Endocrine Sys. Flashcards
Define Endocrinology
the study of….
1. Endocrine Glands
2. Hormones secreted by these glands
3. Mechanisms of action of hormones
define hormone
A chemical which affects target cells or organs +
travels via blood
define homeostasis
to maintain equilibrium
define neuroendocrine system
when the nervous + endocrine sys. work together
What are the major differences between the endocrine system and the nervous system?
endocrine sys:
- controls body activities by
releasing mediator molecules = hormones
- results = within secs + effects = last a long duration of time
nervous sys:
- controls body actions
through nerve impulses
- results + effects = brief
What is the difference between an exocrine gland and an endocrine gland?
- endocrine = secretes products into bloodstream
- exocrine = secretes products into ducts
What does the term infundibulum mean?
is the pituitary stalk which is how the pituitary gland is attached to the hypothalamus
what is the major integrating center for the pituitary gland?
hypothalamus
Name the 5 cell-types in the anterior pituitary
- somatotrophs
- thyrotrophs
- gonadotrophs
- lactotrophs
- corticotrophs
what hormone is secreted by somatotrophs
Growth hormone (GH)
what hormone is secreted by thyrotrophs
Thyroid-stimulating hormone (TSH)
what 2 hormones are secreted by gonadotrophs
- Follicle-stimulating hormone (FSH)
- luteinizing hormone (LH)
what hormone is secreted by lactotrophs
Prolactin (PRL)
what 2 hormones are secreted by corticotrophs
- Adrenocorticotrophic hormone (ACTH)
- melanocyte-stimulating hormone (MSH)
How is secretion of the hormones of the anterior pituitary regulated?
through the hypophyseal portal system
where does the blood supply to the pituitary gland come from?
the superior hypophyseal arteries
What are the 2 hormones of the posterior pituitary?
- Vasopressin (is like ADH)
- Oxytocin
what cells secrete the posterior pituitary hormones ?
pituicytes = supporting neurosecretory cells
What is the hypophyseal portal system?
is a portal system that allows regulated hormones from the hypothalamus to specifically reach the anterior pituitary
Vasopressin function =
antidiuretic = helps retain/absorb H2O in body
Oxytocin function =
stimulate uterine muscles (ex = for contraction during childbirth)
what is a portal system?
it is a vein or artery
between two capillary beds, that is used to divert blood
supply for a specific purpose or to a specific location
What 2 cell-types are present in the thyroid gland?
- Parafollicular (C cells)
- Follicular cells (principal cells)
What hormones do Follicular cells secrete?
- thyroxine (T4)
- triiodothyronine (T3)
What hormone do C cells secrete?
calcitonin
what makes the thyroid hormones T4 and T3?
thyroglobulin
What hormone is secreted by the parathyroid gland?
Parathyroid hormone
parathyroid hormone function =
regulates the homeostasis of
calcium and phosphate
what are the 3 different zones present in the adrenal cortex?
- zona glomerulosa (outer)
- zona fasciculata (middle)
- zona reticularis (inner)
What hormones are secreted by the zona glomerulosa?
secretes mineralocorticoids
What hormones are secreted by the zona fasciculata ?
secretes glucocorticoids
What hormones are secreted by the zona reticularis?
secretes androgens (DHEA)
what is a mineralocorticoid?
aldosterone
what is a glucocorticoid?
cortisol
What hormones are secreted by the adrenal medulla?
epinephrine (Epi) +
norepinephrine (NE)
what 4 cells are present in the islets of Langheran (in the pancreas) ?
- Alpha cells
- Beta cells
- Delta cells
- F cells
what hormone do alpha cells produce?
glucagon
what hormone do beta cells produce?
insulin
Which Pancreatic Islet cell-type is present in the highest number?
beta cells (70%)
what can be classified as both an endocrine and an exocrine gland
pancreas
what hormone do delta cells produce ?
somatostatin
what hormone do F cells produce ?
pancreatic
polypeptide
What hormone is secreted by the pineal gland?
melatonin
What functions have been attributed to this hormone?
- responsible
for setting biological clock - involvement in jet lag
- involvement in seasonal
affective disorder (SAD)
what kind of feedback is glucagon + insulin regulation?
negative feedback
Low blood glucose stimulates release of ?
glucagon
High blood glucose stimulates secretion of ?
insulin
