Transport in human Flashcards
Explain how the blood functions to protect the body against infections [4]
Lymphocytes produce antibodies [1] to agglutinate pathogens [1] and neutralise toxins [1] and the phagocytes engulf and ingest pathogens by phagocytosis. [1]
Explain why it is impossible for a person of bloodtype A to receive B type blood during blood transfusion? [3]
Bloodtype A has A antigen on the surface of the RBC, thus the blood plasma contain B antibodies / anti-B[1]. Blood type B has B antigen on the surface of the RBC, upon transfusion, the anti-B in plasma will bind with the transfused B antigen RBCs and cause agglutination[1]. Agglutination of RBCs will cause blockage in blood vessels resulting in heart attack or stroke[1].
explain why is blood type O considered ‘universal donor’ and blood type AB considered ‘universal recipient’? [4]
Blood type O-
Bloodtype O has no antigens on the surface of the RBC, however the blood plasma contain both A and B antibodies / anti-A and anti-B[1]. Upon transfusion, only the RBC is donated, thus it will not react with any blood type antibodies from the recipient blood plasma. No agglutination will occur [1].
Blood type AB-
Bloodtype AB has both A and B antigens on the surface of the RBC, however the blood plasma do not contain A and B antibodies / anti-A and anti-B[1]. Upon transfusion, it will not react with any cell types from donor. No agglutination will occur [1].
Explain how the blood functions to prevent entry of foreign body from wounds [4]
Damaged tissues and platelets release an enzyme known as thrombokinase.
Thrombokinase converts prothrombin in blood plasma to thrombin in the presence of calcium ions.
Thrombin converts soluble fibrinogen to insoluble fibrin threads
which form a mesh to entangle blood cells and form a clot to seal the wound,
thus preventing pathogens entering the wound causing infections / disease.
Describe how carbon dioxide is transported from the tissue cells to the
lungs to be breathed out. [6] *combined with respiration chap
CO2 produced during aerobic respiration in tissue cells and diffuse out of cell into
blood plasma down concentration gradient
CO2 diffuse into RBC and combines with water molecule to form carbonic acid in the presence of carbonic anhydrase
The carbonic acid dissociates into hydrogen ions and hydrogencarbonate ions to dissolve into the blood plasma to be transported. The hydrogen ions in blood plasma helps in regulating blood pH.
Transport via blood to the right side of the heart via vena cava, then to the lungs via
pulmonary artery.
In the lung, hydrogen ions and hydrogencarbonate ions diffuse into RBC and recombine to form carbonic acid.
carbonic acid is converted back into CO2 and water molecule in the presence of carbonic anhydrase in RBC
CO2 diffuse into alveoli down the conc gradient to be breathed out during exhalation
Describe how a molecule of oxygen is transported from the alveoli to the heart muscles [6]
Molecule of oxygen dissolves in the layer of moisture on the surface of the alveolus and diffuse from alveoli into blood down the conc gradient
Binds with haemoglobin in RBC to form oxyhaemoglobin and transported in the blood capillaries
Oxygenated blood from the lungs enters the left atrium through the pulmonary veins
Atrial systole, muscles in left atrium contracts forcing more oxygenated blood into left ventricle.
Ventricular systole, muscles in left ventricle contracts and increase in pressure higher than aorta opens semi-lunar valve and forces oxygenated blood into the aorta
The oxygenated blood flows into coronary artery to supply the heart muscles with oxygen for aerobic respiration to release energy for muscle contraction.
Explain how high altitudes will have an impact on the oxygen transport in the human body and briefly describe how the body can adapt to the environment. [4]
High altitude has lower air pressure and lower concentration of O2. The concentration gradient between the air and the blood in the lung is less steep[1], thus rate of diffusion of O2 from air space into blood in the lung will decrease. Less O2 will bind to haemoglobin in RBC thus less O2 transported in body tissues. [1]
The body will adapt to the environment by increase the production of RBC and haemoglobin [1] to be able to carry more / sufficient O2 to meet the body oxygen demand for aerobic respiration to release energy for normal cellular activities[1].
Describe and explain the effects of smoking in oxygen transport in humans [2/3] *combine with respiration chap
Carbon monoxide in smoke binds irreversibly to haemoglobin forming carboxyhaemoglobin [1]; reduce transport of O2 in haemoglobin[1]; less O2 supplied to tissues for aerobic respiration to release E for normal cellular activities [1]
Compare and contrast between the structures of artery and vein. [4]
Similarity
Muscular and elastic tissue present
One cell thick endothelium present
Differences
Vein has wider lumen than artery to accommodate more blood per unit time
Vein has semi-lunar valves along the vessel to prevent backflow of blood while artery don’t have
Artery has thicker muscular and elastic layer compared to vein for stretching and recoiling to push the blood in spurts along artery, giving rise to pulse.
Explain how the presence of valves would help in maintaining one directional flow of blood in the heart [6]
*note the 5 steps to ans cardiac Q: name of processmuscle contract /relaxpressure changesvalves opening /closingblood flow direction
The one directional flow is always from the atrium to the ventricle and then to the aorta / pulmonary artery. [1]
During passive filling, both atrium and ventricle undergo diastole, bicuspid and tricuspid valve are open to allow blood to flow from atria into ventricles. [1]
During atrial systole, muscles in atria contracts and pressure increases, bicuspid and tricuspid valve are still open to allow more blood to flow from atria into ventricles. [1]
Ventricular systole, muscles in ventricles contract, the bicuspid and tricuspid valve close to prevent the backflow of blood into the atria when the pressure in the ventricle is higher than that of the atria [1]
When the pressure of the ventricle is higher than that of the aorta / pulmonary artery, semi-lunar valve is forced open and blood is forced from ventricles into the aorta / pulmonary artery [1]
During ventricular diastole, muscles in ventricles relax. the semi-lunar valve close to prevent backflow of blood back into ventricle as the pressure in ventricle drops below the pressure of aorta / pulmonary artery [1]
When pressure in ventricle drop below the pressure of atria, bicuspid / tricuspid valve open again to allow passive filling from atria to ventricles for the next cycle. [1]
Account for the four chambers of the heart and explain why the chambers of the heart have different muscle thickness [4]
The ventricles generally have thicker muscles than the atria [1] the atria only need to force blood into the adjacent ventricles during atrial systole, thus less force and pressure are needed. Ventricles need to pump blood out of the heart to other organs thus need more force and pressure generated [1]
The left ventricle has thicker muscle than the right ventricle [1] as it is responsible for pumping blood to the rest of the body, thus need to generate more force and pressure. Right ventricle only need to pump blood to the lungs which are close to the heart. [1]
explain how blood is continuously returned from the rest of the body back to the heart. [3]
During diastole of the heart, the pressure in the heart drops which create a suction force to allow blood to flow back to the heart [1]
The skeletal muscles along the veins will squeeze on the veins during contractions to help pushing the blood along. [1]
The presence of semi lunar valves in the veins will prevent backflow of blood thus only allow blood to move towards the heart [1]
Explain why heart rate increases during exercise [3] * combined with respiration chap
Vigorous contraction of muscles require increasing energy demand[1]
Heart rate increases and pump more volume of blood at faster rate to muscles to
supply more oxygen and glucose [1]
for increasing aerobic respiration to release more E to meet energy demand [1]
