Chapter 14- Hormonal Communication Flashcards
Define an endocrine gland
Is a group of cells that are specialised to secrete chemicals- these chemicals are known as hormones directly into the bloodstream
Structure of adrenal gland
Adrenal cortex
Adrenal medulla
What are the hormones produced by the adrenal cortex?
Glucocorticoids-regulate metabolism and how body converts fats,proteins and carbohydrates to energy. Also helps regulate blood pressure. Another glucocorticoid is corticestrone which suppresss inflammatory response
Mineralcorticoids- Main one produced is alderstone which controls blood pressure
Androgens-Small amounts of male and female sex hormones are produced
Hormones realeased by adrenal medulla
Adrenaline-Increases HR sending blood quickly to the muscles and brain. It also rapidly increases blood glucose concentration by converting glycogen to glucose.
Noradrenaline-Produces effects such as increasing HR, widening of pupils
When are hormones in adrenal medulla released?
When body is stressed released from sympathetic nervous system
Histology of the pancreas
Islets of langerhans lightly stained large spherical clusters
Pancreatic acini darker stained small berry like clusters
Function of islets of langerhans
Contains two types of cells
Alpha cells- secrete glucagon
Beta cells- secrete insulin
How to increase blood glucose conc
Diet- eat carbohydrate rich foods, they are broken down to release glucose
Glycogenlysis- break down glycogen to glucose which is released into the bloodstream
Gluconeogenesis- production of glucose from non carbohydrate sources. For example liver is able to make glucose from glycerol and amino acids
How can blood glucose be decreased?
Respiration
Glycogenesis- production of glycogen
How insulin lowers blood glucose conc?
Increasing rate of absorption of glucose by cells
Increasing respiratory rate
Increasing rate of glycogensis
Increasing rate of glucose to fat conversion
Inhibits release of glucagon by alpha cells
What is negative feedback?
Ensures that in any control system, changes are reversed and returned back to the set level
How does glucagon raise blood glucose concentration
Glycogenlysis
Reducing amount of glucose absorbed by liver cells
Increasing gluconeogensis
How is insulin secretion controlled?
In resting state potassium ions diffuse out of the cell
However when blood glucose levels increase, glucose enters the cell via a glucose transporter resulting in the production of ATP. The ATP binds to the potassium channel and causes them to close.
As potassium ions can no longer diffuse out the potential difference increases to -30 mv. This is known as depolarisation and causes Ca2+ channels to open. Which causes the vesicles to release insulin by exocytossi
Type 1 diabetes
Unable to produce insulin
The beta cells do not produce insulin
Type 2 diabetes
Cannot effectively use insulin and control their blood sugar
