Not every relation is a function. But every function is a relation. Function is just a part of relation.
The cubic function.
Range
A formula or graph are two ways to describe a math function. How a math function is described depends on the domain of the function or the complexity of the function.
The Mandelbrot graph is generated iteratively and so is a function of a function of a function ... and in that sense it is a composite function.
The perineurium is found in the peripheral nervous system. It is a membrane which forms a protective sheath around the fascicles (bundles of nerve fibres).
Perineurium is a dense connective tissue layer that surrounds nerve fascicles, or bundles of nerve fibers, within a peripheral nerve. It provides structural support and protection to the nerve fibers. The perineurium also helps create a barrier that regulates the passage of substances into and out of the nerve fascicle.
Perimysium.
Endoneurium - first Perineurium - second Epineurium - third
The coarse connective tissue that covers each fascicle (bundle of fibers)
Each bundle of nerve fibers is surrounded by connective tissue called the perineurium. This protective layer helps to support and protect the bundle of nerve fibers as they travel throughout the body.
epineurium, perineurium, endoneuriumEpinerium, perineurium, endoneurium.
The perineurium connective tissue covers and encapsulates bundles of nerve fibers called fascicles within a nerve. It is located between the endoneurium (which surrounds individual nerve fibers) and the epineurium (which surrounds the entire nerve).
The connective tissue surrounding the fascicle of a muscle is the perimysium.
Fascia is up of sheets or bands of connective tissue fibres.
Axons are covered by connective tissue called endoneurium. Multiple axons are bundled together within fascicles, which are surrounded by perineurium. Finally, the entire nerve is enveloped by epineurium.
The irregular fibrous (dense) connective tissue is covering most of the organs of our body: Fasciae (muscle, tendons, and below the skin), periosteum (bone), deep layer of dermis (our entire body), pericardium (heart and its valves), perichondrium (cartilage), joint capsules (joints), membrane capsules of liver, kidney, and lymph nodes, tunica albuginea (testicle), etcetera.