NEURO: Intro to Nervous System Flashcards
How is the nervous system divided?
PNS and CNS
What is the function of the PNS
Conduct impulses to or away from the CNS
What is the function of the CNS
Integrate & coordinate incoming and outgoing neural signals Carry higher mental functions
Where is the gray matter found?
In the cortical layer (cortex) on the surface of the forebrain and cerebellum
What are tracts?
A bundle of axons traveling from one are to another within the CNS. In the PNS axon bundles are called a nerve.
What are the main fissures?
Longitudinal
Central sulcus of Roland
Lateral or Sylvian fissure
Parietooccipital fissure
What are the main sulcus?
Cingulate sulcus
Paracentral sulcus
Central sulcus (Roland)
Marginal sulcus
Parietooccipital sulcus
Calcarine sulcus
How is the forebrain divided?
Telencephalon
Diencephalon
How is the diencephalon divided?
Thalamus, hypothalamus, epithalamus, subthalamus
How is the hindbrain divided?
Metencephalon and medulla
What is the primary motor cortex gyrus of contralateral voluntary movements?
Precentral gyrus
What is the primary somatic sensory cortex gyrus?
Postcentral gyrus
Which lobe is the primary motor cortex controling voluntary movements?
Frontal lobe
What is Broca’s area?
Production of written and spoken language, primarily in the dominant (typically left)
What cortex is in charge of processing intellectual and emotional events?
Prefrontal cortex
Which lobes is important in regulating somatosensory, language and spatial orientation functions?
Parietal lobe
Which cortex and gyrus process tactile and pain information form parts of the body?
Somatosensory cortex, postcentral gyrus
Which lobe is important for processing auditory information (Primary auditory cortex), language, and certain complex functions?
Temporal lobe
Which lobe is involved in processing visual information. Visual association areas surround it and mediate the ability to see and recognize objects?
Occipital lobe
A portion of neocortex covered by portions of frontal, parietal and temporal lobes is called:
Insula (Island of Reil)
What is the insula’s cortex function?
Receives nociceptive and viscerosensory input
Loss of addictive behaviors
A ring of cortex in the frontal, parietal and temporal lobes that contributes to “this” lobe, however, it is NOT a true lobe: modulates memory, learning and behavior
Limbic lobe
What are limbic structures?
Amygadala, hippocampus, stria terminalis
Play a central role in a number of neurological conditions such as:
• Parkinson
• Obsessive Compulsive Behavior (OCD)
Routine, habit behaviors
Basal ganglia
Bounded anteriorly by the anterior commissure, a fiber bundle containing many olfactory and temporal lobe fibers and posteriorly by the posterior commissure
Diencephalon
hypothalamus plays a role in limbic system by:
coordinating and integrating endocrine, autonomic and homeostatic functions. It regulates temperature, endocrine functions, feeding, drinking, emotional & sexual behaviors:
A critical “station” that process all sensory information (except for olfaction) on its way to the cortex:
Thalamus ‘gatekeeper’
Provides the conduit by which all ascending and descending information travel to the brain from the spinal cord and viceversa:
Brainstem
Cavities within each hemisphere that contains cerebrospinal fluid:
Ventricles
Order of brain ventricular system:
Lateral ventricle - interventricular foramen - 3rd - aqueduct - 4th
CSF circulation:
choroid plexus - ventricles - foramen of luschka and magendie - central canal - subarachnoid space
Which nuerons are glutamatergic and project axons from the dorsal and intermediate gray horn to the thalamus, brainstem or cerebellum?
Second-order sensory neurons
Which neurons located in the ventral horn and project to skeletal muscle?
Cholinergic motor neurons(Ach)
Which neurons are located in the intermediate gray matter and project to autonomic ganglia?
Cholinergic autonomic preganglionic neurons
Which neurons Integrate segmental activity that controls spinal sensory processing & motor and autonomic outputs?
Interneurons
Inhibitory interneurons are:
GABAergic or glycinergic
Excitatory neurons are:
glutamatergic
Which nuerons axons remain on ipsilateral (same side) gray matter within a cord segment?
Local neurons
Which neurons axons cross midline to terminate in contralateral (opposite side) gray matter?
