Test 2: Endocrine Lecture Flashcards
1
Q
endocrine system definition
A
Ductless glands that produce hormones that regulate metabolism, growth, development, tissue function, reproduction, sleep, mood, etc.
Regulates homeostasis in collaboration with the nervous system
2
Q
key features of endocrine system
A
–cells often arranged in clusters or cords
–release hormones into intercellular or perivascular connective tissue spaces
–associated with dense capillary beds and wide thin-walled vessels called sinusoids
3
Q
endocrine system is associated with dense capillary beds and wide thin-walled vessels called ___
A
sinusoids- very leaky, large pores
4
Q
single cells that have endocrine functions
A
neural crest cell
Stomach: G cells: gastrin
Small intestine: I cells: cholecystokinin and S cells: secretin
5
Q
endocrine cell groups/clusters
A
Endocrine cell groups/clusters in “non-endocrine” organs
•hypothalamic neurosecretory neurons
-various, regulate pituitary function
•pancreatic islets
-insulin, glucagon, others
•atrial cardiac myocytes
-atrial natriuretic factor
•theca interna of ovarian follicles
-androgens, progesterone
•interstitial cells of testes (aka Leydig cells)
-testosterone
6
Q
hypothalamic neurosecretory neurons
A
endocrine cell group
that regulates pituitary function
7
Q
pancreatic islet cells make what?
A
insulin, glucagon and others
type of endocrine cell group/cluster
8
Q
atrial cardiac myocytes produce what
A
atrial natriuretic factor
type of endocrine cell group/cluster found in a non endocrine organ
9
Q
theca interna of ovarian follicle produce what
A
androgens, progesterone
type of endocrine cell groups/clusters in “non-endocrine” organs
10
Q
Leydig cells produce what
A
testosterone in the testes
type of endocrine cell groups/clusters in “non-endocrine” organs
11
Q
types of endocrine organs
A
Hypophysis (pituitary)
Thyroid gland
Parathyroid gland
Adrenal glands
Pineal gland (not covered)
12
Q
what is a common feature of endocrine organs
A
all have dense capillary beds and wide thin-walled vessels called sinusoids
13
Q
another name for pituitary gland
A
hypophysis
14
Q
two parts of pituitary gland
A
Adenohypophysis –anterior pituitary–glandular portion
Neurohypophysis –posterior pituitary- where secretion of things made in the hypothalamus
15
Q
There is an intimate neural and vascular relationship between the hypothalamus and ___
A
hypophysis/ pituitary gland
16
Q
Pituitary functions are tightly controlled by the ___
A
hypothalamus
17
Q
__ is the anterior glandular portion of the hypophysis
A
Adenohypophysis
18
Q
___ is the posterior part of the hypophysis where hormones made by the hypothalamus are secreted
A
Neurohypophysis
19
Q
development of the hypophysis
A
20
Q
___ is a funnel like structure that is residual from the formation of the pituitary gland and is found in the ___
A
infundibular recess
neurohypophysis (posterior part)
21
Q
___ is a small residual lumen in the ___ part of the pituitary that acts as a landmark
A
residual lumen of rathke’s pouch
adenohypophysis (anterior part)
22
Q
Three parts of the Adenohypophysis
A
pars distalis
pars intermedia (cells that secrete melanocyte stimulating hormone)
pars tuberalis (collar of the stock- portal venules go through here)
23
Q
Three parts of the neurohypopysis
A
pars nervosa (infundibular process)
infundibular stalk
median eminence (where primary capillary reside)
24
Q
Pars distalis
A
anterior lobe, major part of the adenohypophysis
dense fibrous capsule of collagenous tissue w/ stromal fibers
–parenchyma organized as cords and clusters of cells- polarized make hormones go in one direction
–closely associated with a dense network of sinusoidal capillaries
25
Cells of the pars distalis
**Chromophobes-** do not stain well
**Chromophils-** stain well and can be **Acidophils or Basophils**
Cells are classified by their staining properties but can also be immunochemically distinguished based on the hormones they produce.
