Chapter 14-15-16 - The Peripheral Nervous System PDF

Peripheral Nervous System CNS PNS ✓  What is a Nerve? Inside a nerve (spinal or cranial) → organized bundles of axons some have axons of both sensory and motor neurons (called mixed nerve, like the one shown to the right) Some have axons of only moto...

Peripheral Nervous System CNS PNS ✓  What is a Nerve? Inside a nerve (spinal or cranial) → organized bundles of axons some have axons of both sensory and motor neurons (called mixed nerve, like the one shown to the right) Some have axons of only motor neurons (motor nerve) Some have axons of only sensory neurons (sensory nerve)  Nerves = Communication Lines BRAIN CRANIAL NERVE Sensory (from skin) SPINAL CORD SPINAL NERVE  Grouping of Nerves Nerves that are connected to the spinal cord – SPINAL NERVES → 31 pairs – Covered in Chap 16, section 16.4 Nerves that connect to brain or brainstem – CRANIAL NERVES → 12 pairs – Covered in Chap 15, section 15.8  Spinal Nerves There are 31 pairs of nerves connected to spinal cord Almost all of them are mixed nerves (contain axons of both sensory and motor neurons)  Spinal Nerves Closer look at attachment of spinal nerves to spinal cord POSTERIOR (dorsal) ROOT GANGLION POSTERIOR (dorsal) ROOT Spinal Nerve ANTERIOR (ventral) ROOT  Spinal Nerves Spinal nerves (extended view) Posterior (Dorsal) root Post. Root Ganglion Spinal nerves Anterior (Ventral) root (Anterolateral view)  Spinal Nerves Spinal nerves extensions/branches Dorsal ramus Posterior (Dorsal) root Post. Root Ganglion Rami communicantes Sympathetic Trunk Spinal nerves Anterior (Ventral) root (Anterolateral view)  Spinal Nerves Information travel in spinal nerves (mixed nerve shown below) – SENSORY information travels into spinal cord along posterior root Axons of neurons carrying signals synapse with other neurons in the sensory nuclei that will either connect to motor neurons (seen below) or that will carry the signal up the spinal cord to the brain/brainstem – MOTOR information travels out from spinal cord along anterior root Motor neurons (whose cell bodies lie in motor nuclei) carry signals out to skeletal muscle or involuntary tissues (smooth muscle, cardiac muscle, glands)  Nerve Plexuses Spinal nerves in certain areas of spinal cord intertwine to create a network called a plexus  What is a Nerve Branch? Spinal nerves of a plexus are numbered → further parts of plexus network are named We will learn the names, locations and functions of NERVE BRANCHES  Nerve Plexuses Spinal nerves in certain areas of spinal cord intertwine to create a network called a plexus We are going to learn about several nerves (actually, nerve branches) in 4 of the major plexuses Remember → stick to the highlighted info in your reading assignments  Nerve Plexuses Upper Body Plexuses – Cervical and Brachial Cervical Plexus – SN C1 thru C4 Spinal nerve C5 actually part of brachial plexus, so phrenic nerve “technically” part of both plexuses Cervical Plexus – SN C1 thru C4 Phrenic nerve controls diaphragm Spinal nerve C5 actually part of brachial plexus, so phrenic nerve “technically” part of both plexuses Brachial Plexus – SN C5 thru T1  Brachial Plexus - Branches Branch (nerve) Name Motor Fxn Sensory Fxn  Brachial Plexus - Branches Branch (nerve) Name Motor Fxn Sensory Fxn  Brachial Plexus - Branches Branch (nerve) Name Motor Fxn Sensory Fxn  Brachial Plexus - Branches Branch (nerve) Name Motor Fxn Sensory Fxn  Brachial Plexus - Branches Summary of brachial plexus nerves * Note: Nerves denoted by T1 (medial antebrachial cutaneous nerve) and T2 (medial brachial cutaneous nerve) are not covered in our class  Lower Plexuses Lumbar Plexus Sacral Plexus Note spinal nerve L4 shared between plexuses  Lower Plexuses Lumbar Plexus Sacral Plexus Lumbar Plexus – SN L1 thru L4  Lumbar Plexus - Branches Branch (nerve) Name Motor Fxn Sensory Fxn  Lumbar Plexus - Branches Branch (nerve) Name Motor Fxn Sensory Fxn  Sacral Plexus – SN L4 thru S4 --> Is a combination of 2 nerves (tibial and common fibular) Sciatic nerve Common fibular Tibial division division  Sacral Plexus - Branches Branch (nerve) Name Motor Fxn Sensory Fxn  Sacral Plexus - Branches Branch (nerve) Name Motor Fxn Sensory Fxn  Cranial Nerves 12 pairs of nerves connected to the brain and brain stem – Some pure sensory, some pure motor, some mixed  Cranial Nerve Memorization Oh Some See Tables 15.7 and 15.8 for all info on cranial nerves Once Say One Marry Takes Money The But Anatomy My Final Brother Very Says Good Big Vacations Brains Are Matter Heavenly More ** Know names, numbers and indicated function(s) of each cranial nerve!!!  Cranial Nerve Memorization Textbook reading assignments Look at it, where does it go? What does it do: Sensory? Motor? Autonomic?  Cranial Nerves 1-8 Oculomotor Mixed nerves Cranial Nerves 9-12 Mixed nerves