Comparative Circulatory SystemsBiology 11

G.Burgess2006

Circulatory Systems

• Nutrients, fluids and metabolic wastes are cycled through an organism’s circulatory system

• Microscopic animal like protists and the least evolved animal species use cyclosis and diffusion to cycle their materials through cells and between cells.

• Plants use xylem and phloem to circulate materials between the roots, stems and leaves.

• Animals (more complex than the cnidarians/jelly fish) use either an open or closed circulatory system

Open circulatory system

• Common among shellfish and arthropods (arachnids and insects)

• Heart collects blood from a hemocoel (blood space)

• Heart pumps blood through open ducts or tubes to be circulated to the body tissues and bathe them with fluids.

• Cycled blood collects in hemocoel to be collected by the heart

Closed Circulatory System

• Common among annelids, fish, mammals and many other animals

• All blood vessels form a continuous closed circuit

• Blood is collected by atria and pumped to body by ventricles

• At no time does the blood actually come in contact with other body tissues.

Earthworm Circulation

• Closed circulatory system– Blood from the dorsal blood

vessel travels to the anterior region and is pumped by 5 aortic arches to the ventral blood vessel

– Blood from the ventral blood vessel travels posteriorly

– Small tubes connect the ventral blood vessel to the dorsal blood vessel in the posterior region.

Earthworm Circulatory system

Dorsal Blood

Flow

Ventral Blood

Flow

Grasshopper Circulation

• Grasshoppers have open circulatory system

• Their blood bathes their internal tissues

• Grasshopper do not have hemoglobin, their blood is green and is called hemocyanin

Grasshopper Circulatory System

Other animals

Fish Frog

Human

Mammalian Circulation• All mammals have a 4

chambered heart• 2 Atria and 2 ventricles

• The atria collect blood from the circulatory system and pump it to the ventricles

• The ventricles pump the blood to parts of the body

• 2 paths of circulation:– Systemic circulation: pumps

blood to and from body tissues– Pulmonary circulation pumps

blood to and from the lungs

Bibliography

• All images from Biodidac, 2006. http://biodidac.bio.uottawa.ca/