Heart structure of fish, reptiles, and human

&Functions of hematocyte

Fish heart

ATRIUM,deoxygenatedblood flow fromvein

VENTRICLE,Deoxygenatedblood flow out to artery

Reptilian heart (most reptilian)

Right atrium

Right ventricle

Septum

Left ventricle

Left atrium

Human heart

Right atrium

Right ventricle

Left atrium

Left ventricle

Septum

Differences

Fish Reptile (most, not all) Human

2 chambered: 1 atrium and 1 ventricle

3 chambered (4 in case of crocodilians) : 2 atria and 1 ventricle

4 chambered : 2 atria and 2 ventricles

Single circulatory system Double circulatory system Double circulatory system

Only deoxygenated blood flow through

Both deoxy and oxygenated blood flow through, possibility of mixing

Both deoxy and oxygenated blood flow through, but strictly not mixed

No septum Partially dividing septum Complete septum

Similarities

• Made up of cardiac muscle and connecting tissue

• Lies in the anterior part of body cavity, dorsal to the gut

• Surrounded by pericardium

Functions of hematocyte

• Erythrocytes - carry oxygen and collect carbon dioxide through the use of hemoglobin

• Leukocytes - defending the body against both infectious disease and foreign materials

• Thrombocytes - involved in hemostasis, leading to the formation of blood clots

• Thrombocytes – produce growth factor