Endocrine Flashcards
The endocrine system involves the release of chemical transmitter substances known as __ .
• These substances regulate and integrate body functions by acting on local or distant target sites.
• Hormones are generally produced by the endocrine glands but may also be produced by specialized tissues such as those found in the __, __, __
• Chemicals such as neurotransmitters (e.g., __) released by the nervous system can also function as hormones when needed.
hormones
gastrointestinal (GI) system, the kidney, and white blood cells.
epinephrine
Glands of the Endocrine System
• The endocrine system is composed of the (7)
• Most hormones secreted from endocrine glands are released directly into the __.
• However, __ glands, such as ,__ glands, secrete their products through ducts onto epithelial surfaces or into the GI tract.
pituitary gland, thyroid gland, parathyroid glands, adrenal glands, pancreatic islets, ovaries, and testes.
bloodstream
exocrine
sweat
Function and Regulation of Hormones
• Hormones help regulate organ function in concert with the __
• The __ action by the nervous system is balanced by hormonal action.
• The endocrine glands are composed of secretory cells arranged in minute clusters known as __.
• A ___ provides a vehicle for the hormones produced by the endocrine glands to enter the bloodstream rapidly.
• In the healthy physiologic state, hormone concentration in the bloodstream is maintained at a relatively __ level.
• To prevent accumulation, these hormones must be __ continuously by a __ so that when the hormone concentration increases, further production of that hormone is inhibited.
nervous system
rapid
slower
acini
rich blood supply
constant
inactivated
negative feedback system
Hormones are classified into four categories according to their structure:
- amines and amino acids
- peptides, polypeptides, proteins, and glycoproteins
- steroids
- fatty acid derivatives
- amines and amino acids (e.g., __,__, __);
- peptides, polypeptides, proteins, and glycoproteins (e.g., __,__,__)
- steroids (e.g., __; which are hormones produced by the __ or their synthetic equivalents)
- fatty acid derivatives (e.g., __,__)
epinephrine, norepinephrine, and thyroid hormones
thyrotropin-releasing hormone [TRH],
follicle-stimulating hormone [FSH], and growth hormone [GH]);
corticosteroids,
adrenal cortex
eicosanoid, retinoids
Some hormones act locally in the area where they are released; this is called ___
(e.g., the effect of __).
paracrine action
sex hormones on the ovaries
Others may act on the actual cells from which they were released; this is called
(e.g., the effect of __).
autocrine action
insulin from pancreatic beta cells on those cells
Hormones can alter the function of the target tissue by interacting with __ located either on the cell membrane or in the interior of the cell (e.g. __ or __ for peptide and protein hormones).
___, because of their smaller size and higher lipid solubility, penetrate cell membranes and interact with intracellular receptors.
chemical receptors
cyclic AMP or the “second messenger”
- Steroid hormones
• Releasing and inhibiting hormones
• Controls the release of pituitary hormones
HYPOTHALAMUS
Hypothalamus hormones (4)
Corticotropin-releasing hormone (CRH)
Thyrotropin-releasing hormone (TRH)
Growth hormone–releasing hormone (GHRH)
Gonadotropin–releasing hormone (GnRH)
Anterior pituitary hormone
Give 5
Somatostatin
Adrenocorticotropic hormone (ACTH)
Follicle-stimulating hormone (FSH)
Luteinizing hormone (LH)
Prolactin
• Inhibits growth hormone and thyroid-stimulating hormone
Somatostatin
• Stimulates synthesis and secretion of adrenal cortical hormones
Adrenocorticotropic hormone (ACTH)
• Female: stimulates growth of ovarian follicle, ovulation
• Male: stimulates sperm production
Follicle-stimulating hormone (FSH)
• Female: stimulates development of corpus luteum, release of oocyte, production of estrogen and progesterone
• Male: stimulates secretion of testosterone, development of
interstitial tissue of testes
Luteinizing hormone (LH)
• Prepares female breast for breast-feeding
Prolactin
Posterior pituitary hormone
Adh
• Increases water reabsorption by kidney
Antidiuretic hormone (ADH)
ADRENAL CORTEX hormones 2
Mineralocorticosteroids, mainly aldosterone
Glucocorticoids, mainly cortisol
__
• Increase sodium absorption
• potassium loss by kidney
__
• Affect metabolism of all nutrients;
• regulates blood glucose levels,
• affects growth,
• has anti-inflammatory action, and
• decreases effects of stress.
Mineralocorticosteroids, mainly aldosterone
Glucocorticoids, mainly cortisol
THYROID (__)
Thyroid hormones: 2
FOLLICULAR CELLS
triiodothyronine (T3), and thyroxine (T4)
• Increase the metabolic rate;
• increase protein and bone turnover;
• increase responsiveness to catecholamines;
• necessary for fetal and infant growth and development
Thyroid hormones: triiodothyronine (T3), and thyroxine (T4)
Lowers blood calcium and phosphate levels
Calcitonin
THYROID C CELLS hormone
Calcitonin