pancreas, intestines - and some of the urinary structures - the kidney and

WGU Anatomy and Physiology 1

• accessory organs of the digestive system - the liver, gallbladder, and

pancreas

• types of neurons - sensory neurons, interneurons, and motor neurons

Abdominal - Between the chest and the pelvis

Abdominal cavity - Contains most of the digestive organs - stomach, liver, pancreas, intestines - and some of the urinary structures - the kidney and the ureters. The upper boundary is the diaphragm and the lower boundary is the brim of the pelvis (landmark of the pelvis bones)

Abdominopelvic cavity - Since there is no anatomical division between the

• cavities they are occasionally referred to as 1 region

Abducens nerve - motor, eye movements

Accessory nerve - motor, swallowing, and head, neck, shoulder movement

action potential - a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory.Action potentials occur in several types of animal cells, called excitable cells, which include neurons, muscle cells, and endocrine cells. Action potentials are generated by special types of voltage-gated ion channels embedded in a cell's plasma membrane.[b] These channels are shut when the membrane potential is near the resting potential of the cell, but they rapidly begin to open if the membrane potential increases to a precisely defined threshold value. When the channels open (in response to depolarization in transmembrane voltage[b]), they allow an inward flow of sodium ions, which changes the electrochemical gradient, which in turn produces a further rise in the membrane potential. This then causes more channels to open, producing a greater electric current across the cell membrane, and so on. The process proceeds explosively until all of the available ion channels are open, resulting in a large upswing in the membrane potential. The rapid influx of sodium ions causes the polarity of the plasma membrane to reverse, and the ion channels then rapidly inactivate. As the sodium channels close, sodium ions can no longer enter the neuron, and then they are actively transported back out of the plasma membrane. Potassium channels are then activated, and there is an outward current of potassium ions, returning the electrochemical gradient to the resting state.

Adrenal Gland Cortex - Produces mineralocorticoids (aldosterone) affects kidneys and promotes water balance. Also produces Glucocorticoids (cortisol) affects Liver and promotes Immune function. Also produces Macromolecule promotes metabolism.

Adrenal Gland Medulla - Produces Catecholamines (epinephrine and norepinephrine) affects various tissues and stimulates the fight-or-flight response.

Adrenal glands - Produce steroid hormones that regulate metabolic functions during stress, kidney function and sexual function, also secrete epinephrine or adrenaline when stimulated

Alimentary canal, also called the gastrointestinal GI tract or gut - a continuous muscular tube that runs from the mouth to the anus

Alveoli - Tiny terminal air sac that consist of a single cell wall that allows passage of oxygen to blood and diffuses carbon dioxide into the lungs to be exhaled

Amino Acid - any of a class of organic compounds that contains at least

one amino group, -NH 2, and one carboxyl group, -COOH: the alpha-amino

acids, RCH(NH 2)COOH, are the building blocks from which proteins are constructed.

Amylase - enzyme that facilitates the breakdown of carbohydrates

Anaxonic neurons - small, stellate star-shaped cells with processes that all look alike with no apparent axon, can be found in the central nervous system, the retina, and in the adrenal medulla. Their functions are not well understood.

Anterior horn - contains the somatic motor neurons, and it sends efferent signals from the spinal cord to the muscle cells it controls.

Anterior or ventral - Toward the front or toward the belly

Anterior Pituitary - Growth Hormone- affects all Tissues and promotes growth. Adrenocorticotropic hormone (ACTH) affects the Adrenal Cortex

and stimulates release of hormones from the adrenal cortex.Gonadotropins affects the (Follicle stimulating hormone and Luteinizing Hormone)

Apocrine glands - Secretions moisten the skin during pain, fear, sexual arousal and emotional upset

Arachnoid mater - named for the spider-web appearance acts like a cushion for the brain.

Arteries - Carry oxygenated blood from the heart to provide oxygen and nutrients to every cell in the body. Branches are known as arterioles deliver blood to capillaries.

Astrocytes - provide a structurally supportive framework for neurons, help form protective blood-brain barrier, maintain the concentration of chemicals in the extracellular space, react to neural tissue damage by forming scar tissue in the damaged space.

Atom - Basic unit of matter, consists of a nucleus surrounded by electrons

Auricle of ear - Location: Head lateral. Description: Appendage of skin, cartilage, and connective tissue, contains part of external acoustic meatus

Also known as: External ear or pinna. Acts like a funnel to collect and

modify sound waves. Latin: auri = an ear

Autonomic nervous system or ANS - Sends signals from the CNS to the involuntary regions of the PNS, is further subdivided into the sympathetic division and the parasympathetic division.