Revision Quizzes Flashcards
Which of the following most accurately compares the endocrine and nervous systems?
a.
Both systems encode signals with ligands that are received by receptors
b.
Most of the time the actions of the endocrine and nervous systems oppose one another
c.
Only the nervous system utilises integration centres; the endocrine system does not require these
d.
Both systems exclusively secrete water-soluble ligands
Both systems encode signals with ligands that are received by receptors
A reaction in the body that releases energy and heat is described as…
Exergonic
Consider the regulation of the hypothalamic-pituitary-thyroid axis. In a person with insufficient dietary iodine, what changes would you expect to observe?
Increased TRH and TSH secretion
Which is an advantage to using direct calorimetry to measure metabolic rate?
As water is heated directly, it is a very accurate measurement
In Grave’s disease, a hyperthyroid condition, antibodies stimulate the TSH receptors found at the thyroid gland. What is the effect of this?
Increased production and release of thyroid hormones
Respiratory quotient is defined as the ratio of moles of CO2 produced to the moles of O2 consumed, i.e. VC/VO. To make this calculation, both oxygen and carbon dioxide must be measured. What information can RQ provide about a subject?
The type of fuel substrate an individual used during the measurement
hyrotropin releasing hormone (TRH) is produced in the hypothalamus. Where is it released into the circulation from?
The median eminence
What is the common and simple method is recommended by the National Institutes of Health (USA) to estimate body composition and overall health?
Body mass index
Which gland/organ secretes hormones that are most important in regulating metabolic rate?
Thyroid gland
The use of an open circuit indirect calorimeter uses the assumption that aerobic metabolism is being utilised to consume oxygen and produce carbon dioxide. By making this assumption, what needs to be measured to obtain a metabolic rate measurement?
c.
Either oxygen or carbon dioxide, but measuring both is most accurate
What is the main effect of thyroid hormones in adults?
Increasing metabolic rate
In the nervous system, where are the integration centres located?
c.
In the central nervous system
What is the name of the system that describes the recycling of bile salts between the digestive tract and the liver/gall bladder?
Enterohepatic circulation
When proteins are broken down to amino acids, they can be deaminated (removal of the amine terminus) and the organic acid can be used for glucose production. How does the body ultimately deal with the amine group (nitrogenous waste)?
Excretion via the kidneys
Which hormone is primarily responsible for allowing glucose to enter cells from the circulation for use or storage?
Insulin
Which option best describes the process of glycogenesis?
a.
Formation of glucose from amino acids
b.
Formation of a starch from glucose molecules
c.
Formation of proteins from amino acids
d.
Formation of triglycerides from glucose
Formation of a starch from glucose molecules
In some pathologies, e.g. pulmonary oedema, the respiratory membrane can become thicker than normal. What effect does this have on gas exchange?
Increased distance and time for diffusion
What is the major driving force for oxygen delivery to occur at the cells of the systemic circulation?
PO2 in the cells is lower than in the blood
Which of the following best describes external respiration?
a.
Gas exchange occurring at the respiratory membrane
b.
The rate at which gas exchange occurs across the respiratory membrane
c.
Gas exchange occurring at cells performing work
d.
Alveolar perfusion occurring at well ventilated alveoli
Gas exchange occurring at the respiratory membrane
Which of the following best describes internal respiration?
a.
Alveolar perfusion occurring at well ventilated alveoli
b.
The rate at which gas exchange occurs across the respiratory membrane
c.
Gas exchange occurring at the cells performing work
d.
Gas exchange occurring at the respiratory membrane
Gas exchange occurring at the cells performing work
Which of the following changes to atmospheric air would have the greatest effect on the partial pressure of oxygen? Assume initial conditions of 25°C, 0% humidity, atmospheric pressure of 760mmHg, oxygen 21%, carbon dioxide 0.3%, nitrogen 78%.
a.
None of the changes listed will affect the partial pressure of oxygen
b.
Increasing temperature to 30°C
c.
Increasing humidity to 100%
d.
Decreasing temperature to 10°C
c.
Increasing humidity to 100%
The Bohr effect describes how oxygen is more easily delivered to tissues during aerobic metabolism. With a change in pH, how would this be described?
a.
Decreased pH decreases haemoglobin affinity for oxygen
b.
