The partial pressure of carbon dioxide in alveolar air after inspiration of fresh dry air is lower than one would expect, because
a. residual air remaining in the lungs after expiration contributes to the ppCO2
b. CO2 diffuses from the alveoli into blood
c. water vapor contributes to the overall alveolar gas pressure
The pulmonary and systemic circulation have similar
a. blood flow per minute
b. diastolic pressure
c. vascular resistance
d. systolic pressure
e. a and b
e. a and b
Myoglobin is an oxygen binding pigment found in some muscles. It has a higher oxygen affinity than hemoglobin. Therefore, it
a. facilitates the transfer of oxygen from blood to muscle cell
b. can act as a store for oxygen
c. releases oxygen only when ppO2
d. A, b, c
Gas exchange in the lungs takes place between
a. alveoli and alveolar capillaries
b. bronchii and capillaries
c. alveoli and arterioles
d. all of the above
e. none of the above
a. alveoli and alveolar capillaries
The affinity of hemoglobin for oxygen depends on
a. partial pressure of oxygen in the alvelor air
b. partial pressure of oxygen in the red blood cells
c. bicarbonate concentration in the blood plasma
d. the number of red blood cells
e. both b and c
b. partial pressure of oxygen in the red blood cells
Unloading of oxygen from hemoglobin in metabolizing tissues mainly depends
a. blood acidity
b. partial pressure of oxygen of inhaled air
c. partial pressure of oxygen in erythrocytes
d. partial pressure of oxygen alveolar air
e. both a and d
c. partial pressure of oxygen in erythrocytes
CO2 exchange rate in the lungs relies on diffusion between blood and alveolar air and therefore depends on
a. pH
b. diffusion distance
c. diffusion area
d. gas concentration gradient
e. B, c, d
e. B, c, d
The main transport of carbon dioxide in blood is in the form of
a. gaseous CO2
b. dissolved CO2
c. bicarbonate dissolved in blood plasma
d. bound to hemoglobin
e. bicarbonate dissolved in the cytosol of red blood cells
c. bicarbonate dissolved in blood plasma
Hyperventilation of the lungs results in elevated blood pH levels, called respiratory alkalosis. This happens because of
a. an excessive loss of CO2 from the blood
b. a decreased pCO2 in the blood
c. an enhanced activity of erythrocyte carbonic anhydrase
e. A and b
In hypothermia, one's core body temperature decreases to lower than 95 degrees F. This low temperature reduces organ function (muscle, brain) because low temperatures
a. reduce the amount of O2 that can be picked up in the lungs
b. increase the affinity o
e. B and c
During exercise, a vigorously contracting muscle will extract a greater percentage of oxygen from the blood going to it, than will a relaxed muscle somewhere else in the body, Which factor(s) is (are) responsible for this?
a. a reduction in the affinity o
e. c, and d
Central chemoreceptors influence breathing (ventilation rate) by monitoring
a. the pH of the cerebrospinal fluid
b. the pH in red blood cells
c. O2 partial pressure in blood plasma
d. O2 partial pressure in the cerebrospinal fluid
e. both, a and d
a. the pH of the cerebrospinal fluid
Constriction of the afferent arteriole and dilation of the efferent arteriole of a nephron results in
a. an increase in glomerular filtration pressure
b. an increase in glomerular filtration rate
c. an increase in glomerular capillary hydrostatic pressure
e. none of the above
Glomerular filtration rate can be measured in a patient by determining urine production rate and the plasma and urine concentrations of a substance that is
a. freely filtered, completely reabsorbed, and not secreted
b. freely filtered and neither reabsorb
b. freely filtered and neither reabsorbed nor secreted
The primary filtrate (ultrafiltrate) that enters Bowman's capsule of the nephron
a. contains albumin
b. is cell free
c. contains ions such as Na+, K+, Cl-, and glucose
d. is iso-osmotic to blood
e. b, c, d
e. b, c, d
Approximately 70% of all filtered water of the initial ultrafiltrate in nephrons is always reabsorbed in the
