Unit XIII (68-74) - Metabolism and Temperature Regulation Flashcards
ATP is present in all cells.
True or False
True
Guyton Pg 853
Which of the following constitutes 80% of the products of carbohydrate digestion in the GIT?
A. Glucose
B. Fructose
C. Galactose
D. Xylose
A. Glucose
Guyton Pg 854
Which of the following enzymes breaks up glucose-6-phosphate into glucose and phosphate?
A. Phosphorylase
B. Glucose phosphatase
C. Glucokinase
D. Hexokinase
B. Glucose phosphatase
Guyton Pg 854
By what mechanism does glucose get transported into the cytoplasm of the cell?
A. Pores
B. Endocytosis
C. Facilitated diffusion
D. Pinocytosis
C. Facilitated diffusion by binding properties of membrane glucose carrier protein
Guyton Pg 854
Which of the following hormones has the greatest effect on promoting facilitated diffusion of glucose?
A. Glucagon
B. Insulin
C. Estrogen
D. Thyroxine (T4)
B. Insulin
Guyton Pg 855
In the liver, which of the following enzymes catalyzes the phosphorylation of glucose to glucose-6-phosphate?
A. Glucose phosphatase
B. Hexokinase
C. Glucokinase
D. Phosphorylase
C. Glucokinase; Hexokinase catalyzes the same reaction but in most OTHER cells vs the liver.
Guyton Pg 855
Where is glycogen stored in the largest quantities?
A. Liver and kidneys
B. Liver and lung
C. Muscle and kidneys
D. Liver and muscle
D. Liver and muscle
Guyton Pg 855
The phosphorylation of glucose is reversible in which of the following cells (SELECT ALL THAT APPLY)?
A. Hepatocytes
B. Renal tubular epithelial cells
C. Intestinal epithelial cells
D. Cardiac myocytes
A, B, and C. Hepatocytes, renal tubular epithelial cells, and intestinal epithelial cells. Glucose phosphatase is available and when activated can reverse the reaction.
Guyton Pg 855
Which of the following is the correct pathway of glycogenesis?
A. Glucose-6-phosphate –> Glucose-1-phosphate –> Uridine diphosphate glucose –> Glycogen
B. Glucose-6-phosphate –> Uridine diphosphate glucose –> Glucose-1-phosphate –> Glycogen
C. Glucose-1-phosphate –> Glucose-6-phosphate –> Uridine diphosphate glucose –> Glycogen
D. Glucose-1-phosphate –> Uridine diphosphate glucose –> Glucose-6-phosphate –> Glycogen
A. Glucose-6-phosphate –> Glucose-1-phosphate –> Uridine diphosphate glucose –> Glycogen
Guyton Pg 855
During rest, the enzyme phosphorylase is
A. Active
B. Inactive
B. Inactive because phosphorylase phosphorylates glycogen to break it down into glucose for energy (energy is not needed during rest, this promotes storage of glycogen).
Guyton Pg 856
Which of the following pyrogens acts directly on the hypothalamus? A. LPS from bacterial wall B. IL – 1 C. Bacterial endotoxins D. Prostaglandin E2
Answer: B
Ref: Guyton P. 920
Which of the following can cause a decrease in basal metabolic rate? A. Fever B. Malnutrition C. Growth hormone D. Testosterone
Answer: B
Ref: Guyton P. 908
Which one of the following tissues primarily has GLUT 4?
a. Erythrocytes
b. Skeletal muscle
c. Endothelial cells of the blood-brian-barrer
d. Beta-cells of the pancreas
Correct: B Skeletal muscle
Which one of the following is insulin dependent?
a. GLUT 1
b. GLUT 2
c. GLUT 3
d. GLUT 4
Correct: D GLUT 4
Which of the lipoproteins transports triglycerides mainly to adipose tissue?
a. VLDL
b. HDL
c. LDL
d. VHDL
Correct: A VLDL
Which of the following lipoproteins is protective against atherosclerosis?
a. VLDL
b. HDL
c. LDL
d. VHDL
Correct: B HDL
Which of the following lipoproteins transports triglycerides from the liver to various tissues in the body?
a. VLDL
b. HDL
c. LDL
d. VHDL
Correct: C LDL
Are fatty acids generally found bound to albumin or free in the blood?
a. bound
b. free
Correct: A Bound
What is the alternative pathway (to the glycolytic pathway) in the formation of fatty acids?
a. B-oxidation
b. Kreb’s cycle
c. Glycolysis
d. Pentose phosphate pathway
Correct: D Pentose phosphate pathway
How many moles of ATP are formed from a triglyceride molecule?
a. 8
b. 18
c. 28
d. 38
Correct: B 18 from fat
Reminder: 38 from carbs
Ketoacidosis is a result of a deficiency in which one of the following? (The deficiency limits entry of acetyl-CoA into the citric acid cycle.)
a. Oxaloacetate
b. Citrate
c. Succinate
d. Fumarate
Correct: A Oxaloacetate
Name the triglycertide-rich lipoprotein that is synthesized by the liver?
a. VLDL
b. HDL
c. LDL
d. VHDL
Correct: A VLDL
Name the rate-limiting enzyme in cholesterol synthesis.
