12. Endocrine system part 1 Flashcards
What are hormones?
Molecular signals released by specific cell types and influence other cells
What is the endocrine system?
Includes a variety of cell/tissues/organs that produce hormonal molecular signals
Why do cells communicate with each other?
They do so to maintain a stable internal environment
What is a target cell?
A cell that has a receptor specific for a specific hormone
What is a receptor?
A molecule that the hormone binds to and initiates a response
What is hormone activity?
Hormones are secreted into the interstitial fluid, pass into the blood then travel to the target cell
What is the name for hormones being released into the interstitial fluid?
Paracrine and autocrine activity
What is paracrine activity?
Hormone binds to receptors on nearby cell
What is autocrine activity?
Hormones bind to receptors located on the cell that secreted them
What are the three groups that hormones can be divided into?
Peptides or proteins, steroid hormones, amines
How do peptide hormones travel?
- Water soluble so easily transported in blood
- Packaged within vesicles in cells and secreted by exocytosis
How do steroid hormones get transported?
Lipid soluble so they can pass through cell membranes
- They are not stored in vesicles
- Secretion is regulated by regulating synthesis
- Diffuse out of cells and are bound to carrier molecules in blood
Where are steroid or lipid hormones made from?
Synthesised from steroid cholesterol
How do amine hormones get transported in the blood
-Can be water soluble or lipid soluble so mode of action differs
Where are amine hormones synthesised from?
Tyrosine (an amino acid)
What receptor type do each protein and steroid require?
Protein requires membrane bound receptors and steroid requires cytoplasmic receptors
What are the two types of glands in the body?
Endocrine and exocrine
What are endocrine glands?
Aggregation or collection of cells that secrete hormones
What are exocrine glands?
Have ducts that carry molecules to specific location
What is the target cells of hormones TSH Thyrotropin stimulating hormone?
Thyroid gland
What two parts is the adrenal gland divided into?
Outer cortex and inner medulla
What hormones are synthesised from the outer cortex?
cortisol, aldosterone
What hormones are released from the inner medulla?
Epinephrine and norepinephrine
What stimulates the release of epinephrine and norepinephrine
The brain
What is released in response to the fight or flight response?
Epinephrine and norepinephrine are released in response to stressful situations - telling the body to act
-The brain signals adrenal gland to release E and NE
What are some actions/effects of the fight or flight response?
- Heart beasts faster, blood pressure increases
- Divert blood flow to skeletal and cardiac muscles
- Liver cells break down glycogen and secrete glucose (energy)
- Fat cells release fatty acids (energy)
What are the target cells for the fight or flight response?
- Circulatory system
- Muscles
- Liver and Fat cells
What is the pituitary gland composed of?
Anterior and posterior pituitary
What is the name of the surgery used to remove a pituitary tumour?
Trans-sphenoid surgery
