Lecture 20 Endocrine system Flashcards
1
Q
What are the two overview functions of the endocrine system
A
- maintains homeostasis
- coordinates body growth and development
2
Q
in the endocrine system, information conveyed to peripheral cells and organs via what
A
hormones
3
Q
What coordinates the majority of the endocrine process
A
hypothalamus
4
Q
how many hormones/hormonal substances are there
A
over 100
5
Q
Where are the areas which carry hormones to their destination
A
CT spaces and vascular system
6
Q
What are the major endocrine organs
A
- pituitary gland
- pineal gland
- thyroid gland
- parathyroid gland
- adrenal gland
7
Q
What is the function of the hypothalamus which gives it its name as the “master gland”
A
it lines the nervous system to the endocrine system
8
Q
The hypothalamus secretes what that directly affect the secretion of hormones by the anterior pituitary gland
A
regulatory hormones
9
Q
What system allows for regulatory hormones synthesized in the hypothalamus to be delivered to the anterior pituitary
A
the hypothalamohypophyseal portal system
10
Q
is the posterior pituitary considered an endocrine gland? why or why not?
A
No it is not because it harbors the axons from cell bodies present in the hypothalamus
11
Q
Which hormones are produced by the hypothalamus which are transmitted to the posterior pituitary for storage and release
A
oxytoxin and ADH
12
Q
What connects the pituitary gland to the hypothalamus
A
the infundibulum and a vascular network
13
Q
What are the two components of the pituitary gland
A
anterior lobe and posterior lobe
14
Q
What major histopathological differences are there between the anterior and posterior lobes
A
Posterior is lighter staining anterior is darker staining
15
Q
What are the two major set of arteries in the pituitary gland
A
- superior hypophyseal arteries
- Inferior hypophyseal arteries
16
Q
what does the hypophyseal portal system do
A
connects primary and secondary capillary plexus
17
Q
What do the superior hypophyseal arteries arise from
A
internal carotid arteries and posterior communicating artery
18
Q
What does the superior hypophyseal artery supply
A
pars tuberalis, median eminence and infundibulum
19
Q
What do the inferior hypophyseal arteries arise from
A
internal caratid arteries
20
Q
What do the inferior hypophyseal artery supply
A
pars nervosa
21
Q
What are the two capillary beds of the superior hypophyseal arteries
A
primary capillary plexus
secondary capillary plexus
22
Q
What is the importance of the hypothalamohypophyseal portal system
A
allows for regulatory hormones synthesized in the hypothalamus to be delivered to the anterior pituitary
23
Q
What are the main components of the anterior lobe
A
- pars distalis
- pars intermedia
- pars tubularis
24
Q
What part of the anterior lobe makes up its bulk
A
pars distalis
25
What are the main components of the posterior lobe
- pars nervosa
| - infundibulum
26
What do the pars nervosa of the posterior lobe contain
neurosecretory axons
27
What does the infundibulum of the posterior lobe of the pituitary gland contain
hypothalamohypophyseal tracts
28
What are the three cell types based on staining found in the pars distalis of the anterior lobe of the pituitary gland
- basophils
- acidophils
- chromophobes
29
What color are basophils
blue
30
what color are acidophils
pink
31
what are the five cell types based on function of the pars distalis of the anterior lobe of the pituitary gland
- somatotrops
- lactotropes
- Corticotropes
- Gonadotropes
- thyrotropes
32
Somatotropes produce what hormone and what is th
GH: growth hormone
33
What stimulates GH and what inhibits GH
somatostatin inhibits
| ghrelin stimulates
34
Lactotropes produce what hormone and what is its function
prolactin: inhibitory control of dopamine, mammary gland development and milk formation
35
Corticotropes produce which hormone and what is its function
ACTH (adrenocorticotropic hormone): stimulates secretion of glucocorticoids by adrenal cortex
36
Gonadotropes produce which hormones
FSH (sollicle stimulating hormone) and LH (luteinizing hormone)
37
What does FSH stimulate
