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simplest level of structural hierarchy in humans. Atoms form molecules, which form organelles, which form cells.
Cells are the smallest units of living things. All cells have some common functions, but individual cells vary widely in size and shape, reflecting their unique functions in the body.
tissues are groups of cells that have a common function. The tissue level is there in organisms that are more complex, such as humans.
organisms do this to keep the internal environment distinct from the external environment
can occur at the cellular or organismal level. In cells, the cell divides and creates a daughter cell. In humans, the sperm and egg unite to form a zygote
accounts for 60-80% of body weight and is the single most abundant chemical source in the body
normal body temperature
98.6 degrees F in humans. If the temperature drops too drastically cold or hot, the organism will die.
process by which organisms maintain a relatively stable internal environment even though the outside world is changing constantly.
determines the set point(the level or range at which a variable is to be maintained), analyzes the input it receives and then determines the appropriate response or course of action.
positive feedback mechanisms
the result or response enhances the original stimulus so that the activity(output) is accelerated
standard body position where the body is erect with the feet slightly apart. Also called the anatomical reference point.
runs horizontally from right to left, dividing the body into superior and inferior parts
runs within the bony vertebral column. it encloses the delicate spinal cord.
ventral body cavity
as two major subdivisions(thoracic cavity and abdominopelvic cavity). it houses organs collectively called the viscera.
surrounded by the ribs and muscles of the chest. divided into pleural cavities and medial mediastinum
encloses the heart, and surrounds the remaining thoraric organs (esophagus, trachea, and others)
division of the thoraric cavity. It contains the abdominal cavity and the pelvic cavity.
superior portion of the abdominopelvic cavity that contains the stomach, intestines, spleen, liver, and other organs.
inferior part of the abdominopelvic cavity that lies in the bony pelvis and contains the bladder, rectum, and some reproductive organs.
thin layer of lubricating fluid that separates the serous membranes. This fluid fills the cavity between the membranes.
right and left iliac/inguinal regions
located lateral to the hypogastric region(iliac=superior part of the hip bone)
oral and digestive cavities
mouth. it contains the teeth and tongue. it is part of and continuous with the cavity of digestive organs, which opens up to the anus.
located within the posterior to the nose, the nasal cavity is part of the respiratory system passageways.
middle ear cavities
carved into the skull and lie just medial to the eardrums. they contain tiny bones that transmit sound vibrations to the hearing receptors in the inner ears.
joint cavities. they are enclosed with fibrous capsules that surround freely moveable joints of the body.
closer to the origin of the body part or the point of attachment of a limb to the body trunk
farther away from the origin of the body part or the point of attachment of a limb to the body trunk
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