26
Chromophobes
50% cells of pars distalis which is part of the adenohypophysis
–small round cells w/ very little cytoplasm and **no detectable granules (do not stain well)** (by light microscopy)
–usually present in clusters and may form the centers of cell cords
–may be degranulated chromophils or chromophil precursors
27
Chromophils
type of cell in the pars distalis which is part of the pituitary/adenohypophysis
−**contain secretory granules**
**larger then chromophobes**
−arranged in cords or clusters of cells
−**polarize** toward sinusoidal capillaries (apical secretion)
**basophilic** 10% (purple) or **acidophilic** 40%(orange)
28
types of acidophils
–**Acidophils (~40%)**
**Somatotropes**
**Lactotropes (mammotropes)**
Chromophils type of cell of the pars distalis which is part of the adenohypophysis
29
types of hormone basophils
Basophils (~10%)
**Thyrotropes, Gonadotropes, Corticotropes**
Chromophils type of cell of the pars distalis which is part of the adenohypophysis
30
somatotropes produce ___ and lactotropes produce \_\_. These are __ types of cells
somatotropin (STH)= growth hormones (GH)
prolactin
Acidophil Chromophils cell of the pars distalis
31
Thyrotropes produce ___ , gonadotropes produce ___ and corticotropes produce \_\_\_. These are ___ types of cells from the \_\_\_
**Thyrotropin**- thyroid stimulating hormone (TSH)
**gonadotropin**= follicle stimulating hormone (FSH) luteinizing hormone (LH) or interstitial cell stimulating hormone (ICSH)
**corticotropin-** adrenocorticotropin ACTH
Basophils Chromophils cell of the pars distalis
32
Acidophils of the Pars Distalis are ___ than chromophobes. Contain granular \_\_\_cytoplasm and are often\_\_\_.
larger
acidophilic
polarized
33
**Somatotropes produce**
–somatotropin (STH; aka growth hormone, GH)
type of acidophil chromophils of the pars distalis
34
Lactotropes (mammotropes) produce \_\_\_
prolactin (PRL)
type of acidophil chromophils of the pars distalis
35
Basophils of the Pars Distalis have granular ___ cytoplasm. Contain numerous ___ granules and are often \_\_\_
basophilic
PAS-positive
polarized
36
Thyrotropes produced \_\_\_
Thyrotropin (TSH)
type of basophil chromophils of the pars distalis
37
Gonadotropes produce \_\_\_
follicle-stimulating hormone (FSH)
luteinizing hormone (LH); also called interstitial cell-stimulating hormone (ICSH)
type of basophil chromophils of the pars distalis
38
corticotropes produce \_\_\_
adrenocorticotropin (ACTH)
most common basophil
type of basophil chromophils of the pars distalis
39
POMC (proopiomelanocortin) is a precursor for \_\_\_
adrenocorticotropin (ACTH)
melanocyte stimulating hormone (MSH)
b-lipotropic hormone (b-LPH)
b-endorphin
40
Melanotropes reside in the \_\_\_
pars intermedia
41
pars distalis
## Footnote
Note:
**cell clusters and cords**
**sinusoids-** big gaps orange dots inside are red blood cells
chromophobes
acidophils (orange)- cluster/group together
basophils (purple)
42
pars distalis of the adenohypophysis of the hypophyseal
orange cells= acidophils= chromophils
purple= basophils= chromophils
clear/ no stain uptake= chromophobes
43
pars distalis of the adenohypophysis of the hypophyseal
very pink= acidophils= chromophils
purple/pink= basophils= chromophils
clear/ no stain uptake= chromophobes
44
**Pars Tuberalis**
Part of the adenohypophysis
Sleeve around the neural stalk/median eminence
Transversed by numerous portal venules that receive tributaries from the capillary plexus of the median eminence
45
outer→ pars tuberalis (little wholes- pituitary portal system)
inner grey → infundibular stalk
center whole→ infundibular recess
slice of the hypophyseal at the level of the pituitary stalk
46
Cells of the pars tuberalis
**Weakly basophilic cuboidal cells**
–organized as cords
–some clusters or follicles (function not established)
**Some gonadotropes, thyrotropes (basophils)**
**Subject to seasonal variations**
–High density of melatonin receptors
–May play a role in establishing **seasonal reproductive cycles**
47
**Pars intermedia**
**Part of the adenohypophysis adjacent to the neural lobe**
–separated by a thin sheet of connective tissue and the residual lumen of Rathke’s pouch
**Well developed in domestic animals**
(not prominent in humans)
48
Cell of the pars intermedia
**Melanotropes**
–basophil
–present in cords, clusters
–some follicles w/ colloid (variable w/ species)
–secrete **melanocyte-stimulating hormone** (MSH; aka melanotropin)→ Stimulates melanocyte melanin production & release
**Others cells variable w/ species**–include those abundant in pars distalis (i.e. **corticotropes**)
49
little balls- follicles
