1
Q
Endocrine signaling involves ____ secretion into the blood by an ____ gland.
A
Hormone
Endocrine
2
Q
What is paracrine signaling?
A
One cell produces a hormone which impinges on an adjacent cell (which can be either the same cell type or different)
3
Q
What is autocrine signaling?
A
An extreme version of paracrine signalling.
Cell produces hormone and receptor for that hormone which loops back and makes a response
4
Q
True or false?
Regulation can occur at any of the 6 steps of communication by hormones.
A
True
5
Q
How many types of hormone-producing cells are there in the anterior pituitary?
A
6
6
Q
______ (hormone) is a source of _______ (‘female’ hormone) in males.
A
Testosterone
Estradiol
7
Q
____ (hormone) is the main circulation estrogen.
A
Estradiol
8
Q
__ (number) of thyroid hormones, which are derived from ___ (amino acid).
A
2
Tyrosine
9
Q
True or false?
Thyroid hormones are not iodinated.
A
False, they ARE iodinated
10
Q
Hormonal feedback mechanisms are often ____ (positive/negative) feedback loops.
A
Negative
11
Q
Histologically, the anterior pituitary is _____ tissue.
A
Endocrine
12
Q
The posterior pituitary is ______ tissue.
A
Neural
13
Q
The posterior pituitary gland secretes ____ and _____.
A
Oxytocin
Vasopressin
14
Q
True or false?
The thyroid gland is larger in females.
A
True
15
Q
When T4 and T3 in blood increases, they exert a _____ (positive/negative) feedback at both hypothalamic and pituitary levels to _____ (increase/decrease) release of TRH and TSH.
A
Negative
Decrease
16
Q
Thyroid can form a ____ due to iodine deficiency.
A
Goitre
17
Q
What is a non-toxic goitre?
A
The enlarged thyroid is unable to synthesize biological active thyroid hormones (ex: due to iodine deficiency)
18
Q
Thyroid hormones ______ (increase/decrease) BMR.
A
Increase
19
Q
Primary hypothyroidism occurs at the level of the ____.
A
Thyroid
(Note: inability to synthesize active thyroid hormones)
20
Q
Secondary hypothyroidism occurs at the level of the _____
A
Pituitary
(Note: synthesis of little to no thyroid stimulating hormone (TSH))
21
Q
Tertiary hypothyroidism occurs at the level of the ____
A
Hypothalamus
(Note: synthesis of little to no thyrotropin releasing hormone (TRH))
22
Q
True or false?
All types of hypothyroidism are effectively treated by administration of thyroid hormones.
A
True
23
Q
True or false?
The negative feedback loop is broken for Graves dissease (toxic diffuse goiter).
A
False
24
Q
What are treatments to hyperthyroidism?
A
- Surgery + replacement therapy
- Administration of radioactive Iodide
- Administration of anti thyroid drugs such as propylthiouracil
25
Removal of **parathyroids** causes a…
Severe drop in **plasma calcium** levels causing tetanic convulsions and death.
26
PTH binds to ______ receptor on target cells exerts.
Cognate
27
Hypoparathyroidism: low levels of ___ in circulation
PTH
28
What is the treatment for **hypoparathyroidism**?
Administration of 1,25-dihydroxyvitamin D and calcium supplements
29
What are treatments for **hyperparathyroidism**?
Removal of affected parathyroid(s), therapy with 1,25D3 and Ca2++.
30
Cortex adrenal glands = derived from ____.
Medulla adrenal glands = derived from ____.
Mesoderm
Neural crest
31
Synthesis of adrenal steroids controlled by pituitary hormone _______.
Adrenocorticotropin (ACTH)
32
What does **aldosterone** do?
Increase the reabsorption of Na+ by the kidney
(Also affects the plasma concentration of K+ and H+)
33
____ (humans)
___ (rodents)
(Glucocorticoids)
Cortisol
Corticosterone
34
Is **salt retention** more effective in glucocorticoids or aldosterone?
Aldosterone
35
**Glucocorticoids** ______ (increase/decrease) glucose uptake by muscle and adipose tissue and _____ glycolysis to conserve glucose for other tissues.
Decreases
Decreases
36
Glucocorticoids _______ blood glucose levels
Increases
37
Increased blood glucose due to excess of glucocorticoid activity is known as ______.
Adrenal diabetes
38
True or false?
If prolonged, **adrenal diabetes** can lead to true **diabetes mellitus**
True
39
Glucocorticoids lead to ____ of protein matrix of the bone through their protein ___ (anabolic/catabolic) effect
Decrease
Catabolic
40
True or false?
Glucocorticoids decrease chance of osteoporosis.
False, they increase
41
True or false?
Glucocorticoids increase inflammatory responses
False, they reduce them
42
Glucocorticoids cause ____ of the lymphatic system (lymph nodes, thymus spleen)
Atrophy
43
What hormone is used in organ transplantation?
