Endocrine System Flashcards
What system controls body activities by releasing mediators(hormones)?
Endocrine system
What mediator molecule is released in one part of the body but regulates activity of cells in other parts of the body?
Hormone
What are the 2 kinds of glands?
Exocrine and Endocrine glands
All glands are made up of what type of tissue?
Epithelial tissue
What type of gland secrete their products into ducts and carry secretions into body cavities, into lumen of an organ, or to the outer surface of the body?
Exocrine glands
What type of gland secrete their products (hormones) into the interstitial fluid surrounding the secretory cells rather than into ducts?
Endocrine glands
What glad includes: pituitary, thyroid, parathyroid, adrenal, and pineal glad?
Endocrine gland
(T/F) The hypothalamus, thymus, pancreas, ovaries, testes, kidneys, stomach, liver, small intestines, skin, heart, adipose tissue, and placenta contain cells that secrete hormones.
True - these organs and tissues are not exclusively classified as endocrine glands
All endocrine glands and hormone-secreting cells constitute what kind of system?
Endocrine system
The science of the structure and function of the endocrine glands and the diagnosis and treatment of disorders of the endocrine system.
Endocrinology
What type of cells for a given hormone have receptors that bind and recognize that hormone?
Target cells
Hormones, like neurotransmitters, influence their target cells by chemically binding to specific protein _________.
Receptors
If a hormone is present in excess, then number of target-cell receptors may decrease. What is this effect called?
Down-regulation - target cell is less sensitive to a hormone
When a hormone is deficient, the number of receptors may increase. What is this phenomenon known as?
Up-regulation - target cells more sensitive to a hormone
(T/F) Synthetic hormones that block the receptors for some naturally occurring hormones are available as drugs.
True - RU486 used to induce abortion
Most endocrine hormones that pass from the secretary cells into interstitial fluid and then into the blood.
Circulating hormone
Other hormones that act locally on neighboring cells or on the same cell that secreted them w/o first entering the bloodstream.
Local hormones
Local hormones that act on neighboring cells.
Paracrine
Local hormones that act on the same cell that secreted them
Autocrines
(T/F) Local hormones usually are inactivated quickly.
True
(T/F) Circulating hormones are inactivated quickly.
False - they may linger in the blood in a few minutes or hours
In time, circulating hormones are inactivated by the _______ and excreted by the _______.
Liver; kidneys
What are the 2 chemical classes of hormones?
1) Lipid-soluble hormones
2) Water-soluble hormones
What are the 3 lipid-soluble hormones?
1) Steroid hormones
2) 2 thyroid hormones
3) Gas nitric oxide (NO)
What are the 3 water-soluble hormones?
1) Amine hormones
2) Peptide hormones and protein hormones
3) Eicosanoid hormones
How do most water-soluble hormones circulate?
In the watery blood plasma in “free” form
How most lipid-soluble hormones travel?
Bound to transport proteins
Where are the receptors for lipid-soluble hormones located?
Inside target cells
Where are the receptors for water-soluble hormones located?
Part of the plasma membrane of target cells
Hormone secretion is regulated 3 ways.
1) Signals from the nervous system
2) Chemical changes in blood
3) other hormones
What is the “master” of the pituitary gland?
Hypothalamus
What is the small region of the brain below the thalamus is the major link between the nervous and endocrine systems.
Hypothalamus
Cells of the hypothalamus synthesize at least _____ different hormones, and the pituitary gland synthesizes at least _____
9; 7
What do the hypothalamus and pituitary gland regulate?
Growth, development, metabolism, and homeostasis
What gland lies in the hypophyseal fossa of the sella turcica of the sphenoid bone?
Pituitary gland
The pituitary gland attaches to the hypothalamus by a stalk called?
Infundibulum
What gland was once called the “master” endocrine gland?
Pituitary gland or hypophysis
What are the 2 anatomically and functionally separate portions of the pituitary gland?
Anterior and posterior pituitary
What are the 2 parts of the anterior pituitary?
- pars distalis
- pars tuberalis
What are the 2 parts of the posterior pituitary?
- Pars nervosa
- Infundibulum
(T/F) the posterior pituitary accounts for about 75% of the total weight of the gland.
False - it’s the anterior pituitary.
Releasing of anterior pituitary hormones is stimulated by _____ ________ and suppressed by ________ _________ from the hypothalamus.
Releasing hormones; inhibiting hormones
Hypothalamic hormones reach the anterior pituitary through a ________ ________
Portal system
As part of the hypophyseal portal system, what branches of internal carotid arteries and brings blood into the hypothalamus?
Superior hypophyseal arteries
What are the 5 anterior pituitary cells?
1) Somatotrophs (hGH - human growth)
2) Thyrotrophs (TSH - thyroid stimulating hormone)
3) Gonadotrophs (FSH - follicle-stimulating hormone)
4) Lactotrophs (PRL - prolactin - milk production)
5) Corticotrophs (ACTH - adrenocorticotropic hormone - cortisol)
What are the 2 ways the anterior pituitary hormones are regulated?
1) Neurosecretory cells
2) Negative feedback
What is the most numerous cells in the anterior pituitary?
Somatotrophs
What is the most plentiful anterior pituitary hormone?
Human growth hormone (hGH)
The main function of hGH is to promote synthesis and secretion of small protein hormones called ______ ________ _______.
Insulin growth factors (IGFs)
