PHGY 216 MIDTERM 1 QUESTIONS WITH VERIFIED
ACCURATE ANSWERS
What are the six primary functions of the endocrine system - Answers - 1. maintain
constant internal environment
2. growth and development
3. adaptive stress response
4. reproduction
5. red blood cell production
6. integrating with ANS regulating digestive functions
Define lipophilic hormones - Answers - water insoluble, can pass through plasma
membrane but need a carrier transport to move through the blood, cellular receptors are
within the cell- include steroid hormones and thyroid hormones
Define hydrophilic hormones - Answers - hormones that are water soluble and do not
need transporter in the blood. Cannot pass through plamsa membrane and act on
membrane receptors. Include catecholamines and peptide hormones
Explain the synthesis of hydrophilic hormones - Answers - 1. preprohormones made by
ribosomes in the endoplasmic reticulum
2. packaged and sent to the golgi where they are turned into active hormones
3. stored in vesicle until signal is received- this initiates endocytosis to release
hormones into blood
Synthesis of lipophilic hormones - Answers - made by specific tissues that posses
enzymes needed for synthesis- not made before needed as they cannot be stored-
therefore production is regulated
Describe the binding process of hydrophilic hormones- using cAMP - Answers - bind to
receptor in membrane, causes activation of g-protien, this activates adenylyl cyclase
which turns ATP into cAMP which is a secondary messanger that activates kinase A-
this activates target protein by interact with genes
Describe the binding process of hydrophilic hormones- using calcium - Answers - -
hormone binds to membrane receptor, activates g-protein, which activates
phopholipase C enzymes thta convert PIP2 into IP3 and DAG. IP3 mobilizes
intracellular calcium to bind to calmodulin. This complex can then activate calmodulin-
Ca2+ protein kinase to interact with target protein
Explain the binding complex of lipophilic proteins - Answers - -passes through
membrane and into cell where it binds with receptor and this complex binds to the
hormone element in the DNA which affects production of mRNA and thus affects
transcription
,What are some key differences between the nervous and endocrine system - Answers -
nervous: short duration, quick, close proximity
endocrine: long duration, slower, can target large range of tissues
What type of tissue is the posterior pituitary - Answers - neruhypophysis
What type of tissue is the anterior pituitary - Answers - adenohypophysis
Where are the hormones released by posterior pituitary produced - Answers -
hypothalamus
Where are the hormones released by the anterior pituitary produced? - Answers -
anterior pituitary (stimulated by hypophysiotropic hormones)
What are the two types of neurons that connect the posterior pituitary - Answers -
supraoptic nucleus and the paraventricular nucleus
What is the connection between the anterior pituitary and the hypothalamus - Answers -
hypothalamus- hypophyseal portal system (arteries and capillaries)
What are the hormones released by the posterior pituitary - Answers - Vasopressin/
ADH- controls water retention, Oxytocin
What are the hormones released by the anterior pituitary - Answers - GH, ACTH, TSH,
FSH, LH, PRH
List the hypophyseal tropic hormones - Answers - Thyrotropin releasing hormone
(TRH)- release of prolactin and TSH, Gonadotropin releasing hormone (GnRH),
Gonadotropin inhibiting hormone (GnIH), Growth hormone releasing hormone (GHRH),
Growth hormone inhibiting hormone (GHIH), Cortiotropin releasing hormone (CRH)-
stimulates release of ACTH, Prolactin releasing hormone (PRH), Prolactin inhibiting
hormone (PIH)
What are the cellular components of the thyroid glands - Answers - follicular cells
colloid (storage)
c-cells (produce calcitonin)
What are the major components of the thyroid hormone - Answers - tyrosine and iodine
What are the functions of the thyroid hormone? - Answers - 1. increases metabolic rate
and heat production
2. intermediary (fuel) metabolism
3. sympathetic- increases amount of catecholamine receptors
, 4. cardiovascular- sympathetic effect on heart rate, strength of contraction to increase
CO
5. growth- stimulates release of GH and insulin from tissues
What are the two major types of thyroid horomones - Answers - tetraiodothryonine
hormone (T4)
Triiodotyronine hormone (T3)
What is the function of tetraiodothryonine hormone - Answers - - inactive form but
makes up 90% of hormone present
What is the function of triiodothyronine hormone - Answers - - active form making up
10% of hormone produced
Explain thyroid synthesis - Answers - 1. tyrosine containing hemoglobin are profuced
within the follicular cells and transported to the colloid
2. follicular cells uptake iodine molecules into colloid through Na+ facililitated transport-
as it is moved it is turned into active state Io which immediately attached to tyroglobin
molecule
3. attachment of one iodine makes monoiodotyrosine and attachment of another make
diiodotryosine.
