Chapter 18 Flashcards
(32 cards)
What is the function of the endocrine system?
Coordinates the function of body systems along with the nervous system
What do exocrine glands secrete through ducts on epithelial surfaces
Usually enzymes that aid in digestion and lubrication
What do endocrine glands usually secrete
Hormones for regulating the metabolism
What are hormones?
Chemical messengers that interact with specific cells to stimulate physiological changes
What is the cell that contains a specific receptor site for a specific hormone
A target cell
What is a paracrine hormone
A type of local hormone that is secreted by cells then diffuse to nearby cells and tissues
In what direction do true endocrine hormones travel
Away from the site of release to stimulate other tissues.
This contrasts local hormone secretion
What type of hormone interacts with receptors of the cell that originally released it
Autocine hormones
How can a cell become more sensitive to stimulation
Through “Up-regulation” which increases the number of hormone receptors
How can a cell become less sensitive to stimulation
Through “Down-regulation” which reduced the amount of hormone receptors
What is a synergistic effect
When two or more hormones act together to produce a greater effect than one by itself
What is it called when one hormone opposes the action of another hormone
The antagonistic effect
How are hydrophobic hormones transported in the blood
Via various proteins through the plasma membrane
What are the steps of hormone-cell interaction with lipid soluble hormones
- The hormones diffuse across plasma membrane
- Once inside, the hormone interacts with specific receptor sites that usually initiate transcription
- The new proteins create a physiological change
What are the steps to water soluble hormone interaction with target cells
- The primary messenger interacts with the receptor site on the outer surface of the plasma membrane
- The signal is relayed to the inner surface of the plasma membrane
- The signal activates the enzyme Adenylate Cyclase
- Adenylate Cyclase converts ATP to cyclic AMP which is the secondary messenger
- cAMP activate enzymes that activate physiological changes
- cAMP is deactivated by Phosphodiesterase
What is the primary control center for the autonomic nervous system
The hypothalamus
What attaches the hypothalamus to the pituitary gland
The infundibulum
What are 4 effects that growth hormones have on the body
- Increases cellular uptake of amino acids and protein synthesis
- Increases lipid catabolism (breaks down triglycerides
- Increases glucose utilization
- Stimulated kidneys to resort electrolytes
Overall GH increases bone and muscle growth
What are 3 conditions that come with over or under active GH hormone production
- Giantism
- Acromegaly (over production after closure of major growth plates)
- Dwarfism
What hormones are created by the pituitary gland and what is needed for their production
T3 (Triiodothyronine) and T4 (Thyroxine). These hormones require iodine and tyrosine for their production.
What causes Cretinism
hyposecretion of T3 and T4 at birth
What are signs of Cretinism
- infant has cool, yellowish skin
- thick tongue
- if untreated, this can lead to mental retardation
What is Hypersecretion and what are the signs
An autoimmune disorder in which antibodies are produced that mimic the action of TSH, over-stimulating the production of T3 and T4
- signs include an enlarged Thyroid gland (goiter), exophthalmos (bulging eyes), increased activity
What are the two hormones produced in the Pancreas
a.Insulin - produced by Beta cells
- stimulates cells to absorb glucose and amino acids, also stimulates glycogen synthesis
b.Glucagon - produced by Alpha cell
- stimulates the breakdown of glycogen and triglycerides which increases the blood glucose level
