Query about insulin and different types of cell

[tim.tdj]

Hi

As I understand it in perhaps somewhat simplistic terms, cells can be divided into the following two broad types according to how they interact with energy:

Type 1. Energy-storage cells such as fat storage cells and liver glycogen storage cells which store energy.

Type 2. Energy-using cells such as brain cells and muscle cells which use energy to perform various functions including cell division.

I would like to gain some understanding of the differences between how insulin and possibly other hormones interact with different types of cell. I would therefore be very grateful to anyone who can answer the following 14 questions.

01. The two types of cell I have listed above can obviously be further subdivided into lots of different sub-types. Is there an overlap between Type 1 and Type 2 cells?

02. If I understand correctly, insulin acts as a "key" to a "doorway" in each cell which, when open, allows energy (usually in the form of glucose) to enter the cell and that these insulin "keys" respond to various hormonal instructions which depend on various conditions. Am I correct?

03. Am I correct in guessing that insulin is just one out of a range of different "keys" to different types of cell "doorways"?

04. Is insulin required to allow energy into every type of cell or just certain types of cell? If just certain types, which types?

05. I have read that insulin primarily responds to the level of glucose in the blood meaning that if it gets higher than the equilibrium amount, insulin gets activated. Is this correct?

06. What else, if anything, does insulin respond to?

07. When insulin is activated, is there a priority system for which type of cell receives the energy let in by the insulin or is it just randomly allocated? If there is a priority system, how does it work?

08. I am guessing that the "keys" which allow energy out of Type 1 cells in response to the level of glucose in the blood getting lower than the equilibrium amount are not insulin. Am I correct? If yes, what are these "keys"?

09. Is there a priority system for letting energy out of different sub-types of Type 1 cells? If yes, how does it work?

10. Whenever energy is released from liver glycogen storage cells, is it always released in the form of glucose?

11. Whenever energy is released from fat storage cells, is it always released in the form of non-glucose chemicals such as ketones?

12. Do non-glucose energy forms such as ketones require "keys" to be let in to cells? If yes, what are these "keys"?

13. Am I correct that "insulin resistance" is when the "lock" on a cell "doorway" gets broken as a result of overuse?

14. Can a non-glucose energy form such as a ketone get into an insulin resistant cell more easily than glucose?

Thank you very much.

Kind regards

Tim