Topic 8: Transport in Mammals Flashcards
Definitions I:
(a) Circulatory system
(b) Haemoglobin
(c) Cardiac cycle
(a) Circulatory system: Heart, blood, vessels transporting nutrients/waste. (1 mark)
(b) Haemoglobin: Protein in RBCs binding O₂/CO₂. (1 mark)
(c) Cardiac cycle: Heartbeat sequence pumping blood. (1 mark)
State the structure of the mammalian circulatory system in a human. [1 Mark]
Closed double circulation: heart, pulmonary, systemic vessels. (1 mark)
Describe the functions of main blood vessels in a dog’s pulmonary and systemic circulations. [2 Marks]
Pulmonary artery: Deoxygenated to lungs (1 mark); Aorta: Oxygenated to body (1 mark). (2 marks)
Draw a plan diagram of an artery and vein in transverse section from a microscope slide. [2 Marks]
Artery: Thick wall, small lumen (1 mark); Vein: Thin wall, large lumen, labelled (1 mark). (2 marks)
In a human leg, explain how artery and vein structures relate to their functions. [3 Marks]
Artery: Thick elastic/muscle for pressure (1 mark); Vein: Thin, valves prevent backflow (1 mark); Both transport blood (1 mark). (3 marks)
Draw and label red blood cells and neutrophils from a blood smear photomicrograph. [2 Marks]
RBC: Biconcave, no nucleus (1 mark); Neutrophil: Multi-lobed nucleus, labelled (1 mark). (2 marks)
State water’s role in blood and tissue fluid in a mammal. [2 Marks]
Water: Solvent for transport (1 mark); High heat capacity stabilises temperature (1 mark). (2 marks)
In a muscle capillary, describe tissue fluid formation and function. [2 Marks]
High pressure forces fluid out (1 mark); Supplies nutrients, removes waste (1 mark). (2 marks)
In a lung alveolus, describe how red blood cells transport O₂ and CO₂. [4 Marks]
Haemoglobin binds O₂, carbonic anhydrase forms H₂CO₃ (1 mark); Haemoglobinic acid buffers (1 mark); Carbaminohaemoglobin forms (1 mark); CO₂ released in lungs (1 mark). (4 marks)
Explain the chloride shift in red blood cells during exercise. [3 Marks]
HCO₃⁻ exits RBCs, Cl⁻ enters (1 mark); Maintains charge balance (1 mark); Supports CO₂ transport (1 mark). (3 marks)
State the role of plasma in CO₂ transport in a human bloodstream. [1 Mark]
Plasma dissolves CO₂ as HCO₃⁻ for transport. (1 mark)
Describe the oxygen dissociation curve for adult haemoglobin in a resting human. [2 Marks]
S-shaped curve, high O₂ affinity at high pO₂ (1 mark); Releases O₂ at low pO₂ (1 mark). (2 marks)
Explain the importance of the oxygen dissociation curve in lung and muscle tissues. [3 Marks]
Lungs: High pO₂, O₂ binds (1 mark); Muscles: Low pO₂, O₂ unloads (1 mark); Efficient delivery (1 mark). (3 marks)
In a sprinting athlete, describe the Bohr shift and its significance. [3 Marks]
CO₂ lowers pH, shifts curve right (1 mark); More O₂ released to muscles (1 mark); Boosts respiration (1 mark). (3 marks)
Describe the external and internal structure of a sheep heart. [4 Marks]
External: Four chambers, coronary vessels (1 mark); Internal: Atria thin, ventricles thick (1 mark); Valves separate (1 mark); Septum divides (1 mark). (4 marks)
Explain why ventricle walls differ in thickness in a human heart. [2 Marks]
Left ventricle thicker for systemic pressure (1 mark); Right thinner for pulmonary (1 mark). (2 marks)
In a cardiac cycle, explain pressure changes and valve actions with SAN/AVN roles. [4 Marks]
SAN starts beat, AVN delays (1 mark); Purkyne spreads to ventricles (1 mark); Systole: Pressure closes AV, opens semilunar (1 mark); Diastole: Reverse (1 mark). (4 marks)
