Physio (2023) Flashcards
One of these is a correct pairing of blood cell and function:
A. Erythrocyte - gas transport
B. Leukocytes - immune defense
C. Lymphocytes - antibody production
D. Platelets - blood clotting
A. Erythrocyte - gas transport
Rationale: Erythrocytes, or red blood cells, are primarily responsible for transporting oxygen from the lungs to the tissues and carbon dioxide from the tissues back to the lungs.
A person whose blood type is B has:
A. A antigen, anti-B antibodies
B. B antigen, anti-A antibodies
C. A and B antigens, no antibodies
D. No antigens, anti-A and anti-B antibodies
B. B antigen, anti-A antibodies
Rationale: A person with blood type B has B antigens on the surface of their red blood cells and produces anti-A antibodies in their plasma.
Platelets are important in hemostasis because they:
A. Activate formation of plasmin
B. Close tiny ruptures in capillaries
C. Convert fibrinogen into fibrin
D. Maintain fluidity of blood
B. Close tiny ruptures in capillaries
Rationale: Platelets play a crucial role in hemostasis by forming a temporary platelet plug to seal small breaks in blood vessel walls, particularly in capillaries.
The rate-limiting step in blood coagulation is:
A. Conversion of fibrinogen into fibrin
B. Conversion of prothrombin into thrombin
C. Formation of platelet plug
D. Formation of prothrombin activator
D. Formation of prothrombin activator
Rationale: The rate-limiting step in blood coagulation is the formation of prothrombin activator, which then converts prothrombin to thrombin, leading to the final steps of the coagulation cascade.
Compared to primary immune response, secondary immune response has:
A. Greater potency
B. Higher antibody production
C. Shorter duration
D. Faster onset
A. Greater potency
Rationale: The secondary immune response is typically more potent than the primary immune response due to the presence of memory cells, which recognize the antigen more quickly and mount a stronger and more effective response.
The classical pathway of complement system is activated by:
A. Antigen-antibody reaction
B. Blood trauma
C. Damaged blood vessel
D. Polysaccharide of cell membrane
A. Antigen-antibody reaction
Rationale: The classical pathway of the complement system is activated when antibodies bound to antigens (immune complexes) trigger a series of complement protein activations.
Vitamin K is important in blood coagulation because it is needed for:
A. Aggregation of platelets
B. Constriction of blood vessels
C. Conversion of prothrombin to thrombin
D. Formation of prothrombin in the liver
D. Formation of prothrombin in the liver
Rationale: Vitamin K is essential for the synthesis of prothrombin and other clotting factors in the liver, which are crucial for the blood coagulation process.
The extrinsic pathway of coagulation is activated by:
A. Antigen-antibody reaction
B. Injury to blood vessel wall
C. Polysaccharide of cell membrane
D. Trauma to blood
B. Injury to blood vessel wall
Rationale: The extrinsic pathway of coagulation is initiated by tissue factor (TF) released from damaged blood vessel walls, which then interacts with factor VII to start the coagulation cascade.
Passive immunity occurs after administration of:
A. BCG to a 7-year-old boy
B. COVID-19 vaccine to a 65-year-old male
C. Equine anti-rabies to a girl after dog bite
D. Tetanus toxoid to pregnant women
C. Equine anti-rabies to a girl after dog bite
Rationale: Passive immunity is provided by administering pre-formed antibodies, such as equine anti-rabies immunoglobulin, to a person who has been exposed to rabies.
T lymphocytes that are directly involved in rejection of transplant tissues are:
A. Cytotoxic
B. Helper
C. Regulator
D. Suppressor
A. Cytotoxic
Rationale: Cytotoxic T lymphocytes (CTLs) are directly involved in the destruction of foreign transplant tissues, leading to transplant rejection.
What is the difference between B and T lymphocytes?