Glucocorticoids
44
Why are glucocorticoids used in organ transplantation?
They decrease levels of circulating lymphocytes and reduce antibody formation
45
Glucocorticoids _____ **histamine** formation
Decrease
(Hence why they decrease allergic reactions)
46
Glucocorticoids secretion is controlled by _____.
Pituitary adrenocorticotropin (ACTH)
47
Feedback control of cortisol secretion is via _____ and ______.
Hypothalamus
Anterior pituitary
48
Cortisol _____ the release of ACTH
Inhibits
49
Stimulation of **adenylyl cyclase** leads to _____ of cyclic AMP
Increased production
50
True or false?
Cortisol inhibits wound healing
True
51
Prolonged stress would maintain constantly ____ levels of **glucocorticoids** which could lead to _____ blood glucose, ______ immune responses, ______ of bone, etc.
High
Increased
Decreased
Loss
52
What is **Addison’s disease**?
Failure of adrenal cortex to produce **adrenocortical hormones**
53
What is **Cushing’s disease**?
Excessive production of glucocorticoids as well as increased production of mineralocorticoids
54
What causes **Addison’s disease**?
May involve destruction of adrenal gland
Mostly due to autoimmune attack on the adrenal glands, but can also be caused by tuberculosis
55
What causes **Cushing’s disease**?
Increased circulating levels of ACTH (pituitary tumour) or adrenal tumour
56
What disease is characterized by hyperplasia of **an** adrenal cortex (adrenal tumour) or **both** (pituitary tumour)?
Cushing’s disease
57
Beta-cells in the pancreas synthesize ______.
Insulin
(note: beta cells make up ~60% of pancreas)
58
Alpha-cells in the pancreas synthesize _____.
Glucagon
(note: alpha-cells make up ~25% of pancreas)
59
_____ and ______: small protein hormones and both control glucose concentration in blood
Insulin
Glucagon
60
What is more important?
Insulin or glucagon?
Insulin
61
_____: only hormone that acts primarily to **decrease** blood glucose.
Insulin
62
In the **liver** and **muscle cells**, glucose is converted into ____.
Glycogen
63
In adipose tissue, glucose is converted into ____and stored for later use.
Fat
64
Insulin deficiency leads to…
Decreased blood pH, diabetic coma and death unless treated.
65
Untreated diabetes leads to ____ and ____.
Ketosis
Metabolic acidosis
66
In adults, diabetes mellitus may be due to a ______, or ________ to insulin.
Deficiency of insulin
Hyporesponsivevness
67
insulin is an example of which mechanism by which a hormone can exert effects on target cells?
**direct** effects on function at the cell membrane
68
Synthesis and release of TSH is controlled by _____.
hypothalamic *thyrotropin releasing hormone* (TRH)
69
Thyroid hormones stimulate the synthesis of ________ (relating to the CNS), which induces **dendritogenesis** and **regeneration** of **sympathetic** neurons.
nerve growth factor (NGF)
70
**Secondary hypothyroidism**: synthesis of little or no ______.
thyroid stimulating hormone (TSH)
71
**Tertiary hypothyroidism**: synthesis of little or no ________.
thyrotropin releasing hormone (TRH)
72
**Primary hypothyroidism**: inability to synthesize _____.
active thyroid hormones
73
Secondary hyperthyroidism is often due to ...
presence of pituitary tumour
74
Tertiary hyperthyroidism is often due to...
presence of hypothalamic tumour
75
Calcium absorption is increased by ______ and ____.
Vitamin D
PTH
76
Vitamin D ______the circulating levels of Ca2+
increases
77
____ and ____ facilitate the absorption of Ca2+ from the gut
PTH
1,25-dihydroxyvitamin D3 (active form of vitamin D)
^ aka 1,25D3
78
___ stimulates the conversion of 25-Hydroxyvitamin D3 to 1,25-dihydroxyvitamin D3
PTH
79
High circulating Ca2++ ____ PTH release
supresses
80
What often causes hyperparathyroidism?
parathyroid adenoma
81
True or false?
Hypoparathyroidism can lead to kidney stones
False
**hyper**parathyroidism can lead to kidney stones
82
What are some physiological functions of vitamin D?
1. Increase Ca2+ absorption from the intestine (primary function)
2. regulates immune system (protects against infection, anti-inflammatory)
3. Anticancer properties
83
What is vitamin D synthesis depressed by?
high calcium
84
____ in plasma Ca++ increases release of calcitonin
rise
85
Cortex of adrenal glands produces ____.
steroid hormones; **glucocorticoids** (cortisol in humans, corticosterone in rodents) and **mineralocorticoids** (ex: aldosterone), and **progestins**.
