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In this IBDP Biology blog post, we will look at teh emchanisms of blood sugar concentration and how hormones aid to regulate the system.
Insulin and Glucagon
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4979856/725447_935160.png)
Both hormones produced and secreted by pancreas
- These regulate blood glucose levels
- When you eat glucose is absorbed into the blood stream in the capillary beds of the villi of the small intestine increasing blood glucose level
- Works by negative feedback
- In the intestinal villi, glucose travels to hepatic portal vein which takes the blood to the liver
- Hepatic portal vein is the only blood vessel that has large fluctuations in bgl
- Hepatocytes (in the liver) processes the glucose and are triggered by insulin and glucagon
- Beta cells in the pancreas sense an increase/decrease in glucose
If BGL goes above:
- Insulin opens protein channels in cell plasma membrane; allows glucose to diffuse into cell by facilitated diffusion
- Insulin also stimulates the hepatocytes to take in glucose and convert it to glycogen; glycogen stored as granules int he cytoplasm of the hepatocyte; same thing happens in the muscles
If BGL goes below:
- glycogen made and stored by liver is needed in the body
- alpha cells of pancreas begin to produce and secrete the hormone glucagon
- glucagon stimulates hydrolysis of the granules of glycogen stored in hepatocytes and muscle cells; hydrolysis produces the monosaccharide glucose
- glucose enters blood
Diabetes
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4979856/887760_259794.png)
- characterized by hyperglycemia (high blood glucose)
- Cause: Type1 due to immune system destroying beta cells of the pancreas and do not produce sufficient insulin
- Type 2: caused by body cell receptors that do not respond to insulin people with untreated diabetes have sufficient glucose in their body but not in the body cells
- Treatment: Type1 controlled by injections; Type2 due to controlled diet
- untreated: damage to the retina, blindness, kidney failure, nerve damage, risk of cardiovascular disease, poor wound healing
That's all you need to know for the functions of insulin and glucagon!
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_60/4979856/100915_833944.gif)
References:
- https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.sciencephoto.com%2Fmedia%2F729986%2Fview%2Ftype-1-and-2-diabetes-illustration&psig=AOvVaw3_sVv7g_Q-XnD6rHZbqfuY&ust=1626326474652000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCPiS37Lo4fECFQAAAAAdAAAAABAD
- https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.123rf.com%2Fphoto_31016050_stock-vector-type-2-diabetes-labeled-diagram.html&psig=AOvVaw1TU2U3Z7naRgs1xTwVtQY_&ust=1626326465727000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCPi_r73o4fECFQAAAAAdAAAAABAD
Drafted by Venetia (Biology)