,SNEAK PEAK OF STUDY NOTES
1
, Topic 1: Animal Nutrition
Homeostatic Control of Blood Glucose
This topic will discuss the control of the amount of glucose in the blood but first, we go over the
definitions:
● Homeostasis is the ability of an organism to maintain stability of internal conditions (temp, chemical
balance etc) despite changes in the environment. It controls the following aspects
● Negative feedback mechanisms are mechanisms in the human body that detect changes or
imbalances in the internal conditions & restore homeostasis
● Blood Glucose refers to the amount of glucose in the blood
● Insulin is a hormone made in the pancreas & released into the blood to help convert glucose to
glycogen to reduce blood glucose
● Glycogen is the form in which glucose is stored in the liver & cells
● Glucagon is a hormone made by the pancreas that raises blood glucose levels by converting stored
glycogen to glucose
The sequence in a negative feedback mechanism
● An imbalance is detected, stimulating the control centre
● The control centre responds with a message sent to the target organ
● The target organ responds & opposes the imbalance
● Balance is restored
How insulin reduces blood glucose levels
● When the glucose concentration in the blood rises above normal, The Islets of Langerhans
(pancreas) secrete insulin into the blood.
● This insulin stimulates:
○ The absorption of glucose from the blood into body cells
○ The conversion of glucose into glycogen in the liver & skeletal muscles
● The glucose is removed from the blood causing the glucose concentration to decrease &
insulin secretion is inhibited
● A metabolic disorder, called diabetes mellitus occurs when insulin is not released/ does not
function properly
How glucagon increases blood glucose levels
● If the glucose concentration in the blood falls below the normal, The Islets of Langerhans
detect the decrease & secrete glucagon into the blood
● This glucagon stimulates:
○ The conversion of glycogen to glucose in the liver & skeletal muscles
● Glucose to be released into the blood stream, causing the glucose levels to increase
2
1
, Topic 1: Animal Nutrition
Homeostatic Control of Blood Glucose
This topic will discuss the control of the amount of glucose in the blood but first, we go over the
definitions:
● Homeostasis is the ability of an organism to maintain stability of internal conditions (temp, chemical
balance etc) despite changes in the environment. It controls the following aspects
● Negative feedback mechanisms are mechanisms in the human body that detect changes or
imbalances in the internal conditions & restore homeostasis
● Blood Glucose refers to the amount of glucose in the blood
● Insulin is a hormone made in the pancreas & released into the blood to help convert glucose to
glycogen to reduce blood glucose
● Glycogen is the form in which glucose is stored in the liver & cells
● Glucagon is a hormone made by the pancreas that raises blood glucose levels by converting stored
glycogen to glucose
The sequence in a negative feedback mechanism
● An imbalance is detected, stimulating the control centre
● The control centre responds with a message sent to the target organ
● The target organ responds & opposes the imbalance
● Balance is restored
How insulin reduces blood glucose levels
● When the glucose concentration in the blood rises above normal, The Islets of Langerhans
(pancreas) secrete insulin into the blood.
● This insulin stimulates:
○ The absorption of glucose from the blood into body cells
○ The conversion of glucose into glycogen in the liver & skeletal muscles
● The glucose is removed from the blood causing the glucose concentration to decrease &
insulin secretion is inhibited
● A metabolic disorder, called diabetes mellitus occurs when insulin is not released/ does not
function properly
How glucagon increases blood glucose levels
● If the glucose concentration in the blood falls below the normal, The Islets of Langerhans
detect the decrease & secrete glucagon into the blood
● This glucagon stimulates:
○ The conversion of glycogen to glucose in the liver & skeletal muscles
● Glucose to be released into the blood stream, causing the glucose levels to increase
2