Increased pH increases haemoglobin affinity for oxygen
c.
Decreased pH increases haemoglobin affinity for oxygen
d.
Increased pH decreases haemoglobin affinity for oxygen
Decreased pH decreases haemoglobin affinity for oxygen
The Haldane effect is often described as facilitating carbon dioxide delivery to the lungs. Which of the following best explains how this occurs?
a.
The high PO2 at the lungs decreases Hb affinity for carbon dioxide
b.
The low pH in blood increase Hb affinity for carbon dioxide
c.
The low pH in the blood causes the release of carbon dioxide from Hb
d.
The low PCO2 at the lungs decreases Hb affinity for carbon dioxide
a.
The high PO2 at the lungs decreases Hb affinity for carbon dioxide
Which component of haemoglobin is involved in the binding and release of carbon dioxide?
Any amine group
Which component of haemoglobin is involved in the binding and release of oxygen?
Iron (Fe2+)
The Pre-Bötzinger complex plays a role in regulating resting respiratory rate. How is it functionally involved in this process?
It ramps up the number of motor neurons recruited during inspiration
What is the advantage in having the dorsal respiratory group contained within the nucleus tractus solitarius of the medulla?
It is close to the nuclei of the hypoglossal (CNIX) and vagus nerves (CNX), allowing integration of sensory information
What is the link between the limbic system (major emotional centre) and changes in respiration?
Strong emotions can activate the sympathetic nervous system, increasing respiration
Which is the best description of the relationship between blood PCO2 and blood pH?
a.
These are tightly linked, and as PCO2 decreases, pH decreases
b.
These are loosely linked, and as PCO2 decreases, pH decreases
c.
These are tightly linked, and as PCO2 increases, pH decreases
d.
These are loosely linked and as PCO2 increases, pH decreases
c.
These are tightly linked, and as PCO2 increases, pH decreases
Which is the most potent stimulus for increasing rate and depth of breathing?
a.
Increased central carbonic anhydrase activity
b.
Increased PCO2
c.
Decreased PO2
d.
Increased plasma pH
b.
Increased PCO2
One of the by-products of anaerobic metabolism is lactate (or lactic acid), which can be transported to the liver via the circulation. What is the advantage in this?
It can be converted back to glucose via gluconeogenesis
The Cori cycle involves products from skeletal muscle and the liver. What are the major 3-carbon and 6-carbon molecules that are produced in each tissue, and transported via the circulation?
Lactate and glucose
What role does phosphocreatine play in the generation of ATP in anaerobic metabolism?
It can be a phosphate donor to form ATP
Which activity will most rapidly deplete glycogen stores in skeletal muscle?
Heavy exercise
While anaerobic glycolysis occurs rapidly, what is the drawback in comparison with aerobic metabolism?
The relatively low ATP yield
When performing endurance exercise over a prolonged period (>2h), why do we need to rely on gluconeogenesis and β oxidation for ATP production?
Anaerobic metabolism and glycogenolysis can only sustain 1-2h of activity
With extreme endurance exercises being performed frequently, individuals are often more susceptible to infections, e.g. respiratory tract infections. What is the likely cause of this?
A suppressed immune system from cortisol secretion
Where does aerobic metabolism occur within a cell?
The mitochondria
With the onset of exercise, proprioceptors in skeletal muscle and stretch receptors in the lungs are activated, sending messages to the central nervous system. What is the major response from the central nervous system that will support continued exercise?
Activation of the sympathetic nervous system
You are talking to an athlete after they have completed a running event. You notice that they are still out of breath for a few minutes after the end of the event. What phenomenon does this relate to?
The oxygen debt
During heavy exercise, cardiac output can increase 4-7 times that at rest. However, the metabolic rate of skeletal muscle may increase 20-30 times, meaning the increased cardiac output alone is not sufficient to meet demand. How does the cardiovascular system meet this extra demand?
By diverting blood to active tissues via shunts
With the performance of heavy exercise, the demand for oxygen increases greatly. What changes are normally seen in arterial PO2 when this is occurring at <80% capacity?
There is no major change
Which of the following local factors is most likely to cause an arteriole to dilate, increasing perfusion of a capillary bed?
A low PO2
Which type of blood vessel allows the propagation of pressure generated by the heart, without the need for energy input?
Elastic arteries