a. HMG-CoA reductase
b. HMG-CoA synthase
c. Famesyl diphosphate synthase
d. Lanosterol synthase
Correct: A HMG-CoA reductase
HDL returns cholesterol to the liver in a pathway known as ________?
a. Receptor-mediated endocytosis
b. Exogenous pathway
c. Reverse cholesterol transport
d. Endogenous pathway
Correct: C Reverse cholesterol transport
What is the mechanism used by cell to take up LDL cholesterol from the circulation?
a. Receptor-mediated endocytosis
b. Exogenous pathway
c. Reverse cholesterol transport
d. Endogenous pathway
Correct: A Receptor-mediated endocytosis
What protein is required for receptor-mediated endocytosis that allows LDL uptake from the circulation?
a. VLDL receptor
b. HDL receptor
c. LDL receptor
d. VHDL receptor
Correct: C LDL receptor
Which one of the following proteins is integral to buffering the blood?
a. albumin
b. IgG
c. hepsidin
d. IgM
Correct: A albumin
Which of the following organs primarily stores proteins?
a. Kidneys
b. Liver
c. Heart
d. Brain
Correct: B Liver
Which of the following enzymes initiates deaminiation of proteins?
a. Glutamate dehydrogenase
b. Aminotransferase
c. Dehydrogenase
d. Isomerase
Correct: B Aminotransferase
Which of the following hormones promotes fat synthesis by stimulating lipoprotein lipase?
a. Glucocorticoids
b. Insulin
c. Glucagon
d. Thyroid hormone
Correct: B Insulin
Which of the following hormones decreases liver glycogenolysis?
a. Glucagon
b. Epinepherine
c. Glucocorticoids
d. Growth hormone
Correct: C Glucocorticoids
Which one of the following hormones decreases liver gluconeogenesis?
a. Insulin
b. Glucagon
c. Epinephrine
d. Glucocorticoids
Correct: A Insulin
Which one of the following hormones decreases protein synthesis?
a. Insulin
b. Glucocorticoids
c. Thyroid hormone
d. Growth hormone
Correct: B Glucocorticoids
What is the most abundant store of high-energy phosphate bonds in the cells
a. ATP
b. Phosphocreatine
c. Glucose-6-Phosphate
d. Phosphofructokinase
Answer: B (Guyton Ch 73)
Which mechanism of heat loss is the most important at high temperatures?
a. Conduction
b. Convection
c. Evaporation
d. Radiation
Answer: C (Guyton Ch 74)
Which tissue is especially susceptible to damage by hyperpyrexia ?
a) liver
b) brain
c) kidneys
d) red blood cells
Answer : b; Guyton (12th edition), p. 876-877
Which of the following best describes nonshivering thermogenesis in response to cold stress ?
a) Sympathetic stimulation of muscle → production of a large amounts of heat and ATP
b) Sympathetic stimulation of brown fat → production of a large amounts of heat and ATP
c) Sympathetic stimulation of white fat → production of a large amount of heat but almost no ATP
d) Sympathetic stimulation of brown fat → production of a large amount of heat but almost no ATP
Answer : d; Guyton (12th edition), p. 865
What is the rate limiting factor of energy release in resting conditions?
a. ADP
b. ATP
c. GDP
d. GTP
Answer: A
Which of the following does not increase metabolic rate?
a. Fever
b. Thyroid hormone
c. Sleep
d. Growth hormone
e. Appropriate nutrition
Answer: C
When ambient temperature becomes greater than the temperature of skin, what type of cooling is utilized and effective?
a. Convection
b. Conduction
c. Radiation
d. Evaporation
Answer: D
Where is the panting center in dogs that becomes activated when they overheat?
a. Temperature regulating centers in the hypothalamus
b. Pneumotaxic center in the pons
c. Somatosensory neurons
d. Primary motor center in the posterior hypothalamus
Answer: B
When a mammal is cold, the hypothalamus causes all of the following except which mechanism for maintaining body temperature?
a. Non-shivering thermoregulation
b. Shivering
c. Vasoconstriction
d. All of these are methods of maintaining core body temperature
Answer: D
What factors contribute to heat stroke in dogs?
a. As body heat rises, the metabolic rate decreases
b. Evaporation does not remain an effective method of heat loss
c. Since cell function continues appropriately, there is continued heat production from metabolism
d. Humidity levels remain static despite panting
Answer: B
Which of the following correctly describes the biologic function of phosphocreatinine?
a. A backup energy source that can be used instead of ATP to power cellular metabolism
b. A transfer molecule carrying high energy electrons to the electron transport chain
c. An energy buffer allowing quick restoration of intracellular ATP pools
d. An alternative energy source used for energetically demanding reactions only due to the presence of a phosphate bond that can release more energy than ATP
Answer c (Guyton 904)
Which of the following are pyrogenic?
a. IL-1
b. IL-2
c. IL-10
d. TGFB
Answer a (Guyton 920)
By which method is heat transferred from deep tissues to the skin?