found in cat pars intermedia of the adenohypophysis of pituitary gland
50
**Hypothalamic control of the pars distalis**
**Neuro-endocrine cells** of the basal hypothalamus produce **“releasing factors”** or inhibitory hormones
**Transported axonally** to the external zone of median eminence
Released into **hypophysial portal system**
Transported to cells of pars distalis
51
HPA axis
(hypothalamyl-pituitary-adrenal)
## Footnote
**Hormone production stimulated by:**
–neural mechanisms
–physical/psychological stress (starvation, etc)
–diurnal fluctuations
52
HPT axis
hypothalamyl-pituitary-thyroid
53
Regulation of MSH production in the pars intermedia
–Melanotropes are modulated by **hypothalamic axons that penetrate the pars intermedia**
–MIH (also known as Melanostatin), produced by hypothalamus, is associated with neurons that reach into the pars intermedia
–melanotropes are **_not_** **regulated** via the hypophysial portal system
54
**Neurohypophysis**
Derivative of the ventral **hypothalamus**
(divided into the pars nervosa, infundibular stalk and median eminence)
made of **neurosecretory neurons** and **pituicytes**
Connected morphologically & functionally to hypothalamus
unmyelinated neural fibers with cell bodies in the hypothalamus
55
neurohypophysis
neurosecretory neurons
–originate in supraoptic and para-ventricular regions of the hypothalamus
–unmyelinated nerve fibers connect the hypothalamus to the pars nervosa (aka Hypothalamo-hypophyseal tract )
–transport neurosecretory products along axons
–product accumulates near axon terminals (called Herring bodies)
56
\_\_\_ originate in supraoptic and para-ventricular regions of the hypothalamus
neurosecretory neurons
57
neurosectetory neurons are unmyelinated nerve fibers connect the hypothalamus to the ___ (aka Hypothalamo-hypophyseal tract )
pars nervosa
58
neurosecretory neurons
product accumulates near axon terminals (called \_\_\_)
Herring bodies
59
**Pituicytes (neuroglial cells)**
part of neurohypophysis (pituitary gland)
–**modified astrocytes**
–function not well understood
»may regulate hormone secretion
»assist w/ axon growth and regrowth
»remove damaged axons
60
uNeurosecretory neurons of hypothalamus produce\_\_\_
oxytocin
antidiuretic hormone (ADH= vasopressin)
neurophysins (Carrier proteins)
61
Neurosecretory neurons of the hypothalamus have axon terminals abut perivascular spaces of ___ in pars nervosa
sinusoid capillaries
62
pituitary gland
63
herring bodies
hormones stored terminals pars nervosa of the neurohypophysis of the hypophysis (pituitary gland)
64
**herring bodies:** hormones stored terminals pars nervosa of the neurohypophysis of the hypophysis (pituitary gland)
pituicyte nuclei
65
TSH is made by ___ and does
66
ACTH is made by ___ and does \_\_\_
67
FSH is made by ___ and does \_\_-
68
LH is made by ___ and does \_\_\_
69
GH is made by ___ and does \_\_\_
70
Prolactin is made by ___ and does \_\_\_
71
MSH in made by ___ and does \_\_\_
`
72
Oxytocin is made by ___ and does \_\_\_
73
ADH is made by ___ and does \_\_\_
74
Thyroid gland
Thyroid hormone T3,T4
calcitonin
**parafollicular cells (**C Cells)
**follicular cells** filled by **colloid**
follicle help increase **iodine concentration** which is an important precursor to thyroid hormones
75
Follicles of thyroid gland are filled with ___ also called \_\_\_
colloid
thyroglobulin
76
77
Thyroid follicular cells
principal cells
acidophilic
polar cell morphology
make **Thyroglobulin and Thyroperoxidase**
78
Follicular cells produce colloid which is made of ___ and \_\_\_
thyroglobulin
Thyroperoxidase
79
Thyroglobulin is made of ___ and is made by the \_\_\_and secreted via secretory vesicles into \_\_\_
glycoprotein
ER/Golgi complex
follicle lumen
80
Thyroperoxidase is synthesized and secreted into the \_\_\_
follicle lumen
81
thyroperoxidase Iodinates thyroglobulin on \_\_\_
tyrosines
82
Iodine deficiency can cause a ___ to form.
goitre
83
explain how follicular cells secrete T4 and T3
–**thyroglobulin** is taken up from follicular lumen resulting in colloid droplets
–droplets merge with lysosomes (phagolysosomes)
–**thyroglobulin** is broken down into thyroxine (T4) and triiodothyronine (T3)
–T3 and T4 diffuse out cellular base
84
\_\_\_ is a pro-hormone; converted to T3 by target cells
Thyroxine (T4)
85
\_\_\_ accelerates metabolic rate of body
Triiodothyronine (T3)
86
three things Triiodothyronine (T3) can do
–accelerates metabolic rate of body
–Increase cell metabolism, growth, differentiation, development
–increases protein, carbohydrate and fat metabolism
87
hypothyroidism leads to weight loss true or false?