a. collecting duct
b. distal convoluted tubule
c. ascending limb of Henle's loop
d. proximal convoluted tubule and the descending limb of Henle's
d. proximal convoluted tubule and the descending limb of Henle's loop
A specific aldosterone agonist will have the following effects on kidney function
a. enhanced sodium reabsorption in Henle's loop
b. enhanced sodium reabsorption in the distal convoluted tubule
c. decreased blood volume and pressure
d. reduced osmolarity
e. B and d
Hypersecretion of the mineralocorticoid aldosterone by the adrenal glands most likely will result in the following diagnostic characteristics:
a. high blood glucose, high blood ACTH, low plasma Na+, low blood pressure
b. normal blood glucose, normal blood
c. normal blood glucose, normal blood ACTH, high plasma Na+, high blood pressure
Water reabsorption in the kidneys is stimulated by ADH (vasopressin). This occurs by
a. stimulating active transport of water across epithelial cells of the collecting duct
b. decreasing the Na+ reabsorption in the distal convoluted tubule
c. a high water
c. a high water permeability of epithelial cells of the collecting duct
In the Renin-Angiotensin-Aldosterone control system of sodium reabsorption the role of angiotensin I is to
a. stimulate the production of angiotensinogen by the liver
b. induce the production of aldosterone in the cortex of the adrenal glands
c. stimulate
c. stimulate the production of angiotensin converting enzyme (ACE) by the lung epithelia
So called ACE inhibitors can be used to treat hypertension. These drugs reduce blood pressure by
a. decreasing water intake (thirst)
b. increasing water retention
c. increasing sodium excretion in urine
d. increasing water excretion in urine
e. both c and
e. both c and d
Which nephron segment is constitutively (always) permeable to water?
a. collecting duct
b. descending limb of Henle's loop
c. Bowman's capsule
d. distal convoluted tubule
e. ascending limb of Henle's loop
b. descending limb of Henle's loop
The reabsorption of glucose from the ultrafiltrate is coupled to the active reuptake transport of
a. phosphorus in the proximal tubule
b. water in the collecting duct
c. sodium in the proximal convoluted tubule
d. albumen in Henle's tubule
e. creatine in
c. sodium in the proximal convoluted tubule
in a human kidney that produces a maximally concentrated urine (1200 mOsm), the osmolarity of the tubular fluid at the beginning of the proximal convoluted tubule is approximately:
a. 100 mOsm/L
b. 300 mOsm/L
c. 600 mOsm/L
d. 900 mOsm/L
e. 1200 mOsm/L
b. 300 mOsm/L
The upper limit of urine concentration is set by?
a. the osmolarity of the urine as it enters the collecting duct
b. the glomerular filtration rate
c. the osmolarity of the extracellular fluid surrounding the collecting ducts in the center of the renal me
c. the osmolarity of the extracellular fluid surrounding the collecting ducts in the center of the renal medulla
How will an increase of capillary pressure in the glomerulus affect renal clearance of a substance that is completely filtered and not reabsorbed or secreted.
a. no change
b. increase
c. decrease
d. first decrease then increase
e. none of the above
b. increase
Release of Antidiuretic hormone (ADH) from the posterior pituitary gland is stimulated by
a. increased blood pressure
b. renin
c. increased plasma and cerebrospinal fluid osmolarity
d. adrenocorticotropic hormone
e. aldosterone
c. increased plasma and cerebrospinal fluid osmolarity
Oat cell carcinomas (also called small cell carcinomas) are lung cancers that often produce and secrete Antidiuretic Hormone (ADH, vasopressin), but at rates that are not under feedback control. the symptoms this produces are most reminiscent of those pro
a. moderate hemorrhage
Addison's disease is an insufficiency of the adrenal cortex to produce steroids including aldosterone. which of the following symptoms can be expected?