a. Convection
b. Radiation
c. Conduction
d. evaporation
Answer: Convection
An increase in this endogenous product results in an increase in the hypothalamic temperature set point in the face of a fever
a. Prostaglandin E2
b. IL-6
c. IL-1
d. TNFa
Answer: PGE2
Which of the following species does not have a carotid rete for thermoregulation?
a. Dogs
b. Cats
c. Horses
d. Cattle
Answer: C Horses; Cunningham pg 562
In most species sweating is under the control of
A] Sympathetic adrenergic nerve fibers
B] Sympathetic cholinergic nerve fibers
C] Parasympathetic adrenergic nerve fibers
D] Adrenal medulla
Answer: B Cunningham Chapter 53, pg 563
When substrate concentrations become low, the rate of metabolic reactions depend upon
A] Substrate concentration
B] Enzyme concentration
C] Both of the above
D] None of the above
Answer: C Guyton and Hall Chapter 73
Which of the following correctly describes the carotid rete found in sheep and other ungulates?
A. The carotid artery takes a tortuous path to the brain and thus heat dissipates as it travels. By the time the blood reaches the brain, it has cooled sufficiently.
B. The carotid rete is a countercurrent mechanism between the jugular vein and carotid artery. The artery loses heat to the vein as blood flows in opposite directions.
C. The carotid artery forms a complex network of vessels that is bathed in a sinus of arterial blood that supplies the nasal cavity. The arterial blood is therefore colder due to exposure to the environment of the nasal cavities, thus the arterial blood transfers and loses heat to the cooler sinuses and the blood delivered to the brain is cooled prior to entering the brain.
D. The carotid artery forms a complex network of vessels that is bathed in a sinus of venous blood that has drained the nasal cavity. The venous blood is therefore colder than the arterial blood, thus the arterial blood transfers and loses heat to the cooler veins and the blood delivered to the brain is cooled prior to entering the brain.
Correct Answer: D
Ref: Cunningham, pg. 561-562
Which molecule is considered a reserve of energy and forms when excess ATP is present in the body?
a. Creatine Kinase
b. Phosphocreatine
c. Guanine Triphosphate
d. Adenosine Monophosphate
Correct Answer: B
Ref: Guyton pg. #904
Which of the following cytokines is considered most important in the development of fever?
a. IL-1
b. IL-2
c. IL-6
d. IL-13
Answer: A
In most species (except horses), sweating is controlled by which type of nerve fibers?
a. sympathetic adrenergic
b. sympathetic cholinergic
c. parasympathetic adrenergic
d. parasympathetic cholinergic
Answer: B
The most abundant store of high-energy phosphate bonds in the body is normally:
A. Adenosine triphosphate (ATP)
B. Phosphocreatine
C. Phosphofructokinase
D. Glycogen
ANSWER: B (Guyton Ch 73)
The following hormone plays a crucial role in acclimization to heat: A. Thyroid hormone B. Antidiuretic hormone C. Angiotensin II D. Aldosterone
ANSWER: D (Guyton Ch 74)
Which of the following will decrease the body’s metabolic rate?
a. Increased temperature b. Increased thyroid hormone c. Prolonged malnutrition d. Increased growth hormone
Answer: C.
Reference: Guyton Ch. 73 Pg. 908
What is the only means by which the body can rid itself of heat when the temperature of the surroundings is greater than the skin temperature itself?
a. Radiation b. Convection c. Conduction d. Evaporation
Answer: D.
Reference: Guyton Ch. 74 Pg. 913
Which of the following is mainly a PHYSIOLOGIC mechanism to increase body temperature?
a) Decreased thyroid releasing hormone secretion from the hypothalamus
b) Increased neural release of norepinephrine
c) Release of IL-1 from macrophages
d) Increased ATP production from oxidative phosphorylation
Answer: B (Chu). C) this is a pathologic cause that is usually induced by bacteria.
Source: Guyton Ch. 73 p. 909 and Ch. 74 p. 911
Which of the following is the most important mechanism to decrease core body temperature when the ambient temperature is higher than body temperature?
a) Radiation
b) Convection
c) Conduction
d) Evaporation
Answer: D (Chu); Source: Guyton Ch. 74 p. 913
Which of the following decreases metabolic rate? A. Male sex hormone B. Thyroid hormone C. Growth hormone D. Fever E. Sleep
Correct answer: E.
Ref: Guyton, Ch.73 pg. 908
Which of the following constitutes the primary mechanism of heat loss from the body? A. Conduction to air B. Conduction to objects C. Convection D. Evaporation E. Radiation of heat waves
Correct answer: E.
Ref: Guyton, Ch. 74 pg. 913 (Figure 74-4)
Which of the following do not increase the metabolic rate? A. Growth Hormone B. Testosterone C. Thyroid Hormone D. Malnutrition
Answer: D
Which of the following neurotransmitters is not stimulatory to sweat glands? A. Epinephrine B. Norepinephrine C. Dopamine D. Acetylcholine
Answer: C
Which anatomical area has more heat-sensitive neurons than cold-sensitive neurons? A. Anterior hypothalamic-preoptic area B. The skin C. Abdominal viscera D. The spinal cord
Answer: A