4. a mono and diiodtryosine make T3,two diiodotyrosine make T4
- remain attached to thryoglobin
Explain the release of T3 and T4 - Answers - 1. follicular cells engulf part of colloid
containing the T3 and T4 through phagocytosis
2. the vesicles fuse with lysosome which release all MIT, DIT, T3 and T4 from
thyroglobin
3. T3 and T4 are lipophilic and pass through membrane into blood- they bind with
thryoid-binding globin for blood transport
What are the three causes of hypothyroidism - Answers - 1. primary failure of thyroid
gland (cant make enough T3 and T4 despite high levels of TSH)
2. secondary failure of thyroid gland (not enough TSH made at level of anterior pituitary
reducing T3 and T4 production)
3. inadequate dietary supply of iodine (cant make enough T3 and T4 despite high levels
of TSH)
4. congenital hyperthyroidism( birth defect with thyroid hormone deficiency- dwarfism)
What are the causes of hyperthryoidism - Answers - 1. secondary to excess
hypothalamus or anterior pituitary secretions (too much TSH increasing levels of T3 and
T4 production- often caused by tumor which ignores negative feedback control)
2. thyroid tumor- elevates T3 and T4 production despite normal TSH levels
ACCURATE ANSWERS
What are the six primary functions of the endocrine system - Answers - 1. maintain
constant internal environment
2. growth and development
3. adaptive stress response
4. reproduction
5. red blood cell production
6. integrating with ANS regulating digestive functions
Define lipophilic hormones - Answers - water insoluble, can pass through plasma
membrane but need a carrier transport to move through the blood, cellular receptors are
within the cell- include steroid hormones and thyroid hormones
Define hydrophilic hormones - Answers - hormones that are water soluble and do not
need transporter in the blood. Cannot pass through plamsa membrane and act on
membrane receptors. Include catecholamines and peptide hormones
Explain the synthesis of hydrophilic hormones - Answers - 1. preprohormones made by
ribosomes in the endoplasmic reticulum
2. packaged and sent to the golgi where they are turned into active hormones
3. stored in vesicle until signal is received- this initiates endocytosis to release
hormones into blood
Synthesis of lipophilic hormones - Answers - made by specific tissues that posses
enzymes needed for synthesis- not made before needed as they cannot be stored-
therefore production is regulated
Describe the binding process of hydrophilic hormones- using cAMP - Answers - bind to
receptor in membrane, causes activation of g-protien, this activates adenylyl cyclase
which turns ATP into cAMP which is a secondary messanger that activates kinase A-
this activates target protein by interact with genes
Describe the binding process of hydrophilic hormones- using calcium - Answers - -
hormone binds to membrane receptor, activates g-protein, which activates
phopholipase C enzymes thta convert PIP2 into IP3 and DAG. IP3 mobilizes
intracellular calcium to bind to calmodulin. This complex can then activate calmodulin-
Ca2+ protein kinase to interact with target protein
Explain the binding complex of lipophilic proteins - Answers - -passes through
membrane and into cell where it binds with receptor and this complex binds to the
hormone element in the DNA which affects production of mRNA and thus affects
transcription
,What are some key differences between the nervous and endocrine system - Answers -
nervous: short duration, quick, close proximity
endocrine: long duration, slower, can target large range of tissues
What type of tissue is the posterior pituitary - Answers - neruhypophysis
What type of tissue is the anterior pituitary - Answers - adenohypophysis