Commisural neurons
Which neurons axons project rostrally (superiorly) or caudally (inferiorly) in surrounding white matter for several segments before terminating in gray matter?
Propriospinal neurons
The spinal gray matter at each level is divided into 10 cell layers, or____ , on the basis of neuronal size, cell density, staining characteristics, and input and outputs
Rexed laminae
Which nucleus is:
found at all cord levels (in lamina I)
associated with light touch, pain and temperature sensations
contains somas of 2nd-order sensory neurons that project to the thalamus
Dorsomarginal nucleus
Which nucleus is found at all cord levels (mostly in lamina II)
associated with light touch, pain and temperature sensations
contains somas of 2nd-order sensory local interneurons that integrate inputs from incoming primary sensory neurons
Substantia Gelatinosa
Which nucleus is found at all cord levels (mostly in laminas III & IV)
associated with light touch, pain & temperature sensations
contains somas of 2nd-order sensory neurons that project to the thalamus
Nucleus Propius (proper sensory nucleus)
Which nucleus is found at spinal levels (C8)T1-L2 (L3), at the base of dorsal horn or the intermediate gray matter
associated with unconscious proprioception (muscle spindles & golgi tendon organs)
contains somas of 2nd-order sensory neurons that project to the cerebellum
Nucleus Dorsalis of Clarke
Which nucleus is found at spinal levels T1-L3
contains somas of preganglionic sympathetic motor neurons (GVE) that project to sympathetic ganglia
contains, at T1-T2, the ciliospinal nucleus (center of Budge), source of sympathetic innervation of the eye
Intermediolateral Nucleus
Which nucleus is found at all spinal levels, include nuclei for specific motor
nerves, such as the: spinal acc nucleus and phrenic nucleus
Somatic Motor Nuclei
More ___ nuclei (in ventral horn) innervate extensor muscles
Ventral
More ____ nuclei (in ventral horn) innervate flexor muscles
Dorsal
___ nuclei innervate appendicular (extremities) or distal musculature
Lateral
____ nuclei innervate axial or trunk musculature
Medial
Which nuclei is found at spinal levels S2-S4
contains cell bodies of preganglionic parasympathetic motor neurons (GVE) that project to ganglia of the pelvic viscera
Sacral Parasympathetic Nucleus
Which laminae contains projection neurons that send axons across midline in ventral spinal commissure to ascend contralaterally towards thalamus, cerebellum & brainstem. Some neurons project ipsilaterally.
Laminae I, III, IV and V
Which lamina contains local interneurons regulate activity of neurons in other dorsal horn laminae?
Lamina II
Which laminae contain various types of interneurons?
Laminae VI and VII
Which laminae contains interneurons (e.g. Renshaw) and neurons that receive input from muscle afferents and fibers descending from the brainstem and cortex?
Lamina VIII
Which lamina contains motor neurons that project to skeletal muscle?
Lamina IX
Which is the entry zone for primary sensory afferents of the DRG?
Its axons become segregated according to fiber size and function
Dorsal Root Entry Zone
Which axons are skin mechanoreceptors and muscle/tendon proprioceptors and form a medial bundle, entering the dorsal column and ending in deep laminae of dorsal horn
Large myelinated axons
Which axons are for pain, temperature, visceral sensations) form a lateral bundle, the tract of Lissauer, that terminates directly in laminae I and II.
Small myelinated or unmyelinated axons
Which are the ascending pathways?
} Fasciculus Gracillis
} Fasciculus Cuneatus
} Spinocerebellar tracts (D & V)
} Spinothalamic tracts (L & V)
Which are the descending pathways?
