Revision Quizzes Flashcards by Kathryn Robinson

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

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A reaction in the body that releases energy and heat is described as…

Exergonic

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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

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Which is an advantage to using direct calorimetry to measure metabolic rate?

As water is heated directly, it is a very accurate measurement

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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

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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

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hyrotropin releasing hormone (TRH) is produced in the hypothalamus. Where is it released into the circulation from?

The median eminence

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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

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Which gland/organ secretes hormones that are most important in regulating metabolic rate?

Thyroid gland

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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

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What is the main effect of thyroid hormones in adults?

Increasing metabolic rate

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In the nervous system, where are the integration centres located?

c.
In the central nervous system

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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

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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

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Which hormone is primarily responsible for allowing glucose to enter cells from the circulation for use or storage?

Insulin

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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

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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

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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

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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

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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

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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%

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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

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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

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Which component of haemoglobin is involved in the binding and release of carbon dioxide?

Any amine group

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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

What is the most powerful mechanism utilised controlled by the cardiovascular system to rapidly adjust blood pressure in response to baroreceptor signals?

Regulation of vasomotor tone

When manually measuring blood pressure, what event does the first Korotkoff sound coincide with?

Blood pressure overcoming cuff pressure

Juxtamedullary nephrons are more effective at water resorption than cortical nephrons. This is largely due to which factor?

Their loops of Henle project deep into the renal medulla

Over hours to days, what is the major factor that the body acts on to regulate blood pressure when there is a deviation from homeostasis?

Blood volume

What is the stimulus causing atrial natriuretic peptide to be secreted?

Increased atrial stretch

When blood passes through a capillary, which force is normally responsible for causing a net resorption to occur at the venous end of the capillary?

Blood osmotic pressure

When considering heart function, how does the Bainbridge reflex allow the heart to compensate function when there is an increase in venous return?

It increases heart rate

Within which part of the nephron does the majority of resorption occur?

Proximal convoluted tubule

What is normally the major factor contributing to acidity in the body (~99%)?

Carbon dioxide generation, causing carbonic acid formation

Which of the following is the most important source of circulating bicarbonate? a. Renal secretion of hydrogen ions, meaning bicarbonate is not needed b. Renal resorption and generation of bicarbonate c. Phosphate buffering in the renal tubular system d. Generation of bicarbonate by the liver

Renal resorption and generation of bicarbonate

When deep sea diving, how does a rapid ascent cause cardiovascular problems associated with decompression sickness?

Gas bubbles form after quickly moving out of a liquid phase

Which is an acute effect that would be seen if someone rapidly transitioned from sea level to high altitude?

Increased respiratory rate

In a positive energy balance, which change would you predict to occur? a. An increase in white adipose tissue b. An increase in mitochondrial expression in adipose tissue c. A reduction in white adipose tissue d. An increase in catabolic reactions in adipose tissue

a. An increase in white adipose tissue

Most equations relating to energy use in the body assume the use of which substrate as fuel?

Glucose

Which molecule is also referred to as the “unit of biologic energy”?

ATP

Amine hormones are hormones produced from slightly modified amino acids, e.g. epinephrine (adrenaline), and thyroid hormones. Which statement about amine hormones is most correct? a. They have similar properties to water-soluble hormones, like peptide hormones b. They may have similar properties to water-soluble or lipid-soluble hormones c. They have unique properties, that are not comparable to water-soluble or lipid-soluble hormones d. They have similar properties to lipid-soluble hormones, like steroids

b. They may have similar properties to water-soluble or lipid-soluble hormones

Which of the following best describes the signalling in the nervous system? a. Electrical signals are used within neurons, and ligands are released to signal to other cells b. Ligands are released within neurons, and electrical signals are used to signal to other cells c. Most neurotransmitters are secreted into the circulation to act on distant cells d. Most neurotransmitters are lipid soluble, and constantly diffuse out of neurons to act on other cells

a. Electrical signals are used within neurons, and ligands are released to signal to other cells

What is defined by the phrase “the energy required to maintain homeostasis at rest”?

