Unit 5 - Hormonal Communication Flashcards
Exocrine gland
A gland that secretes their products into a duct that carries the molecule to where they are used
Endocrine gland
A ductless gland that secretes hormones directly into the blood
Examples of endocrine glands
Pituitary
Adrenal
Pancreas
Examples of exocrine glands
Mammary
Gastric
Salivary
Pancreas
Why is the pancreas both endo/exocrine?
Releases hormones e.g. insulin and glucagon directly into the blood stream but also releases digestive enzymes e.g. trypsin into ducts
What does the pituitary gland secrete?
ACTH: Adrenocorticotrophic hormone. FSH: Follicle-stimulating hormone LH: Luteinising hormone. GH: Growth hormone. PRL: Prolactin. TSH: Thyroid-stimulating hormone. Oxytocin ADH: Anti-diuretic hormone
What does the adrenal gland secrete?
Adrenaline Androgens Aldosterone Cortisol Noradrenaline
Name the two types of hormones?
Lipid soluble hormones (steroid hormones)
Peptide hormones
What are steroid hormones derived from?
Cholesterol
Hormones released by cortex of adrenal glands
Mineralocorticoids
Glucocorticoids
Androgens
Vital to life e.g. cortisol and aldosterone
What do mineralocorticoids do?
Help control the conc. of minerals e.g. aldosterone
What do glucocorticoids do?
Help control the metabolism of carbs and proteins
What is the role of the Adrenal Medulla?
Manufacture and release non- essential hormones e.g. dopamine and adrenaline
Why must hormone target cells have SPP receptors on their cell surface membrane?
So that the correct hormone can bind and no other molecule will be able to bind and have the same effect
First vs. second messengers
1st bind to cell surface membrane and have an effect by activating a 2nd messenger, this is what actually affects the activity of the cell
Why are steroid hormones able to enter the cell?
Interacts with phospholipid bilayer and dissolve as they are lipid soluble
How do hormones act as secondary messengers?
Hormones bind to spp cell surface receptor
Stimulates production of a messenger molecule e.g. cAMP
cAMP activates or inhibits enzyme pathways
How do hormones act as gene activators?
Hormone permeates any membrane
Binds to intracellular receptor
Hormone-receptor complex is mobilised toward nucleus
Complex binds to spp regions of DNA
Leads to increase/decrease in translation -> protein synthesis
Endocrine part of the pancreas
Islets of Langerhans
alpha cells secrete glucagon
beta cells secrete insulin
Secretes INTO bloodstream
Exocrine part of pancreas
Pancreatic acini
Secretes digestive enzymes INTO DUCT which drains into the pancreatic duct which empties in duodenum
What does insulin act on?
Hepatocytes
Muscle cells
Adipose tissue
Brain cells
When is insulin secreted?
When blood glucose concentration is too high