Page |1
NURS 5663 Exam 3 Review Questions and
Correct Answers/ Latest Update / Already
Graded
Steps involved in the synthesis of thyroid hormones
Ans: (1) iodide (I-) trapped by the thyroid follicular cells;
(2) diffusion of iodide to the apex of the cells;
(3) transport of iodide into the colloid;
(4) oxidation of inorganic iodide to iodine and incorporation of
iodine into tyrosine residues within thyroglobulin molecules in
the colloid;
(5) combination of two DIT molecules to form
tetraiodothyronine (T4) or of MIT with DIT to form T3;
(6) uptake of thyroglobulin from the colloid into the follicular
cell by endocytosis, fusion of the thyroglobulin with a
lysosome, and proteolysis and release of T4, T3, DIT, and MIT;
(7) release of T4 and T3 into the circulation; and
(8) deiodination of DIT and MIT to yield tyrosine. T3 is also
formed from monodeiodination of T4 in the thyroid and in
peripheral tissues.
Insulin Definition
Ans: the storage and anabolic hormone of the body
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General characteristics of Insulin
Ans: - small protein that contains 51 amino acids arranged in 2
chains (A & B) linked by disulfide bridges.
- stored in beta cells of pancreas in form of hexameric crystals
1. Entire human pancreas stores up to 8mg (200 units) of
insulin.
- Insulin is released from pancreatic beta cells at a low BASAL
rate --> plus with stimulation releases at a much higher rate
Insulin synthesis
Ans: Insulin is synthesized as preproinsulin and processed to
proinsulin. Proinsulin is then converted to insulin and C -peptide
and stored in secretary granules awaiting release on demand.
Insulin synthesis is regulated at both the transcriptional and
translational level.
insulin Stimulates release
Ans: glucose, sugars (eg. Mannose), amino acids (esp.
glyconeogenic amino acids like leucine, arginine), hormones
like glucagon-like polypeptide 1 (GLP-1), glucose-dependent
insulinotropic polypeptide (GIP), glucagon, cholecystokinin,
high concentrations of fatty acids, and B-adrenergic
sympathetic activity
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Stimulatory drugs of insulin
Ans: sulfonylureas, meglitinides, D-phenylalanine derivatives,
isoproterenol, and acetylcholine
Insulin Inhibitory hormones:
Ans: insulin, islet amyloid polypeptide, somatostatin, and
leptin; alpha-adrenergic sympathetic activity; chronically
elevated glucose; low concentrations of fatty acids
Insulin Inhibitory drugs:
Ans: diazoxide, phenytoin, vinblastine, clonidine, verapamil,
and colchicine
One mechanism of stimulated insulin release
Ans: 1. in resting cell: normal (low) ATP levels → K+ diffuses
down its concentration gradient through ATP -gated K+
channels, maintaining the intracellular potential @fully
polarized, negative level→ insulin release is minimal
2. if glucose concentration rises → ATP production increases →
K+ channels close --> depolarization results → in muscle/nerve
voltage-gated Ca2+ channels open in response to
All rights reserved © 2025/ 2026 |
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depolarization --> allows more Ca2+ to enter cell --> increased
intracellular Ca2+ results in increased insulin secretion →
insulin secretagugues close the ATP-dependent K+ channel→
depolarizes membrane→ increased insulin release by same
mechanism
Effects of insulin
Ans: - Promotes the storage of fat as well as glucose (both
sources of energy) within specialized target cells & influences
cell growth and the metabolic functions of a wide range of
tissues
-Promotes synthesis and storage of glycogen, trigly cerides, and
protein in its major target tissues: liver, fat, and muscle.
Release of insulin from pancreas is stimulated by increased
blood glucose, incretins, vagal nerve stimulation, and other
factors.
