Unit 1A Flashcards
What are true hormones?
-chemical signaling molecules secreted by ductless gland
How are true hormones transported
They are transported through the blood they exit the gland, diffuse into intestinal space, and are then transported
How do true hormones work?
The responsive target cells contain specific hormone receptors on plasma membrane or inside cell and then hormone binding triggers a response
What can true hormones do to the cell?
-cause changes in ionic membrane permeability
-can inhibit or trigger enzymatic activity
- can activate or inhibit specific genes
What kind of cells can true hormones target?
Cells and tissues that are far away as long as they have receptors on membrane or within cell
What are examples of true hormones?
-thyroid hormones
-growth hormones
What are local hormones?
Signaling molecules that don’t circulate in blood
What are the two types of local hormones?
autocrine and paracrine
What are autocrine hormones?
Hormones that effect same cell where the messenger was formed (binds to the same cell it was released from)
What are paracrine hormones?
Hormones that effect neighboring cells
What are examples local hormones?
eicosanoids and prostaglandins
What are eicosanoids?
a primary type of local hormone formed with fatty acids within the phospholipid bilayer of the membrane
What are prostaglandins?
- A diverse group of widely released eicosanoids that are synthesized by most tissues in the body.
- most stimulate pain, fever, and inflammation by increasing the inflammatory response.
What are NSADS
Medicine that interferes with prostaglandins by inhibiting their formation,
What are similarities between true and local hormones?
-both are signaling molecules that must bind to a receptor to cause a response
What are the three ways hormones can be secreted?
-humoral stimulation
-hormonal stimulation
- nervous stimulation
What is hormonal stimulation?
When a gland releases its hormone in response to another hormone binding to it causing a cascade effect
What are examples of hormonal stimulation?
-t3
-t4
-tsh
How does TSH work?
-the anterior pituitary releases TSH which binds to the thyroid gland stimulating it to release TH (brain, blood, thyroid gland)
What is humoral stimulation?
when a hormone is released in response to changes in blood levels of a nutrient like glucose or ion like calcium
What is a prime example of humoral stimulation?
Blood glucose levels?
How is blood sugar regulated
-through a negative feedback loop
- blood glucose levels increase stimulating the pancreas to release insulin, and released insulin causes blood sugar to go down
What is nervous stimulation?
When a hormone is released in response to direct nervous stimulation