Chapter 18: The endocrine system Flashcards
What is a hormone?
is a molecule that is released in one part of the body but regulates the activity of cells in other parts of the body.
How do hormones enter the blood?
Most hormones enter interstitial fluid and then the bloodstream.
What is an exocrine gland?
secrete their products into ducts that carry the secretions into body cavities
What is an endocrine gland?
secrete their products (hormones) into the interstitial fluid surrounding the secretory cells rather than into ducts
What do molecules do in the endocrine system?
Hormones delivered to tissues throughout body by blood.
What does site of action mean in the endocrine system?
Far from site of release (usually); binds to receptors on or in target cells.
What type of target cells are associated with the endocrine system?
Cells throughout the body.
What does time to onset of action in the endocrine system mean?
Seconds to hours or days
What is the duration of action for the endocrine system?
generally longer (seconds to days)
Hormones influence target cells by binding to a specific protein ____________
receptors
Only the _________ cells for a given hormone have
receptors that bind and recognize that hormone
target
What is the down-regulation of target cell receptors?
When there is an excess of target cells receptors in the blood so the body decreases the sensitivity of the receptors
What is the up-regulation of target cell receptors?
When there is less of target cells receptors in the blood so the body icreases the sensitivity of the receptors
Most endocrine hormones are _________hormones—they pass from the secretory cells that make them into interstitial fluid and then into the blood
circulating
What is a local hormone?
They act only on neighboring cells
Local hormones that act on neighbouring cells are called?
Paracrines
Local hormones that act on the same cell that secreted them are called__________?
autocrines
Local hormones usually are __________quickly
inactivated
Circulating hormones may linger in the blood for how long
a few minutes or occasionally for a few hours
What are the two types of hormone classes?
Lipid-Soluble Hormones
&
Water-Soluble Hormones
The lipid-soluble hormones include what hormones? there are 4
steroid hormones
thyroid hormones
nitric oxide
eicosanoid hormones
The water-soluble hormones include what hormones? there are 3
amine hormones
protein
peptide hormones
What is a steroid hormone?
Steroid hormones are a group of hormones derived from cholesterol that act as chemical messengers in the body.
What are the two types of thyroid hormones?
T3 and T4
What is a thyroid hormone?
The thyroid gland produces hormones that regulate the body’s metabolic rate, growth and development.
What is an eicosanoid hormone?
Eicosanoids are lipid-based signalling molecules that play a unique role in innate immune responses.
Is a steroid hormone lipid-soluble or water-soluble?
Lipid
Is thyroid hormone lipid-soluble or water-soluble?
lipid
Is nitric oxide hormone lipid-soluble or water-soluble?
lipid
Is eicosanoid hormone lipid-soluble or water-soluble?
lipid
Is amine hormone lipid-soluble or water-soluble?
water
Is a peptide hormone lipid-soluble or water-soluble?
water
Is protein hormone lipid-soluble or water-soluble?
water
What are the two ways that hormones can transport?
Free form
and
binding to transport proteins
What is the Mechanism of action of the lipid-soluble steroid hormones and thyroid hormones?
Lipid-soluble hormones bind to receptors inside target cells.
What is the mechanism of action of the water-soluble hormones?
Water-soluble hormones bind to receptors embedded in the plasma membranes of target cells.