Endocrine Effects of Insulin
Ans: LIVER:
-Reversal of Catabolic features of insulin deficiency:
1. inhibits glycogenolysis
2. inhibits conversion of fatty acids & amino acids to keto acids
3. inhibits conversion of amino acids to glucose
-Anabolic action:
All rights reserved © 2025/ 2026 |
NURS 5663 Exam 3 Review Questions and
Correct Answers/ Latest Update / Already
Graded
Steps involved in the synthesis of thyroid hormones
Ans: (1) iodide (I-) trapped by the thyroid follicular cells;
(2) diffusion of iodide to the apex of the cells;
(3) transport of iodide into the colloid;
(4) oxidation of inorganic iodide to iodine and incorporation of
iodine into tyrosine residues within thyroglobulin molecules in
the colloid;
(5) combination of two DIT molecules to form
tetraiodothyronine (T4) or of MIT with DIT to form T3;
(6) uptake of thyroglobulin from the colloid into the follicular
cell by endocytosis, fusion of the thyroglobulin with a
lysosome, and proteolysis and release of T4, T3, DIT, and MIT;
(7) release of T4 and T3 into the circulation; and
(8) deiodination of DIT and MIT to yield tyrosine. T3 is also
formed from monodeiodination of T4 in the thyroid and in
peripheral tissues.
Insulin Definition
Ans: the storage and anabolic hormone of the body
All rights reserved © 2025/ 2026 |
, Page |2
General characteristics of Insulin
Ans: - small protein that contains 51 amino acids arranged in 2
chains (A & B) linked by disulfide bridges.
- stored in beta cells of pancreas in form of hexameric crystals
1. Entire human pancreas stores up to 8mg (200 units) of
insulin.
- Insulin is released from pancreatic beta cells at a low BASAL
rate --> plus with stimulation releases at a much higher rate
Insulin synthesis
Ans: Insulin is synthesized as preproinsulin and processed to
proinsulin. Proinsulin is then converted to insulin and C -peptide
and stored in secretary granules awaiting release on demand.
Insulin synthesis is regulated at both the transcriptional and
translational level.
insulin Stimulates release
Ans: glucose, sugars (eg. Mannose), amino acids (esp.
glyconeogenic amino acids like leucine, arginine), hormones
like glucagon-like polypeptide 1 (GLP-1), glucose-dependent
insulinotropic polypeptide (GIP), glucagon, cholecystokinin,
high concentrations of fatty acids, and B-adrenergic
sympathetic activity
All rights reserved © 2025/ 2026 |
, Page |3
Stimulatory drugs of insulin
Ans: sulfonylureas, meglitinides, D-phenylalanine derivatives,
isoproterenol, and acetylcholine
Insulin Inhibitory hormones:
Ans: insulin, islet amyloid polypeptide, somatostatin, and
leptin; alpha-adrenergic sympathetic activity; chronically
elevated glucose; low concentrations of fatty acids
Insulin Inhibitory drugs:
Ans: diazoxide, phenytoin, vinblastine, clonidine, verapamil,
and colchicine
One mechanism of stimulated insulin release
Ans: 1. in resting cell: normal (low) ATP levels → K+ diffuses
down its concentration gradient through ATP -gated K+
channels, maintaining the intracellular potential @fully
polarized, negative level→ insulin release is minimal
2. if glucose concentration rises → ATP production increases →
K+ channels close --> depolarization results → in muscle/nerve
voltage-gated Ca2+ channels open in response to
All rights reserved © 2025/ 2026 |
, Page |4
depolarization --> allows more Ca2+ to enter cell --> increased
intracellular Ca2+ results in increased insulin secretion →
insulin secretagugues close the ATP-dependent K+ channel→
depolarizes membrane→ increased insulin release by same
mechanism
Effects of insulin
Ans: - Promotes the storage of fat as well as glucose (both
sources of energy) within specialized target cells & influences
cell growth and the metabolic functions of a wide range of
tissues
-Promotes synthesis and storage of glycogen, trigly cerides, and
protein in its major target tissues: liver, fat, and muscle.
Release of insulin from pancreas is stimulated by increased
blood glucose, incretins, vagal nerve stimulation, and other
factors.
Endocrine Effects of Insulin
Ans: LIVER:
-Reversal of Catabolic features of insulin deficiency:
1. inhibits glycogenolysis
2. inhibits conversion of fatty acids & amino acids to keto acids
3. inhibits conversion of amino acids to glucose
-Anabolic action:
All rights reserved © 2025/ 2026 |
