Crayfish Physiology
External Anatomy
Carapace – Outer covering of the crayfish that provides support to the
internal structure and also provides protection from predators.
Rostrum – Part of the carapace.
Antennae and Antennules – These sense organs allow the crayfish to
sense touch and chemical differences in their environment as well as
provide balance.
Eyes – Provides the crayfish with sight.
Chelipeds – Used to breaking up food and pass it onto the mandibles at
the mouth. Also used in defending itself from predators.
Uropod and Telson – These flippers aid the crayfish in backward
swimming to escape from danger.
Walking Legs – Used for locomotion.
Swimmerets – Used for backward locomotion.
Digestive System
Mouth - The opening to the digestive system.
1st, 2nd and 3rd Maxillapeds – Mainly used for moving food onto the
mandibles at the mouth.
Mandibles – Act as teeth to grind up the food before it passes into the
mouth.
Esophagus – The tube connecting the mouth to the stomach. Very short
and hard to see in the crayfish.
Digestive Gland – Produces digestive enzymes (juice) that help break
down food.
Green Gland – These structures help to filter out waste material from
the body. They act like our kidneys.
Intestine – This organ continues to absorb the nutrients from the food
and puts it into the circulatory system.
Anus – The exit door of the digestive system. Found on the ventral side
of the telson.
Circulatory System
Heart – Pumps the blood throughout the body of the crayfish.
Abdominal Artery – transports blood to the tail end of the crayfish.
Respiratory System
Gills – feather like structures the take in oxygen from the water and get
rid of carbon dioxide.
Nervous System
Cerebral Ganglion (brain) – Controls all of the animal’s body
functions.
Nerve Cord – Transmits impulses from the brain throughout the
crayfish’s body.
Reproductive System
Oviduct – This opening at the base of the 2/3rd walking legs of the
females carry eggs from the ovaries to the exterior of the body.
Sperm Duct – This opening at the base of the 4/5th walking legs of the
males pass sperm to the exterior of the body.
Seminal receptacle – This opening at the base of the 4/5th walking legs
of the females receive sperm.
Muscular System
Mandibular Muscles – Controls the movement of the mandibles.
Abdominal Muscles – Control the extension and contraction of the
abdomen.
Thorax Muscles – Control movement in the thorax.
Other
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