Download Hormones and Homeostasis ANSWERS

Homeostasis
Name:__________
Define homeostasis
Homeostasis - involves maintaining a constant environment in the body
Homeostasis regulates….
TEMPERATURE/BLOOD SUGAR/WATER/OXYGEN/CARBON DIOXIDE
What is a hormone and where are they produced?
Hormones are chemical messengers used in the body by the endocrine system. They are
produced by our glands.
The Pancreas
Insulin controls blood sugar level in our bodies.
Glucose is a sugar needed by cells for respiration.
It is important that the concentration of glucose in the blood is kept at a constant level.
Changing glucose levels
After a meal the level of glucose in our bodies increases.
After exercise the levels of glucose in our bodies decreases.
Why do you think this happens?
I think this happens because......................
The body digests the food we eat breaking it down into sugar molecules for absorption
(carbohydrates) – this increases blood sugar levels. When we exercise we use glucose for
respiration which reduces blood sugar levels.
Key words
Glucose
Glycogen
Insulin
Glucagon
Definition
A sugar used in respiration to make energy.
A storage substance made of glucose, it is stored in the liver.
A hormone (chemical messenger) it tells your body to change glucose into glycogen.
It is made by the pancreas.
A hormone that tells your liver to change glycogen back into glucose. Also made by
the pancreas.
Controlling Blood Glucose Levels
Glucose increases
(food intake)
Insulin causes
GLUCOSE to change to
GLYCOGEN in the liver
Glucose decreases
Normal blood
Normal blood
glucose level.
Glucose
decreases
(exercise)
glucose level.
GLUCAGON causes
GLYCOGEN in the liver
to change back to
glucose
Glucose increases
Diabetes
Some people suffer from a disease called diabetes. They do not produce enough of a hormone called
insulin from the organ in the body called the pancreas. Insulin controls the blood sugar levels. Diabetics
have to be careful that they do not eat too much sweet food. They may also need to inject themselves with
the hormone insulin to help control their blood sugar level.
Negative feedback
Explain negative feedback:
• All homeostatic mechanisms use negative
feedback to maintain a constant value (called the
set point).
• Negative feedback means that whenever a
change occurs in a system, this automatically
causes a corrective mechanism to start, which
reverses the original change and brings the
system back towards the set point (i.e. ‘normal’).