stimulates folicle development in ovaries and testis
38
What does LH stimulate
regulates ovulation and maturation of ovarian follicle
39
What regulates FSH and LH
gonadotropin releasing hormone
40
what regulates ACTH
corticotropin-stimulating hormone
41
What hormone is released by Thyrotropes and what is its function
THS (thyroid stimulating hormone): stimulates release of thyroid hormones when TRH from hypothalamus stimulates TSH
42
What is the effect on the pituitary gland in multiparous women during pregnancy and lactation and why
the pituitary gland is 3x larger due to hyperplasia of lactotropes
43
Where is the pars intermedia of the anterior lobe of the pituitary gland located
between pars distalis and pars nervosa
44
What characterizes the pars intermedia
contains colloid filled follicles
| contains basophils and chromophobes
45
What are the basophils of the pars intermedia most likely
corticotropes (precursor molecule of ACTH)
46
What would be the physical characterization of the pars tubularis of the anterior lobe of the pituitary gland
funnel shaped region surrounding infundibulum
47
Why is the pars tubularis highly vasculaarized
contains the hypothalmo-hypophyseal system
48
What is the arrangement of the pars tubueralis
chords
49
What does the pars tuberalis secrete
gonadotropins (FSH and LH)
50
What is the function of the pars nervosa of the posterior lobe of the pituitary gland
- stores and releases secretory products from hypothalamus
| - contains axons and neurons
51
What do the axons of the pars nervosa form
hypothalamo-hypophyseal tract
52
Is the posterior lobe an endocrine gland
no, only a storage site for neurosecretions of hypothalamic neurons
53
Where do the axons of neurons of the pars nervosa terminate
Terminate near fenestrated capillary network of pars nervosa
54
What are the two cell types that can be found in the pars nervosa
Herring bodies and pituicytes
55
What are herring bodies and what dooe they house
- expanded terminal region of nerve fiber
| - house neurosecretions (ADH and oxytocin)
56
What cells does ADH target and what is the physiological outcome
kidney tubular cells and the outcome is increases blood pressure by increasing tubules permeability to water
57
What is the outcome of oxytocin secretion
contraction of uterine wall smooth muscle during copulation and childbirth
contraction of mammary glands during nursing
58
What is the main function of the pineal gland
regulates daily body rhythm
59
What two types of parenchymal cells are found in the pineal gland
```
Pinealocyte
interstitial (glial) cells
```
60
What is the main histopathologicaal identifier in the pineal gland
brain sand
61
What is one hormone released by the pineal gland that gets up-secreted in the dark
melatonin
62
Excessive melatonin production contributes to what disorder
SAD and jet lag
63
What is the bilobed endocrine gland located in the anterior neck region adjacent to the larynx consiting of two large lobes connected by an isthmus
thyroid gland
64
What is the functional unit of the thyroid
thyroid follicle
65
What makes up a thyroid follicle
simple cuboidal/columar epithelium filled with colloid
66
What are the two major cells types of the thyroid
Follicular cells
| parafollicular cells
67
What do follicular cells produce and where are they found
produce T3 and T4
| found in regions adjacent to the thyroid follicle
68
What do parafollicular cells produce and where are they found
they produce calcitonin
will not be adjacent to any colloid or follicle edge but rather in between them
69
What does T3 and T4 regulat
basal metabolism and heat production, influence body growth and development
70
What does calcitonin regulate
calcium metabolism, lowers blood calcium levels by decreasing bone reabsorption
71
Production of T3 and T4 begins with
production of thyroglobulin
72
Walk through the negative feedback loop of T3 and T4 starting with the Hypothalamus
- Hypothalamus secretes thyrotropin releasing hormone
- TRH enters primary capillary plexus of pituitary
- drains into hypophyseal portal veins
- then into secondary capillary plexus in pars distalis
