Book lungs: Respiration organ used for gas exchange in arachnids. This organ is found on the ventral side of the spider and consists of stacks of air pockets and hemolymph-filed tissue that makes them look like pages in a book.
Calcium Ion Channels: A series of proteins that are located along a nerve cell which are selectively permeable and only allow ions to pass through them thus allowing the impulse to move down the nerve cell. The venom from P. fera blocks these channels which blocks nerve impulse from moving through the cell and causing paralysis in the victim.
Chelicerae: A pair of appendages in front of the mouth in arachinds which have claws attached to them.
Copulation: A general term used for the reproductive process whether it be attracting a mate or the actual process of sexual intercourse.
Dioecious: A term used to describe a group of organisms in which there are male and female species. If a species only consists of hermaphroditic organisms it is referred to as monoecious.
Dorsal: Referring to the upper side or back of an animal, plant, or organ. The dorsal side of your pet dog would be the side that you pet when he’s standing up.
Ganglion: A cluster of nerve cell bodies which are linked by synapses. In more primitive organisms such as arachinds a cluster of ganglion will serve as a brain for the spider.
Hemolymph: The circulatory fluid found in most organisms with open circulatory systems. Hemolymph is the equivalent of blood in humans. Blood is iron based however whereas hemolymph is copper based.
Heterotrophic: A term used to describe an organism that must obtain their own food from an outside source and cannot make their own food. Most plants are not considered heterotrophic because they can make their own food through photosynthesis.
Molt: Shedding of the exoskeleton allowing the organism to grow. This process is performed by arthropods as well as nematodes.
Pedipalps: A pair of appendages attached near the mouth of arachnids that have various functions such as manipulating food they are about to eat, various reproductive purposes, or sensory functions.
Predation: The act of feeding on other animals as a means of food source.
Serotonin receptors: Proteins located on the surface of nerve cells which bind to serotonin and allow the chemical to function. The venom of P. fera is known to stimulate these receptors causing great pain in the victim.
Striated: Describing a type of muscle that is characterized by linear marks. Striated muscle tissue is usually multinucleated and makes up skeletal and cardiac muscle.
Ventral: A term used to describe the underside of an animal or organ. In humans the ventral side consists of features such as the face and abdomen muscles.

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