The phrase Physical Unit (PU) refers to the physical body, specifically as it functions as a container for incarnated Monadic Consciousness.
The Physical Unit refers to your physical body and all its various
- structures (e.g. brain, hippocampus, heart, skin, neurons, etc.),
- functions (e.g. Survival, Connection, and Expression) and
- energy flows (charkas, meridians, etc.) (Sosteric, SA1).
The PU may be conceptualized as a manifestation device, or a device designed to allow Consciousness to express within and manipulate the physical universe. As such, the physical unit was designed as a vehicle capable of expressing all Facets of Consciousness within the confines of the Physical Universe.
The physical unit is a sophisticated energy device. The complex and detailed energy system is well documented in Chinese Medicine (e.g., Acupuncture). Chakras are the main energetic conduits. Chakra energies provide support for the body's physical structures and vital organs (i.e. the heart, the brain, the skin, etc.).
Consciousness enters the PU at conception and stays with the unit either until the resident monadic consciousness (RMC) decides to leave the PU, or the PU becomes damaged to the point that it can no longer contain the RMC.
Development is the process of protecting, nurturing, and supporting the physical unit so it can contain high levels of Monadic Consciousness.
Ideally one wishes to manifest inside a fully developed, healthy, and fully functioning physical unit. Toxic Socialization and a violent and abusive system prevent proper development and damage the physical unit. Damage occurs to the PU through accidental or deliberate trauma, abuse, and neglect. All forms of assault (i.e., psychological, physical, emotional, and spiritual) damage the unit and lower the CQ of the body. Damage and a lowering of CQ will lead to Pathology from which the individual must heal. Individuals with severe damage may develop psychosis, Schizophrenia or Sociopathy. Individuals with severe damage may require long-term assistance from Competent Healing Professionals.
The physical unit has three basic functions.
Survival (instincts, survival programming, reflexes)
Connection (includes expression, self actualization, and "transcendence")
Sosteric, Mike. (SOA). The Science of Ascension: A Neurologically Grounded, Spiritually Sophisticated Theory of Mystical/Spiritual Experience. Unpublished. 
Sharp, Michael (GA). The Great Awakening: Concepts and Techniques for Successful Spiritual Practice.