The cell membrane is a biological membrane that separates the interior of all cells from the outside environment.[1]. The cell membrane is selectively-permeable to ions and organic molecules and controls the movement of substances in and out of cells.[2]. It consists of the phospholipid bilayer with embedded proteins, which are involved in a variety of cellular processes such as cell adhesion, ion conductivity and cell signaling. The plasma membrane also serves as the attachment surface for the extracellular glycocalyx and cell wall and intracellular cytoskeleton.
Facts about Coma
Coma is a prolonged period of unconsciousness. Unconsciousness is the lack of appreciation of (or reaction to) a stimulus. Coma differs from sleep in that one cannot be aroused from a coma.
Coma involves two different concepts:
1.) Reactivity: Reactivity refers to the innate (or inborn) functions of the brain, i.e., the telereceptors (eyes and ears), the nociceptors (responses to pain), the arousal reaction (wakefulness) and the orienting response (turning one's head toward the source of sound or movement). We could also refer to these as reflexive movements.
2.) Perceptivity: Perceptivity refers to the responses of the nervous system to stimuli, which have been learned or acquired, i.e., language, communication skills, individual methods of movement such as gestures, etc. Perceptivity also refers to less complex learned or acquired reactions such as flinching when threatened. We can also think of these as conscious movements.
