Chapter 13 Flashcards
Central Nervous System (CNS)
Brain and spinal cord; main processing center.
Peripheral Nervous System (PNS)
Cranial and spinal nerves; sensory and motor pathways.
Spinal Cord
Nervous tissue organ; connects brain to body.
Meninges
Three protective membranes surrounding CNS.
Gray Matter
Contains neuronal cell bodies; processes information.
White Matter
Composed of myelinated axons; transmits information.
Cervical Enlargement
Wider spinal cord region; supplies upper limbs.
Lumbosacral Enlargement
Wider spinal cord region; supplies lower limbs.
Conus Medullaris
Tapered end of spinal cord; below lumbar enlargement.
Cauda Equina
Nerve roots extending below conus medullaris.
Filum Terminale
Fibrous tissue; anchors spinal cord to coccyx.
Spinal Nerves
31 pairs; mixed nerves from spinal cord.
Anterior Root
Contains axons of motor neurons.
Posterior Root
Contains axons of sensory neurons.
Spinal Ganglia
Contains sensory neuron cell bodies.
Rami
Branches of spinal nerves; supply body regions.
Sensory Input
Information received by sensory receptors.
Motor Output
Commands sent to effectors like muscles.
Reflex Centers
Locations in spinal cord for reflex actions.
Neural Reflex
Automatic response to stimuli; involves spinal cord.
Cerebrospinal Fluid (CSF)
Fluid in central canal; protects and nourishes CNS.
Spinal Nerve Classification
Mixed nerves; contain afferent and efferent fibers.
Posterior Ramus
Supplies skin and muscles of the back.
Anterior Ramus
Supplies body wall, skin, and limbs.
Spinal Nerve Naming
Designated by vertebral region and number.
31 Spinal Segments
Each gives rise to a pair of spinal nerves.
Anterior Median Fissure
Deeper groove on anterior side of spinal cord.
Posterior Median Sulcus
Shallow groove on posterior side of spinal cord.
Cervical Region
Uppermost spinal cord segment; includes C1-C8.
Thoracic Region
Middle spinal segment; includes T1-T12.
Lumbar Region
Lower spinal segment; includes L1-L5.
Sacral Region
Includes S1-S5 spinal nerves.
Coccygeal Nerve
Single nerve; designated Co1.
Dura Mater
Outermost meningeal layer; tough and fibrous.
Arachnoid Mater
Middle layer; contains cerebrospinal fluid.
Pia Mater
Innermost layer; adheres to spinal cord.
Epineurium
Outermost layer surrounding spinal nerves.
Perineurium
Middle layer; surrounds nerve fascicles.
Endoneurium
Innermost layer; surrounds individual axons.
Dermatome
Skin area supplied by single spinal nerve.
Nerve Plexus
Network of interwoven nerve fibers.
Cervical Plexus
Innervates neck muscles and diaphragm.
Brachial Plexus
Innervates upper limbs and pectoral girdle.
Lumbar Plexus
Supplies lower abdominal and pelvic regions.
Sacral Plexus
Innervates pelvic organs and lower limbs.
Subarachnoid Space
Contains cerebrospinal fluid; between arachnoid and pia.
Spinal Ganglion
Cluster of sensory neuron cell bodies.
Axillary Nerve
Innervates deltoid and teres minor muscles.
Musculocutaneous Nerve
Innervates arm flexors; sensory from lateral forearm.
Radial Nerve
Innervates extensor muscles of arm and forearm.
Ulnar Nerve
Innervates flexor carpi ulnaris; sensory from hand.
Median Nerve
Innervates forearm flexors; passes through carpal tunnel.
Lumbosacral Plexus
Innervates pelvic girdle and lower limbs.
Femoral Nerve
Innervates quadriceps; sensory from anterior thigh.
Obturator Nerve
Innervates adductor muscles; sensory from medial thigh.
Sciatic Nerve
Largest nerve; splits into tibial and fibular nerves.
Iliohypogastric Nerve
Innervates abdominal muscles; sensory from lower abdomen.
Ilio-inguinal Nerve
Innervates abdominal muscles; sensory from groin area.
Genitofemoral Nerve
Sensory from anteromedial thigh and genitalia.
Lateral Femoral Cutaneous Nerve
Sensory from lateral thigh; L2-L3 roots.
Superior Gluteal Nerve
Innervates gluteus medius and minimus muscles.
Inferior Gluteal Nerve
Innervates gluteus maximus muscle.
Pudendal Nerve
Innervates perineum; sensory from external genitalia.
Phrenic Nerve
Controls diaphragm; arises from C3-C5.
Dorsal Scapular Nerve
Innervates rhomboids and levator scapulae.
Long Thoracic Nerve
Innervates serratus anterior muscle.
Thoracodorsal Nerve
Innervates latissimus dorsi muscle.
Suprascapular Nerve
Innervates supraspinatus and infraspinatus muscles.
Medial Antebrachial Cutaneous Nerve
Sensory from skin over forearm’s medial surface.
Carpal Tunnel Syndrome
Median nerve compression; causes sensory changes.
Spinal Nerve Segments
C1-C8, T1-T12, L1-L5, S1-S5.
Ansa Cervicalis
Innervates extrinsic laryngeal muscles via CN XII.
Cervical Plexus Nerves
Includes lesser occipital, great auricular, transverse cervical.
Posterior Femoral Cutaneous Nerve
Supplies skin over perineum and posterior thigh.
Saphenous Nerve
Supplies sensory innervation to the foot.
Sural Nerve
Provides sensory innervation to the posterior leg.
Fibular Nerve
Divides into superficial and deep fibular nerves.
Tibial Nerve
Innervates muscles in the posterior compartment of the leg.
Sensory Neurons
Bring information into the CNS; about 10 million.
Motor Neurons
Send commands from CNS to effectors; about 0.5 million.
Interneurons
Coordinate signals within the CNS; about 20 billion.
Reflexes
Automatic responses triggered by specific stimuli.
Spinal Reflexes
Controlled by spinal cord without brain input.
Reflex Arc
Neural pathway acting on impulse before brain processing.
Components of Reflex Arc
Includes sensory receptor, neuron, CNS processing, motor neuron, effector.
Monosynaptic Reflex
Simplest reflex arc with one synapse.
Polysynaptic Reflex
Involves one or more interneurons; slower response.
Innate Reflexes
Genetically programmed reflexes formed before birth.
Acquired Reflexes
Learned motor patterns enhanced by repetition.
Somatic Reflexes
Control skeletal muscle contractions; include stretch reflexes.
Visceral Reflexes
Control smooth muscle, cardiac muscle, or glands.
Stretch Reflex
Regulates muscle length; example: patellar reflex.
Withdrawal Reflex
Moves body part away from painful stimulus.
Reciprocal Inhibition
Inhibits antagonistic muscles during reflex actions.
Ipsilateral Reflex Arc
Occurs on same side as stimulus.
Crossed Extensor Reflex
Straightens opposite limb during flexor reflex.
Plantar Reflex
Toe-curling response; normal in adults.
Babinski Reflex
Toe extension in infants; indicates CNS damage in adults.
Hyporeflexia
Decreased reflex response; linked to PNS disorders.
Hyperreflexia
Increased reflex response; associated with CNS disorders.