Exam 2 Flashcards
The neurons of the CNS are located where?
Brain and spinal cord
Differences between the afferent and efferent neuron
Afferent = sensory, towards CNS
Efferent = motor neuron, CNS out to affector
Neuroglial Cells
Nerve glue cells, support and protect neurons
Six neuroglial cells
4 CNS
Astrocyte, Microglial cells, Ependymal cells, oligodendrocytes
2 PNS
Satellite cells
Schwann cells
Astrocycte
CNS Neuroglial cell
Blood brain barrier
Metabolize old neurotransmitter
Maintenance of Na and K levels
Microglial cells
CNS Neuroglial cell
Phagocytic
Ependymal cell
CNS Neuroglial cell
Choroid plexus, secretes CSF
Oligodendrocytes
CNS Neuroglial cell
“Few”
Myelinates axons in CNS
Satellite cells
PNS Neuroglial cell
Supports cell bodies in ganglia
Schwann Cells
PNS Neuroglial cell
Myelinates axons in PNS
Three basic parts of a neuron and function
Dendrite - carry impulses towards cell body
Cell body(Soma) - Control Center
Axon - carry impulses away from cell body
Path an impulse moves along neuron
Dendrite to cell body to axon
Multipolar neuron
Most common
Several dendrites, 1 axon
Bipolar neuron
Rare
1 dendrite, 1 axon
Associated with smell, vision, hearing
Two points of contact to cell body
Unipolar neuron
Rare
1 point of contact that spits into 1 axon and 1 dendrite
Peripheral sensory, not associated with motor function
Define stimulus
Any change in the internal or external environment
What causes a cell to be polarized?
RMP Resting Membrane Potential, Unequal distribution of Na and K, more Na outside, K in
All or none principle
If a stimulus is strong enough to reach a threshold, a complete nerve firing occurs, -70 to -55
Most common neurotransmitter
Acetylcholine
Continuous conduction
Waves of depolarization along entire membrane of a neuron
Present only in unmyelenated
Gray matter
Saltatory conduction
Impulse leaping over sheath to each node of ranvier to the next
Fastest
Three factors that influence nerve impulse conduction
Myelinated or not
Diameter of the axon(Bigger means better, more SA for ion channels)
Temperature, warm is better
Type A Nerve Fibers
Large diameter myelinated
130m/s
Type B Nerve Fibers
Medium diameter myelinated
15m/s
Type C Nerve Fibers
Small diameter unmyelinated
0.5-2m/s
Slow axonal transport
Moving materials within a neuron
One way mechanism, cell body to axon
1-5mm/day
Growth/Development
CELL REPAIR
Fast axonal transport
Two way mechanism
Cell body to axon and back
200 to 400mm/day
Daily maintenance
Autonomic Nervous System ANS
Subconscious sensation, control of smooth, cardiac, and glandular muscle tissue
Involuntary
Two parts of the Peripheral Nervous System PNS
Somatic and Autonomic
Somatic Nervous System SNS
Conscious, skeletal muscle, voluntary
Term for a collection of cell bodies found outside the CNS
Ganglion
Inferior structures associated with the spinal cord
Conus multilaris
Filum Terminalae
Cauda equina
Order of the meningeal layers of spinal cord
(Superficial to Deep)
Dura mater
Arachnoid Mater
Pia Mater
Area of the spinal cord that contains cell bodies of the somatic and autonomic motor neruons
Anterior grey horn(Somatic motor)
Lateral grey horn(Autonomic)
What is contained the posterior(dorsal) root ganglion?
Cell bodies of the unipolar sensory neurons
Five components of a reflex arc
Sensory receptor, sensory neuron, integrating center(spinal cord or brain), motor neuron, affector
Basic function of a sensory receptor
Convert a stimulus into a nerve impulse
Five types of reflexes
Spinal, Cranial, Somatic, Visceral, Pathological
Three Spinal Somatic Reflexes
Stretch, Tendon, Flexor/Crossed Extensor
Stretch Spinal Somatic Reflex
Monosynaptic
Ipsilateral
Segmental
Receptor: Muscle Spindle
Effect: Contract stretch muscle and relax antagonist
Tendon Spinal Somatic Reflex
Polysynaptic
Ipsilateral
Segmental
Receptor: Tendon organ
Effect: Relax the muscle that is generating tension and contract the antagonist
Flexor/Crossed Extensor Spinal Somatic Reflex (Withdrawal reflex)
Polysynaptic
Ipsilteral/Contralateral
Intersegmental
Receptor: Pain receptor
Effect: Contract flexor muscles to withdraw limb from pain/Contract extensor muscles on opposite side
How many pairs of spinal nerves?
31 pairs
8C
12T
5L
5S
1 cocyx
Connective Tissue Surrounding Nerves
Endoneurium
Surrounds individual axons
Connective Tissue Surrounding Nerves
Perineurium
Surrounds bundles(fascicles) of axons
Connective Tissue Surrounding Nerves
Epineurium
Surrounds the entire nerve
Ramus
Branch of a spinal nerve
Posterior ramus
Supplies DEEP muscle of skin on back(posterior aspect)
Anterior Ramus
Largest, supplies superficial back muscles, anterolateral trunk, upper and lower limb
Meningeal Ramus
Spinal cord, vertebral ligaments
Rami Communicantes
Supplies ANS sympathetic ganglion
What is a plexus?
