Endocrine System Flashcards
Paracrines
-Chemical substances secreted by all cells
-Can diffuse to adjacent cells (move through the extracellular fluid), which allows cells to communicate with other cells within the same tissue.
Hormones (endocrine)
-Secreted by specialised cells and transported through the bloodstream
-They are only able to influence cells that have the correct receptor for the hormone (specific)
Whare can hormone receptors be described as?
Specific, targeting certain cells
exocrine (gland)
Secrete substances into a duct that carries the secretion to the body surface or to one of the body cavities
Exocrine Gland examples
Sweat glands, mucous glands, salivary glands, glands of alimentary canal
Endocrine (gland)
Secrete hormones into the extracellular fluid that surrounds the cells that make up the gland.
The hormone then travels into the capillaries to be transported by the blood.
Can be described as ductless.
Receptor proteins on target cells are what?
-Specific to a particular hormone
-Each type of receptor will bind to only one specific hormone
-However more than one type of receptor may be affected by multiple hormones on a target cell
PAWSL
Protein/Amine are Water Soluble while Steroid hormones are Lipid soluble
Steroid Description
Lipids derived from cholesterol
Steroid Properties
Lipophilic- Can cross membrane
Undergoes constitutive secretion
Steroid Examples
Testosterone
Estrogen/Progesterone
Peptide Description
Short polypeptide chains
Protein Amine vs Steroid contrast/table
Powerpoint slide 11 and 12 Endocrine 1
Or alternatively make flashcards on
(table comparing mode of action)
learn mode of action for both and how to draw
Peptide properties
Hydrophilic- Cannot cross membrane
Undergoes regulatory secretion
Peptide Examples
Insulin and glucagon
Amine Description
Derived from aromatic amino acid
Amine Properties
Hydrophilic- Cannot cross membrane
Undergoes regulatory secretion
Amine Examples
Thyroxine
Homeostasis
-The process of keeping the environment inside the body fairly constant.
-This is known as a steady state and operates (fluctuates) within a set of tolerance limits.
-Coordination of homeostasis is controlled by the endocrine and nervous system
Endocrine system purpose
influences the activity of cells by the release of chemical messengers called hormones.
How do hormones affect cells
By changing the type, activities or quantities of proteins produced influencing metabolic activity
Enzyme Amplification
-One hormone molecule does not cause the manufacture or activation of just one molecule of an enzyme- it activates thousands of molecules
-Results in small stimulus producing very large effect
Saturation
+what it results in
-When all receptor molecules are occupied by hormone molecules
-Results in hormone affect stagnating
Hormone Clearance
-Once a hormone has produced the required effect it must be turned off
-The hormone molecules are broken down either in the target cell (some) or in the liver and the kidneys (most)
-Degraded hormones are then excreted in the bile or urine.
Reminder to check out atar questions and review stuff
BET CHAT