Basal metabolic rate

Which of the following statements is most correct regarding endocrine signalling? a. Water-soluble hormones activate receptors on the surface of target cells, whereas lipid-soluble hormones activate intracellular receptors at target cells b. Both water-soluble and lipid-soluble hormones only act on cell membrane receptors at target cells c. Water-soluble hormones are produced and secreted on-demand, whereas lipid-soluble hormones are produced and stored in intracellular vesicles for later secretion d. Both water-soluble and lipid-soluble hormones only act on intracellular receptors at target cells

a. Water-soluble hormones activate receptors on the surface of target cells, whereas lipid-soluble hormones activate intracellular receptors at target cells

What phrase best describes metabolism? a. The sum of all chemical processes to maintain life b. Maintenance of a relatively stable internal environment c. All synthesis reactions in the body d. All breakdown processes in the body

a. The sum of all chemical processes to maintain life

Which individual would you expect to have the highest basal metabolic rate? a. A 60-year-old b. A toddler c. An adolescent d. A 35-year-old

b. A toddler

How does the secretion of cholecystokinin (CCK) assist with lipid absorption from the digestive tract?

CCK causes bile secretion, which allows absorption to the lymphatic system

Proteins or peptides are generally too large to be absorbed from the digestive tract, and require lysis via enzymatic activity. At which level is the secretion of these enzymes regulated?

The enteric plexus

The liver is sometimes referred to as being at a “metabolic crossroads”. Which of the statements below best explains why this is?

The liver can convert molecules into the form currently needed by the body

Under the influence of insulin, how does the liver deal with most absorbed glucose?

Glucose is stored primarily as glycogen

What is one of the major reasons why catabolic effects of stress hormones, e.g. cortisol, are necessary for gluconeogenesis to occur within the liver?

Catabolism provides substrates for gluconeogenesis

Calculate the partial pressure gradient for oxygen to move into the capillaries at the respiratory membrane. Assume alveolar PO2 = 100mmHg, pulmonary PO2 = 40mmHg

60mmHg

During heavy exercise active cells, e.g. in skeletal muscle, utilise a lot more oxygen. How does this cause more oxygen to be delivered to these active cells?

This increases the partial pressure gradient for oxygen, increasing delivery

Healthy lungs contain approximately 300 million alveoli. With this many alveoli, what property do they provide to facilitate gas exchange?

A large surface area

If some alveoli are not being well ventilated, e.g. due to local bronchoconstriction, what happens to the blood flow in the area?

More blood is diverted to ventilated alveoli

In comparison with oxygen, carbon dioxide requires less of a pressure gradient for effective diffusion to occur. What property of carbon dioxide allows this efficiency?

It is highly plasma soluble

Assume that you are working in a metabolic lab. You have a patient who is undergoing testing, and they are starting to show cyanosis (blue colouration) of the fingers and lips. How is cyanosis caused?

By a low oxygen saturation in the tissues

Haemoglobin changes shape with the binding of oxygen, having a tense and a relaxed state. How does this relate to the affinity of haemoglobin for oxygen?

Oxygen affinity increases with some oxygen binding to haemoglobin

How is the majority of carbon dioxide transported in the blood?

As bicarbonate

In a healthy person at rest, what is the normal oxygen saturation of haemoglobin in mixed venous blood?

75%

Red blood cells are important in buffering pH of blood plasma, utilising carbonic anhydrase to convert carbon dioxide to bicarbonate. Which ion enters the red blood cell to allow bicarbonate to exit into the plasma?

Chloride

Arterial PO2 is measured at the carotid bodies, and will increase respiration below 60mmHg (normal is ~100mmHg). How does this help to maintain homeostasis?

It allows for detection and compensation if oxygenation is deficient

At which location would you find the respiratory centres in the body?

The brainstem

The body has relatively large respiratory reserves for increased demand. In addition to passive effects, how can the body increase oxygen uptake with higher workloads?

