ESS1002 Human Physiology Multiple Choice Questions

Homeostasis
1. refers to the unwavering control of a physiological setpoint.
2. refers to maintaining a stable internal environment.
3. refers to maintaining a stable external environment.
4. A and B.
5. A and C.
The concept of homeostasis
1. includes the concept of an error signal.
2. refers to maintaining physiological functions in a stable condition.
3. refers only to the regulation of body temperature.
4. A and B.
5. B and C.
Hormones
1. are chemical regulators that are conveyed from one organ to another via the blood stream.
2. may be secreted by endocrine cells.
3. may be secreted by nerve cells.
4. A and B.
5. A, B and C.
Some neurons in the vagus nerve terminate on sinoatrial (pacemaker) cells in the heart. These neurons secrete acetylcholine, which ultimately results in a decreased heart rate. This is an example of
1. endocrine control.
2. exocrine control.
3. hormonal control.
4. neural control.
5. none of the above.
The internal pacemaker that sets biological rhythms
1. is located in the brain.
2. is located in the heart.
3. does not function in the absence of light or other environmental cues.
4. A and C.
5. none of the above.
Diffusion
1. depends upon the random motion of molecules.
2. results in net movement of molecules from regions of low concentration to regions of high concentration.
3. is important for moving molecules over large distances in the body.
4. A and B.
5. A and C.
The term “metabolism”
1. refers to all the chemical reactions that occur in the body.
2. includes the synthesis of complex molecules from simpler molecules.
3. includes the breakdown of complex molecules into simpler molecules.
4. includes anabolism and catabolism.
5. is described by all of the above.
ATP
1. is formed during the hydrolysis of ADP.
2. is used by cells for the storage of energy.
3. represents the energy “currency” of all cells.
4. A and C.
5. B and C.
The site where most of the ATP is generated in a cell is the
1. nucleus.
2. plasma membrane.
3. endoplasmic reticulum.
4. Golgi apparatus.
5. mitochondria.
Glycolysis
1. does not occur in the absence of O2.
2. does not occur in the presence of O2.
3. may result in the formation of two moles of lactate for each mole of glucose.
4. A and C.
5. B and C.
Which of the following metabolic pathways does not require oxygen?
1. Glycolysis.
2. Oxidative phosphorylation.
3. The Krebs cycle.
4. The breakdown of fatty acids to CO2 and H2O.
5. None of the above.
Glycolysis
1. yields two moles of ATP for each mole of glucose processed.
2. may yield two moles of lactate for each mole of glucose processed.
3. takes place in the mitochondria of cells.
4. A and B.
5. A, B and C.
The reactions of the Krebs cycle
1. take place in the cytosol of cells.
2. generate ATP directly by substrate phosphorylation.
3. are important for the metabolism of carbohydrates but not other molecules.
4. A and B.
5. All of the above.
Which of the following statements concerning complete oxidation of glucose is true?
1. Carbon dioxide is not released.
2. Oxygen is released.
3. Oxygen is used during the Krebs cycle reactions.
4. Carbon dioxide is released during the Krebs cycle reactions.
5. None of the above.
When glucose is catabolised in the absence of oxygen,
1. pyruvate formed in glycolysis will generally be converted to lactate.
2. pyruvate formed in glycolysis will generally be converted to acetyl coenzyme A, which will enter the Krebs cycle.
3. the number of ATP moles formed per mole of glucose will be less than the number formed in the presence of oxygen.
4. A and C.
5. B and C.
Which of the following statements concerning energy storage in the body is true?
1. Most is stored in the form of ATP.
2. Most is stored in the form of glucose.
3. Most is stored in the form of fat.
4. Most is stored in the form of protein.
5. Most is stored in the form of DNA.
The resting membrane potential
1. occurs only in nerve and muscle cells.
2. is the same in all cells.
3. is oriented so that the cell's interior is positive with respect to the extracellular fluid.
4. requires the separation of most of the cell's charged particles.
5. none of the above.
For an action potential to occur,
1. the stimulus must reach or exceed threshold.
2. Na+ influx must exceed K+ efflux.
3. the membrane must be out of the relative refractory period.
4. A and B.
5. A, B and C.
During the rising phase of an action potential,
1. Voltage-gated Na+ channels open.
2. Voltage-gated K+ channels open.
3. Voltage-gated Na+ channels close.
4. Voltage-gated K+ channels close.
5. A and D.
Which of the following statements concerning the rate of action potential propagation is true?
1. It is faster in large-diameter axons than in small-diameter ones.
2. It is faster for a strong stimulus than for a weak one.
3. It is faster in myelinated nerve fibres than in non-myelinated ones.
4. A and C.
5. A, B and C.
Thick filaments in skeletal muscle are composed of
1. actin.
