Crying causes several different activities at once. The most important is the increase in fluids in the mouth, nose and eyes. The tears come out through tear ducts in the eyes the overflow goes to the sinuses and down the back of the throat.
Head and neck
Human anatomy (gr. ἀνατομία, "dissection", from ἀνά, "up", and τέμνειν, "cut") is primarily the scientific study of the morphology of the human body. Anatomy is subdivided into gross anatomy and microscopic anatomy. Gross anatomy (also called topographical anatomy, regional anatomy, or anthropotomy) is the study of anatomical structures that can be seen by the naked eye. Microscopic anatomy is the study of minute anatomical structures assisted with microscopes, which includes histology (the study of the organization of tissues), and cytology (the study of cells). Anatomy, human physiology (the study of function), and biochemistry (the study of the chemistry of living structures) are complementary basic medical sciences that are generally together (or in tandem) to students studying medical sciences.
In some of its facets human anatomy is closely related to embryology, comparative anatomy and comparative embryology, through common roots in evolution; for example, much of the human body maintains the ancient segmental pattern that is present in all vertebrates with basic units being repeated, which is particularly obvious in the vertebral column and in the ribcage, and can be traced from very early embryos.
Head and neck anatomy focuses on the structures of the head and neck of the human body, including the brain, bones, muscles, blood vessels, nerves, glands, nose, mouth, teeth, tongue, and throat. It is an area frequently studied in depth by surgeons, dentists, dental technicians, and speech language pathologists.
The head is positioned upon the superior portion of the vertebral column, attaching the skull upon C-1 (the atlas). The skeletal section of the head and neck forms the superior segment of the axial skeleton and comprises skull, hyoid bone, auditory ossicles, and cervical spine. The skull can be further subdivided into:
Body fluid, bodily fluids, or biofluids are liquids originating from inside the bodies of living people. They include fluids that are excreted or secreted from the body as well as body water that normally is not.
The dominating content of body fluids is body water. Approximately 60-65% of body water is contained within the cells (in intracellular fluid) with the other 35-40% of body water contained outside the cells (in extracellular fluid). This fluid component outside of the cells includes the fluid between the cells (interstitial fluid), lymph and blood. There are approximately 6 to 10 liters of lymph in the body, compared to 3.5 to 5 liters of blood.
Paranasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity (maxillary sinuses), above the eyes (frontal sinuses), between the eyes (ethmoidal sinuses), and behind the ethmoids (sphenoidal sinuses). The sinuses are named for the facial bones in which they are located.
Humans possess a number of paranasal sinuses, divided into subgroups that are named according to the bones within which the sinuses lie: