Crayfish PreLab External Structures Carapace Appearance Hard outer

Crayfish Pre-Lab

External Structures

Carapace • Appearance: Hard outer shell • Location: Exterior of the body • Function: Tough exoskeleton made of chitin; protects internal organs

Antennae • Appearance: 2 long stalks • Location: Front of head. • Function: Sensory reception.

Chelipeds • Appearance: Large pincher-claws • Location: Anterior end; near the head • Function: Used to grab food and for defense

Walking Legs • Appearance: Long, thin legs • Location: Ventral (belly) side, mid section • Function: Movement

Swimmerets • Appearance: Tiny feather-like legs • Location: Ventral (belly) side near posterior • Function: Help with swimming + grasping during mating

Uropods & Telson • Appearance: Fan-like tail • Location: Posterior (rear) end • Function: Propel during swimming.

Mouth • Appearance: Tiny lips • Location: Front of head/anterior • Function: Eating, intake of food

Maxillipeds • Appearance: Tiny claws • Location: Under head and Chelipeds. • Function: Bring food to mouth.

Internal Structures

Brain • Appearance: Fleshy piece • Location: Directly inside head, by eyes. • Function: Controls organs + responses.

Digestive Glands • Appearance: Light yellowish masses • Location: 1 on each side of head behind eyes • Function: Secrete enzymes needed to digest food. Also called “green glands”

Stomachs • Appearance: Fleshy light gray sacks • Location: In between digestive glands • Function: Grind up food (uses teeth-like structures).

Heart • Appearance: Light brown lobe/flap. • Location: Behind stomach + digestive glands • Function: Pump + circulate throughout body

Intestine & Anus • Appearance: Skinny tube + posterior opening • Location: Leaving stomach, going down back. • Function: Absorb nutrients + carry waste out of body.

Gills • Appearance: White colored feathers • Location: Sides of head, under shell. • Function: Gas exchange (oxygen and CO 2).

--Dissection Notes-1. Lay crayfish on its belly. 2. Find carapace behind head. 3. Cut along lines + gently remove carapace. 4. Identify internal + external organs.

Virtual Dissection… • https: //www. youtube. com/watch? v=2 c. BGu EDxv. No • https: //www. youtube. com/watch? v=w. SGEt 1 m. Y 2 OM

Internal (Dorsal):

Deeper Internal (Dorsal):

Internal (Lateral)

Abdomen (Dorsal):