Compare the functions of the CNS & PNS

 Identify the principle parts of the nervous system  Describe the cells that make up the nervous system  Describe what starts and stops a nerve impulse (action potential)  The role of neurotransmitters  Compare the functions of the CNS & PNS  Identify the principle parts of the brain

 CNS = spinal cord & brain  PNS = nerves carry (tissue) impulses to and from brain  Motor Output side of chart has 2 divisions: somatic and autonomic  Focus Somatic 1 st then Autonomic

 Requires only one neuron system: CNS to cell  12 pairs cranial nerves ◦ From brain’s underside/brain stem ◦ Brain to muscles, glands, head, neck, thorax, abdomen  31 pairs spinal nerves ◦ Originate from spinal cord ◦ Dorsal root ganglia– sensory incoming AP from tissues to cord ◦ Ventral root ganglia– motor outgoing AP away from cord to body  Connects CNS to body parts

 Spinal Reflexes – require no conscious thought – spinal cord only  E.g. flexor reflex – withdrawal of foot from something sharp  Knee-jerk reflex (check up) – tap below patella causes contraction of thigh and upward movement of foot and leg  Stretch (quadriceps) reflex – posture maintenance – stand and move w/out having to think about it

 Sympathetic – stress / high activity  Parasympathetic – resting, homeostasis  2 neuron system to transmit impulses to target cells  1 st neuron - preganglionic in CNS  2 nd neuron – postganglionic outside CNS & extending to the far reaches of the body (glands/organs)  Sympathetic & Parasympathetic oppose each other – work antagonistically for homeostasis

 Neurotransmitters ◦ Sympathetic – norepinephrine (adrenalin) - stress ◦ Parasympathetic – acetylcholine - relax

 Central location & action  Integrating & processing of information  Info in  CNS  Complex Output

 Normal thoughts Dark thoughts

 Reflexes and the reflex arc – terms  Learning Target #5 (Nervous System) p 135: Describe the structure of a reflex arc and the function of a reflex

 Bone, meninges & blood-brain barrier  Bone: skull & hollow vertebrae  Meninges: CNS enclosed by 3 membranous layers ◦ Out  In ◦ Dura matter – arachnoid matter – pia matter

CNS is bathed in cerebrospinal fluid  Fills the space between the arachnoid matter & pia matter  Functions as a liquid shock absorber  Isolates the CNS from infection (meningitis: bacterial or viral infection of meninges can spread to CNS)

 CSF is like the interstitial fluid that bathes all cells but it does not exchange substances as freely with blood  Capillaries in this area are “tight” = not leaky & substances must pass through the actual capillary cells (vs. slipping between narrow slits of adjacent capillary cells) to get from blood to the brain

 Lipid soluble substances pass easily (O & CO 2 )  Glucose requires active transport  Larger molecules: proteins, viruses, bacteria kept out  What can pass through BBB? ◦ Alcohol ◦ Caffeine ◦ Nicotine ◦ Cocaine ◦ Anesthetics

 Information super highway for APs between the brain and the body  Recall – spinal reflexes don’t involve brain and therefore are considered “unconscious”  Size – about the diameter of your thumb  Location – runs from the base of your skull to the area of the 2 nd lumbar vertebra ~ 17 inches

white matter – ascending sensory nerves & descending motor nerves  Outer portions of the cord consist of bundles of axons = nerve tracts that are mylenated = white matter – ascending sensory nerves & descending motor nerves gray matter – here sensory & motor neurons synapse & transmit to the brain…  Inner portions consist of cell bodies, dendrites, neuroglial cells that are unmylenated = gray matter – here sensory & motor neurons synapse & transmit to the brain…