Circulatory Diversity

Amoeba Does this organism have a circulatory system? Why or why not? How does it internally transport molecules? Other organisms that don’t have a circulatory system include sponges, jellyfish, and tapeworms.

Plants Xylem are the tubes in plants that carry water and minerals upward. Phloem are the tubes in plants that carry food (sugar) downward from the leaves. Xylem is more interior than phloem.

Arthropods and other Invertebrates They have an open circulatory system. Arteries carry blood to organs and bathe organs in blood. Blood freely moves around inside body cavity. No capillaries or veins. Blood eventually works its way back up toward heart to be pumped again.

Closed Circulatory System Fish, Amphibians, Reptiles, Birds, and Mammals all have a Closed Circulatory System. This is were the blood stays inside blood vessels such as arteries, capillaries, and veins. The heart keeps blood pumping inside this closed system. Nutrients and Gases leave the system by diffusing through capillary walls.

Fish Heart pumps blood past gills where oxygen is picked up. Delivers oxygen to body and returns to heart. Heart only has two chambers.

Pulmonary and Systemic Circulation Amphibian, Reptiles, Birds, and Mammals circulation is broken into two circuits – the pulmonary circulation and systemic circulation. Pulmonary circulation is when blood leaves the heart, goes to the lungs, and returns to the heart. Systemic circulation is when blood goes to the rest of the body and returns to the heart.

Chamber Diversity Amphibians have a 3 chambered heart…which allows them to take in oxygen from lungs and from their skin. The can absorb oxygen through their skin when under water. Reptiles, Birds, and Mammals have 4 chambered hearts.