Where are the hormones released by posterior pituitary produced - Answers -
hypothalamus
Where are the hormones released by the anterior pituitary produced? - Answers -
anterior pituitary (stimulated by hypophysiotropic hormones)
What are the two types of neurons that connect the posterior pituitary - Answers -
supraoptic nucleus and the paraventricular nucleus
What is the connection between the anterior pituitary and the hypothalamus - Answers -
hypothalamus- hypophyseal portal system (arteries and capillaries)
What are the hormones released by the posterior pituitary - Answers - Vasopressin/
ADH- controls water retention, Oxytocin
What are the hormones released by the anterior pituitary - Answers - GH, ACTH, TSH,
FSH, LH, PRH
List the hypophyseal tropic hormones - Answers - Thyrotropin releasing hormone
(TRH)- release of prolactin and TSH, Gonadotropin releasing hormone (GnRH),
Gonadotropin inhibiting hormone (GnIH), Growth hormone releasing hormone (GHRH),
Growth hormone inhibiting hormone (GHIH), Cortiotropin releasing hormone (CRH)-
stimulates release of ACTH, Prolactin releasing hormone (PRH), Prolactin inhibiting
hormone (PIH)
What are the cellular components of the thyroid glands - Answers - follicular cells
colloid (storage)
c-cells (produce calcitonin)
What are the major components of the thyroid hormone - Answers - tyrosine and iodine
What are the functions of the thyroid hormone? - Answers - 1. increases metabolic rate
and heat production
2. intermediary (fuel) metabolism
3. sympathetic- increases amount of catecholamine receptors
, 4. cardiovascular- sympathetic effect on heart rate, strength of contraction to increase
CO
5. growth- stimulates release of GH and insulin from tissues
What are the two major types of thyroid horomones - Answers - tetraiodothryonine
hormone (T4)
Triiodotyronine hormone (T3)
What is the function of tetraiodothryonine hormone - Answers - - inactive form but
makes up 90% of hormone present
What is the function of triiodothyronine hormone - Answers - - active form making up
10% of hormone produced
Explain thyroid synthesis - Answers - 1. tyrosine containing hemoglobin are profuced
within the follicular cells and transported to the colloid
2. follicular cells uptake iodine molecules into colloid through Na+ facililitated transport-
as it is moved it is turned into active state Io which immediately attached to tyroglobin
molecule
3. attachment of one iodine makes monoiodotyrosine and attachment of another make
diiodotryosine.
4. a mono and diiodtryosine make T3,two diiodotyrosine make T4
- remain attached to thryoglobin
Explain the release of T3 and T4 - Answers - 1. follicular cells engulf part of colloid
containing the T3 and T4 through phagocytosis
2. the vesicles fuse with lysosome which release all MIT, DIT, T3 and T4 from
thyroglobin
3. T3 and T4 are lipophilic and pass through membrane into blood- they bind with
thryoid-binding globin for blood transport
What are the three causes of hypothyroidism - Answers - 1. primary failure of thyroid
gland (cant make enough T3 and T4 despite high levels of TSH)
2. secondary failure of thyroid gland (not enough TSH made at level of anterior pituitary
reducing T3 and T4 production)
3. inadequate dietary supply of iodine (cant make enough T3 and T4 despite high levels
of TSH)
4. congenital hyperthyroidism( birth defect with thyroid hormone deficiency- dwarfism)
What are the causes of hyperthryoidism - Answers - 1. secondary to excess
hypothalamus or anterior pituitary secretions (too much TSH increasing levels of T3 and
T4 production- often caused by tumor which ignores negative feedback control)
2. thyroid tumor- elevates T3 and T4 production despite normal TSH levels