Corticospinal tracts (L & V)
Rubrospinal tract
Reticulospinal tract
Vestibulospinal tract (L & M)
Tectospinal tract
Innervates EXTRAFUSAL muscle fibers
Alpha (α) LMNs
Innervates intrafusal muscle fibers
Gamma LMNs
Alpha (α)-motor neurons project axons to extrafusal muscle fibers where they form a specialized synapse called the ____
motor end plate
Responds to stretch/length change providing signal to CNS
Muscle spindles
originate at center region of intrafusal fibers
Ia and II sensory endings
Innervate contractile polar ends of intrafusal fibers
Gamma motor neurons
Only polar ends are contractile; central regions are non-contractile
Intrafusal muscle fibers
Resist sustained contraction of a muscle to protect tendon from damage during contraction of the muscle
Golgi tendon reflex
Reception of painful or noxious stimulus results in contraction of ____ muscles on same side
flexor
Excitation of motor neurons innervating CONTRALATERAL ___ muscles
extensor
Inhibition of MNs innervating CONTRALATERAL ___ muscles
flexor
muscle spindles are organized in parallel with extrafusal muscle fibers, during voluntary/conscious movement it is necessary to activate:
alpha-gamma coactivation
funnel shaped interruptions in myelin sheath structures of nerve fibers
Schmidt Lanterman incisures: SLIs
in schwann cells
Upon Schwann cell adherence and axonal myelination
Sodium Channel Clustering at Nodes of Ranvier
what pathology causes: Experimental allergic encephalomyelitis
myelin pathology
Chronic disease that damages the nerves in the white matter of the CNS and spinal cord.
multiple sclerosis
Used as experimental model for investigation of demyelination.
• Immunopathology and neuropathology mechanisms leads to key pathological features of MS: inflammation, demyelination, axonal loss and gliosis in the CNS.
Experimental allergic encephalomyelitis (EAE)
Autoimmune disease: attack peripheral nerve myelin (Schwann cell myelination).
Guillain-Barre Syndrome
Blood-brain barrier consists of:
(1) endothelial cells lining… the capillary wall with tight junctions between them.
(2) processes of astrocytes… abutting on the capillaries as perivascular end-feet.
(3) a capillary basement membrane.
examples of endothelial cells in the BBB?
clauddin, occludin, jams, zo1, zo2, zo3
Ensheathe blood vessels in the brain and are believed to provide structural integrity to the cerebral vasculature.
Astrocyte end feet
Sheet-like ECM (extracellular matrix) complex beneath epithelium and endothelium.
Basement Membrane
Functions of microglia:
- Immune role in CNS
- Maintain central homeostasis
- Combat disease: neuroprotective role
(microglia>phagocytic macrophages)
polarization!!!
M0- resting
M1-Inflammatory marker??
iNOS
M2- Antiinflamatory marker
Arginase I
Structures locate in the midline of the ventricular system.
Participate in biochemical signaling and cell exchange between the brain and the blood (ex. hormonal control).
Circumventricular Organs
gatekeeper of neurological function
Claudin-5 in the BBB
deficiency of ____ brain will not grow
glut-1
brain metabolism requires:
glucose, fructose, lactose
have evolved to enhance blood flow and utilization of metabolites in areas of neural activity:
neurovascular and neurometabolic coupling mechanisms
blocks 20-HETE to produce more blood
NO-
what is Neurovascular coupling
blood flow (CBF), glucose consumption and oxygen metabolism increased in localized regions of activity after neuronal stimulation.
NEUROMETABOLIC COUPLING:
neurons use more ____
muscles use more ____
oxidation
glycolisis
astrocytes prefer ___ for neuron feeding
lactose
insufficient oxygenation
hypoxic
insufficient blood-flow
ischemic
hypoxia First result of energy depletion:
failure of Na and K pumps
Depolarization
Glutamate release
Main Consequences of CNS Ischemia:
angiogenesis
edema
vascular permeability
What can cross the BBB?
glucose, aminoacids - carrier mediated
non polar, lipid soluble - diffusion
vomiting after chemo occurs in
area postrema
what part can allow molecules in the brain to affect function?
circumventricular organs, no bbb
osmotic edema and rapid death is caused by:
hypoxia
The autonomic nervous system is. subdivided into:
Sympathetic and parasympathetic
Sensory (afferent) and motor (efferent) innervation of all body
Somatic
The CNS responds to the external and internal world via:
somatic efferent and autonomic nervous sistems
The 4 PNS ganglia:
- Dorsal Root Ganglia
- Sympathetic Chain Ganglia (Paravertebral)
- Sympathetic Prevertebral Ganglia
- Parasympathetic Ganglia
The region of skin innervated by each segmental nerve is a
Dermatome
CNS blood supply:
2 posterior spinal arteries
2 vertebral arteries
Intercostal arteries
