W5 - Endocrine System Flashcards
Why is the pituitary gland considered the ‘master gland’?
It can control the function of multiple other endocrine glands
When staining the pituitary gland with H+E, which lobe of the PG stains darker?
Anterior PG
How does the PP lobe and APG form from tissue growths?
PP lobe - downgrowth of nervous tissue from hypothalamus, APG - upgrowth from roof of primitive oropharynx
What controls the pituitary gland?
The hypothalamus
What 5 HMs produced by the PG act on non-endocrine tissues?
GH, ADH, PRL, OT, MSH
What 4 HMs act on endocrine tissues?
TSH, ACTH, FSH and LH
What are the thyroid, adrenal and gonad glands referred to as?
Pituitary-dependent endocrine glands
THe PP lobe releases ADH and OT, where are these synthesised?
ADH - supraoptic nucleus, OT - paraventricular nucleus
ADH and OT pass down the axons of the ??? within the pituitary stalk
Hypothalamo-hypophyseal tract
Where are ADH and OT stored and what controls their release?
The axon terminals, nerve impulses from HT
What wraps around the infundibular stalk?
Pars tuberalis
What are Herring bodies?
Clusters of neurosecretory
The APG has 3 divisions, what are these?
Pars distalis, intermedia and tubularis
What is the difference between PP lobe and APG?
PP - only stores HMs, no production, APG - can produce and secrete HMs
The APG have two main cell types, when staining with H+E, which stains darker and which stains lighter?
Darker - chromophils, Lighter - chromophobes
What are the two types of chromophil cells?
Acidophils and basophils
THe pars intermedia is derived from remnants of Rathke’s pouch and is located between the AP and PP, what cells is it composed of?
Basophilic cells
What does the pars intermedia consist of?
Cysts filled with colloid that are lined by cuboidal epithelium
What controls the thyroid gland and what two hormones are produced/secreted by the HT and by the APG?
The hypothalamus, thyrotropin releasing HM (HT) and thyroid stimulating HM (APG)
What is the spheroidal, basic unit of a thyroid gland and what type of epithelium lines these?
Follicle, cuboidal epithelium
Follicles are filled by colloid, what divides the thyroid gland into lobules?
Fibrous sepate
What are the two major HMs that are produced by the thyroid gland? (And what is another minor HM produced?)
T3 and T4 (Calcitonin for Ca2+ homeostasis)
T3 and T4 regulate metabolic functions, what are the 3 things that they can do?
Controls how quickly the body burns energy, makes proteins and how sensitive the body is to other HMs
When the thyroid gland is inactive, what happens to the follicles and epithelial cells?
Follicles - stain darker (colloid containing), epithelial cells become flattened
When the thyroid gland is active the epithelial cells become taller and the follicles stain paler with scalloped edges, why does it stain paler?
More cytoplasm is produces alongside the colloid
Calcitonin is produced by parafollicular C cells, how are these seen?
Small clumps in between follicles
Calcitonin is the physiological antagonist of parathyroid HM, what does it do?
Lowers blood calcium
Parathyroid glands are thin and closely related to the posterior surface of the thyroid, what two cells are found in the parathyroid gland?
Chief cells and oxyphil cells
Chief cells are small with dark nuclei, what is the difference between the cytoplasm of chief cells and of oxyphil cells? (+ what do they do?)
Chief - pale (secrete PTH), oxyphil - very pink (not secretory, mainly just structural)
What is the main function of parathyroid HM?
Regulate levels of calcium, phosphorus and magnesium