A. B lymphocytes are responsible for humoral immunity
B. B lymphocytes have receptors on their cell membrane
C. T lymphocytes activate the classical pathway of the complement system
D. T lymphocytes produce antibodies
A. B lymphocytes are responsible for humoral immunity
Rationale: B lymphocytes are responsible for humoral immunity, which involves the production of antibodies to neutralize pathogens. T lymphocytes, on the other hand, are involved in cell-mediated immunity, directly attacking infected cells or helping other immune cells.
Physiologic significance of surfactant is to INCREASE:
A. Compliance of lungs
B. Resistance of airways
C. Surface tension of alveolar fluid
D. Work of breathing
A. Compliance of lungs
Rationale: Surfactant decreases the surface tension of the alveolar fluid, which increases the compliance (elasticity) of the lungs, making them easier to expand during inhalation. This reduces the work of breathing and helps prevent the collapse of alveoli.
The primary determinant of airway resistance is:
A. Length of airway
B. Radius of airway
C. Temperature of air
D. Viscosity of air
B. Radius of airway
Rationale: The radius of the airway is the primary determinant of airway resistance. A smaller radius significantly increases resistance, whereas a larger radius decreases resistance.
DECREASING inspiratory reserve volume will DECREASE:
A. Expiratory reserve volume
B. Functional residual capacity
C. Inspiratory capacity
D. Tidal volume
C. Inspiratory capacity
Rationale: Inspiratory capacity is the sum of tidal volume and inspiratory reserve volume. Decreasing the inspiratory reserve volume directly decreases the inspiratory capacity.
Diffusion of gases is DECREASED when there is INCREASED:
A. Pressure difference across respiratory membrane
B. Solubility of gas in respiratory membrane
C. Surface area of respiratory membrane
D. Thickness of respiratory membrane
D. Thickness of respiratory membrane
Rationale: Increased thickness of the respiratory membrane hinders the diffusion of gases, making it more difficult for oxygen and carbon dioxide to pass between the alveoli and the blood.
The main factor that affects gas exchange in NORMAL lungs is:
A. Pressure difference across respiratory membrane
B. Solubility of gas in respiratory membrane
C. Surface area of respiratory membrane
D. Thickness of respiratory membrane
A. Pressure difference across respiratory membrane
Rationale: In normal lungs, the primary factor that affects gas exchange is the pressure difference (gradient) across the respiratory membrane, driving the diffusion of gases.
Oxygen-hemoglobin dissociation curve shifts to the left when there is INCREASED:
A. Arterial CO2 pressure
B. Arterial pH
C. Body temperature
D. 2,3-diphosphoglycerate (2,3-DPG)
B. Arterial pH
Rationale: An increase in arterial pH (alkalosis) shifts the oxygen-hemoglobin dissociation curve to the left, indicating higher affinity of hemoglobin for oxygen.
Mnemonic: “CADET, face Right!”
• C: CO2 (increased PCO2) • A: Acid (decreased pH, increased H+ concentration) • D: 2,3-DPG (increased 2,3-diphosphoglycerate) • E: Exercise (increased metabolic activity) • T: Temperature (increased body temperature)
The basic rhythm of respiration is due to:
A. Communication between neurons in pons and medulla
B. Control neurons in medulla oblongata
C. Discharge of impulses from pontine neurons
D. Modulation by higher brain centers
B. Control neurons in medulla oblongata
Rationale: The basic rhythm of respiration is primarily controlled by neurons in the medulla oblongata, which generate the rhythmic impulses that drive the breathing process.
One of these will produce the greatest effect on central chemoreceptors:
A. Acute hypercapnia
B. Acute hypoxemia
C. Chronic hypercapnia
D. Chronic hypoxemia
A. Acute hypercapnia
Rationale: Acute hypercapnia (elevated CO2 levels) has the greatest effect on central chemoreceptors. These chemoreceptors are highly sensitive to changes in CO2 levels and pH in the cerebrospinal fluid, and acute increases in CO2 levels rapidly stimulate the respiratory centers to increase ventilation. Chronic hypercapnia leads to adaptation and decreased sensitivity over time, reducing its immediate impact compared to acute hypercapnia.
