Spider anatomy

Quick Spider anatomy

Spider anatomy: The body of a spider consists of two easy to recognize parts, the large bulbous part on the back is the abdomen (also called the opisthosoma) contained inside the abdomen is the spiders intestine, heart, ovary, stercoral pocket, oviduct, silk gland, book lung and digestive tubeules, see below in the image of the brown recluse anatomy.

Anatomy of a brown recluse spider

The other recognizable parts of a spider is the cephalothorax which is also known as the prosoma, all  appendages are attached to the cephalothorax. The cephalothorax contains the sucking stomach and heart as well as the venom glands, all important parts of a spider.

The spiders jaws, which are also known as chelicera are tipped out with the spiders fangs (the business end) and are under the spiders eyes. All spiders have venom glands and are capable of  injecting venom through the openings in the tips of their fangs and the spider’s mouth parts are primarily intended for envenoming it’s prey and an important part of Spider anatomy.

See spider anatomy diagram.

Book lungs The spiders book lungs are another interesting part of a spider anatomy, the book lung is a kind of respiration organ and each of these organs are found inside a ventral abdominal cavity and they connect with the

Cross section of a spiders "book lungs"

surroundings through a small opening, the best way to describe a spiders book lungs is them being several parallel membranous folds that are arranged very much like the pages you would find in a book.

Book lungs are also found in scorpions which are also just like the spider an arachnid, the anatomy of the book lung is best described as being like small hollow flat plates that air passes over the outer surface.

The blood then circulates within them, facilitating in the exchange of gases, the lung doesn’t move as such as by means of a diaphragm like a mammal as the air passing over the small plates is enough to respireate the spider, spider anatomy is different.