Nervous System Introduction, Brachial Plexus Flashcards
List the functions of the nervous system
- Sensory, Motor, Cognitive
Name the major components of the nervous system
DIAGRAM - Anatomical organization of the nervous system
Compare characteristics of the central and peripheral nervous system
Central Nervous System (CNS)
- Unpaired, bilaterally symmetrical structure extending along the longitudinal axis of the midsagittal plane of the body
- Structures arising directly from the neural tube.
- Includes: brain, spinal chord
Peripheral Nervous System (PNS)
- Made up of transmission pathways carrying information between the CNS and external/internal environments.
- Afferent (sensory) pathways: carry information to the CNS
- Efferent (motor) pathways: carry information form the CNS.
- Includes: Cranial nerves (12 pairs) , spinal nerves (31 pairs)
- Also includes sensory receptors in skin and wall of gut tube as well as in tendons and skeletal muscles
- Also includes motor end plates between motor neurons and skeletal muscle fibers.
How many cranial nerve pairs and spinal nerve pairs are there?
- PNS includes cranial nerves (12 pairs), spinal nerves (31 pairs)
Describe characteristics of the autonomic nervous system, compare its two subdivisions and explain why it might be considered a subdivision of the peripheral nervous system.
- considered a subdivision of the PSN. WHY???**
- Entirely motor
- Innervates smooth muscle and glands (viscera)
ANS subdivisions - Sympathetic system: fight or flight, also called thoracolumbar
- Parasympathetic system: feed and breed (rest and digest), also called craniosacral.
Describe the general development pattern of the central nervous system and list the major derivatives from the cranial end of the neural tube.
Stages in neural tube development - Neural plate - Neural folds - Neural tube Subdivision of cranial end of tube - Tripartite brain - Pentapartite brain. ** do we need to know slides 12-16?
Describe the basic structural (anatomical) unit of the nervous system
- Cell body: tropic unit, perikaryon
- Dendrites: receptive unit
- Axon: conductive unit
Describe the characteristics of the cell body
- part of a neuron that encloses the nucleus and other organelles necessary to maintain and repair neurons Cell body organelles: - Nucleus - Golgi apparatus - RER: Ribosomes, =Nissan substance.
Describe the characteristics of the dendrites
- branches off the cell body that carry information to the cell body
- usually several to many
- relatively short
- often branched
- have receptors for neurotransmitters
- conduct local potentials
Describe the characteristics of the axon
- part of the neuron that carries information to another neuron or muscle cell
- relatively long
- single
- conducts action potential (nerve impulse)
- cell membrane is called axolemma
- cytoplasm is called axoplasm.
- ends in short branched processes called telodendria: give off endings Calle terminal boutons, terminal boutons contain synaptic vesicle of neurotransmitters.
- may ave collateral branches
- contain: mitochondria, neurofilaments, neurotubules
- covered by neurolemma: often myelinated
- Note: axon is only part of neuron that is ever myelinated
Describe the myelin sheath and identify the cells that form the myelin sheath
- Myelin is formed by Schwann cells
- Describe myelin sheath???? **
Name and describe the branches of the typical spinal nerve and distinguish between afferent and efferent paths
Spinal Nerve Branches - Dorsal primary ramus - Ventral primary ramus - Ramus recurrens - White ramus communicants - Gray ramus communicants Reflex Arc - Afferent (sensory) pathways: somatic, visceral (splanchnic) - Efferent (motor) pathways: somatic, visceral (splanchnic)
Nucleus
- aggregation of dendrites and nerve cell bodies in the CNS
Ganglion
- aggregation of dendrite and nerve cell bodies in the PNS
Nerve
- bundle of fibers (axons) in the PNS
Tract
- bundle of fibers (axons) in the CNS
Commissure
- tract in the CNS that crosses from one side to the other
White matter
- areas of myelinated axons
Gray matter
- areas of unmyelinated axons, cell bodies, and dendrites
Describe a reflex arc and distinguish between monosynaptic and polysynaptic reflex arcs
Reflex arc - Afferent (sensory) pathways - Efferent (motor) pathways - Association neurons (interneurons) Synapse - Monosnaptic pathways: Fig. 1-29 - Polysynaptic pathways: Fig. 1-29
List and describe the components of a synapse
- Presynaptic membrane: with synaptic vesicles filled with neurotransmitters
- Synaptic cleft:
- Postsynaptic membrane: with receptors for neurotransmitters
Describe the general cross-sectional anatomy of the spinal cord and distinguish between columns and horns
- Fig 1-34 —- 1-43
Cross-sectional anatomy of the spinal cord is organized into horns and columns - Horns: arenas of gray matter, posterior (dorsal), anterior (ventral), lateral
- Columns: areas of white matter, posterior (dorsal), lateral, anterior (ventral)
Describe the overall morphology of the spinal cord
- Cross-section through spinal cord showing locations of gray matter (blue) and white matter (yellow).
