13. Endocrine System Flashcards
What does the pituitary do?
Coordinates the endocrine organs through feedback loops
What are the 2 functional components of the pituitary?
Posterior and Anterior Pituitary
What is the posterior pituitary?
Downward extension of hypothalamus
What is the neural tissue of the posterior pituitary?
Axons and glial cells
What does the posterior pituitary store/secrete?
Oxytocin and Antidiuretic hormones
Describe the anterior pituitary.
- Nested epithelial cells
- Richly vascular fibrous stroma
- Several different types of epithelial cell not distinguishable on H&E
What are the 5 anterior pituitary epithelial cell types?
- Somatotrophs
- Lactotrophs
- Corticotrophs
- Gonadotrophs
- Thyrotrophs
What do somatotrophs secrete?
Growth hormone
What do lactotrophs secrete?
Prolactin
What do corticotrophs secrete?
ACTH
Alpha-MSH
Beta-lipotrophin
Beta-endorphin
What do gonadotrophs secrete?
FSH and LH
What do thyrotrophs secrete?
TSH
Where are somatotrophs present?
Throughout the anterior pituitary gland, lateral wings of anterior pituitary
Describe lactotrophs.
- Polygonal cells
- Cytoplasmic processes wrap around other cells
- Variable prolactin staining
Describe thyrotrophs.
- Angular chromophobes
- Elongated cytoplasmic processes
- Variable TSH staining
Describe gonadotrophs.
Scattered round/oval cells
What do gonadotrophs stain with?
Alpha subunit, beta LH and beta FSH
Describe corticotrophs.
- Round basophilic cells
- Median of gland
- Large cytoplasmic vacuoles
What are the anterior pituitary supporting cells?
Sustentacular cells that surround normal follicles
Describe the pineal gland.
Pinealocytes in rosettes
Brain sand
What does the pineal gland secrete?
Melatonin
What are the epithelial cells of the thyroid?
Follicular cells and colloid cells that are richly vascular
The thyroid gland produces what?
Thyroxine and Calcitonin
What sits between the follicles in the thyroid gland?
C-cells
What are the 3 epithelial cell types of the parathyroid glands?
Chief cells, oxyphils and adipocytes
What does the parathyroid gland secrete?
Parathyroid hormone (PTH)
Describe the parathyroid chief cells.
- Polygonal cells
- Scant cytoplasm
What do the chief cells of the parathyroid gland do?
Raise serum Ca2+
Describe parathyroid gland oxyphil cells.
- Large polygonal cells
- Increase with age
- Abundant eosinophilic cytoplasm
- Finely granular
- Unknown function
What are Islets of Langerhans?
Balls of cells with a thin fibrous capsule mostly in the pancreatic tail
What are the 4 epithelial cells of the endocrine pancreas?
- Beta cells
- Alpha cells
- Delta cells
- PP cells
What do B cells produce?
Insulin
What do A cells produce?
Glucagon
What do D cells produce?
Somatostatin
What do PP cells produce?
Pancreatic polypeptide
What are the 3 epithelial parts of the adrenal cortex?
- Zona glomerulosa
- Zona fasciculata
- Zona reticularis
What does the zona glomerulosa produce?
Aldosterone
Describe the zona glomerulosa.
- Thin, incomplete
- Small cells
- Vacuolated cytoplasm
What does the zona fasiculate produce?
Cortisol
Describe the zona fasiculate.
- Most prominent
- Large polygonal cells
- Almost clear cytoplasm
What does the zona reticularis produce?
Androgenic steroids
Describe the zona reticularis.
- Innermost cortical layer
- Anastomosing columns of small polygonal cells
What epithelial cells are in the adrenal medulla?
Chromaffin cells
Describe the adrenal medulla.
- Centre of adrenal gland
- Large polyhedral
What is secreted from the adrenal medulla?
Adrenalin and noradrenalin
What is a phaeochromocytoma?
Rare malignant tumour of adrenal medulla