a. excessive urine production
b. excessive loss of sodium in the urine
c. excessive loss of glucose in
e. both b and d
The hormone that regulates the secretion of HCl by gastric parietal cells is:
a. motilin
b. gastrin
c. secretin
d. somatostatin
e. cholecystokinin (CCK)
b. gastrin
Pepsinogen, secreted by gastric chief cells, is the inactive precursor for the enzyme pepsin. production of pepsin from the pepsinogen is enhanced by
a. HCl
b. autocatalysis
c. gastrin
d. CCK
e. a and b
e. a and b
Gastrin is secreted by G-cells in the antrum of the stomach in response to
a. sympathetic stimulation
b. HCl acid secreted into the stomach
c. parasympathetic stimulation
d. pepsin secretion from chief cells
e. bicarbonate in blood plasma
c. parasympathetic stimulation
Parietal cell secretion is stimulated by
a. interleukin
b. cholecystokinin
c. histone
d. cholesterol
e. histamine
e. histamine
Which of the following processes in gastric secretion is termed autocatalysis
a. the stimulation of HCl secretion by gastrin
b. the conversion of pepsinogen into pepsin by HCl
c. the conversion of pepsinogen into pepsin by pepsin
d. the stimulation of gas
c. the conversion of pepsinogen into pepsin by pepsin
HCl acid production in gastric parietal cells generates bicarbonate. What prevents the cystosol of these cells to become too alkaline? Bicarbonate
a. combines with Na+ to form NaHCO3
b. combines with H+ to form carbonic acid (H2CO3)
c. is neutralized in t
d. is transported out of the cells through the basolateral membrane in exchange for Cl-
Insufficient secretion of secretin by endocrine cells in the walls of the duodenum after a meal will result in
a. reduced secretion of HCl acid by the stomach
b. a low pH in the duodenum
c. reduced secretion of bicarbonate by the pancreas
d. reduced diges
e. B, c, and d
When a food bolus is entering the duodenum from the stomach it contains partially digested food molecules such as peptides, aminoacids, lipids, saccharides, and hydrochloric acid. Which of these molecules is the main stimulus for the secretion of cholecys
b
What are zymogens?
a. stimulants for cholecystokinin (CCK) secretion by the duodenum
b. antagonists of digestive enzymes
c. packages of proenzymes produced by acinar cells of the pancreas
d. products of lipid digestion
e. absorbable units carbohydrate dig
c. packages of proenzymes produced by acinar cells of the pancreas
Diabetes insipidus is a condition with the following symptoms and causes.
a. production of normal volumes of urine
b. elevated urine glucose concentrations
c. production of large volumes of urine
d. insufficient vasopressin (ADH) secretion or loss of ADH
e. both c and d
A patient is given a glucose tolerance test in which he drinks a glucose-rich drink and his blood glucose is measured over the next several hours. Compared to a healthy person the blood glucose concentrations are normal at the beginning of the test and pe
e. a or d are possible
Which of the following statements about how the chemical properties of hormone molecules determine their actions on target cells is INCORRECT?
a. lipophilic hormones can bind to membrane receptors
b. hydrophilic hormones bind to membrane receptors
c. ster
e. steroids affect all cells
Peptide hormones are released from the endocrine cell by
a. exocytosis
b. facilitated diffusion
c. simple diffusion
d. endocytosis
e. osmosis
a. exocytosis
After a steroid, such as cortisol, is synthesized inside an endocrine cell, it immediately leaves the cell. The driving force for the steroid to exit the cell is the
a. membrane Na+ electrochemical gradient
b. steroid concentration gradient
c. osmotic pot
b. steroid concentration gradient
Human leptin is a protein of 167 amino acids that is produced by fat cells. One of its functions is to signal content of lipids (fat stores) to the brain. Which of the following predictions most likely is INCORRECT? Leptin
a. is stored in fat cells
b. act
c. travels in the blood bound to a specific binding protein
Endocrine regulation is often based on negative feedback loops involving several endocrine glands and their hormones such as in the following: Gland A produces hormone A. Hormone A acts on gland B to stimulate release of hormone B. Hormone B acts on gland
d. gland A lost its receptors for hormone C
When an extract of a certain gland (hormone) is applied to some cells, the cells respond by initiating cell division. However, when a compound that inhibits adenylate cyclase is first applied to the cells and the gland extract is then applied, the cells d
c. a protein hormone
Which of the following represents parallel flow in the circulatory system of mammals?
a. blood flow through kidney and skeletal muscles
b. total flow through capillaries and arteries
c. total flow through capillaries and veins
d. output from the right and
a. blood flow through kidney and skeletal muscles
Unloading of oxygen from hemoglobin in metabolizing tissues mainly depends
a. blood acidity
b. partial pressure of oxygen of inhaled air
c. reduced partial pressure of oxygen in tissues
d. partial pressure of oxygen in alveolar air
e. both a and d
c. reduced partial pressure of oxygen in tissues