By increasing both respiration rate and depth

The pre-Bötzinger complex forms a part of the ventral respiratory group (VRG), containing neurons that spontaneously discharge. What is the role of this region of the VRG?

It provides basic pacemaker activity for respiration

During anaerobic glycolysis, glucose is used to produce two pyruvates and… what at the end of the process?

2 ATPs

For approximately how long can anaerobic glycolysis be sustained during moderate to high intensity activity?

90 seconds

How does adenylate cyclase contribute to ATP formation during anaerobic metabolism?

It passively converts ADP to ATP and AMP

In which part of cells does anaerobic glycolysis occur?

Cytoplasm

In which tissue or organ does the majority of gluconeogenesis occur?

The liver

During heavy exercise, epinephrine (adrenaline) suppresses insulin secretion. How is it thought that skeletal muscle overcomes this to allow glucose uptake?

It seems that contraction causes expression of GLUT4

How is exercise thought to improve management of type 2 diabetes mellitus?

The combined effects of exercise increase insulin sensitivity

What is one of the adaptations to exercise that facilitates cooling of the body?

A more rapid onset of sweating

What modifications are seen in slow-twitch oxidative muscle fibres in order to sustain prolonged aerobic metabolism?

More mitochondria than other muscle fibres

What process occurs in the mitochondria to allow metabolism of fatty acids for ATP production?

β oxidation

As exercise is performed, cardiac output is greatly increased, often to 5-fold that at rest. What is the major factor that prevents blood pressure from increasing to a lethal 600/320 mmHg?

Vasodilation, reducing total peripheral resistance

During exercise cardiac output is increased. Using your knowledge of the Frank-Starling law of the heart, what is the major factor that drives this increase?

Increased venous return, stretching cardiac muscle fibres

Collectively, which class of blood vessels contains the greatest volume of blood in the body?

Systemic veins

Which of the following blood vessels will have the lowest blood pressure? a. Vena cava b. Systemic capillary c. Renal vein d. Arteriole

a. Vena cava

Mean arterial pressure (MAP) is defined as (diastolic BP + 1/3 systolic BP – diastolic BP), and is usually > 60 mmHg. What is the practical advantage to knowing this in a clinical setting?

This value gives an estimate of tissue perfusion

What changes normally occur in the chemoreflex of blood pressure, i.e. a reduction in arterial PO2?

Increased sympathetic activity, increasing blood pressure

How does antidiuretic hormone (AKA vasopressin) allow increased resorption to occur in the kidneys?

It causes insertion of aquaporin channels in the collecting ducts

In response to a low blood pressure, the kidneys will secrete renin. What is the role of renin in regulating blood pressure?

Renin performs the first step of cleavage, allowing angiotensin II formation

Some people have a disorder causing increased secretion of aldosterone, hyperaldosteronism. What action of aldosterone puts them at risk of hypokalaemia (low potassium concentration)?

Aldosterone stimulates sodium resorption and potassium secretion in the kidneys

What is the major effect of angiotensin II that allows powerful regulation of blood pressure?

It stimulates widespread vasoconstriction

When blood pressure is sustained above normal for hours to days, how does the body respond to restore homeostasis?

Glomerular filtration increases, reducing blood volume

When blood reaches a capillary bed, which force is the primary factor that causes a net filtration to occur at the arterial end of the bed?

Blood hydrostatic pressure

Arterial blood gasses (ABG) are important in determining whether a patient has an acid-base disorder. Consider the following, a patient has the following ABG data: pH 7.32 (ref 7.35-7.45), pCO2 123 mmHg (ref 80-120 mmHg), and HCO3 24mmol/L (ref 22-26 mmol/L). What is the condition that the patient has?

Respiratory acidosis

Proteins can act as buffers within cells and in the blood plasma. Which part(s) of the protein can potentially act as a buffer?

The carboxyl terminus, the amine terminus, and side the chain

How does the pressure on the body differ at a depth of 10m below the sea, compared with being in air at sea level?

It will increase two-fold

What is the approximate oxygen concentration in air at 8848m above sea level, the height at summit of Mt Everest?

21%