- Also note central canal and “H”-shape of gray matter
- Cross-section through human spinal cord showing locations of ascending and descending tracts.
Explain how spinal nerves are numbered
** slide 38
List the contents of the axillary sheath
- Axillary artery
- Axillary vein
- Brachial plexus
Draw the components of the brachial plexus as related to the rami, trunks, cords and terminal nerves.
** slide 46?
List the ventral rami that give rise to the brachial plexus and the direct branches from these rami
Ventral rami of C5-T1
- exits neck between scalenus anterior and scalenus mediums muscles
Direct branches from rami
- Dorsal scapular nerve: C5 to rhomboid muscles
- Long thoracic nerve: C5-7 to serrated anterior muscle
Identify the trunks of the brachial plexus, the rami that form the trunks and direct branches from the trunk(s)
Formed by ventral rami, located superior to clavicle above and behind subclavian artery
- superior (upper): from C5 and C6 ventral rami
- middle: from C7 ventral ramus
- interior (lower): from C and T1 ventral rami
Direct branches from trunk - from superior trunk
- Suprascapular nerve: C5, C6, to supraspinatus and infraspinatus muscles
- Nerveto subclavius
Distinguish between the anterior and posterior divisions of the brachial plexus and identify the destinations of the fibers they carry.
Anterior divisions
- carry fibers from trunks to anterior compartments of upper extremity
- form lateral and medial cords
Posterior divisions
- carry fibers from trunks to posterior compartments of upper extremity
- from posterior cord
Identify the cords of the branches plexus, their relations to the axillary artery, and their origins
Accompany axillary artery: named for relationship to artery
- Lateral: from anterior divisions of upper and middle trunks
- Posterior: form posterior division of all trunks
- Medial: from arterial division of lower trunk
For the lateral cord of the bronchial plexus, identify direct and terminal branches, spinal cord levels, and specific muscles innervated
Direct branches
- lateral pectoral nerve: C5-7, to clavicles head of pectoralis major muscle.
Terminal nerves
- musculocutaneous: C5-7
- lateral root of median nerve: C5-7
For the medial cord of the bronchial plexus, identify direct and terminal branches, spinal cord levels, and specific muscles innervated
Direct branches
- medial pectoral nerve: C8-T1, to eternal head of pectoralis major muscle and pectoralis minor muscle.
- medial cutaneous nerve to arm (brachium)
- medial cutaneous nerve to forearm (antebrachium)
Terminal branches:
- Ulnar: C8-T1
- Medial root of median nerve: C8-T1
For the posterior cord of the bronchial plexus, identify direct and terminal branches, spinal cord levels, and specific muscles innervated
Direct branches
- upper subscapular nerve: C5(6), to subscapularis muscle
- Thoracodorsal nerve: C6-7, to latissimus dorsi muscle
- Lower subscapular nerve: C(5)6, to subscapularis and there’s major muscles
Terminal branches
- Axillary nerve: C5-6
- Motor: to deltoid and there’s minor muscles
- Sensory: skin on the arm over deltoid muscle, upper lateral cutaneous nerve
- Radial nerve: C5-T1
- Motor: posterior compartments of arm and forearm, brachioradialis muscle
- Sensory: back of arm, forearm, hand
