Regulation of blood glucose

Question 1

What is the pancreas?

Answer 1

small organ below stomach, endocrine and exocrine functions

Question 2

What do the majority of cells in the pancreas do?

Answer 2

manufacture and release digestive enzymes, exocrine function, cells found in small groups surrounding tiny tubules into which enzymes are secreted

Question 3

What do the tubules in the pancreas join up to form?

Answer 3

pancreatic duct which carried fluid containing enzymes into first part of small intenstine

Question 4

What does the fluid that is carried by the pancreatic duct contain?

Answer 4

amylase (a carbohydrase), trypsinogen (an inactive protease), lipase, sodium hydrogencarbonate = makes fluid alkaline, helps neutralise contents of digestive system that have just left acidic condition of stomach

Question 5

What are the islets of Langerhans?

Answer 5

small patches of tissue that have an endocrine function, where alpha and beta cells are found

Question 6

What do alpha and beta cells secrete?

Answer 6

alpha: hormone glucagon, beta: hormone insulin

Question 7

What does the release of insulin and glucagon do?

Answer 7

insulin: causes blood glucose levels to go down
glucagon: causes blood glucose levels to rise

Question 8

What is the normal blood glucose concentration? What is blood glucose monitored by?

Answer 8

90 mg 100 cm-3 (90 mg in every 100cm3 of blood) or 4-6 mmol dm-3. cells in islets of Langerhans monitor

Question 9

What is a high glucose blood concentration detected by?

Answer 9

by beta cells, secrete insulin in blood, target cells: hepatocytes, muscle cells, some brain cells

Question 10

What happens when insulin binds to receptors on target cells?

Answer 10

activates adenyl cyclase inside each cell, converts ATP to cAMP = series of enzyme controlled reactions

Question 11

What are the effects that insulin has on a cell?

Answer 11

more glucose channels into cell membrane, more glucose enters cell, glucose in cell converted to glycogen to storage (glycogenesis), more glucose converted to fats and used in respiration: blood glucose reduced

Question 12

What is a low blood concentration detected by?

Answer 12

alpha cells, secrete glucagon, target cells: hepatocytes

Question 13

What are the effects of glucagon?

Answer 13

conversion of glycogen to glucose (glycogenolysis), use more fatty acids in respiration, production of glucose from amino acids and fats (gluconeogenesis): blood glucose increased