Histology of Endocrine Glands Flashcards
What are the physical properties of exocrine glands?
- Maintain continuity with surface e[ithelium,
- Have polarized cells with polarized secretions
- Lots of RER
What are the physical properties of endocrine glands?
- Lose contact with surface epithelium
- Non-polarized cells with non-polarized secretion
- Little RER
NOTE: The thyroid gland is one exception to this rule
Label
Label
Compare and contrast exocrine cell, peptide-secreting endocrine cells, and steriod- secreting endocrine cells.
Exocrine cell
- Secretion granules
- Golgi
- Nucleus
- Lots of RER
- basal lamina
Peptide-secreting endocrine cell
- Small secretions
- Capillaries
- Little RER
Steroid -secreting endocrine cell
- Stored lipid (non secretion granules_
- SER
- Capillaries
- Little RER
Location of the major endocrine glands of the body
Label
Label
Thyroid Follicle
How do warmth and cold regulate TSH secretion?
- Cold acts on the hypothalamus stimulating the release of TRF.
- TRF stimulates the anterior pituatary to release TSH
- TSH stimulates the thyroid to release free T3 and T4, causing you to feel warmth
- T3 and T4 then send negative feeback signals to the anterior pituatary and the hypothalamus to inhibit release of those hormones
What causes the eye to protrude in patient’s with Grave’s disease?
Edema behind the eye
NOTE: Grave’s disease is characteristic of hypersecretion of thyroid hormones
Why is low iodine associated with goiters?
If you don’t get enough iodine the thyroid gland will continously make thyroglobulin and will secrete that into the extracellular space but it will never make the complet hormone because of the lack of iodine. When the gland gets larger you get a goiter.
How do you distinguish between parafollicular cells (C cells) and follicle cells?
- C cells are larger and more lightly stained than follicle cells.
- C cells don’t touch the lumen
Label
Function of Calcitonin
- Reduces level of blood calcium
- Inhibits oseoclastic activity
Where is the parathyroid gland located?
Dorsal to the thyroid gland
Label
Label
What are the effects of PTH?
- Raises blood calcium levels
- Increased reabsorption of calcium in proximal convuluted tubules
- Stimulates osteoclastic activity
- Increased absorption of calcium from GI tract when calcium is present in the diet.
NOTE: PTH is secreted by the principal (chief) cells of parathyroid gland
The adrenal cortex is derived from ___________ and secretes __________. The adrenal medulla is derived from __________ and secretes _____________.
Mesoderm; steroid hormones
Neural crest; catecholamines
What are the three distinct layers of the adrenal cortex?
- Zona Glomerulosa
- Zona Fasciculata
- Zona Reticularis
Zona Glomerulosa (Images)
Zona Fasciculata (Images)
The cells of the zona fasciculata are termed _______.
Spongiocytes
NOTE: Lipid-filled cells are arranged in long rows between fenestrated capillaries.
What at the components of the lipid droplets found in spongiocytes?
- sER
- Cholesterol
- Mitochondria filled with tubular cristae
- Lipofusin
The zona reticularis (image)
Adrenal Medulla: The Chromaffin Reaction
Junction between Adrenal Medulla and Cortex
Islet of Langerhans
Cells of the islet of langerhan. What hormones are secreted by each?
- Alpha- Glucagon
- Beta- Insulin
- Delta- Somatostatin
- F Cells- Pancreatic polypeptide
Of the glucose transporters, which is insulin- independent?
GLUT-2
NOTE: GLUT2 transports glucose to insular cells and hepatocytes
________ is insulin-dependent and serves to remove glucose from blood.
GLUT2
What are the two types of diabetes and what are the characteristics of each?
-
Type I
- Juvenile onset
- Due to an autoimmune attack upon islets
-
Type II
- Adult onset
- Involves resistance of tissues to effects of insulin
NOTE: Type II diabetes is the leading cause of blindness, renal failure, and amputations
Label
Label
Label
NOTE: Sialic acid-rich carbohydrate groups on hormones account for both basophilia andPAS-reactivity
What cells of the anterior pituatary constitute as acidophils? What hormones are secreted by each?
-
Somatotrophs
- Growth hormone (GH)
-
Mammotrophs
- Prolactin
What cells of the anterior pituatary constitute as basophils? What hormones are secreted by each?
-
Thyrotrophs
- Thyroid-stimulating hormone (TSH)
-
Gonadotrophs
- Follicle-stimulating hormone (FSH)
- Luteinizing hormone (LH)
-
Corticotrophs
- Adrenocortitrophic hormone (ACTH)
- Melanocyte-stimulating hormone (MSH)
Where are MSH- secreting cells found?
In the pars intermedia
Which two cells of the anterior pituatary have the largest vesicles?
Components of the neural lobe of the pitutary
- Nerve terminals from vasopressin and oxytocin neurons
- Glia called pituicytes
Which hormones are found in the neurohypophysis?
-
Vasopressin
- Lack of vasopressin leads to diabetes insipidus
-
Oxytocin
- Stimulates milk release from the mammary gland
Herring bodies
Herring bodies are large amorphous nerve terminals
NOTE: Vasopressin is stored in herring bodies and when need is released. Oxytocin is found in a seperate set of terminal in the posterior lobe
Label
Exocrine pancreas
Label
Enzymes that digest proteins
–Trypsinogen (active form = trypsin)
–Chymotripsinogen (active form = chymotrypsin)
–Procarboxypeptidase (active form = carboxypeptidase)
