Endocrine System Flashcards
(79 cards)
What are hormones?
Chemical messengers that are secreted from one cell, travel through the bloodstream and affect another cell in another part of the body.
What does endocrine communication enable?
Enables homeostasis and cellular activities to be coordinated throughout the body
What is the general process of endocrine communication?
Stimulus –> Hormone release from endocrine cell and into the blood –> hormone binds to a specific receptor in a distant cell –> distant cell responds to stimulus
What are hormones made of?
- Amino acids (proteins)
- Cholesterol (lipid)
How do amino acids travel through the blood?
Amino acids are water soluble so they travel in blood unbound because they are soluble
How does cholesterol travel through the blood?
Cholesterol is fat soluble so travel in blood bound to carrier proteins because they are insoluble
How do hormones have specific effects?
Hormones only bind to receptors specifically designed to receive it
What happens to the hormone once it has served its purpose?
It is removed, broken down and recycled or excreted in sweat and urine
How can you detect hormones in sweat?
Non-invasive, skin patches
How can you determine pregnancy through urine?
By detecting Human Chorionic Gonadotrophin (hCG) in the urine
What is the chemical classification of water soluble hormones?
Proteins, peptides and some amines (catecholamines eg. adrenaline)
What is the chemical classification of lipid soluble hormones?
Steroids and some amines (thyroid hormones)
Where are the receptors for water soluble hormones located?
Plasma membrane receptors. Can’t cross through the lipid based membrane
Where are the receptors for lipid soluble hormones located?
Intracellular receptors (in cytosol or nucleus). Once they become unbound to the carrier protein they can go right through the cell.
How do water soluble hormones work in the cell to produce an effect?
Activation of 2nd messengers to amplify hormone response
How do lipid soluble hormones work in the cell to produce an effect?
Alternation of gene transcription (to make new proteins)
How long does it take for water soluble hormones to initiate a response?
Fast - the effects last milliseconds to seconds)
How long does it take for lipid soluble hormones to initiate a response?
Slow - the effects last hours to days
What is an example of a water soluble hormone?
Example: Adrenaline (fast, short-acting response to stress)
- Anti diuretic hormone
- Oxytocin
- Insulin
What is an example of a fat soluble hormone?
Example: Cortisol (slow, long-lasting response to stress)
- Estrogen
- Progesterone
- Testosterone
What is the connection between the hypothalamus and the posterior pituitary gland?
Axon connection
Where are the posterior pituitary hormones made?
In the hypothalamus then travel down axons and stored in axon terminals
Action potentials cause hormone release from posterior pituitary
What is the connection between the hypothalamus and the anterior pituitary?
Blood vessel connection. (two hormones)
One hypothalamus hormone and one anterior pituitary hormone
What is anterior pituitary hormone secretion influenced by?
Releasing/inhibiting hormones made in the hypothalamus travel through the bloodstream to release or inhibit release of anterior pituitary hormones.