- TRH stimulates thyrotropes to release TSH
- TSH acts on follicular cells
- T3 and T4 are released
- T3 and T4 get to brain and act as inhibitors of TRH release from hypothalamus
73
What is hypothyroidism
- insufficient dietary iodine
- hashimotos thyroiditis
- inflammation and immune system inactivate thyroid
74
What is hyperthyroidism
- antibodies bind to TSH receptor on follicle cells leading to continuous stimulation of follicle cells
75
How is the parathyroid gland arranged
two pairs: superior and inferior
76
How are the cells in the parathyroid gland arranged
densly packed chords
77
What are the two major cell types of the parathyroid
chief - synthesize store and secrete PTH
| oxyphil - minor subset with no secretory function
78
PTH is released by what and where and what is the function of the hormone
released by chief cells in parathyroid and PTH (primary calcium regulator) stimulates bone absorption and Ca release
79
PTH increases calcium in the blood by
osteoclast stimulation
calcium reabsorption in kidneys
increases formation of Vitamin D3 promoting resorption of calcium in kidneys
80
what would be the patient outcome if all parathyroid tissue is removed
death due to tetanic contraction of muscles
81
What is histopatholigically characteristic of osyphil cells
lighter staining regions of parathyroid
82
What is histopathologically characteristic of chief cells
darker staining regions of parathyroid
83
What gland is superior to the kidney
adrenal gland
84
what re the three regions of the adrenal gland
- capsule
- cortex
- medulla
85
What are the three regions of the adrenal cortex
- Zona glomerulosa
- Zona fasciculata
- Zona regicularis
86
What is the zona glomerulosa activated by, what does it secrete, and what function does it regulate
- Angiotensin II
- mineralcorticoids
- Electrolyte and osmotic balance
87
What is the zona fasciculata activated by, what does it secrete, and what function does it regulate
- ACTH
- glucocorticoids
- Normal metabolism
88
What is the zona retucularis activated by , what does it secrete, and what function does it regulate
- ACTH
- gonadocorticoids
- Masculinizing effect
89
What does the medulla secrete in the adrenal gland
catacholamines (epinephrine and norepinephrin)
90
The outermost level of the cortex is the
zona glomerulosa
91
The innermost level of the cortex is the
zona reticularis
92
What is the histopathological characteristic of the zona fasciculata
arranged in liniar chords
93
How do glucocorticoids and catecholamines of the adrenal gland prepare the body for fight or flight
glucocorticoids mobilize free fatty acids = energy
| catecholamines cause increase in blood pressure = oxygen to muscles
94
What is the main cell type of the adrenal medulla
chromaffin cells
95
What are the two hormonal products of the adrenal medulla (generally called catecholamines)
epinephrine and norepinephrine
96
What are the three patterns of blood distribution in the adrenal gland
capsular capillaries
fenestrated cortical sinusoidal capillaries
medullary arterioles
97
What do the capsular capillaries supply blood to in the adrenal gland
capsule
98
What do the fenestrated cortical sinusoid capillaries supply blood to in the adrenal gland
supply cortex then drain into fenestrated medullary capillary sinusoids
99
What do the medullary arterioles supply blood to
transverse cortex artery blood to cortex
100
What is the blood supply to the medulla
dual supply
- medullary arteries
- venous blood suppl;y from cortical capillaries
101
What is the sponge effect of the adrenal gland
longitudinal smooth muscle bundles in tunica media of central vein decreases gland volume and increases hormone efflux
102
Cushings disease is an example of what
a hyper-functional adrenal gland causing increased glucocorticoids due to excess ACTH released by pituitary gland
103
Symptoms of cushings disease are
obesity, round face, weakened bones
104
Addisons diesease is an example of what
Hypofunctional adrenal gland disorder due to decreased production of cortisol
105
Symptoms of addisons disease are
weight loss, muscle weakess, low blood pressure