false, they **gain weight** due to lack of thyroid hormones
88
TRH from hypothalamus stimulates ___ to release TSH
adenohypophysis
89
TSH stimulates \_\_\_, ___ and ___ of thyroid follicular cells
–synthesis, iodination and follicular storage of thyroglobulin
90
TSH stimulated the follicular storage of ___ by follicular cells
thyroglobulin
91
TSH stimulates thyroid follicular cells to release thyroid hormones (\_\_\_ and __ ) into general circulation
T3 and T4
92
parafollicular cells are derived from \_\_\_
neural crest cells
93
where can parafollicular cells be found
**in the thyroid**
in small clusters within the basal lamina of follicles
or
outside of the follicle (dogs)
94
parafollicular cells
found in thyroid→ C cells
pale staining cytoplasm
clusters or single cells
Little ER, abundant Golgi, many small secretory granules, mitochondria
Secrete **calcitonin**
95
parafollicular cells secrete \_\_\_
calcitonin, seratonin and somatostatin
96
97
98
8 parafollicular cells
5: follicular cells in transcut
99
Calcitonin
produced by parafollicular cells of the Thyroid
–Lowers blood calcium levels
–Reduces number and activity of **osteoclasts** in bones
–production is _not_ controlled by pituitary functions
–Stimulated by **high blood Ca++ levels**
100
Parathyroid is found \_\_\_
in the thyroid, usually 4 in mammals
101
\_\_\_ is separated from thyroid by thin capsule of dense irregular connective tissue
parathyroid
102
Parathyroid have cells that are arranged in cords or clusters, with many blood vessels and \_\_\_colloid filled follicles.
rare
103
Parathyroid produces __ when __ is low
PTH
calcium
104
Parathyroid produces parathormone (PTH) which regulates blood ion levels- especially \_\_\_
calcium
105
What will happen is parathyroid is damaged?
If removed/ablated, all muscles will undergo **rigid spasms** as blood calcium level falls
106
107
parathyroid
thyroid
108
two types of parathyroid cells
**chief cells (principal cells)**
- produce parathyroid hormone (PTH parathormone)
not regulated by hypophysis (pituitary glands)
**oxyphil cells** (unknown function)
109
Chief cells produce ___ and are not regulated by the \_\_\_
parathyroid hormone (PTH, parathormone)
hypophysis
110
PTH production is regulated by __ levels
blood calcium
111
\_\_\_ is the antagonist to thyroid calcitonin
parathyroid hormone (PTH)
**PTH increases** blood calcium
**calcitonin decreases** blood calcium
112
explain how calcium levels effect PTH
**increases calcium levels**
–triggers increased **Vit D3 production** in kidney (necessary for Ca++ absorption in gut)
–stimulates **Ca++ absorption** by distil convoluted tubules
–raises Ca++ levels by **stimulating osteoclast** activity and proliferation (indirectly via osteoblasts)
113
deficiencies in PTH lead to
**Decreased blood calcium**
–Fibrillary twitching in muscles
–Spasms of limb muscles
–Rigid spasms
–Death
114
**Parathyroid Oxyphil Cells**
**Unknown function**
Large (27 um), single or in clusters
**Abundant in horses and ruminants**
Rare in other domestic mammals
Very rich in mitochondria
Scarce in Golgi, rER, granules **(inactive secretion)**
115
**Parathyroid Oxyphil Cells**
116
117
adrenal gland
118
3 parts of adrenal gland
**capsule**
**cortex**
zona glomerulosa
zone fasciculata
cona reticularis
**medulla**
119
adrenal gland is surrounded by a ___ made of \_\_\_, ___ and \_\_\_
capsule
–dense irregular connective tissue
–occasional smooth muscle fibers
–clusters of undiffentiated cells»precusers to zona glomerulosa
120
The cortex of the adrenal gland has a __ origin
mesodermal
121
The medulla of the adrenal gland has a ___ origin
neuroectodermal
122
123
124
the zona glomerulosa produces ___ and is found in the \_\_\_
mineralcorticoids (aldosterone)
cortex of the adrenal gland
125
The zona fasciculata produces __ and is found in the \_\_
glucocorticoids (cortisol, cortisone)
cortex of the adrenal gland
126
The zona reticularis makes ___ and is found in the \_\_\_
Glucocorticoids (cortisol) Sex hormones (DHEA)
cortex of the adrenal glands
127
The medulla of the adrenal gland makes \_\_\_
catecholamines (epinephrine, norepinephrine)
128
129
130
Zona glomerulosa
