Earthworm: Blood Circulation, Respiratory & Nervous System (55x90cm)

An “Earthworm: Blood Circulation, Respiratory & Nervous System” (55×90 cm) educational chart provides clearly labeled diagrams showing the closed circulatory system, skin-based respiration, and segmentally organized nervous system, supporting zoology and biology lessons.​

Circulatory (Blood) System

Closed Circulatory System: Blood circulates only within vessels—a dorsal blood vessel runs above the digestive tract, and a ventral vessel below, connected by five pairs of aortic arches (pseudohearts) in segments 7–13.​

Directionality: Dorsal vessel collects blood and pumps it forward; aortic arches pump blood to the ventral vessel, distributing it through lateral vessels and capillaries to tissues.​

Blood Composition: Blood contains plasma and colorless corpuscles, with hemoglobin dissolved in plasma (not in cells) giving it a red color.​

Respiratory System

Skin Respiration: Earthworms lack lungs or gills—gas exchange occurs by diffusion across their moist skin.​

Moist Cuticle: The skin must remain moist to enable effective exchange of oxygen and carbon dioxide between blood capillaries and the environment.​

Nervous System

Central Nervous System: Comprised of a dorsal brain (cerebral ganglia) in the third segment, subpharyngeal ganglia below the pharynx, and a ventral nerve cord with paired ganglia in each segment.​

Peripheral & Sympathetic Nerves: Lateral nerves arise from the main cord, supplying the body wall and organs for movement and response.​

Sensory Ability: Despite lacking eyes, earthworms possess receptor cells in the skin and anterior end sensitive to light, touch, vibration, and chemicals.​

This chart is ideal for illustrating the functional anatomy and physiology of earthworms, reinforcing comparative biology lessons between vertebrate and invertebrate organ systems.