Chapter 2 - ENDOCRINE SYSTEM Flashcards
Name all of the glands in the endocrine system
- Pineal Gland
- Hypothalamus
- Pituitary Gland
- Thyroid Gland
- Parathyroid Glands
- Thymus
- Adrenal Glands
- Kidneys
- Pancreas
- Gonad (uterus, testes, ovaries)
What are the two types of glands in the body
Exocrine and Endocrine glands
what are exocrine glands
Glands that secrete into a duct that carries the secretion to the body surface. Eg, Sweat glands, mucous glands, salivary glands.
What are endocrine glands
Glands that secrete hormones into the extracellular fluid that surrounds the cell making up the gland. Secretion transported by blood, also called ductless glands
How do hormones change the functioning of cells
by changing the type, activities or quantities of enzymes produced
how do hormones effect enzyme activity or concentration
- Activate certain genes in the nucleus so a particular enzyme is produced
- Change the shape or structure of an enzyme so it is turned ‘on’ or ‘off’
- Change the rate of production of enzyme by changing rate of transcription or translation
what cells do hormones effect
- All cells of the body
- Target Cells
- Target Organs
what are the three types of hormones
Steroids, Proteins or amines
What are steroid hormones
Lipid soluble (don’t dissolve in water) hormones that bind to transport proteins, enabling them to travel in the bloodstream. When they reach target cells, they seperate from the transport proteins and diffuse across cell membrane. Inside the cell they work by combining with a receptor in the nucleus. Steroid hormones are slow to have an effect but the effect is long lasting
What are four examples of steroid hormones
Oestrogen, progesterone, cortisol, aldosterone
What are protein and amine hormones
Protein and amine hormones are water soluble meaning they are unable to diffusion across the cell membrane The work by attaching to receptor proteins in the membrane of the target cell. the combination of the hormone with the receptor causes a secondary messenger to diffuse through the cell and activate particular enzymes. Protein and amine hormones are quick to cause a response however the effect is short lasting
explain hormone receptors
Receptor proteins are specific. Each type of receptor will bind with only one specific molecule. Lock and key analogy can be used. Saturation can occur, meaning once all the receptor molecules are occupied by hormone molecules, he addition of more hormones does not result in a greater effect
What is enzyme amplification
The hormone triggers a cascading effect in which the number of reacting molecules involved is increased hundreds or thousands of times. One hormones molecule does not cause the manufacture of just one enzyme.
what is hormone clearance
once a hormones had produced the required effect, it must be turned off. This is done by breaking down the hormone molecules. Some hormones are broken down in the target cells, but most are broken down in the liver and kidneys
what is a negative feedback system
Where the response produced by the secretion of the hormone is the opposite of the stimulus that causes the secretion.
