Intorudction To The Endocrine System Flashcards
Homeostasis definition?
Regulation of the bodies internal environment so that it can work at its best.
What are the basic principles by which homeostasis works?
A sensor detects deviation — the control centre sends a signal to the — effectors which changes the variable back to its original — this is detected by the sensor and then switched off.
What is autocrine signalling?
Cell signalling where a cell secretes a chemical messenger which binds to receptors on the same cell and triggers a response in that cell
Paracrine signalling?
Cell signalling where a cell secrets a chemical messenger which travels between cells over a very short distance and not via the blood. It binds to the receptor on the other cell and triggers a response.
Endocrine signalling?
Cell signalling where a cell secretes a hormone that travels via the blood to the target organ/cell and attaches to receptors here and triggers a response.
What is a hormone?
A molecules that acts as a chemical messenger and travels via the blood stream.
What are the three types of hormones?
A.a.
Peptide
Steroid
What is an a.a. Hormone and how does it function?
A hormone that has been synthesised from the a.a. Tyrosine
Does not contain a chain of a.a unlike a peptide hormone.
Hydrophilic - dissolves in water/blood
They produce a rapid response.
A.a hormones are also pre-made in the cell and stored in cell ready to be released when needed. The hormone then dissolves in the blood And attaches to an outside receptor on the target cell.
What is a peptide hormone and how does it function?
A hormone that varies in size and contain a peptide chain, some also have a CHO side chain.
They are also hydrophilic and produce rapid responses.
They are pre-made and stored and then released when needed. They dissolve in the blood and travel quickly to the target cell where they attach to cell surface receptors.
What is a steroid hormone and how does it function?
A hormone that as been made from cholesterol. Diffferent enzymes modify cholesterol to produce different hormones.
They can’t dissolve in water, but can dissolve in lipids.
Made by cell and diffuses out straight away. They are transported in the blood blind to transport proteins as they don’t dissolve. They enter the target cell and attach to receptors inside.
They therefore produce a slow response.
Name 5 x different endocrine glands…
Hypothalamus Pituitary Adrenals Testis Thyroid
What is positive feedback?
What is negative feedback?
Positive feedback = when the end product of an action causes more and more of that action to occur. Oxytocin in contractions during labour.
Negative feedback = when the end result of an action inhibits that reaction from continuing to occur. Deviation from a set point…
