The Endocrine Pancreas- control of metabolism and biochemistry Flashcards
Energy intake (food) is controlled by the balance of which two hypothalamic centres?
Feeding centre
Satiety centre
What does the feeding centre do?
Promotes the feelings of hunger and drive to eat
What does the satiety centre do?
Promotes feeling of fullness by supressing the feeding centre
Which centre is sensitive to insulin?
Satiety centre
Which peptide hormone is released by fat stores and depresses feeding activity?
Leptin
What are the three classes of energy output?
Cellular work
Mechanical work
Heat loss
Metabolism?
Integration of all biochemical reactions in the body
What are the three elements of metabolism?
- extracting nutrients from food
- storing that energy
- utilising that energy for work
Anabolic pathways?
Higher bio :)))
Build up- synthesis of larger molecules from smaller ones
Often for storage purposes
Catabolic pathways?
Higher bio again :)))
Break down- degradation of large molecules into smaller
Releases energy in process
After eating, we enter an absorptive state. What does this mean?
Ingested nutrients supply the energy needs of the body and the excess is stored
Is the absorptive state an anabolic or catabolic phase?
Anabolic
Between meals and overnight, we enter a post-absorptive state where we rely on body stores to provide energy. Is this stage an anabolic or catabolic phase?
Catabolic
Most cells can use carbs, fats or protein for energy but which part of the body ca only use glucose?
Brain
Therefore, in the post-absorptive state, even though no new carb are gained, blood glucose conc. must remain sufficient to meet needs to brain.
What ay occur if there is low blood glucose?
Hypoglycaemia which can lead to coma and death
How are blood glucose levels maintaned?
By synthesising glucose from glycogen (glycogenolysis) or amino acids (gluconeogenesis)
What is a normal blood glucose level?
4.2-6.3 but tends to be remembered as 5mM
At which blood glucose level will result in hypoglycaemia?
< 3mM
Blood glucose is maintained over a fairly tight range regardless of what we eat or do due to which two endocrine hormones?
Insulin
Glucagon
Where are insulin and glucagon produced?
Pancreas
Which process allows the creation of glucose from amino acids?
Gluconeogenesis
Which process breaks down glycogen stores?
Glycogenolysis
Glycogenolysis
and gluconeogenesis are both stimulated by which hormone?
Glucagon
-> when the glucose is ‘gon’- thanks Mr Page xx
Is glucagon catabolic or anabolic?
Catabolic
-> breaks down glycogen
->stimulates liver to create new glucose from amino acids
Which hormone raises blood glucose?
Glucagon
Which hormone lowers blood glucose?
Insulin
Is insulin an anabolic or catabolic hormone?
Anabolic
When is the only time there will be glucose in the urine?
When there is no insulin as it’s the only hormone that reduces BG levels
->those w diabetes may have glucose in urine so if a GP suspects diabetes, urine tests will be done
The pancreas is a mixed endocrine and exocrine gland but does it have more endocrine or exocrine secretions?
Exocrine
->99% exocrine as releases enzymes to support digestion
Where are the hormones produced in the pancreas?
Islets of Langerhans
What are the four types of Islets of Langerhans?
Alpha cells
Beta cells
Delta cells
F cells
What do alpha cells produce?
Glucagon
What do beta cells produce?
Insulin
What do delta cells produce?
Somatostatin
What do F cells produce?
Pancreatic polypeptide
What happens when insulin is dominant over glucagon?
Glucose is taken up by cells from plasma so BG decreases
What happens when glucagon is dominant over insulin?
Glucose released into plasma from stores so BG increases