The reduction in lung volume during forceful expiration is primarily due to:
A. Contraction of expiratory muscles
B. Elastance of chest wall
C. Elevation of alveolar pressure
D. Resistance of airways
A. Contraction of expiratory muscles
Rationale: During forceful expiration, the reduction in lung volume is primarily due to the contraction of expiratory muscles, such as the abdominal and internal intercostal muscles, which increase the pressure in the thoracic cavity and force air out.
This lung volume provides air in alveoli to oxygenate blood between breaths:
A. Expiratory reserve volume
B. Inspiratory reserve volume
C. Residual volume
D. Tidal volume
C. Residual volume
Rationale: Residual volume is the amount of air remaining in the lungs after a forceful exhalation. This volume ensures that there is always air in the alveoli to maintain continuous gas exchange between breaths.
Obstructive lung disease has one of these characteristics:
A. High residual volume
B. High FEV1
C. Low lung compliance
D. Low total lung capacity
A. High residual volume
Rationale: Obstructive lung disease is characterized by difficulty in exhaling all the air from the lungs, leading to an increased residual volume.
Increased RV/TLC ratio in restrictive lung disease is due to:
A. High residual volume
B. High total lung capacity
C. Low residual volume
D. Low total lung capacity
D. Low total lung capacity
Rationale: In restrictive lung disease, both residual volume and total lung capacity are reduced, but the reduction in total lung capacity is more significant, resulting in an increased RV/TLC ratio.
Phase 0 of cardiac action potential represents:
A. Final early repolarization
B. Partial early repolarization
C. Rapid depolarization
D. Resting state of polarization
C. Rapid depolarization
Rationale: Phase 0 of the cardiac action potential represents rapid depolarization, primarily due to the influx of Na⁺ ions.
Calcium channel antagonists block phase _ of cardiac action potential.
A. 0
B. 1
C. 2
D. 4
C. 2
Rationale: Calcium channel antagonists primarily affect phase 2 of the cardiac action potential, which is characterized by the plateau phase due to Ca²⁺ influx.
The amplitude of cardiac action potential is dependent on:
A. Ca²⁺ influx
B. K⁺ efflux
C. K⁺ influx
D. Na⁺ influx
D. Na⁺ influx
Rationale: The amplitude of the cardiac action potential is primarily dependent on the rapid influx of Na⁺ ions during phase 0.
One of these will DECREASE heart rate:
A. Faster rate of phase 0 depolarization
B. Faster rate of phase 3 repolarization
C. More negative resting membrane potential
D. More negative threshold potential
C. More negative resting membrane potential
Rationale: A more negative resting membrane potential makes it harder for the cell to reach the threshold for depolarization, thus decreasing the heart rate.
Conduction velocity changes when there is alteration in:
A. Membrane potential at the end of repolarization
B. Slow diastolic depolarization of phase 4
C. Threshold potential
D. All of these
D. All of these
Rationale: Conduction velocity can change with alterations in the membrane potential at the end of repolarization, slow diastolic depolarization of phase 4, and threshold potential.
Difference between fast response and slow response action potential includes:
A. Fast response has less negative phase 4
B. Fast response has no phase 1
C. Slow response has less prolonged phase 2
D. Slow response has more steep phase 0
C. Slow response has less prolonged phase 2
Rationale: Slow response action potentials, typical of the sinoatrial and atrioventricular nodes, have a less prolonged phase 2 compared to fast response action potentials found in atrial and ventricular myocytes.
Opening of tricuspid valves occurs during _ phase of cardiac cycle.
A. Isovolumic contraction
B. Isovolumic relaxation
C. Rapid ejection
D. Rapid filling
B. Isovolumic relaxation
This phase of the cardiac cycle coincides with the R wave of the electrocardiogram:
A. Isovolumic contraction
B. Isovolumic relaxation
C. Rapid ejection
D. Rapid filling
A. Isovolumic contraction
Rationale: The R wave on the electrocardiogram corresponds to the onset of ventricular depolarization, which initiates the isovolumic contraction phase of the cardiac cycle.
