1) Peripheral Nervous System (PNS) outside of brain and spinal cord
a) Somatic Nervous System – things that are voluntary
i) Afferent nerves- PNS to CNS sensory signals like eyes, ears, smell; signals coming from outside in ii) Efferent nerves- CNS to PNS skeletal muscle; signals coming from the inside out; most inside it could be is the brain
b) Autonomic Nervous System – processing things that are involuntary; king of viscera (organs)
i) Afferent nerves- Viscera to CNS; from outside in; from organs to brain ii) Efferent nerves- CNS to PNS; from inside out
(1) Parasympathetic nervous system- rest and digest; acts to conserve, save energy; related to psych relaxation; doing things to your body that help you later on when you will need to use your sympathetic NS; Behaviorally: decrease in heartbeat, in blood pressure, increase in digestion; Neuroanatomically: known as cranio-sacral because they originate between brain stem (medulla) and sacral (S2,S3,S4); Biochemically: travel thru 2 ganglia to effector organ, 1st ganglia (preganglion): long myelin, 2nd ganglia (postganglion); short (unmyelinated), preganglion: acetylcholine, postganglion: acetylcholine cholinergic receptors
(2) Sympathetic nervous system- fight or flight; stimulates, organizes, and mobilizes energy in threat; related to psych arousal; Behaviorally: increase in heartbeat, increase in blood pressure, decrease in digestion, increase in metabolism of fat and glycogen; Neuroanatomically: originates from thoracic (T1-) and lombar (L2); Biochemically: travel thru 2 ganglia to effector organ, 1st ganglia (preganglion): SHORT unmyelin, 2nd ganglia (postganglion): LONG (myelinated), preganglion: acetylcholine, postganglion: norepinephrine adrenergic receptors (sweat glands ACh)
-Groups of axons that are in PNS are defined as nerves; groups of axons in CNS are defined as tracts
-Groups of cell bodies that are in PNS are defined as ganglia; groups of cell bodies in CNS (brain) are defined as nuclei
-Sympathetic & parasympathetic are always working but depending on situation, one is dominating the other
- Acetylcholine (cholinergic effect)- neurotransmitter to help with learning and memory
Functions of the Sympathetic and Parasympathetic
1. Sympathetic Effect (Noradrenergic Receptors): Salivary gland- decreases secretion, heart- increases heart rate, blood vessels- constricts blood vessels, iris radial muscle- dilutes pupil, iris sphincter muscle- no effect, tear gland- no effect, sweat gland- stimulates secretion, stomach & intestine- no effect, lungs- dilates bronchioles, arrector pili muscle- piloerection, penis – ejaculation.
2. Parasympathetic Effect (Cholinergic Receptors): Salivary gland- increases secretion, heart- decreases heart rate, blood vessels, dilates blood vessels, iris radial muscle- no effect, iris sphincter muscle- constricts pupils, tear gland- stimulates secretion, sweat gland- no effect, stomach & intestine- stimulates secretior, lungs- constricts bronchioles, arrector pili muscle- no effect, penis- erection (MSF).
Penis is a smooth muscle (hollow organ) involuntary in terms of changing its shape.
Relaxed smooth muscle cell (erection)- increase relaxation of smooth muscle (walls of blood vessels), increase blood flow, blood fills cavern.
Contracted smooth muscle cell (soft)- the arteries of a limp penis are constricted, and they keep blood from entering the corpus cavernosa.
Viagra? Was first developed for treatment of hypertension, and high blood pressure. Encourages the release of acetylcholine which means the parasympathetic nervous system is activated.
-Over the meds (sympathomimetics) virus invade mucous membranes (nose), blood vessels dilate (swelling)
1. Sympathetic: blood vessels – constricts blood vessels, salivary gland- decreases secretion, heart- increases heart rate, iris muscle- dilates pupils
2. Parasympathetic: blood vessels- dilate blood vessels, salivary gland- increases secretion, heart- decreases…