CNS PNS and ANS Central Nervous System Brain

CNS, PNS, and ANS Central Nervous System Brain Spinal Cord Peripheral Nervous System Cranial nerves Spinal nerves Autonomic Nervous System Sympathetic Parasympathetic

Central Nervous System Brain Sensory information received, motor control initiated; integration; sentience Protected by 8 cranial bones Surrounded by meninges and cerebrospinal fluid ▪ Dura mater, arachnoid mater, pia mater Spinal Cord Center for reflex arc Integration center for brain and spinal nerves Protected by vertebrae Surrounded by meninges and cerebrospinal fluid ▪ Lumbar puncture

Spinal Cord: Gross Anatomy Flattened cylinder Cervical enlargement Upper limb Lumbar enlargement Lower limb In adult ends at L 2 Conus medullaris Filum terminale (pia) Cauda equina Dorsal and ventral roots of most inferior spinal nerves The area of the spinal cord from which each pair of spinal nerves arises is called a spinal segment

Spinal Cord: Protection Vertebral column, meninges, cerebrospinal fluid, and vertebral ligaments .

Structures Covering the Spinal Cord Vertebrae Epidural space filled with fat Dura mater Dense irregular CT tube Subdural space filled with interstitial fluid Arachnoid mater Collagen fibers Subarachnoid space : CSF Pia mater Thin CT layer

Spinal Cord: Gross Anatomy Cross Section Gray matter (cells), white matter (axons) Central canal ( continuous with 4 th ventricle of brain) Posterior median sulcus, Anterior median fissure Dorsal root (afferent), Ventral root (efferent), Mixed spinal nerve Dorsal root ganglia (cell somas for sensory)

Gray Matter: Sectional Anatomy Horns of gray matter Posterior ▪ Somatic and visceral sensory Anterior ▪ Somatic motor Lateral ▪ Visceral motor (SNS) ▪ T 1 – L 2

Gray Matter: Sectional Differences Amount of gray to white matter dependent on level Presence/absence of lateral horn (ANS) dependent on level

Spinal Nerves Connect the CNS to sensory receptors, muscles, and glands Part of the peripheral nervous system 31 pairs of spinal nerves are named and numbered according to the region and level of the spinal cord from which they emerge Roots of the lower lumbar, sacral, and coccygeal nerves are not in line with their corresponding vertebrae and thus form the cauda equina Spinal nerves connect to the cord via an anterior and posterior root Posterior (dorsal) root contains sensory axons Anterior (ventral) root contains motor axons Exit CNS as mixed nerve

PNS: Spinal Nerves 31 pairs C 1 -C 8, T 1 -T 12, L 1 -L 5, S 1 -S 5, Co 1 Formed by fusion of dorsal and ventral roots C 1 exits between skull and first cervical vertebra 8 pairs of cervical spinal nerves but only 7 cervical vertebrae; above C 8 nerve pairs are named for the vertebra caudal to their exit, below C 8 they are named for the vertebra cranial to the exit

Nerve Plexus Segments of spinal cord that control the neck and limbs have a different distribution pattern for the ventral ramus Four Cervical (C 1 -C 5) Brachial (C 5 -T 1) Lumbar (T 12 -L 4) Sacral (L 4 -S 4)

Divisions of the ANS

Interactive Powerpoints Brain small Brainventricles Headmidsagittal (nervous system) Nervoussystem Neuron Spinalcordxs

Pituitary Hormones: Target Organs