2. myosin.
3. troponin.
4. calmodulin.
5. tropomyosin.
During isotonic contraction of a skeletal-muscle fibre the
1. sarcomeres shorten.
2. A bands shorten.
3. I bands shorten.
4. A and C.
5. B and C.
Which of the following statements regarding the shortening of a skeletal-muscle fibre is not true? When a skeletal-muscle fibre shortens,
1. the sarcomeres shorten.
2. the distance between Z lines decreases.
3. the myofilaments shorten.
4. the myofilaments slide past each other.
5. the length of the A bands remains the same.
In skeletal muscle, calcium facilitates contraction by binding to
1. tropomyosin.
2. actin.
3. troponin.
4. myosin.
5. the thick filament.
Rigor mortis occurs in a dead animal because
1. ATP, which is necessary for the detachment of cross bridges, is not being formed.
2. ATP, which is necessary for the formation of cross bridges, is not being formed
3. ATP, which is necessary for the formation of cross bridges, continues to be formed for several hours after death.
4. deterioration of muscle proteins prevents detachment of cross bridges.
5. none of the above.
“Motor unit” refers to
1. a single motor neuron plus all the muscle fibres it innervates.
2. a single muscle fibre plus all of the motor neurons that innervate it.
3. all of the motor neurons supplying a single muscle.
4. a pair of antagonistic muscles.
5. all of the muscles that affect the movement of any given joint.
An action potential in the motor end plate rapidly spreads to the central portions of a muscle cell by means of the
1. Z lines.
2. sarcoplasmic reticulum.
3. H zone.
4. transverse tubules.
5. pores in the plasma membrane.
During an isometric contraction of a skeletal muscle,
1. the I bands shorten and the A bands stay the same length.
2. the thick and thin filaments slide past each other.
3. sarcomere length does not change.
4. A and B.
5. none of the above.
Which of the following is not true regarding the comparison of type I (slow oxidative) and type II b (fast-glycolytic) skeletal-muscle fibres?
1. Type I fibres have more abundant mitochondria.
2. Type I fibres fatigue more readily.
3. Type I fibres have more abundant myoglobin.
4. Type I fibres have more abundant capillaries.
5. Type I motor units contain fewer fibres than type IIb motor units.
Which of the following statements about different kinds of skeletal-muscle fibres is true?
1. Slow-oxidative fibres have a greater abundance of glycogen than do fast-glycolytic fibres.
2. Fast-glycolytic fibres have a greater abundance of myoglobin than do slow-oxidative fibres.
3. Fast-glycolytic fibres can generate greater tension than can slow-oxidative fibres.
4. A and B.
5. A, B and C.
Fast-glycolytic muscle fibres differ from slow-oxidative fibres in that
1. the former rely on creatine phosphate as an ATP source for the first few seconds of contraction whereas the latter do not.
2. the former have a smaller diameter than the latter.
3. the former can generate greater maximal tension than the latter.
4. the former generate less lactic acid than do the latter.
5. all of the above are true.
John is a sprinter who specialises in quick and powerful bursts of speed followed by periods of rest. Jim is a marathon runner who specializes in long, steady runs. Compared to Jim, John is likely to have
1. legs with a larger diameter.
2. legs with a smaller diameter.
3. hypertrophy of type I muscle fibres.
4. A and C.
5. B and C.
The fibres in a muscle spindle
1. are not true muscle fibres because they cannot contract.
2. are innervated by gamma motor neurons.
3. function to maintain tension on spindle receptors.
4. B and C.
5. A, B and C.
Golgi tendon organs
1. are located in the tendons joining muscle and bone.
2. monitor the strength of muscle contractions.
3. are associated with monosynaptic reflexes.
4. A and B.
5. A, B and C.
The “master gland” of the endocrine system
1. is the anterior pituitary gland.
2. is the posterior pituitary gland.
3. is the hypothalamus.
4. is the pancreas.
5. is the testis.
Which of the following statements is not true of the endocrine system?
1. It is one of two major regulatory systems of the body.
2. It is composed of glands that secrete chemical messengers into the blood.
3. It is an important regulator of homeostatic mechanisms.
4. It influences and is influenced by the nervous system
5. None of the above.
Endocrine regulation
1. refers to chemical regulators that are conveyed from one organ to another via the blood stream.
2. is slower than regulation by neurotransmission.
3. differs from paracrine regulation in that endocrine regulators act on different cell types from those that secreted them, whereas paracrine regulators are secreted by the same cell type on which they act.
