A 19-year-old with type 1 diabetes comes in for a routine check-up. Where in the islets of Langerhans is the root of her condition?
(A) the β cells, which should be centrally located; patients with type 1 diabetes do not produce enough insulin
You realize that you have not eaten in six hours. In the image, what cell in the islets of Langerhans is working overtime?
(B) the α cell, which should be peripherally located; it produces glucagon because of your fasting state
The zona glomerulosa of the adrenal gland is regulated by _____ and secretes _____.
The zona fasciculata of the adrenal gland is regulated by _____ and secretes _____.
Adrenocorticotropic hormone and hypothalamic corticotropin-releasing hormone; cortisol and sex hormones
The zona reticularis of the adrenal gland is regulated by _____ and secretes _____.
Adrenocorticotropic hormone and hypothalamic corticotropin-releasing hormone; sex hormones (eg, androgens)
The adrenal medulla is primarily regulated by (parasympathetic/sympathetic) fibers and is composed of (chromaffin/chromophobe) cells.
The most common tumor of the adrenal medulla in adults is _____, whereas in children it is _____.
What are the effects of pheochromocytomas and neuroblastomas on blood pressure?
Pheochromocytomas cause episodic hypertension whereas neuroblastomas do not
What mnemonic helps you remember the three layers of the adrenal cortex and their corresponding products?
Zona Glomerulosa (salt), Zona Fasciculata (glucocorticoids), Zona Reticularis (sex hormones): GFR corresponds to salt, sugar, and sex ("the deeper you go, the sweeter it gets")
Trace the blood flow from the left adrenal gland to the inferior vena cava.
Left adrenal gland to the left adrenal vein to the left renal vein to the inferior vena cava
Trace blood flow from the right adrenal gland to the inferior vena cava.
Right adrenal gland to the right adrenal vein to the inferior vena cava
Which gonadal vein drains directly into the inferior vena cava: the right or the left?
Right gonadal vein
Embryologically, the posterior pituitary is derived from the _____, whereas the anterior pituitary is derived from the _____.
Neuroectoderm; oral ectoderm
What does the posterior pituitary gland secrete?
Vasopressin (antidiuretic hormone) and oxytocin
Where are the secretory products of the posterior pituitary formed?
In the hypothalamus
What are the secretory products of the anterior pituitary?
Follicle-stimulating hormone (FSH), luteinizing hormone (LH), adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), Prolactin, growth hormone (GH), and melanotropin (remember: FLAT PiG)
Which pituitary hormones have a common alpha subunit?
Thyroid-stimulating hormone, luteinizing hormone, follicle-stimulating hormone, and human chorionic gonadotropin
What is the clinical significance of the shared subunit of thyroid-stimulating hormone, luteinizing hormone, follicle-stimulating hormone, human chorionic gonadotropin?
At high enough concentrations, a given hormone can partially activate the receptor of another hormone with the same a subunit
What is the significance of the subunit of pituitary hormones?
It determines the hormone specificity of thyroid-stimulating hormone, luteinizing hormone, follicle-stimulating hormone, and human chorionic gonadotropin
Which hormones are secreted from acidophilic cells?
Growth hormone, prolactin
Which hormones are secreted from basophilic cells?
Basophils secrete follicle-stimulating hormone (FSH), luteinizing hormone (LH), adrenocorticotropic hormone (ACTH), and thyroid-stimulating hormone (TSH) (remember: B-FLAT)
What cell types are found in the islets of Langerhans?
, , and δ endocrine cells
In the islets of Langerhans, α- endocrine cells are located _____ and secrete _____.
In the islets of Langerhans, β- endocrine cells are located _____ and secrete _____.
Centrally; insulin (remember: INSide INSulin)
In the islets of Langerhans, δ endocrine cells are located _____ and secrete _____.
Where are islets of Langerhans most numerous?
In the tail of the pancreas
From what embryonic structures do the islets of Langerhans arise?
-Cells in the pancreas make insulin in response to what cellular process?
Increased glucose metabolism increases adenosine triphosphate, which closes potassium channels and depolarizes the cell
What effect would a -cell potassium channel blocker have on the release of insulin?
Increased insulin release, because potassium channel closure depolarizes the β-cell
Insulin release from -cells is increased by (opening/closing) potassium channels and (opening/closing) calcium channels.
What is the effect of insulin on -cells of the pancreas?
Insulin inhibits glucagon release
What is the effect of insulin on electrolyte (Na+, K+) handling?
Insulin increases Na+ retention by the kidneys and shifts K+ into cells
What effects does insulin have on glucose, protein, and lipid production and storage?
Insulin increases glucose transport into cells, increases glycogen and triglyceride synthesis and storage, and increases protein synthesis in muscles
Which cells require insulin for glucose uptake?
Skeletal muscle and adipose have glucose transporter type 4 (insulin-responsive) glucose transporters (remember: Insulin moves glucose Into cells)
Which cells do not need insulin for glucose uptake?
BRICK L: Brain, RBCs, Intestine, Cornea, Kidney, and Liver
Which cells have glucose transporters type 1?
Red blood cells and brain cells have glucose transporters type 1, which do not require insulin for glucose uptake
Which cells have bidirectional glucose transporters?
Those with glucose transporters type 2 channels: islet cells, liver, kidney
What causes the exocytosis of insulin from -cells?
The influx of calcium, following depolarization of the cell by potassium channel closure
What makes adipose and skeletal muscle dependent on insulin for glucose uptake?
They have insulin-responsive glucose transporters type 4
Why are red blood cells and the brain not dependent on insulin for glucose uptake?
They have insulin-independent glucose transporters (glucose transporter type 1)
What does the brain use for metabolism under starvation states?
Ketones made by the liver
What do red blood cells use for metabolism under starvation states?
Glucose; red blood cells only have the glycolysis pathway to make adenosine triphosphate; thus, they cannot use ketones like the brain in starvation states