Do Spiders Have Cells?
WouterSpiders have two basic body sections: the prosoma and the opisthosoma. They are connected by a thin tube called the pedicel. The opisthosoma contains reproductive organs, as well as the digestive system.
The opisthosoma has little rigidity and is usually unsegmented. In the opisthosoma, spiders have a heart, which pumps blood into the body cavity. The heart is located in the pericardium. It has one-way valves at each end.
The opisthosoma also has circulatory organs. These organs help the spiders to move around. The lungs are in the center of the opisthosoma.
The opisthosoma contains a mouth. It is also home to the venom glands. These glands produce venom, which is used to subdue prey. The venom may contain lipase and trypsin-like proteases. The venom glands also produce neurotoxins. These neurotoxins may subdue prey, liquefy its tissues, and break down its connective tissue.
Aside from the mouth, the opisthosoma is also home to the silk glands. The spinnerets are fleshy finger-like appendages. They emit silk from tiny spigots on their tips.
The tracheae are tubular. They may have a single opening or multiple ones. They can be simple, like a sieve, or they can be branched. In many species, tracheae are unbranched.
The exoskeleton of spiders is composed of cuticle. The cuticle is a protein-based membrane that is tough. The exocuticle is the toughest part of the cuticle. The exocuticle also forms the outer layer of the mouth. The cuticle is also composed of microfibres of chitin.
