Lesson two: The Pancreas

HOMEOSTASIS!!
What’s in your fish tank?

REVIEW!!
Tank
Water
Food
Air pump
Heater
Thermometer
Water filter

THE NERVOUS SYSTEM
What makes up the CNS? ( the brain)
Peripheral NS? (everything else)

Negative Feedback

Review Animations
Homeostasis
Sweating

How Do Hormones work?

Hormones
Hormones are secreated by various organs in the body to effect change on target cells. There are two types of Hormones...steroid hormones and Amino Acid based ones

Steroid Hormones are able to penetrate the cell membrane and effect change right in the Nucleas. However, they need a receptor cell to affect.

Amino Acid based Hormones aren't able to penetrate the cell membrane...instead they effect change by attaching to a receptor protein on the outside of the target cell.

SB2 take a look at pg 252, 253

Fish has gotta eat!
You're not constantly feeding your face, so how does the body keep the level of glucose at an optimal level? HOMEOSTASIS! Your body has 2 hormones that are opposit, and counteract one another; they are used in various levels to maintaing a constant level of glucose in the blood.

The hormones are produced in the pancreas

After a huge meal, your body stores the excess glucose as a storable subastance called Glycogen. You are able to store this in your liver and muscles. If there is more glycogen than you body can store, then it is converted to adipose tissue (fat).

Check out that Pancreas

Where ‘s the Islet?
The Alpha cells produce a hormone called glucagon. This hormone targets the hepatocytes in the liver, causing them to turn the stored glycogen into useable glucose.

On the flip side, the Beta cells in the body produce insulin. This causes the hepatocytes to take glucose and transform it into glycogen. This hormone also causes the muscles to uptake more AA and turn it into protein.
What do they really look like?

Recap : the Endocrine System
ENDOCRINE


Food for Thought
Type I Diabetes - Juvenile onset diabetes
Type II Diabetes - adult onset diabetes


Fish needs a clean tank


Excretion
Who does what?
Plants and Photosynthesis - waste is Oxygen
Animals and Cell respiration - waste is carbon dixide

What are nitrogenous wastes?
Waste produced after AA’s are broken down (Deamination of AA’s results in NH3)
Ammonia is extremely toxic to living creatures, so it must be removed from the body.

How cheap are you?
Organisms want to expend as little energy as possible to excret their wastes, conserve as much water as possible.

Fish! They can excrete Ammonia because they are constantly expelling excess water. They dont have to transform the ammonia into anything.

Marine Animals excrete Urea and Trimethylamine oxide.../
Birds - Uric Acid (insoluble)
birds must ensure that they are carrying as little weight as possible, therefore their waste is almost a solid. It's insoluble uric acid, which doesn't dissolve in water. (the white stuff)
Mammals Urea... less toxic than ammonia,costs a lot to produce, but uses relatively little water.

What have you done for me lately?
Should have finished:
SB2 pp247-251, 255, 258

Please Finish
Oxford pp 52, 53
SB2 pp256-257, 260-264