Pancreas Flashcards
(27 cards)
Describe role of pancreas:
Release digestive enzymes
~~>amylase, protease, lipase
Control blood glucose levels
State the difference between exocrine glands and endocrine glands?
Exo –> release chemicals into a duct
Endo –> releases hormones into blood stream
What is the pancreatic acini?
Exocrine tissue
Darker stain
Small berry-like clusters
Produce = secrete digestive enzymes
Goes to pancreatic duct —> duodenum
What are the Islets of Langerhans
Endocrine tissue
Lightly stained
Large spherical clusters
Produce + secrete hormones
Capillaries –> transport hormones in blood stream
What are the two types of cells in the Islets of Langerhans?
Alpha cells –> produce glucagon
~~>increase blood glucose level
(larger)
Beta cells –> produce insulin
~~> decrease blood glucose levels
Regulated by negative feedback
Describe glycogenesis?
Converting glucose to glycogen
Describe gluconeogenesis?
Converting amino acids + glycerol to glucose
Describe glycogenolysis?
Converting glycogen to glucose
What is the value for normal blood glucose levels?
90mgcm-3 of blood
What causes blood glucose levels to rise?
Intake of food
~~> carbs broken down = glucose released
Gluconeogenesis
Glycogenolysis
What causes for blood glucose levels to decrease?
Exercise
~~> glucose used in respiration
Fasting
Glycogenesis
What happens when blood glucose levels rise?
Beta cells –> release insulin
Target liver + most body cells
Decrease levels of glucagon released by alpha cells
Increase of glucose uptake into cells (skeletal muscle cells=)
Increased respiration rate
Increase conversion of glucose to fat
Increases glycogenesis
What happens when blood glucose concentrations decreases?
Alpha cells release glucagon
Target liver + fat cells
Increases glycogenolysis
Decrease glucose intake into cells
Increase rate of gluconeogenesis
Why is it important we maintain our BGL at normal levels?
BGL –> affect WP gradient of cells
Too high = more water leaves via osmosis –> dehydrated
Too low -= more water enters via osmosis –> cell lysis
Both cases = disrupt concentrations of other chemicals in cell
Inability to do this = diabetes
What happens to a beta cell when there are normal levels of glucose?
Resting potential = -70mV
Potassium channels =open
~~> K+ diffuse out of cell
V-gated Ca 2+ channels = closed
What happens to a beta cell when there are high levels of glucose?
(6 marks)
Glucose transporters move glucose into B cells.
Mitochondria metabolises glucose (aerobic respiration) –> release ATP.
High ATP level within beta cell cause K+ channels to close
~~> stops K+ moving out of the cell
Leads to build up of K+ inside beta cell
—-> depolarisation of cell membrane (-30mV)
Causes V-gated Ca2+ channels to open –> influx of Ca2+
Secretory vesicles within insulin move + fuse with plasma membrane —> exocytosis
What is diabetes?
Inability to metabolise glucose properly
hyper/hypoglycaemia
What is Type 1?
B cells cannot make insulin
Cause = unknown
Autoimmune response to B cells
What is Type 2?
B cells = not enough insulin
Cells not sensitive to insulin
Causes:
*Obesity
*Bad diet
Glycoprotein insulin receptor = malfunctioning
What are the treatments for Type 1 diabetes?
Insulin injection
Pancreas transplant
Stem cell therapy
What are the treatments for Type 2 diabetes?
Regulate carb intake
Regular exercise
Drugs
Insulin injection
Why is bacteria GM to make human insulin?
Higher yield –> easy to grow bacteria
Purer insulin –> lower risk of allergy
Cheaper
No religious/ethical concerns
Why was GM of bacteria used?
Problems with pig insulin:
–> Allergy
–> Religious
–> Problems with purification.
What issues arise from Type 1 diabetes treatment?
Transplant:
–> Rejection
–> Low organ availability
Hard to inject B cells
