Endocrinology Flashcards
what is the definition of an endocrine organ? An exocrine gland?
Endocrine organ:
Secretes to the inside of the body (via blood)
Exocrine gland:
Secretes to the outside of the body (must have
ducts, convey secretions to a free surface of the
body)
What are the 4 structural types of hormones? Give an example of each
- Proteins & peptides
a. Aldosterone
b. cortisol - Steroids
a. Estrogens
b. androgens - Amino acids derivatives
a. Derived from amino acids tryptophan & tyrosine - Fatty acid
a. Prostaglandins
b. prostacylins
3 types of exocrine glands and their mechanism of secretion
- Holocrine
- secretory products in its cytoplasm and then die and disintegrate
- sebaceous gland in the skin
- Merocrine
- Secretions are excreted via exocytosis from secretory vesicles opening into a gland’s lumen and flowing through a duct and then onto a free surface of the body
- apocrine
- : intermediate, because their secretions gather at the outer ends of the gland cells and then pinch off to form the secretions
What part of the brain is specifically involved in the endocrine system? What 7 hormones does is produce? What organ is its primary target?
- Hypothalamus
- 7 hormones:
a. Corticotropin (CRH)
b. Thyrotropin (TRH)
c. Growth hormone (GHRH)
d. Gonadotropin (GnRH)
e. Prolactin (dopamine)
f. somatosatin
g. Prolactin releasing hormone (PRH) - pituitary gland
which endocrine gland is the master gland?
Pituitary gland –> “master gland”
the two main divisions of the pituitary gland?
Adenohypophysis (anterior pituitary)
i. Classic gland
Neurohypophysis (posterior pituitary)
ii. Extension of the hypothalamus
iii. Forms the infundibulum
iv. Pars nervosa
what 2 hormones does pars nervosa secrete?
- Oxytocin
- Vasopressin
what are the 3 subdivisions of the adenohypophysis?
- Pars distalis
- Pars intermedia
- Pars tuberalis
what are the 3 types of cells found in pars distalis? What are their characteristics and what do they produce?
- Acidophils (pink)
a. Growth hormone (aka somatotropin)
b. Prolactin - Basophils (purple)
a. Thyroid stimulating hormone
b. Follicle stimulating hormone
c. Luteinizing hormone
d. Adrenocorticotrophic hormone - Chromophobes (unstained)
a. Minimal hormonal content
what hormone does pars intermedia secrete?
melanocyte stimulating hormone (MSH)
what are the two types of cells in the pineal gland? What hormone does the pineal gland secrete?
- Pinealocytes
- Astrocytes
- Secretes melatonin
what are the 3 zones of the adrenal cortex and what are their functions?
- Zona glomerulosa
a. Region of “little globes”
b. Cells forms small arches of cells
c. Thin, outermost zone
d. Secretes: mineralocorticoids (aldosterone) - Zona fasciculata
a. Where cells form more regular rows
b. “bundle of sticks”
c. Largest of the 3 zones
d. Forms foamy appearance
e. Secretes glucocorticoids (cortisol) - Zona reticularis
a. Cells lose their regularly arrangement
b. Rows are separated by irregular channels like the sinusoids in the liver
c. Secretes the sex steroid hormones (androgens)
What is the primary cell type of the adrenal medulla and what does it secrete?
- chromaffin cell is the primary cell type
- Produce catecholamines
a. Epinephrine
b. norepinephrine
what innervates the adrenal medulla?
Directly innervated by the autonomic nervous system
what is the only endocrine organ that stores its product extracellularly?
Thyroid gland
