Endocrine System Flashcards
Function of the endocrine system
secrete messenger substances (hormones)
Hormones may be comprised of:
proteins
peptides
cholesterol derived steroids
amino acid derivatives
Endocrine cells have 3 possible anatomical distributions:
- endocrine cells gather in a single specialized organ to form an ENDOCRINE GLAND
- endocrine cells for discrete clusters in a specialized organ
- endocrine cells disperse singly amongst other cells in epithelial tissues DIFFUSE NEUROENDOCRINE SYSTEM
Example of endocrine glands (4)
pituitary
thyroid
parathyroid
adrenals
example of clusters of endocrine cells
pancreas - Islet of Langerhans
ovary
testis
Examples of diffuse neuroendocrine system
gastrointestinal tract
respiratory system
T/F - supporting tissue lacks vasculature
FALSE - rich in vasculature to facilitate rapid dissemination of hormones into blood stream
Two anatomical parts of the Pituitary Gland
Anterior Pituitary (Adenohypophysis) –> Dark staining
synthesizes hormones
Posterior Pituitary (Neurohypophysis) –> Light staining
stores and secretes hypothalamic hormones
Components of anterior pituitary
pars distalis - most of anterior pituitary
pars intermedia - less defined in humans
pars tuberalis - layers/extension of anterior pituitary that surrounds the neural stalk of the hypothalamus
5 Cell types & their function
Somatotrophs (GH - growth hormone)
Mammotrophs (prolactin)
Corticotrophs (corticotrophin - ACTH - adrenocorticotrophic hormone)
Thyrotrophs (thyrotropin - TSH - thyroid-stimulating hormone)
Gonadotrophs (FSH - follicle-stimulating hormone, LH - luteinizing hormone)
Pituitary Portal System
Low oxygen, high nutrients
Network of capillaries from GIT to liver
Posterior Pituitary
Continuation of hypothalamus, comprised of axons of neuronal cells (unmyelinated)
Supporting glial cells in the posterior pituitary
Pituicytes
Where is the Islet of Langerhans located?
Pancreas - endocrine function
cord and clump organization
lighter staining than the rest of the pancreas
4 cells in the pancreas & what they release
B (beta) cells - Insulin (70%)
A (alpha) cells - Glucagon (20%)
D (delta) cells - Somatostatin (5-10%)
PP-cells - Pancreatic Peptide (1-2%)
Three layers of the Adrenal Cortex
Zona Glomerulosa - secretes mineralocorticoids (aldosterone)
Zona Fasciculata - secretes glucocorticoids (cortisol)
Zona Reticularis - secretes androgenic steroids (DHEA - dehydroepiandosterone) (DHEA-S - dehydroepiandosterone-sulfate) and some glucocorticoids
GFR, Salty Sweet Sex
Hyperadrenalism
excess secretion of glucocorticoids
Crushing’s syndrome
excess secretion of mineralocorticoids
Conn’s syndrome
Hypoadrenalism
hormones of the cortex are not secreted
could be due to cellular destruction
Addison’s disease
What controls the adrenal medulla
sympathetic nervous system
Type 1 Diabetes
Begins early in life; childhood/adolescence
Islet and Beta cells are destroyed (viral infection. autoimmune disease)
Inability to regulate carbohydrate metabolism
HYPERGLYCEMIA
treatment - insulin
Type 2 Diabetes
Occurs later in life, young are also affected
Cells become resistant to insulin
Islet and Beta cells are still able to produce insulin
Treatment - lifestyle modifications, some drugs
Enterochromaffin cells
secretion of motilin, gherlin and serotonin
VIP
vasoactive inhibitory peptide
