Flashcards in Lecture 18- Endocrine System Deck (61):
1
What do all endocrine glands have in common (or what defines an endocrine gland?
They secrete hormones into the blood
2
What is paracrine secretion?
Hormone to a target cell
3
What is autocrine secretion?
Hormone to self
4
What makes up the posterior pituitary gland?
- infundibulum or pituitary stalk
- pars nervosa
- tissue develops from brain
5
What makes up the anterior pituitary gland?
- pars tuberalis
- pars intermedia
- pars distalis
- tissue derived from ectoderm
6
What are sinusoids?
Essentially giant capillaries
7
What are degranulated cells?
Cells that turn back into an acidophil or basophil
8
What are progenitor cells?
Cells that go on to produce other cell types
9
What are chromophobes?
Either degranulated cells or progenitor cells
10
What are the acidophils?
- somatotropes (growth hormone)
- mammotropes (prolactin)
11
What are the basophils?
- gonadotropes (FSH and LH)
- thyrotropes (TSH)
- corticotropes (POMC) cleaves to (ACTH)
12
What is the best way to differentiate these cells?
- immunohistochemistry
13
The blood supply to the median eminence, infundibulum, and anterior pituitary is a portal system? What does that mean
Two capillary beds
14
What does the pars tuberalis secrete?
mainly basophilic gonadotropes
15
What does the pars intermedia secrete?
basophilic cortico tropes. POMC cleaved to melanocyte stimulating hormone. In pars distalis POMC cleaved to ACTH
16
What does oxytocin do?
- milk let down
- uterine contraction during labor
17
What are pituicytes?
Glial cells that surround the unmyelinated axons
18
What are herring bodies?
Cells that store the hormone
19
Where are the neuronal cell bodies for the posterior pituitary?
hypothalamus
20
Where are the alpha cells located in the islets of langerhans?
Along the periphery- glucagon- raises blood glucose
21
Where are the beta cells located in the islets of langerhans?
On the interior- insulin that lowers blood glucose
22
Where is the adrenal gland found?
On top of the kidney, suprarenal gland
23
What are the three layers of the adrenal gland?
- capsule
- cortex derived from mesoderm
- medulla derived from neural crest
24
What are the three layers of the cortex?
- zona glomerulosa
- zona fasciculata
- zona reticularis
25
They precursor to hormones produced in the adrenal cortex is cholesterol. What does this tell you?
Lipid soluble, hydrophobic
26
What is secreted in the zona glomerulosa?
aldosterone
27
What are mineralocorticoid and give an example.
aldosterone, influence salt and water balance
28
What does aldosterone do?
Released from the adrenal gland under low BP to stimulate Na+ retention and for the kidney to release renin and angiotensin II
29
What effect does aldosterone have on blood K+ levels?
increases secretion of K+ in the collecting duct to lower blood K+
30
What does the zona fasciuluta release?
glucocorticoids (eg cortisol), washed out lipid droplets that contained steroids
31
What signals the release of cortisol?
ACTH
32
What effect does cortisol have on the hypothalamus?
negative feedback
33
What effects does cortisol have on the body?
- immunosuppressive
- anti- inflammatory
34
What is released in the zona reticularis?
androgens- lipid soluble steroids, wide capillaries or sinusoids
35
What induces the release of androgens from the adrenal gland?
ACTH
36
Where are chromaffin cells?
adrenal medulla, derived from the neural crest
37
What effect does the sympathetic pre-ganglionic neuron have on the adrenal medulla?
release epinephrine
38
If the sympathetic pre-ganglionic synapses on a post ganglionic neuron, what will be secreted?
norepinephrine
39
What are the main parts of the thyroid?
- capsule
- septa
- thyroid follicles
40
What are the follicular cells?
Simple epithelium, cuboidal or columnar
41
What is the colloid filled lumen?
thyroglobulin
42
What is stored in the C cells?
Calcitonin
43
If the follicular cells are inactive (No TSH) they are more?
squamous
44
If the follicular cells are active, they are...
more cuboidal or columnar, thyroid hormone
45
What are three effects of thyroid hormone?
- increase basal metabolic rate
- increase lipid metabolism
- increase in carbohydrate metabolism
46
Which cell has secretory granules?
C cells
47
What effect does the caclitonin from the secretory granules have on the body?
inhibit osteoclasts
48
What does thyroglobulin help store?
Iodine in T3 and T4
49
What stimulates the production and release of thyroid hormone from the thyroid gland?
TSH from anterior pituitary
50
What shuts off TSH release from the pituitary?
Thyroid Stimulating Hormone
51
What shuts off TSH release from the pituitary?
Thyroid Hormone, negative feedback
52
What would the cells look like if a test revealed elevated serum TSH levels?
Follicular cell hyperplasia but with little colloid
53
What cells are found in the parathyroid gland?
- chief cells
- oxyphil cells
54
What do chief cells secrete?
Parathyroid hormone, purple nuclei with pale but acidophilic cytoplasm
55
Low blood calcium levels stimulate parathyroid hormone secretion. How does PTH raise blood Ca++ levels?
Increases Ca++ reabsorption in the kidney tubule
56
What does PTH do in the kidney?
increases the synthesis of 1-ahydroxylage in the PCT of the kidney. Activates Vitamin D to enable Ca++ absorption from the gut
57
What does the pineal gland secrete?
melatonin
58
What does melatonin do?
regulates circadian rhythm, darkness promotes the release of melatonin
59
What is a corpora arenacea?
brain sand, Ca, Mg salts.
60
What are the other cells found in the pineal gland?
- pinealocytes
- astrocytes
- corpora arenacea
- septa
61