12. Histology of the Endocrine Organs Flashcards
Which hormone is secreted by somatotropic cells?
Growth hormone.
What is contained within the thyroid follicles?
Thyroglobulin.
(Storage form of T3 and T4.)
What are secreted by chromaffin cells, and where are they located?
What embryological layer do they come from?
Epinephrine and norepinephrine.
They are located in the adrenal medulla.
Neural crest cells.
What is the name for the thin stalk connecting the pituitary gland to the hypothalamus?
The infundibulum.
Which hormones are secreted by gonadotropic cells?
Follicle stimulating hormone.
Luteinizing hormone.
What embryonic layers give rise to the pituitary?
Two different layers of ectoderm – just ectoderm.
What are the two ways thyroid hormone accomplishes its own negative feedback?
The effect of thyroid hormone (e.g. increased body temperature) decreases the amount of thyroid releasing hormone secreted by the hypothalamus.
Also thyroid hormone can directly inhibit the binding of thyroid releasing hormone on the anterior pituitary.
What would you have to do to tell apart epinephrine cells from norepinephrine cells?
Perform electron microscopy.
The norepinephrine cells are much more electron dense (darker) than epinephrine cells.
What two structures come together to form the pituitary gland?
Rathke’s pouch – from the ectodermal placode.
The infundibulum from the diencephalon.
Identify this organ.
What two types of cells are shown here?
This is the parathyroid gland.
The cheif cells are smaller and more basophilic. The oxyphil cells are larger and “poofier.”
What occurs in patients with excess production of growth hormone both before and after their growth plates close?
Before the growth plates close, excess production of growth hormone can cause the individual to grow as tall as 8 feet.
After the growth plates close, excess growth hormone leads to the enlargement of the extremities and organs (acromegaly)
Which ventricle of the brain is surrounded by the hypothalamus?
The third ventricle.
What blood flow system allows for influence of the pancreatic acinar cells by the islets of Langerhans?
The insuloacinar portal system.
What are the layers of the adrenal cortex from external to internal?
Zona glomerulosa.
Zona fasciculata.
Zona reticularis.
What are the three blocked out parts of the anterior pituitary called?
What are the three types of stimuli that can control hormonal release?
Humoral stimuli.
Neuronal stimuli.
Hormonal stimuli.
What hormones are secreted by corticotropic cells?
Adrenocorticotropic hormone.
Melanocyte stimulating hormone.
What kind of hormones are produced in the zona glomerulosa, zona fasciculata, and zona reticularis?
Zona glomerulosa = mineralcorticoids [aldosterone].
Zona fasciculata = glucocorticoids [cortisol].
Zona reticularis = androgens.
(“Salt, sugar, sex. The deeper you go the sweeter it gets.”)
Histologically, what does the pineal gland consists of?
Pinealocytes.
Neuroglia.
Calcified granular material.
What four ways does parathyroid hormone increase blood calcium levels?
Stimulates osteoclasts to resorb bone.
Increases calcium retention by the kidneys.
Stimulates the kidney to activate vitamin D (inactive vitamin D -> calcitriol).
Increases calcium absorption by the intestine.
What is the primary issue in Cushing’s syndrome?
What are the main symptoms? (9 things)
Hypersecretion of glucocorticoids (e.g. cortisol) because of either an adrenocorticotropic hormone secreting pituitary tumor or a tumor in the adrenal cortex.
Swollen face, fat redistribution (buffalo hump and moon face), high glucose levels, weight gain, sweating, thinning skin, muscle weakness, lethargy, depression of the immune and inflammatory responses.
What sort of stimulus causes the release of epinephrine?
Neuronal stimulus – sympathetic nerve fibers to the adrenal medulla.
What is found just posterior to the crossing of the optic nerves?
The hypothalamus.
Which of the cells of the anterior pituitary are basophilic?
Corticotrophs.
Thyrotrophs.
Gonadotrophs.
