Transcript 12-Primary systems

Organ Systems
organ  a group of tissues organized to perform
specific functions
organ system a group of organs organized to
perform specific functions
Primary Systems
the three systems necessary to keep all cells alive
involved in bringing needs to a cell
and removing wastes from a cell
the key needs are oxygen and nutrients
the key wastes are carbon dioxide and urea
1. Respiratory System
a. getting air into and out of the body
a series of tubes bring the air inside the body
trachea
bronchus (2)
bronchiole
(thousands)
once inside the lungs
it moves to tiny air sacs  alveoli
gases
inhaled air
exhaled air
nitrogen
78 %
78 %
oxygen
21 %
16 %
argon
1%
1%
CO2
0.035 %
5%
the only two gases that change are O2 and CO2
b. Diffusion of gases
the air in the alveoli has more O2 than the blood
as a result O2 moves into the blood
O2
the air in the alveoli has less CO2 than the blood
as a result CO2 moves into the alveoli
CO2
O2
When the blood gets to the cells
the blood has more O2 than the cell
as a result O2 moves into the cell
the blood has less CO2 than the cell
as a result CO2 moves into the blood
Additional systems of gas exchange
a frog has lungs
but Canadian frogs spend the winter buried in mud
they can also exchange gases through their thin skin
but as there is less surface area of thin skin
than in the lungs
this only works when the frog
is inactive
a turtle has shell and has thicker skin
yet in Canadian winters
they are buried in the mud with frogs
so how do they do gas exchange?
they gas exchange via their cloaca
roughly equivalent to your rectum
like a lung it has thin wall
& a large surface area
but only supplies enough
O2 for inactive turtles
2. Digestive System
key function is to convert food into nutrients
a. foods can be assigned to three macronutrients
carbohydrates  starch, sugar
from foods such as cereals, potatoes, fruit
lipids  vegetable oils and fats
from foods such as nuts, seeds & meat
proteins  muscle, food for young and seeds
from foods such as meat, milk, eggs, nuts, & seeds
nutrients are:
carbohydrates  glucose
Lipids  glycerol & fatty acids
+
fatty acid
proteins  amino acids
3 amino acids
a protein
b. Physical breakdown
muscular action breaking down food
into smaller pieces of food
mostly occurs in the mouth
the chewed food called a bolus is now swallowed
and muscular action called peristalsis
moves the food down the esophagus to the stomach
esophagus
bolus
stomach
bile from the liver (via the gall bladder) enters
and breaks large drops of fat into small droplets
c. Chemical breakdown
enzyme action breaking down food into nutrients
1. it starts in the mouth
amylase in saliva breaks down starch
2. in the stomach
pepsin breakdown proteins
acid and pepsin
3. the duodenum, part of small intestine is the
major site of digestion
protein to amino acids  continues
starch to glucose  continues
lipids to fatty acids  starts
29 different enzymes
from the pancreas enter here
d. Absorption of nutrients
the small intestine absorbs the amino acids
and glucose directly into the blood
the fatty acids are absorbed into the lymph
and then go into the blood
e. Eliminating wastes
all of the undigested food
+ dead bacteria
leave through the anus as feces
3. Circulatory System
a. Fluid
this consists of plasma and cells
cells were discussed in the tissues section
plasma is mostly water with some proteins
plus dissolved nutrients and minerals
b. Vessels
muscular tubes that move the blood cells, plasma and
dissolved substances throughout the body
arteries move blood away from the heart
under high pressure
they have thick, muscular walls
and usually carry
oxygen-rich blood
so are shown as red in diagrams
veins move blood towards the heart
under low pressure
they have thin, muscular walls
and usually carry
oxygen-poor blood
so are shown as blue in diagrams
capillaries connect arteries and veins
these are tiny vessels with walls one cell thick
they are the site of the diffusion of gases,
nutrients, and wastes
in or out of a cell
thick
small opening
thin
large opening
single cell
c. Pump
the heart is actually two separate pumps
one pumps oxygen-poor blood
to the lungs
one pumps oxygen-rich blood
to the body
the right atrium
receives the oxygen-poor blood from the body
the right ventricle
pumps the oxygen-poor blood to the lungs
right atrium
right ventricle
the left atrium
receives the oxygen-rich blood from the lungs
the left ventricle
pumps the oxygen-rich blood to the body
left atrium
left ventricle
less active animals such as frogs
have two atria but only have one ventricle
the oxygen-poor and oxygen-rich blood might mix
on their way to the lungs & body