Anterior rami fuse together
Cervical plexus
Posterior head, neck, top of shoulder. diaphragm
Brachial Plexus
Supplies upper limb C5-T1
Lumbar Plexus
Supplies anterolateral abdominal wall
Part of lower limb, anterior aspects
External genitals
L1-L4
Sacral Plexus
Supplies buttocks, lower limb posterior aspect, perineum
L4-S4
Coccygeal Plexus
Skin around coccyx
S5-Co1
Where is no plexus found?
Between T2-T12, intercostal nerves
Dermatome
Constant specific area of skin(innervated) to a specific spina nerve
No C1
Four principle parts of brain with subdivisions
Brain stem - medulla, pons, midbrain
Cerrebellum-2nd largest
Diencephalon - thalamus, hypothalamus
Cerebrum - largest,7/8, seat of intelligence
Where is CSF produced and what space does it circulate?
Corroid plexus secretes CSF in Two Lateral ventricles into the third ventricle, into the fourth ventricle into the subarachnoid space
What is the principle source of energy for the brain cells?
Glucose
Where are the cardiac and vasomotor centers located?
Medulla, most basic foundational primitive area
Cranial Nerves involved in eye movement
3,4,6
Cranial Nerves with only sensory, no motor
1,2,8
Functions of hypothalamus
Small inferior to thalamus
Coordination of ANS
Thirst Center
Hunger
Temperature regulation
Intermediary between nervous and endocrine system
Secrete ADH and oxytocin
Sleep and Wake cycle
Psychosomatic disorder, rage, agression, pain
Deep groves on surface of brain
Fissure
Shallow groove on surface of brain
Sulcus
Where are visual sensations identified?
Occipital lobe
Where is the primary motor area of the brain located?
Precentral gyrus of the frontal lobe
Function of the cerebellum?
Coordinate the postural(skeletal muscle) subconsciously that pertain to balance, equilibrium and posture
Post central gyrus of the parietal lobe
Somatosensory, dealing with sensation
Occipital lobe
Visual area
Temporal lobe
Hearing and olfaction
Anterolateral parietal lobe
Gustatory
Wernicke’s Area
Convert speech or written word into thought
Common integrative Area
Total sensory experience, merge all sensory information together
Precentral gyrus
Controls all skeletal muscle
Broca’s Area
Muscles in speech production
Frontal lobe pre motor area
Complex motor skills
Frontal eye field area
Controls muscles of eyeball for scanning eyeball movement
Four neuropeptides
Enkephalin - 200x more powerful than morphine
Endorphin
Dynophin - Natural opium, modify pain perception less than enkephalin
Substance P - spinal nerves, enhances pain perception
What plexus supplies the diaphragm?
Cervial plexus, phrenic nerve
Which part of brain links the nervous and endocrine system?
Hypothalamus
Where are the apneustic and pnemotaxic centers located?
Pontine Respiratory Center
Pons
Lateral gray horn
Contains cell bodies for the autonomic motor neurons
Posterior gray horn
Receives unipolar sensory neurons
Anterior gray horn
Cell bodies for the somatic motor neurons
CN I
Olfactory Smell(sensory)
CN II
Optic (Sensory) Vision
CN III
Oculomotor (mixed, primarily motor)
Motor: Movement of eyelid and eyeball, accommodation of lens for near vision, constriction of pupil
Sensory: muscle sense (proprioception)
CN IV
Trochlear (mixed, primarily motor)
Motor: Movement of eyeball
Sensory: muscle sense
CN V
Trigeminal
Ophthalmic, Maxillary, Mandibular Branches
Motor: Chewing
Sensory: Touch, pain, temperature from structures supplied, muscle sense
CN VI
Abducens (mixed, primarily motor)
Motor: movement of eye ball
Sensory: muscle sense
CN VII
Facial (mixed)
Motor: facial expression and secretion of saliva and tears
Sensory: taste, muscle sense
CN VIII
Vestibulocochlear (sensory)
Vestibular branch: conveys impulses associated withdraw with equilibrium
Cochlear branch: conveys impulses associated with hearing
CN IX
Glossopharyngeal (mixed)
Motor: swallowing movements and secretion of saliva
Sensory: Taste and regulation of blood pressure, muscle sense
CN X
Vagus (mixed)
Motor: Visceral muscle movement and swallowing movements
Sensory: Sensations from organ supplied, muscle sense
CN XI
Accessory (mixed, primarily motor)
Motor: bulbar portion mediates swallowing movements, spinal portion mediates movement of head
Sensory: muscle sense(proprioception)
Muscle sense
Proprioception
CN XII
Hypoglossal (mixed, primarily motor)
Motor: Movement of tongue during speech and swallowing
Sensory: muscle sense
Trigeminal Neuralgia
Chronic pain condition affecting Trigeminal(V) nerve in face, electric shock
Agnosia
Inability to recognize the significant of sensory stimulus such as sounds, sights, smells, tastes, and touch
Multiple sclerosis
Disease causing progressive destruction of myelin sheaths surrounding the neurons in the CNS
Parasthesia
Burning or prickling sensation felt in extremities
Neuralgia
Attacks of pain along the entire course or branch of a sensory nerve
Sciatica
Pain from pressure on sciatic nerve, typically runs down posterior aspect of lower extremities from herniated disc or bone spur
Nerve block
Loss of sensation in a region due to an injected anesthetic
Cranial nerves involved in eye movement IMPORTANT
3,4,6
Cranial nerves only involved in sensory
1,2,8
