Nervous System Flashcards
What are the subdivision of each branched of the Nervous System?
CNS -Brain -Spinal Cord PNS -cranial nerves -spinal nerves ANS -sympathetic -parasympathetic
The sympathetic system is also referred to as…?
Thoracumbar
What is the parasympathetic system also called?
Craniosacral system
Efferent fibers function as _______ fibers and Afferent fibers function as __________ fibers.
Efferent: motor
Afferent: sensory
What is characteristic of dendrites?
Theres many of them, that are relatively short branched and carry information to the cell body.
They have receptors for neurotransmitters and conduct local potentials
What are some characteristics of a neuron Axon?
Long, single, conducts action potential. Ends branch into telodendria
Collateral branches
Cell membrane called axolemma
Cytoplasm called axoplasm
The axon contains
- mitochondria
- neurofilament
- neurotubules
Neuroleptic: schwann cells, that’s usually myelinated.
What part of the neuron is capable of axonal transport?
The axon
- antegrade
- retrograde
- slow transport
- fast transport
A nerve in the PNS is comparable to ______ in the CNS. What is a ‘nerve’?
tracts in CNS,
Nerves and tracts are bundles of fibers, these fibers are only axons, but not the entire cells.
A ganglion in the PNS is what in the CNS?
Nucleus. Ganglion and Nucleus are aggregation of dendrites and nerve cell bodies in the PNS and CNS respectively
What’s the difference between white matter and grey matter?
White matter is areas of myelinated axons while great matter is areas of unmyelinated axons, cell bodies and dendrites.
What is the structure of synapses?
Presynaptic membrane
-neurotransmitters in
Synaptic vesicles
Synaptic cleft
-tiny space, where neurons are
Released into
Postsynaptic membrane
-with receptors for the
neurotransmitters that were
released
Part of pathways that can be composed of one or more synapses
What are the neuroglial cells?
Schwann cells Astrocytes Oligodendrocyes Ependymal cells -all derive from neural crest cells Microglial cells -derive from monocytes
What are the basic stages of neural tube development?
Neural plate
-folds
Neural folds
-or groove
Neural tube
-when the folds meet
Then it subdivides, into a tripartite brain,
Part of the that triad further divides giving a pentapartite brain.Parts of the pentapartite brain
Prosencephalon
-telencephalon
-diencephalon
Mesencephalon
Rhombencepalon
-meteencephalon
-myelencephalonWhat does the telencephalon primordia subdivide into in an adult brain?
Lumina -> lateral ventricles (I, II)
Floor -> Basal ganglia and olfactory lobes and nerves
Roof -> cerebral hemispheres
What does the dienchephalon form in the adult brain?
the lumen forms the third ventricle
The roof forms the Epithalamus
The walls from the thalamus
The floor forms the hypothalamus and infundibulum
The mesencephalon forms what structures in the adult vertebrate brain?
The lumen forms the cerebral aqueduct of Sylvius
The roof or the tectum breaks into the corpora bigemina in lower verts
In higher verts the corpora quadrigemina which becomes the superior and interior colliculi
The floor becomes the tegmentum
The metencephalon derive which adult structures in the brain?
Lumen: part of the fourth ventricle
Roof: cerebellum
Floor: pons
The myencephalon becomes which adult brain structures?
Lumen: remainder of the fourth ventricle that is not formed by the lumen of the metencephalon
Main part: medulla oblongata
Roof: posterior choroid plexus
Describe the histogeniesis of the neural tube
The first tube wall forms pseudostratified epithelium
An outermost membrane called the external limiting membrane.
Epitheliel cells either remain connected to the basement membrane or migrate away.
Attached - ependymal cells: line the ventricular system and neural canal
Unattached -
-Mantle cells - neuroblasts, forms
grey matter and extends to form
the other layer in the form of axons
-Merginal layer - beyond the
external limiting membrane, forms
grey matter, the axons of the
bodies in the mantle layer.
The dorsal ramiof a spinal nerve innerves what type of musculature? what about the ventral rami?
Dorsal Ramus innervates epaxial musculature
Ventral ramus innervates hypaxial musculature
Where are the cell bodies of motor neurons located in the brain and spinal cord?
Where are the cell bodies of sensory neurons?
Motor neurons:
- spinal cord: grey matter called ventral horns (or anterior)
- CNS: grey matter called nuclei
Sensory neurons:
-located along dorsal roots in grey matter called ganglia. Spinal or cranial - outside the CNS
How is the spinal cord organized?
Grey matter forms an ‘H’ shape with dorsal and ventral horns.
Dorsal or posterior horns:
entry point for incoming sensory neurons
-synapse with secondary neurons
-travel up white matter
Ventral or anterior horns:
Location of cell bodies for motor neurons
Dorsal columns - myelinated fibers up to the brain- sensory afferent tracts
Lateral columns - both sensory and motor tracts
Ventral columns - mostly motor tracts
What composes the meninges?
