Body parts

The body of a spider has two distinct parts. The first part consists of head and breast, called as prosoma or cephalothorax. It is made from a hardened material, called as chitin. The second part is the soft abdomen, called as opisthosoma. A tiny tube called as pedicel connects the cephalothorax and abdomen. The back of a spider is a dorsal side and at the bottom is ventral side.

The eight legs, the two jaws (chelicera) and the two feelers (palps) are connected to the prosoma. The males have a bulb at the end of their palps. These are filled with semen before copulation and are used to inject the semen into the sexual organs of the female. On the prosoma there are usually eight eyes. In Europe one can also find spiders with six eyes. Outside Europe one can find spiders with no and up to twelve eyes

Inside the body there is an extensive nerve system (blue). The brains are located in the prosoma and the heart at the front upper side of the abdomen (red). The heart beats with a frequency between 30 and 70 beats per minute. When the spider is tensed or exhausted the heartbeat can go up to 200 beats per minute. At the rear of the abdomen the silk making spinners are located (white). These are connected to glands that produce different proteins. When these proteins are mixed, it polymerizes to form silk. By pressing the fluid silk through the spinners a thread is made. The sexual organ and the egg-producing organ (white) are located between the book lungs (red) and the spinners.

The alimentary canal (yellow) runs through the whole body. At the end (green) of it there is the excretory system.
 

Cross section of a spider (7)