One of these processes is involved in excitation-contraction coupling during systole:
A. Ca²⁺ dissociates from troponin C
B. Ca²⁺-troponin complex inhibits troponin on actin
C. Myosin blocks binding site on actin
D. Myosin interacts with active site on actin
D. Myosin interacts with active site on actin
Rationale: During excitation-contraction coupling, calcium binds to troponin C, causing a conformational change that moves tropomyosin away from the actin binding sites, allowing myosin to interact with these sites and generate contraction.
The force of myocardial contraction INCREASES when there is:
A. Decreased preload
B. Decreased aortic pressure
C. Increased afterload
D. Increased heart rate
A. Decreased preload
Heart sound heard best at 2nd intercostal space, left sternal border is associated with closure of valve:
A. Aortic
B. Mitral
C. Pulmonic
D. Tricuspid
C. Pulmonic
Rationale: The pulmonic valve closure is best heard at the 2nd intercostal space along the left sternal border.
APTM
Which of these will DECREASE preload?
A. Decreased aortic pressure
B. Decreased venous return
C. Increased aortic pressure
D. Increased venous return
B. Decreased venous return
Rationale: Preload is primarily influenced by venous return to the heart. A decrease in venous return will decrease preload.
Regarding glomerular filtration rate (GFR), under normal physiologic circumstances, which of the following statements is correct?
A. GFR is less than the filtration rate of systemic capillaries
B. GFR is greater than the filtration rate of systemic capillaries
C. GFR is equal to the filtration rate of systemic capillaries
D. GFR is directly proportional to the filtration rate of systemic capillaries
B. GFR is greater than the filtration rate of systemic capillaries
Rationale: The GFR is significantly higher than the filtration rate of systemic capillaries due to the high permeability and large surface area of the glomerular capillaries.
Regarding the filtration barrier, negatively charged solutes like Cl⁻ and HCO₃⁻ can cross the negatively charged filtration barrier because:
A. These solutes are relatively small in size
B. Cl⁻ and HCO₃⁻ have a low concentration in the blood
C. The concentration of these solutes is greater in Bowman’s space
D. These solutes have a high concentration in the glomerulus
A. These solutes are relatively small in size
Rationale: Negatively charged solutes like Cl⁻ and HCO₃⁻ can cross the negatively charged filtration barrier primarily due to their small size, despite the repulsive charge.
An abnormal increase in ADH secretion may lead to increased water reabsorption. Which of the following fluid compartment adjustments will be correct if a hypothetical 3 liters of excess water is reabsorbed?
A. 1.5 liters will be added to the ECF; 1.5 liters will be added to ICF
B. 2 liters will be added to the ECF; 1 liter will be added to the ICF
C. 1 liter will be added to the ECF; 2 liters will be added to the ICF
D. 3 liters will be added to the ECF
A. 1.5 liters will be added to the ECF; 1.5 liters will be added to ICF
Rationale: If excess water is reabsorbed due to increased ADH secretion, the water will distribute between the extracellular fluid (ECF) and intracellular fluid (ICF) compartments according to osmotic balance, typically in a roughly equal manner.
An increase in membrane thickness will have what effect on the rate of simple diffusion of a non-polar substance?
A. Increase
B. Decrease
C. No Change
B. Decrease
Rationale: An increase in membrane thickness reduces the rate of simple diffusion of a non-polar substance as it increases the distance that the substance must travel.
Which would be an appropriate cation associated with a glucose symporter (cotransporter)?
A. Na+
B. K+
C. H+
D. Cl-
A. Na+
Rationale: Sodium (Na+) is commonly used in glucose symporters, where glucose is cotransported with Na+ across the cell membrane.
Which of the following releases CCK?
A. S cells
B. D cells
C. I cells
D. ECL cells
C. I cells
Rationale: Cholecystokinin (CCK) is released by I cells in the duodenum and jejunum in response to the presence of fats and proteins in the chyme.