layer directly under capsule of adrenal gland
**Cell chords:**
– irregular spherical clusters -**Glomeruli** (most domestic animals, ruminants)
– arcs or loops of tall columnar -**Zona arcuata** (horses, some carnivores, pigs)
– surrounded by sinusoidal capillaries
**Cell features:**
– Abundant sER, mitochondria, Golgi, lipid droplets
– Secrete **mineralocorticoids**
131
Zona fasciculat
2nd zone (in between zona glomerulosa and zone reticularis)
Radially arranged cords of cuboidal or
columnar cells separated by sinusoidal
capillary network
Cells of zona fasciculata
–contain numerous lipid droplets, which are
not well preserved in standard tissue preps
– Spongy appearance (spongiocytes)
– Produce **glucocorticoids (GCs)**
132
produces glucocorticoids
133
zona reticularis
deepest part of cortex of adrenal gland
## Footnote
Irregular network of cell cords
**Polyhedral cells**
fewer lipid droplets than cells of zona fasciculata produce **glucocorticoids**, and **sex hormones**
134
aldosterone
**a mineralocorticoid**
– Produced in **zona glomerulosa (top layer of adrenal gland cortex)**
» NOT regulated by hypophysis
– Increases sodium reabsorption from glomerular filtrate in kidney
– Increases potassium excretion
– Increases fluid volume
– **Restores electrolyte balance**
– Raises blood pressure
135
Glucocorticoids
**cortisol, cortisone**
## Footnote
Produced in **zona fasciculata and zona reticularis (middle and bottom layer of cortex of adrenal gland)**
– Regulate blood sugar levels
– Regulate protein, fat, carbohydrate metabolism
– Suppress inflammatory response
– **Regulated by ACTH** from adenohypophysis **(HPA axis)**
136
aldosterone increases ___ reabsorption from glomerular filtrate in the kindey
sodium
137
aldosterone ___ potassium excretion, increases ___ volume, restores ___ balance and ___ blood pressure
increases
fluid
electrolyte
raises
138
Glucocorticoids regulate blood sugar levels, regulate protein, ___ and ___ metabolism
fat, carbohydrate
139
glucocorticoids ___ inflammatory response
suppress
140
glucocorticoids are regulated by ___ from the \_\_\_
ACTH from adenohypophysis (HPA axis)
141
sex hormones such as ___ are made in the \_\_\_
dihydroepiandrosterone-DHEA
zona reticularis
142
cortisol = ___ hormone
pleiotropic
143
what are some things cortisol does
144
hyperadrenocortism
cushings
hair growth issues
145
HPA axis
146
adrenal medualla cells are called \_\_\_
chromaffin cells
147
adrenal medulla cells are
Modified **post-ganglionic sympathetic neurons**
– **Basophilic** polyhedral cells arranged as irregular cords and clusters
– Regulated by **preganglionic sympathetic innervation** (not by hypophysis/pituitary)
Separated by **dense sinusoidal capillaries**
* *make Catecholamines (epinephrine,**
* *norepinephrine) (fight or flight)**
148
fight or flight is stimulated by
adrenal medulla function
## Footnote
Catecholamines (epinephrine, norepinephrine)
149
Catecholamines production is regulated by ___ via sympathetic nervous system in response to \_\_\_
(epinephrine, norepinephrine)
hypothalamus
fear or acute stress
150
epinephrine, norepinephrine which are ___ produced by the ___ will ___ heart rate and cardiac output and blood flow and will also ___ blood glucose from the liver
catecholamines
adrenal medulla
increase
induce a surge of
151
overview of thyroid
**Follicle cells**: T3, T4 → increase metabolism
**Parafollicular cells**: Calcitonin → decrease blood Ca++
152
overview of parathyroid
**Chief cells**: Parathormone → increase blood Ca++
**Oxyphil cells:** unknown function
153
overview of adrenal cortex
**Mineralocorticoids** (aldosterone) →electrolyte balance. made in zone glomerulosa
**Glucocorticoids** (cortisol, cortisone)→ blood sugar levels during stress, etc, made in zone fasciculate and zona retucularis
**Sex hormones (DHEA)** (probably insignificant), made in zone reticularis
154
adrenal medulla overview
Catecholamines **(epinephrine, norepinephrine)** → “fight or flight” response
155
basophils in pituitary gland effect what?
156
acidophils in pituitary gland effect what?
157
MSH produced in the pituitary gland effect what?
158
**Hypothalamic control of pituitary hormone release**
159
