Download Diversity Gas exchange and Circulation Assignment

Diversity Gas exchange and Circulation
Assignment
Human
Humans have a closed system where the blood is contained
entirely in the vessels. They also have a double circuit where the
blood flows from one circuit to the other.
Gas exchange is carried out in the lungs. The oxygen that we
inhale is passed through the trachea which then splits into two
bronchi. The bronchioles branch of the bronchi and divide into
smaller branches.
The oxygen passes through the bronchiole and into the alveoli
(air sacs).The alveolar surface is very close to the lung capillary
which will let the oxygen for rapid diffusion. The capillary
which carries red blood cells the oxygen binds with the red
blood cells by a protein called haemoglobin.
As the oxygen travels with the red blood cells the body tissue
capillary is very close to the body cell which allows rapid
diffusion of oxygen and carbon dioxide back and forth. The
oxygen diffuses into the body cell from the capillaries and the
carbon dioxide is diffuses into the capillaries.
As the capillary travels back to the lungs the carbon dioxide is
expelled by the lungs and out your mouth.
Fish
Fish use gills for gas exchange underwater. Fish have a closed
circulatory system where the blood is entirely contained within
the vessels. Fish have a single circuit system where the blood
goes directly to the body from it gills and only flows once
through the heart.
Gas exchange occurs by diffusion between the water and the
blood that flows across the gill membrane and capillaries. The
operculum (gill cover) prevents the exit of water and acts as a
pump drawing water past the gill filament. As the water flows
over the gill filaments in the opposite direction to the blood
flows through the gills. This is called countercurrent flow. As
the blood flows in the opposite direction to the water the oxygen
from the water is absorbed into the blood which carries the
gases to and from the cells. As the blood carries the carbon
dioxide back around the circuit the carbon dioxide is diffused
out of the gills and into the water.
Insects
Insects have an open circulatory system where the Haemolymph
does not carry the oxygen. The open system allows the
Haemolymph to flow freely through body cavity.
Gas exchange occurs through their tissues and the air system of
air –filled tubes called tracheae. The tracheae open to the
outside through a small hole called Spiracles. The spiracle opens
on the side of the body that allow air to enter and exit the body.
As the air travels through the tracheae tube network in the body
the tube branches of into smaller tubes called the tracheoles.
When the tube ends and makes contact with the cells this is
when the gas exchange occurs where the oxygen is taken into
the cell and carbon dioxide is out of the cells and travels up the
tube network and out of the Spiracles. This tracheal system is
only good for small bodies such as the insect.
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/T/Trach
eal_Breathing.html
Heart
Humans
The human heart
has 4 chambers
separated into 2
separate pumps
one for each
circuit.
As the right
Atrium receives
the deoxygenated
blood from the
body it travels
through the Right
Ventricle which
pumps the
http://www.heart-healthweightwatcher.com/images/HumanHeartDiagram.jpg
deoxygenated blood
to the lungs. When the
oxygenated blood from the lungs travels through the Left
Atrium and is pumped into the Left Ventricle where the blood is
pumped to the body by the veins. As the veins carry the
oxygenated blood to the capillaries the cells allow quick gas
exchange to occur. Then the veins carry the deoxygenated blood
back to the heart which then repeats the same cycle again.
This human heart requires a higher oxygen rate then the fish or
insects because it pumps more oxygen into our body which lets
us do everyday activities.
Fish
The fish heart has 3
chambers connected in a
series acting as a single
pump.
The Sinus Venosus receives http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/
F/fish_heart.gif
deoxygenated blood from the
body which is pumped to the Atrium and then pumped to the
Ventricle which will then pump the deoxygenated blood to the
gills. As the oxygenated blood travels from the gills the blood
loses some oxygen as it travels to the tissues. When the blood
arrives at the tissues less oxygen is absorbed into the cells. The
deoxygenated blood is pumped back to the heart and repeats the
cycle.
This heart is only suitable for the fish as their oxygen needs are
lower, as they are supported by the water.
Insects
The Dorsal Vein is a single tube
that runs along the back of the
insect. The Tubular heart is a
series of chambers where it pumps
the Haemolymph back towards the
head. The Ostia are small holes
that allow re-entry of the
Haemolymph to the heart.
The open system allows the
Haemolymph to flow freely
http://bugs.bio.usyd.edu.au/Entomology/ima
ges/Topics/intAnatomy/heart2.gif
through out the body and into the tissues where diffusion of
oxygen and carbon dioxide occur.
This open system is suitable for the insects as the short distances
for diffusion throughout the body.