86
Cortisol and ACTH are at their lowest at _____ and highest in the ______
(times of day)
midnight
morning (~8:00AM)
87
________: Insulin levels are normal or abnormally high
-Problem in **hyporesponsiveness** of target cells to insulin
type 2 diabetes (insulin-independent diabetes mellitus)
88
true or false?
insulin receptors increased in response to frequent endurance exercise, **independent** to changes in body weight.
True
89
Glucagon raises blood sugar by promoting _____ and ____ in the liver.
**glycogenolysis** (Breakdown of glycogen)
**gluconeogenesis** (synthesis of glucose)
90
Glucagon-like peptide-1 (GLP-1) is produced by....
enteroendocrine L cells of the intestine
91
GLP-1 is a member of a family of hormones known as ____.
**incretins** (gut-derived hormones released in response to nutrient ingestion)
92
GLP-1 only stimulates insulin release when ____ is present
glucose
93
What does GLP-1 do?
Makes you feel full (decreases appetite and increase satiety)
94
True or false?
Synthetic GLP-1 receptor agonists (GLP1RAs) such as semaglutide (Ozempic, Wegovy) mimic GLP-1 but are less stable.
False.
They are **more** stable
95
Somatomedins _____ protein synthesis and ____ growth.
increase
stimulate
96
Somatomedins: produced by the _____ under stimulate of ____
liver
GH - somatomedins
97
________: structurally similar to insulin and are named insulin-like growth factors I and II (IGF-I and IGF-II)
somatomedins
98
excess of GH in adulthood produces the condition of ____
acromegaly (many bones get longer and heavier)
99
Differences in reproductive endocrinology in males and females is ______.
**quantitative** (not qualitative)
100
estrogen maintains _____ in males.
bone density
101
Estrogen deficiency in males leads to... (2)
- increased body fat
- contributes to sexual desire and erectile function
102
Estrogen in males produced locally in tissues by the conversion of _____ of testosterone to the estrogen estradiol.
aromatase
103
Gonadotropin releasing hormone (GnRH) stimulates release of ______.
pituitary gonadotropins (FSH and LH)
104
Gonads produce _____ protein which also feeds back on the anterior pituitary.
inhibin
105
The process of spermatogenesis takes place within the _____ of the testes.
coiled seminiferous tubules
106
The process of maturation from immature spermatogonia to the mature spermatozoon takes approximately __ days in humans.
60
107
Which 2 cell types are critical for the maturation of spermatozoa?
1. Leydig cells (synthesize androgens in response to LH)
2. Sertoli cells (intimately involved with the sperm maturation process - envelop the germ cells throughout their development)
108
True or false?
Leydig cells are located outside the seminiferous tubules.
True
109
True or false?
Sertoli cells are located outside the seminiferous tubules.
False
located inside
110
In response to FSH, Sertoli cells synthesize ______ and ______.
androgen binding protein (ABP)
inhibin
111
Spermatogenesis is critically dependent on ____ concentrations within seminiferous tubules.
androgen
(note: concentrations must be approximately 10x higher than androgen concentrations in circulation otherwise spermatogenesis ceases)
112
Presence of _____ synthesized by _____ cells ensures high androgen concentration within seminiferous tubules.
ABP
Sertoli
113
Leydig cells produce androgen, which inhibit release of ____, ___, and ____.
GnRH
LSH
FSH
114
non steroidal **inhibin** secreted by Sertoli cells inhibits _____ release only.
FSH
115
True or false?
There is a positive feedback control in both males and females
False.
Only in females
116
Once initiated, growth of primordial follicles into primary follicles is controlled by ____ and ____ until the follicles either ovulate or degenerate (atresia)
gonadotropins
steroid hormones
117
Primary follicles are influenced by ____ and _____.
FSH
estrogens
118
______ important for expression of LH receptor on granulosa cells
estrogens
119
under FSH and LH, primary follicle develops into a _______.
secondary follicle
120
______ and the _____ cells collaborate for synthesis of higher amounts of estrogen
theca interna
granulosa cells
121
What are the 2 events possible after follicular development?
**follicular atresia**: remaining secondary follicles degenerate after 1 follicle ovulates in each reproductive cycle
**ovulation**
122
Ruptured follicle transforms into _____ which secretes progesterone
corpus luteum
123
the corpus luteum is a _____ endocrine structure within the ovary that synthesizes progesterone and estrogens
temporary
124
Prior to day 1 of the menstrual cycle, endometrium thickens under the influence of _____
estradiol
125
_____ induces the appearance of specialized glycogen-secreting glands in the menstrual cycle.
progesterone
126
Menses (bleeding) begins when estradiol and progesterone are very ____ in circulation.
low
127
low estradiol and progesterone lead to ____ pituitary FSH secretion
increased
128
Day _, one follicle becomes dominant
8
PHGY 210
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