Endocrine II Flashcards
Parathyroid glands are covered by what? What does this do/provide?
Collagenous capsule that sends septa into the lobes and provides vessels/nerves
What is the specialization of the capillaries in the parathyroid?
Fenestration
What is present in the parathyroid glands in adults as we age?
Fat
How are the parenchya cells in the parathyroid glands arranged?
Cords or clusters
What are the three type of cells in the parathyroid gland?
- Chief cells
- Oxyphil cells
- Intermediate cells
Are the chief cells of the parathyroid hormone basophilic or eosinophilic?
Eosinophilic
What is the function of the chief cells of the parathyroid gland?
Secrete PTH
What are the steps in PTH synthesis (3)
Preproparathyroid hormone (pre-PTH) produced by rER ribsomes
This is carried to the rER luimen to form proPTH.
Golgi make the final modification to PTH
How is PTH secreted from cells?
via secretory granules
What are oxyphil cells?
Dark staining, eosinophilic cells near parathyroid cells that have no known function
What is the function of the intermediate cells in the parathyroid gland?
Unknown
What is the function of PTH?
Increases [Ca] and decreases [PO4]
PTH glands have receptors for Ca. What stimulates/inhibits parathyroid glands?
Low [Ca] stimulates
High [Ca] inhibits
What is the effect of PTH in bone?
causes osteoblasts to release osteoclast-stimulating
factor, which triggers osteoclast activity, freeing calcium from bone to enter the bloodstream
What is the effect of PTH in the kidney?
Prevents Ca loss in the urine
Promotes phosphate loss in the urine
What is the effect of PTH in the GI tract?
Indirectly increasse Ca absoption by changing Vit D formation by kidney
What hormone has the inverse effect as PTH?
Calcitonin
What happens if parathyroid glands are removed?
Hypocalcemia–tetanus-like symptoms
What is the function of the capsule that surround the pancreas?
Gives rise to septa and vessels etc
Partitions lobes
What does the exocrine part of the pancreas contain? Endocrine part?
Exocrine = digestive enzymes
Endocrine = hormones
What are the five cell types contained in the islets of Langerhans?
Alpha cells Beta cells Delta cells G cells PP (F) cells
What is the function of the A cells in the islets of langerhans?
Release glucagon
What is the function of the B cells in the islets of langerhans?
Produce insulin
What is the function of the Delta cells in the islets of langerhans?
Release somatostatint to reduce smooth muscle contraction of GI and gallbladder
What is the function of the G cells in the islets of langerhans?
Secretes gastin which stimulates HCl synthesis
What is the function of the PP (F) cells in the islets of langerhans?
Rlease pancreatic polypeptide, which inhibits pancreatic exocrine secretions
What are the two specific causes of DM?
- beta cells do not produce insulin
2. Defective insulin receptors
What is the function of the capsule surrounding suprarenal (adrenal) glands?
CT trabeculae carry blood vessels and nerve fibers deep into the gland
What are the two layers of parenchyma in the adrenal glands?
Cortex and medulla
What is the function of the cortex of parenchyma cells in the adrenal glands?
Produce corticosteroids
What is the function of the medulla of parenchyma cells in the adrenal glands? What is the innervation of this region?
Produce catecholains (epi and norepi)
Sympathetics
What are the three histological regions of the adrenal cortex?
Zona glomerulosa
Zona Fasciulata
Zona Reticularis
What is the outer zone of the adrenal cortex? What is this area’s function?
Zona glomerulosa
Produces aldosterone
What is the cell type found in the zona glomerulosa? How are these arranged?
Columnar cells arranged in cords and clusters
What are the histological distinct characteristics of the cells in the zone glomerulsa?
Abundant sER lipid droplets
free ribosomes
What is the target and effect of the aldosterone that is produced by the zona glomerulosa?
i) Main target: distal convoluted tubule of the kidney
ii) Function: stimulate water balance, absorption of
sodium and excretion of potassium
What is the second layer of the adrenal cortex? What type of cells are present here? How are they arranged?
Zona fasiculata
Spongiocytes arranged i radial columns
What imparts the “foamy” appearance of the spongiocytes found in the zona fasiculata?
Lipids
What are the histological characteristics of spongiocytes?
Abundant SER, GA, mitochondria, lipofuscin pigment
What do the spongiocytes of the zona fasciculata produce?
Cortisol
Corticosterone
What is the function of cort and corticosterone?
Function in control of carbohydrate, fat and protein metabolism
What is Cushing’s syndrome the result of?
Results from small tumors of the basophils in the anterior pituitary gland. Tumors produce excess ACTH which over stimulates the suprarenal cortex (cortex enlarges) and produces excess cortisol.
Affected individuals become obese, impotent
What is the innermost layer of the adrenal cortex?
Zona reticularis
What type of cells are found in the zona reticularis? How are they arranged?
Intensely acidophilic, cells contain lipofuscin pigment
Cells form anastomosing cords
What are the two products formed by the zona reticularis?
(“weak”) androgens:
- Dehydroepiandrosterone
- Androstenedione
What type of cells is the adrenal medulla derived from? What type of cells is it now?
Neural crest cells
Is a modified sympathetic ganglion
What are the two cell types found within the suprarenal medulla?
Chromaffin cells
Sympathetic ganglion cells
What are chromaffin cells?
Modified neurons that form cord or clusters in the adrenal medulla
What do chromaffin cells synthesize?
Catecholamines
epi and nor epi
Chromaffin cells receive what nerve terminals?
Of preganglionic sympathetic neurons of splanchnic nerves
Where are the sympathetic ganglion cells of the adrenal cortex found? Where do they go?
In the CT of the medulla
send their axons to the cortex where they modulate cortical activity and innervate blood vessels
