Endocrine glands and hormones

zijanive's version from 2016-02-28 05:46

Section 1

Question Answer
What are hormonesSpecific signalling molecules that control the functions of cells, tissues, and organs in the body
How else could you describe hormonesAs chemical messenger molecules
How are hormones secreted(usually) from specialized endocrine glands directly into the blood stream
How do the hormones reach their site of action Hormones are carried in the blood to their target tissue
What is the difference between exocrine and endocrine secretionsExocrine glands secrete their products into a duct onto the surface of epithelium. Hormones secrete products into blood
When are hormones released In response to physiological systems

Section 2

Question Answer
Where do hormone molecules travel toSpecific target cells at some distance from site of release
What happens when hormones reach their destinationThey attach to specific receptor protein molecules in the target cell membrane or inside the target cell
What happens to the target cell once a hormone has reached itIt responds to the hormone signal
Which cells resond to a particular hormoneSpecific target cells
What are the specific target cells for secretinPancreatic endocrine cells
How do the pancreatic endocrine cells react to secretinThey respond by secreting water and bicarbonate ions into the duodenum
How are secretions delivered from the pancreasPancreatic secretions are collected in the pancreatic duct and transported directly to the duodenum (exocrine gland)

Section 3

Question Answer
Why can hormones only affect specific target cellsBecause all taraget cells have specific receptor protein molecules i.e. oxytocin - uterine muscle cells / IGF - liver cells / cortisol - adipose cells and liver cells
What is the purpose of hormone specifityIt allows different hormones to have different effects on the same target cell i.e. in the liver cotisol signals enzymes to breaks down glycogen while GF signals the release of IGF-1
What is hormone specificityFunctional orgnaization of endocrine system
What can vary the number of receptors expressed by a cellControl of differential gene expression
What is a ligand hormonebinds to specific protein receptors in cell membrane
How is speed of hormone delivery to target site (communication) determinedDepends of rate of blood flow and distance between endocrine tissue and target cells
How fast is neural signalling speed (synapse)Rapid. Speed of saltatory conduction in myelinated axons is about 100 m per sec