There are two types of<unk> s: superficial<unk> s and deep<unk> s. As arteries do not travel within the superficial fascia (loose connective tissue under the skin), superficial<unk> s differ from deep<unk> s in both composition and function. Superficial<unk> s Superficial<unk> s do not include arteries, and consist primarily of capillaries and nerves. Because capillaries function as the sites for substance exchange between interstitial fluid and blood, they tend to have large surface area and short diffusion path. Normally, capillaries consist of a central lumen lined with an endothelium, a single layer of smooth epithelial cells. Deep<unk> s Deep<unk> s, which often include arteries, have a more complicated structure than superficial<unk> s. Since arteries have high intraluminal blood pressure relative to capillaries and veins, these<unk> s have smooth muscle and connective tissue structures outside the endothelium. This structure allows arteries to contract, relax and remain flexible and transfer blood when under pressure.
Neurovascular bundle
Cardiopulmonary nerves
Parasympathetic nervous system
Intrascleral plexus
Cerebrospinal fibers
Postganglionic nerve fibers
Nerve plexus
Preganglionic nerve fibers