Epidural space - not in the brain Dura mater Subdural space Arachnoid Subarachnoid space - with CSF Pia mater - delicate innermost layer Denticulate ligaments
where does the sympathetic nervous system originate?
Thoracic and lumbar areas of the spinal cord
-thoracolumbar system
Parasympathetic systems
Motor neurons arise from the brain and sacral regions of the spinal cord
-craniosacral system
Whats the difference between pregangiolion and postganglion axons?
Preganglionic axons - are myelinated and have cell bodies in the grey matter of the CNS with the axons going out the the periphery
Postganglionic axons come out of cell bodies in the eripheral ganglia and are never myelinated
what’s the basics of the autonomic nervous system? what are the branches?
Part of the peripheral nerve system, a motor system
Control of all visceral activity
Sympathetic -thoracolumbar system
Parasympathetic - craniosacral system
What’s the setup up of a typical autonomic pathway?
Two neurons:
One which originates in the CNS -> preganglion axons
Second with cell body in the periphery, synapse with the first and gives off the postganglionic neuron/axon.-unmyelinated- Axons terminate in smooth muscle
What are the CN patterns in anamniotes and amniotes?
10 in anamniotes
12 in amniotes
Arguably: 25 CN’s
CN are characterized by:
- superficial origin: where a cranial nerve emerges from the surface of the brain
- deep origin: site where the motor fibers arise and sensory fibers terminate in nuclei within the brain stem
What’s the structure of spinal nerves?
Approximates one pair for each vertebrae
Attached to spinal cord by two branches:
-Dorsal root: sensory fiber to the spinal cord
-Ventral root: motor fibers from the spinal cord
Spinal nerves divides into dorsal and ventral rami
- dorsal rami: epaxial musculature
- ventral rami: hypaxial musculature
Cell bodies for motor: CNS- columns or nuclei
Cell bodies for sensory: peripherial ganglia
What are the CN of the tongue?
CN XII - hypoglossal nerve
(Extrinsic and intrinsic)
CN VII - Facial nerve
-taste
CN IX - Glossopharyngeal Nerve
- taste
- sensation
Which CN are parasympathetic?
Oculomotor III
Glossopharyngeal IX
Vagus X
Facial VII
CN I
Olfactory Nerve
Go from olfactory receptor cells (bipolar neurons)
Through cribriform plate and into the olfactory bulbs
SVS
-special visceral sensory
CN II
Optic Nerve
Begins in ganglion layer of retinue exits throug optic canal
SSS
-special somatic sensory
CN III
oculomotor nerve
Supplies four of the six extrinsic muscles of the eye
Parasympathetic component
GSM - skeletal
GVM: parasympathetic
-preganglion: edinger-Westphalia nucleus
-ciliary ganglion
Postganglion: sphincter pupillae (from ciliary)
CN IV
Trochlear Nerve
Innervates superior oblique muscle of eye
GSM
-General somatic motor
Emerges dorsal
CN VI
Abducten’s Nerve
Innervates lateral rectus muscle of the eye
GSM
- -General somatic motor
- skeletal
CN VIII
Vestibulocochlear nerve
SSS
-special somatic sensory
Auditory component: cell bodies in spiral ganglion of cochlea
-hearing
Vestibular component:
- cell bodies in vestibular ganglion
- balance and equilibrium
CN XI
Spinal Accessory Nerve
Cranial root leaves cranial cavity with vagus nerve
Supplies strenocleidomastoid and trapezius
SVM
- somatic visceral motor
- -pharyngeal arch muscles
CN XII
Hypogloassal Nerve
Gives of superior root of NASA cervicalis and a nerve to thyrohyoid muscle
Supplies instrinsic and extrinsic muscles of tongue
GSM
- general somatic motor
- -skeletal
CN V
Trigeminal Nerve
Three branches:
- ophthalmic
- maxillary
- mandibular
Face sensory nerve
Motor: mastication
SVM: Special Visceral Motor
GSS: General Somatic Sensory
CN VII
Facial Nerve
Branches:
- temporal
- zygomatic
- buccal
- mandibular
- cervical
Taste for anterior 2/3 on tongue
GVM
-pregang- supoerior salivatroy and lacrimal nuclei
-postgang- to lacriminal gland, submandibular gland, sublingual gland and mucous glands of mouth and nose
GSS
-part of external ear
SVS
-taste
CN X
SVM
GVS
GSS
GVM
Parasympathetic
Forth and fifth pharyngeal arches
Swallowing and speaking
CN IX
Glossopharyngeal nerve
SVM
GVS
GVM
GSS
SVS
Sensation, third pharyngeal arch
