1. Entry slip: What is diastolic pressure?
Lesson 4.9- Explain how transport systems
maintain homeostasis in the body.
(p301) of Biology-McGraw-Hill Ryerson)
I. Homeostasis (p772):
a. The body’s maintenance of a relatively
constant internal environment (i.e. water
content, O2 level, temperature, etc..)
b. In this case of homeostasis, the “internal
environment” that the body wants has:
i. Nutrition: All the cells in the body
need protein, lipids, CHO’s, water,
minerals and vitamins for their
functions, or they will die.
A.The circulatory system transports
these nutrients from where they
are digested and absorbed in the
digestive tract as well as where
they are stored for future use (i.e.
vitamins in the liver).

2. ii. O2: all the cells of the body need
oxygen for making energy or they will
die.
A. The circ. system brings O2 from
the air in the lungs to all cells.
iii. Little primary metabolic wastes as
possible: build up of primary
metabolic wastes will sicken and
eventually kill the body.
A. CO2 is transported to the lungs
for exhalation.
B. Urea, uric acid and creatinine are
transported to the kidneys for
excretion.
iv. Good communication between the
brain, glands and organs.
A.The circ system transports
hormones from the area where
they are produced to the target
tissues and organs where they
pass on important information

3. (i.e. noradrenaline produced in
the adrenal glands).
v. A good fluid balance:
A.The circ system will take excess
water from the body to the
kidneys for excretion. As well, it
will take water that you drank to
areas of the body which are in
need of water such as your sweat
glands.
vi. A good temperature balance around
37oC:
A.When your hands and feet are
cold, the circ system will shunt or
move warmer blood from your
chest and abdominal area to your
extremities.
B. When you are too hot, the circ
system will move more blood
closer to your skin to aid in
cooling it off. The circ system also

4. will bring water to your sweat
glands to allow you to perspire.
vii. Strong defence again foreign invaders
such as bacteria, fungi and viruses, so
the body will not get sick.
A.Leucocytes engulf and digest
bacteria and fungi.
B. Lymphocytes create antibodies
that will kill off a returning virus
to the body.
II. Youtube search:
a. Circulatory System-(mhoowen)
III.Homework:
i. No homework-take a breather.