4. A and B.
5. A, B and C.
The pacemaker of the heart is normally the
1. sinoatrial node.
2. atrioventricular node.
3. mitral valve.
4. bundle of His.
5. left ventricle.
In an electrocardiogram, the QRS complex represents the
1. depolarisation of the atria.
2. repolarisation of the atria.
3. depolarisation of the ventricles.
4. repolarisation of the ventricles.
5. the delay at the AV node.
An ECG would be useful for determining a patient's
1. heart murmur.
2. stroke volume.
3. cardiac output.
4. blockage of conduction of electrical signals between the atria and the ventricles.
5. none of the above.
During the cardiac cycle,
1. the volume of blood leaving the left side of the heart is greater than that leaving the right side.
2. the pressure of blood leaving the right side of the heart is greater than that leaving the left side.
3. the duration of systole is greater than that of diastole.
4. the duration of diastole is greater than that of systole.
5. A and D.
The aortic valve
1. prevents the backflow of blood into the aorta during ventricular diastole.
2. prevents the backflow of blood into the left ventricle during ventricular diastole.
3. prevents the backflow of blood into the left ventricle during ventricular ejection.
4. prevents the backflow of blood into the aorta during ventricular ejection.
5. closes when the first heart sound is heard.
Cardiac output is the
1. volume of blood pumped per minute by both ventricles.
2. volume of blood flowing through the systemic circulation each minute.
3. product of the number of heartbeats per minute and the volume pumped per beat.
4. A and C.
5. B and C.
According to the Frank-Starling mechanism of the heart,
1. the left ventricle ejects a larger volume of blood with each systole than the right ventricle.
2. the intrinsic rate of the heart's pacemaker is 100 beats/min.
3. cardiac output increases with increased heart rate.
4. stroke volume increases with increased venous return.
5. both ventricles contract simultaneously.
Distinguishing characteristics of veins include which of the following?
1. All veins carry deoxygenated blood.
2. All veins carry blood toward the heart.
3. All veins have thick, elastic walls.
4. A and B.
5. B and C.
During exercise, there is an increased flow of blood to
1. the brain.
2. the kidneys.
3. the skin.
4. B and C.
5. A, B and C.
Which of the following does not contribute to increased stroke volume during exercise?
1. Increased contractility of cardiac muscle.
2. Increased venous return.
3. Increased length of filling time during diastole.
4. Increased sympathetic stimulation of ventricular muscle.
5. Increased end-diastolic volume.
Inhalation/inspiration occurs as a result of
1. an upward movement of the diaphragm.
2. movement of the ribs closer together due to contraction of the inspiratory/inhalatory intercostal muscles.
3. a downward movement of the diaphragm.
4. A and B.
5. B and C.
In order for the lungs to function normally, the intrapleural pressure must
1. be lower than alveolar pressure.
2. be between +5 and +10 mmHg above atmospheric pressure.
3. alternate between being less than and greater than atmospheric pressure.
4. change as the respiratory demands of the body change.
5. be the same as atmospheric pressure.
During a physical examination, Joe learns that his resting tidal volume is 500 mL; his average resting respiratory rate is 12 breaths per minute; his total lung capacity is 6000 mL; and his anatomic dead space is 150 mL. Joe's resting alveolar ventilation is
1. 72.0 L×min-1.
2. 6.0 L×min-1.
3. 4.2 L×min-1.
4. 1.8 L×min-1.
5. 0.5 L×min-1
Oxygen is carried in blood
1. bound to haemoglobin.
2. dissolved in the plasma.
3. dissolved in the cytosol of erythrocytes.
4. A and C.
5. A, B and C.
Which of the following would cause a decrease in the binding affinity of haemoglobin for oxygen?
1. Increased pH of the blood.
2. Increased temperature of the blood.
3. Decreased DPG levels in erythrocytes.
4. A and B.
5. B and C.
Most of the CO2 that is transported in blood
1. is dissolved in the plasma.
2. is bound to hemoglobin.
3. is in carbonic acid.
4. is in bicarbonate ion.
5. is in carbonic anhydrase.
Insulin
1. increases the uptake and utilization of glucose by muscle and adipose-tissue cells.
2. increases the uptake and utilization of glucose by most nerve cells.
3. decreases the uptake of amino acids by muscle cells.
4. A and B.
5. A and C.
Which of the following tissues is most dependent upon a constant blood supply of glucose?
1. Liver.
2. Brain.
3. Adipose tissue.
4. Skeletal muscle.
5. Cardiac muscle.

ESS1002 Human Physiology Multiple Choice Questions

Quiz