Transcript “Open” circulatory system

Transport in animals
Why we need a transport system?
3 week old larval
anchovy
How big can you be and still meet O2 demand of tissue simply
by diffusion?
The larval anchovy (average body radius = 0.6 mm) can meet all of
its metabolic demand by uptake of O2 by diffusion. The respiratory
and circulatory systems will take over to supply O2 to the tissues.
Any animal larger than 1 mm cannot rely on diffusion alone.
Gases diffuse far more readily through gas than aqueous solutions
Radius (distance to the geometric body center) increases
proportionally to body size.
Again, any animal with a body (made of water) radius > 1 mm
cannot obtain (or release) gases simply by diffusion, so you need a
circulatory system and a medium in that system, i.e. blood.
Length = 2
Radius = 0.5
Length = 4
Radius = 1
Why have blood?
Transport of nutrients
from digestive tract to tissues, to
and from storage organs
Transport of metabolites
(e.g., lactic acid from muscle to liver)
Transport of excretory products
from tissues to excretory organs
Transport of gases
respiratory organs to/from tissues
Transport of hormones
Transport of cells
including cells of nonrespiratory
function (e.g., leukocytes in verts,
numerous cell types in inverts)
Transport of heat
Transmission of force
e.g., locomotion (earthworms,
spiders), erection of penis
Coagulation
Open vs Closed Circulation
Closed circulatory system: is
found in all vertebrates and
some inverts (e.g., cephalopods).
Blood remains in vessels;
capillaries allow close contact
between blood and tissues
Arterial system: high pressure,
takes blood away from heart
Low volume (5-10% of body
mass)
“Open” circulatory system: is
characteristic of many inverts.
Blood (hemolymph) empties
into hemocoel and bathes
tissues and organs directly
Low pressure, high volume
(up to 40% of body mass)
Animal typically has hard shell
or exoskeleton. Insects have an
open circulatory system, but do
not use it for oxygen transport.
Mass flow transport
Needed for a constant supply of:
Oxygen
Nutrients
Also needed to get rid of waste
products such as:
Carbon
3 Major Parts of the Circulatory system
Blood Vessels
- routes blood travels
Heart
– pumps or pushes blood through
Blood
– carries important “ *stuff ” through
body
body
head, neck
superior vena
cava
and arms
lungs
pulmonary artery
aorta
right
inferior vena
cava
hepatic vein
pulmonary
vein
atrium
right
ventricle
left
atrium
left
ventricle
hepatic artery
liver
hepatic portal vein
mesenteric artery
gut
renal vein
kidneys
body and
legs
renal artery
The Heart
The heart is mainly made
of cardiac muscle,
each muscle cell is
joined to the next by an
intercalary disc.
These cells are ‘myogenic’,
this means they can
contract and relax of
their own accord
throughout a human life
superior
vena cava
aorta
right
pulmonary
artery
left
pulmonary
artery
pulmonary
veins
pulmonary
veins
right
atrium
left atrium
bicuspid
valve
left ventricle
tricuspid
valve
right ventricle
septum
inferior vena
cava
semi-lunar valves
Your Blood is made of
Plasma
Plasma- water, ions, proteins
Plasma proteins
albumin- provides osmotic pressure
globulinsalpha and beta- transport
gamma- antibodies (produced by
lymphocytes; other proteins by liver)
fibrinogen- clotting
Plasma volume regulated by hormones like ADH
Formed Cells
Erythrocytes- (red blood cells)
no nuclei or mitochondria
circulate for about 120 days
280 million hemoglobin molecules per cell
Leukocytes (white blood cells)
granular and agranular
granular: neutrophils, eosinophils, basophils
agranular: lymphocytes, monocytes
capable of amoeboid movement
Platelets- involved in clotting
The Cardiac Cycle
ATRIAL SYSTOLE - Heart
END OF PRESENTATION!