lecture 6- endocrine regulation, insulin secretion

Question 1

beta cell vs alpha cells

Answer 1

beta cells secrete insulin to regulate increased glucose levels while alpha cells regulate decrease glucose by secreting glucagon

Question 2

pancreas

Answer 2

organ that secretes insulin. it lies along the small intestine. it undertakes an exocrine function (secrete digestive enzymes- langerhans). secretes enzymes that have been digested from the stomach.

Question 3

type 1 diabetes vs type 2 diabetes

Answer 3

type 1:autoimmune, the body attacks itself, their beta cells are destroyed
type 2:metabolic. still have beta cells but is not regulated properly.

Question 4

parts of the pancreas without relation to glucose regulation

Answer 4

most of the pancreas secretes digestive enzymes (exocrine). it processes, secretes digestive enzymes. the green part with the duct exiting into the small intestine- food goes from stomach to intestine which stimulates secretion of digestive enzymes. this has nothing to do with glucose regulation.

Question 5

islet of lagnerhans

Answer 5

flower like structure surrounding the green part of the pancreas. they surround the pancreas and we have about 3 million. they are composed of multiple different cells. they are mostly made up of beta cells.

Question 6

beta cells

Answer 6

primarily makes up islets of langerhans. this and other cells work together to secrete insulin and glucagon to regulate glucose.

Question 7

beta cells as a centre point to release insulin

Answer 7

beta cells can respond to glucose, amino acids and hormones (GLP1). when you eat, the beta cells just sit in your body and take up all the glucose. this increase in glucose stimulate beta cells, increasing production of insulin.

Question 9

somastotatin

Answer 9

inhibits release of hormones fro different organs including the pancreas

Question 10

stimulus secretion coupling in a beta cell (how beta cells respond to glucose to detect that its too high)

Answer 10

glucose enters though GLUT 2 transporter-always there so the beta cell can always sense glucose.
2 it undergoes a normal process of metabolism through the mitochondria and generate ATP. KATP channel (potassium channel) detects production of ATP and switches off. - because we now have a more negative charge because of the increased ATP in the cell, KATP channels closed to make it more positive (combined with another channel) and to allow depolarisation and thus entry to CA2 and release of insulin. the calcium channel opens as it becomes more positive and calcium enters. this triggers diffusion of insulin containing granules in the membrane and when it fuses, it goes out of the cell- this works because proteins that bind the insulin granule to the membrane which are calcium sensitive- calcium attaches to this and the cell changes it confirmation, binding to the membrane (fuses). the inulin is secreted. calcium. this response takes about a minute, quite slow. after a while though, the cell go down again to a more negative and then go up again after a while, giving pulses of insulin secretion we don’t yet understand.
1. GLUT 2 transporter
2. metabolism.
3 ATP
4. Kate channel closure
5. depolarisation
6 calcium chanel opens
7. increase amount of calcium
8. insulin is secreted

Question 11

Hormone GLP1

Answer 11

GLP 1 is secreted by cells lining the gut which detect contents in the gut eg. changes in calcium. The GLP 1 goes into the circulation and around the body. the first target is the beta cells, espclifically the cAMP in beta cells. This stimulates insulin secretion.results into many thing, act on exocytosis, calcium channels, and gene transcription. this however by itself does not stimulate insulin secretion. we can only do this by adding glucose. this gives us more impact/more insulin production.

Question 12

type 1 diabetes

Answer 12

almost no beta cells, no insulin response. Their alpha cells get damaged. The modal age for getting diabetes are 12 yea old- problem of kitoacidosis- not really true. Its an autoimmune disease. The beta cells are not recognised and are treated as foreign. We generate antibodies (auto antibodies like GAD). This is the first stage. After a while, we trigger the T cells which specifically target Beta cells. This process takes about 2-3 years.

Question 13

symptoms of type 1 diabetes

Answer 13

Weight loss
Fatigue
Frequent urination: blood glucose is too high, that gets filtered in the kidneys, thus having an osmotic effect and leading to higher volume of urine.
Excessive thirst

Question 14

treatment of type 1 diabetes

Answer 14

Insulin injection: identify where your blood glucose level is which will determine how much insulin you need.
T1D: continuous glucose monitor reads out your glucose levels. You can detect your glucose levels throughout the day and its history. This ensures that you can accurately determine your glucose levels and accurately identify how much they need.

Question 15

type 2 diabetes

Answer 15

Not an autoimmune disease. Muscles, fat and liver cannot respond to insulin as they should. This means they dont have enough sugar and their ancreas also cannot keep up with making a good amount of glucose.

Question 16

symptoms of type 2 diabetes

Answer 16

Symptoms:
Slow healing wounds
Constant hunger
Frequent urination
Blurred vision
Unexplained weight loss
Numbness of hands and feet