Sympathetic Nervous System Molly Fiser Michael Banta Landon Reynolds Justin Mosteller

What is sympathetic nervous system? The sympathetic nervous system is a division of the autonomic nervous system responsible for “fight” or “flight” reactions; primarily concerned with the elevation of metabolic rate and increased alertness. Ex: adrenaline rush. Being crushed under a 2 ton boulder. Your body will know it is in danger and adrenaline will be released to give your body the strength it needs to lift the boulder off of yourself.

Functions Maintain normal digestive tract contractions and secretions. Maintain the normal tone of smooth muscle. Maintaining blood pressure. “Fight” or “Flight”- The body’s response to emergency situations that induce high stress levels. Serves as the defense mechanism against stress.

What triggers it? Sympathetic neurons communicate with peripheral sympathetic neurons through the ganglia. They join together through chemical synapses. During the synapse the preganglionic sumpathetic neurons realease ACh. The ACh binds to and activates nicotinic acetylcholine receptors. In response to the stimulus, the postganglionic neurons release norepinephrine. This prolonged activation releases adrenaline from the adrenal medulla. Once released the adrenaline and norepinephrine bind together, which causes the effects seen during the flight or flight response.

Epi-Pen The epi in epi-pen stands for epinephrine also known more commonly as adrenaline. When injecting your self you stimulate your 4 major receptors causing a fight of flight syndrome. This adrenaline rush will suppress your immune system, causes a higher blood supply, helps breathing, and stops bladder contraction. All these factors help with allergies and allergic reactions, which may save your life.

Effect on body! Dilates pupil in eye. Inhibits salivary gland secretion. Relaxes bronchi in lungs. Accelerates heart. Inhibits activity of stomach and intestines. Stimulates glucose release from liver; inhibits gallbladder. Stimulates adrenal medulla. Inhibits emptying of bladder. Promotes ejaculation and vaginal contractions.

Adrenaline Adrenaline is a hormone produced by the adrenal gland. When it is produced in the body it stimulates the heart rate, dilates blood vessels and air passages. It’s naturally produced in high stress or physically exhilarating situations.

Receptors Alpha receptors- –alpha-1: The result is the release of intracellular calcium ions from reserves in the endoplasmic reticulum. –alpha-2: Has an inhibitory effect on the cell. Beta receptors- –beta-1: Increase in heart rate and force of contraction in the heart. Increase in metabolic activity in skeletal. –beta-2: Create a relaxation of smooth muscle.

Sources McGuigan, Brenden. (2009, December 01). What is Adrenaline?. Retrieved from Martini, F. H. (1995). Fundamentals of anatomy and physiology. Englewood Cliffs, New Jersey: Prentice Hall. Campbell, Neil, & Reece, Jane. (2009). Biology. Benjamin Cummings Pub Co. Armbruster, David, Musker, Frank, Irwin, Leslie, Anthony, Catherine, & Thibodeau, Gary. (1987). Textbook of anatomy & physiology. Times Mirror Magazine. Sympathetic nervous system. (2009). Retrieved from