Transport in animalsWhy 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 = 2Radius = 0.5 Length = 4

Radius = 1

Why have blood?

Transport of nutrientsfrom digestive tract to tissues, to and from storage organs

Transport of metabolites(e.g., lactic acid from muscle to liver)

Transport of excretory productsfrom tissues to excretory organs

Transport of gasesrespiratory organs to/from tissues

Transport of hormones

Transport of cellsincluding cells of nonrespiratoryfunction (e.g., leukocytes in verts,numerous cell types in inverts)

Transport of heat

Transmission of forcee.g., locomotion (earthworms,spiders), erection of penis

Coagulation

Open vs Closed Circulation

Closed circulatory system: isfound in all vertebrates andsome inverts (e.g., cephalopods).

Blood remains in vessels;capillaries allow close contactbetween blood and tissues

Arterial system: high pressure,takes blood away from heartLow volume (5-10% of body mass)

“Open” circulatory system: ischaracteristic of many inverts.

Blood (hemolymph) emptiesinto hemocoel and bathestissues and organs directlyLow pressure, high volume(up to 40% of body mass)

Animal typically has hard shellor exoskeleton. Insects have an open circulatory system, but do not use it for oxygen transport.

Mass flow transport

Needed for a constant supply of:

OxygenNutrients

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 body

Blood – carries important “ *stuff ” through body

head, neck

and arms

lungs

right

atrium

right

ventricle

leftatrium

leftventricle

liver

gut

kidneys

body and legs

aorta

inferior vena cava

superior vena cava

pulmonary artery

pulmonary vein

hepatic veinhepatic artery

renal veinrenal artery

hepatic portal vein mesenteric artery

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

The Heart

superior vena cava

aorta

left pulmonary artery

right pulmonary artery

pulmonary veins

pulmonary veins

right atrium

left atrium

tricuspid valve

bicuspid valve

right ventricleleft ventricle

septum

semi-lunar valves

inferior vena cava

Your Blood is made of

Plasma- water, ions, proteins

Plasma proteinsalbumin- provides osmotic pressure

globulins-alpha and beta- transportgamma- antibodies (produced bylymphocytes; other proteins by liver)

fibrinogen- clotting

Plasma volume regulated by hormones like ADH

Plasma

Formed Cells

Erythrocytes- (red blood cells)no nuclei or mitochondriacirculate for about 120 days280 million hemoglobin molecules per cell

Leukocytes (white blood cells)granular and agranulargranular: neutrophils, eosinophils, basophilsagranular: lymphocytes, monocytescapable of amoeboid movement

Platelets- involved in clotting

ATRIAL SYSTOLE - HeartATRIAL SYSTOLE - HeartThe Cardiac CycleThe Cardiac Cycle

END OF PRESENTATION!