Unit 2 Chapter 2

Biomedical 2.1.5

Positive Feedback

Causes a reinforcement of the original action. The input causes the reaction to increase.

Negative Feedback

Causes the system to stop doing the original action, and to either take no action or to perform an opposite action.

10 step Food to Energy Process

1. High Carb Meal
2. Food gets METABOLIZED or “broken down”
3. GLUCOSE is released into the bloodstream
4. Glucose levels in the bloodstream are TOO HIGH

\~ Regulation \~


5. Pancreas releases INSULIN
6. Insulin ATTACHES to the INSULIN RECEPTOR
7. GLUCOSE TRANSPORTER opens
8. GLUCOSE is able to enter the cell

\~ Inside of the Cell \~


9. Chemical Reaction called CELLULAR RESPIRATION (requires O2/oxygen+glucose)

\~ Inside of the Mitochondria \~


10. Make ENERGY in the form of ATP

Goals of the Food to Energy Process

1. Lower glucose levels in blood stream
2. Make energy → “ATP”

Glucose

A simple sugar that the body uses for energy

ATP

~~The~~ ENERGY ~~compound that powers all our activities~~

Cellular Respiration

A series of chemical reactions the cells use to make energy that occurs in the mitochondria of our cells

INSULIN vs. Glucagon

A hormone produced by the pancreas in order to lower the glucose levels. Released for blood glucose balance when there is too much glucose.

Insulin vs. GLUCAGON

A hormone produced by the pancreas in order to raise glucose levels. Released for blood glucose balance when there is not enough glucose. Stimulates the liver to release stored glucose into the bloodstream.

6 Step Negative Feedback Loop: Blood Glucose Level Regulation

Blood Glucose Level Rises


1. Pancreas releases insulin into the bloodstream
2. Insulin causes cells to take in glucose
3. Blood glucose level drops

Normal Glucose Level

Blood Glucose Level Drops


1. Pancreas releases glucagon
2. Liver releases stored glucose
3. Blood glucose level rises

Normal Glucose Level

Why does glucose need to enter the cells?

To make energy

Positive feedback…

Reinforces the same (original) action (and causes reaction to increase)

Where are the hormones made that help regulate blood glucose levels? (Insulin & Glucagon)

Pancreas

What does insulin do? (2 jobs)

1. Decreases blood glucose levels


2. Causes the cells to take in glucose

Cellular respiration is performed in the cell to make what?

ATP

What are the 2 hormones that regulate blood glucose levels?

1. Insulin
2. Glucagon

When glucose enters the cell it performs…

cellular respiration (to make ATP/energy)

Where is extra glucose stored?

Liver

Negative feedback…

Stops the original action (and causes the system to take no action or perform an opposite action)

What does glucagon do?

Causes the liver to release (stored) glucose

Where does cellular respiration take place?

Mitochondria

3 Steps After Blood Glucose Level Rises

1. Pancreas releases insulin
2. Insulin causes cells to take in glucose
3. Blood glucose level drops

goal: go back to normal blood glucose level → insulin decrease blood glucose level

3 Steps After Blood Glucose Level Drops

1. Pancreas releases glucagon
2. Liver releases glucose
3. Blood glucose level rises

goal: go back to normal blood glucose level → glucagon increase blood glucose level