Hormones as Chemical Regulators Flashcards
U4L2 (8 cards)
What are hormones?
Hormones are chemical regulators that are produced by cells in one part of the body and effect cells in another part of the body.
Endocrine hormones are produced by glands (like the pituitary) and are secreted into the bloodstream.
How do the Endocrine and Nervous systems work together?
Nervous system = Quick adjustment to change
Endocrine system = maintains control over a longer duration
What are the two types of hormones?
Steroid and Protein hormones
What are steroid hormones?
Steroid hormones are primarily made up of lipids (sterols). These include sex hormones and cortisol.
They are made up of C-H-O rings and can pass through the bilipid layer of the cell membrane.
They can combine with hydrophilic carrier proteins to form water-soluble complexes, for
transport in the blood.
How does a steroid hormone function?
The hormone (Cortisol) diffuses through the bilipid layer. Once the Cortisol enters the cytoplasm, it binds to a receptor molecule to form a hormone-receptor complex.
This H-R receptor then moves to the nucleus and attaches itself to a segment of the DNA.
The receptor behaves as an inhibitor and enabler. It could send messages to the ribosome in the cytoplasm to either start or stop the production of proteins.
What are protein hormones?
Protein hormones are hormones/molecules that are typically composed of amino acid chains.
Examples of them include insulin & growth hormones.
They function by combining with receptors on the cell membrane.
They are also water soluble and diffuse well in blood.
How does the protein hormone function?
The hormone protein binds to a receptor on the cell membrane. The receptor molecule then changes shape which activates and signals the hormone-receptor complex to enter the cell.
Changes in the cell such as the production of enzymes and proteins can then be activated or deactivated.
How do hormones work in the case of a negative feedback loop?
Hypothalamus sends a thyroid-releasing hormone which is received by the pituitary.
Pituitary sends a thyroid stimulating hormone which gets received by the thyroid. The thyroid releases the desired hormones.
Once enough hormones are released, the thyroid hormones inhibit the pituitary from releasing TSH which stops the production of the hormone until it is needed.
