fluid. Hydrostatic pressure - higher at arterial end of capillary than venous end Oncotic pressure - changing water potential of the capillaries as water moves out, induced by proteins in the plasma https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc How is tissue fluid formed? https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc How is tissue fluid formed? As blood is pumped through increasingly smaller vessels, hydrostatic pressure is greater than oncotic pressure, so fluid moves out of the capillaries. It then exchanges substances with the cells. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Why does blood pressure fall along the capillary? https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Why does blood pressure fall along the capillary? Friction Lower volume of blood https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc What happens at the venous end of the capillary? https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc What happens at the venous end of the capillary? Oncotic pressure is greater than hydrostatic pressure Fluid moves down its water potential gradient back into the capillaries https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc How is tissue fluid removed? https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc How is tissue fluid removed? Tissue fluid drains into the lymphatic system where it is referred to as ‘lymph’ The lymph returns to the blood via the subclavian veins https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Give some examples of intracellular and extracellular body fluids in which water is the primary component. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Give some examples of intracellular and extracellular body fluids in which water is the primary component. Water is a component of: Blood plasma (for the transport of substances) Cytoplasm Tissue fluid (bathes cells) Lymph Urine for excretion Serum https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc  *Why is water important in body fluids? *2022-2024 specification https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc *Why is water important in body fluids? Water acts as a solvent in order to transport material in biofluids Water has a high specific heat capacity - a large amount of energy is required to change its temperature - facilitating the maintenance of homeostatic conditions *2022-2024 specification https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Describe the role of haemoglobin. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Describe the role of haemoglobin. Present in red blood cells. Oxygen molecules bind to the haem groups and are transported around the body. They are released where oxygen is needed in respiring tissues. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc How does the partial pressure of oxygen affect oxygen-haemoglobin binding? https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc How does partial pressure of oxygen affect oxygen-haemoglobin binding? Haemoglobin has variable affinity for oxygen depending on the partial pressure of oxygen, p(O2): At high p(O2), oxygen associates to form oxyhaemoglobin At low p(O2), oxygen dissociates to form deoxyhaemoglobin https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc How is carbon dioxide carried from respiring cells to the lungs? https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc How is carbon dioxide carried from respiring cells to the lungs? Transported in aqueous solution in the plasma As hydrogen carbonate ions in the plasma Carried as carbaminohaemoglobin in the blood https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc  What is the chloride shift? *2022-2024 specification https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc What is the chloride shift? Process by which chloride ions move into the erythrocytes in exchange for hydrogen carbonate ions which diffuse out of the erythrocytes One-to-one exchange *2022-2024 specification https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc  Why is the chloride shift important? *2022-2024 specification https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Why is the chloride shift important? It maintains the electrochemical equilibrium of the cell. *2022-2024 specification https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc What is the function of carbonic anhydrase? https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc What is the function of carbonic anhydrase? Catalyses the reversible reaction between water and carbon dioxide to produce carbonic acid. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Write equations to show the formation of hydrogen carbonate ions in the plasma. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Write equations to show the formation of hydrogen carbonate ions in the plasma. Carbonic anhydrase enzyme catalyses: CO2 + H2O ⇌ H2CO3 (carbonic acid) Carbonic acid dissociates: H2CO3 ⇌ HCO3- (hydrogen carbonate ions) + H+ https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc State the Bohr effect. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc State the Bohr effect. The loss of affinity of haemoglobin for oxygen as the partial pressure of carbon dioxide increases. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Explain the role of carbonic anhydrase in the Bohr effect. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Explain the role of carbonic anhydrase in the Bohr effect. Carbonic anhydrase is present in red blood cells Catalyses the reaction of carbon dioxide and water to form carbonic acid, which dissociates to produce H+ ions H+ ions combine with the haemoglobin to form haemoglobinic acid Encourages oxygen to dissociate from haemoglobin https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc  Why is a higher concentration of erythrocytes important for human populations living at high altitudes? https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Why is a higher concentration of erythrocytes important for human populations living at high altitudes? High altitude, low p(O2), oxygen saturation in erythrocytes will decrease To carry an equal volume of O2 in blood, a higher concentration of erythrocytes is required https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc What is plasma? https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc What is plasma? Main component of the blood (yellow liquid) that carries red blood cells Contains proteins, nutrients, mineral ions, hormones, dissolved gases and waste. Also distributes heat https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc  Describe and explain the shape of a dissociation curve for adult haemoglobin. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Describe and explain the shape of a dissociation curve for adult haemoglobin. Sigmoidal curve (S-shaped): When first O2 molecule binds, it changes the tertiary structure of haemoglobin so that it is easier for the second and third molecules to bind Third molecule changes the tertiary structure of haemoglobin so that it is more difficult for the fourth molecule to bind https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Draw a diagram of the human heart, including the names of chambers, vessels, and valves. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Draw a diagram of the human heart, including the names of chambers, vessels, and valves. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Describe what happens during cardiac diastole. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Describe what happens during cardiac diastole. The heart is relaxed. Blood enters the atria, increasing the pressure and opening the atrioventricular valves. This allows blood to flow into the ventricles. Pressure in the ventricles is lower than in the arteries, so semilunar valves remain closed. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Describe what happens during atrial systole. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Describe what happens during atrial systole. The atria contract, forcing the atrioventricular valves open. Blood flows into the ventricles. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Describe what happens during ventricular systole. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Describe what happens during ventricular systole. The ventricles contract. The pressure increases, closing the atrioventricular valves to prevent backflow, and opening the semilunar valves. Blood flows into the arteries. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Explain how the heart contracts. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Explain how the heart contracts. SAN initiates and spreads impulse across the atria, so they contract. Thick fibrous walls prevent impulse spreading directly to ventricles AVN receives, delays, and then conveys the impulse down the bundle of His Impulse travels into the Purkinje fibres which branch across the ventricles, so they contract from the bottom up. Top tip: consider the importance of this ↑ https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc The walls of the chambers of the heart vary in thickness - explain this. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc The walls of the chambers of the heart vary in thickness - explain this. Walls of both atria relatively thin, only have to cap blood in ventricles as ventricles fill mostly passively Left ventricle wall significantly thicker than right, left must provide pressure for systemic flow, right only has to supply pulmonary system. Both are thicker than the atria https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc