Nervous System Flashcards
CNS
Spinal Cord
Brain
Peripheral NS
Spinal Nerves
Cranial Nerves
Two Major Peripheral Pathways
Somatic (body) and Visceral (viscera)
Viscera has sympathetic and parasympathetic
Nervous Tissues
Cells:
Neurons
Neuroglia Cells
FYI:
CNS- has cells and extracellular matrix
PNS- has cells and extracellular matrix and collagenous c.t.
Neurons
Multipolar (the classic you think of) --efferent neuron or interneuron Pseudounipolar Neuron ( cell body centered and atop a a connector) ---afferent neuron (general senses) Bipolar Neuron --- afferent (special senses)
Neuronal Function
ED comes with CP
It’s a electrochemical molecular movement.
Nerve Impulse = electrochemical current
this is what goes down:
EXCITABILITY has to occur which DEPOLARIZES the membrane (all this occurs in the axon)
CONDUCTIVITY occurs, which is the PROPAGATION of the membrane depolarization
3 kinds of neuronal circuits
Cats Dogs and Fish
Convergence
Divergence
Feedback Loop
Neuroglia Cells
Every Astro is Obligated to Micromanage Solar systems
Ependymal- epithelial cells that line ventricular cavities of CNS. fx: facilitate exchange between csf and neural tissue.
Astrocyte- two kinds: protoplasmic (many, thick processes) and fibrous (long, thin infrequent processes). fx: framework, external surface of capillaries
Oligiodendrocyte- rounde with few processes. Fx: processes form myelin sheath of neurons in CNS
Microglial- in both gray and white matter, near astrocytes. fx: involved in phagocytic activity in nervous tissue.
Schwann- oval cell of PNS, (from neural crest) form myelin sheaths that surround peripheral neurons.
Key Fxn Relations between Neurons and Neuroglia in PNS
PNS
- Schwann and axons
- -Neurolemma (non mylenating swahnn’s)
- -Myelin Sheath (mylentating schwann cells)
Key Fxn Relations between Neurons and Neuroglia in CNS
CNS
- Astrocytes and axons = Gray matter (non myelinated neurons)
- Oligodendtrocytes and Axons = White matter (myelination process)
Fxn Signficance of Myelin Sheath
Structure: internodal segments and nodes of Ranvier
Saltatory conduction: jumping e-chemical depolarization
Receptor Organs
Receptors that translate stimilus ie light into neural message:
Mechano-
Thermo-
Chemo-
Photo-
Synapse
Synaptic Vesicles: hold neurotransmitter
Neurotransmitters: chemical messenger
Receptors: receive neurotransmitter
Nerve Structure ( just like muscle, if stuck just say the muscle version) PEPsi FEels wrong
Peripheral Nerve Fiber Endoneurium Perineurium Fasciculus Epineurium
Conglomerations of cell bodies (Ganglions)
There are two
Sensory Ganglion
Autonomic Ganglion
Vertebral Column Nerves
8 Cervical 12 Thoracic 5 Lumbar 5 Sacral Coccyx
White Communicating Rami
What are these?
only on T1-L2 nerves
Pathway for myelnited (white) preganglionic sympathetic axonssss
Posterior and Anterior Ramus Pathways of Aerial View
Describe it
Posterior branch out
Anterior branch out and then around outer muscle layer
Somatic Neuronal Pathway
***trace
ie touching something hot
Easiest * afferent -somatic sensory neuron ventral ramus spinal trunk dorsal root dorsal root ganglion dorsal root dorsal rootlets spinal cord skeletal motor neuron (efferent) ventral rootlets ventral root spinal trunk ventral ramus muscle to flinch
Internuerons
can be used to integrate various neurons in response. They travel within spinal cord in gray matter to other neuron in spinal cord.
Distribution of Visceral Branches of the Spinal Nerve
– autonomic pathways —
Sympathetic:
On the Ventral Ramus we have the Communicating Rami - white and gray
Sympathetic Trunk (which stands alone)
Sympathetic Splanchnic Nerves and Plexus come off the Sympathetic Trunk
In terms of Ganglia we have:
- Sympathetic Trunk Ganglia
- -Sympathetic Splanchnic nerve Ganglia:
Autonomic Pathways to Coelomic Viscera
Sympathetic
**trace
large intestine visceral sensory neuron (afferent) splanchnic nerve splanchnic nerve ganglion splanchnic nerve sympathetic trunk sympathetic trunk ganglion white ramus ventral ramus spinal trunk dorsal root dorsal root ganglion dorsal root dorsal rootlets spinal cord preganglionic motor (efferent neuron) ventral rootlets ventral root spinal trunk ventral ramus white rami sympathetic trunk ganglion sympathetic splanchnic nerve sympathetic splanchnic nerve ganglion postganglion motor neuron (efferent) sympathetic splanchnic nerve viscera ---> norepinephrine
Parasympathetic Neuronal Pathway from Sacral Origin
viscera of large intestine visceral sensory neuron (afferent) parasympathetic pelvic splanchnic nerve ventral ramus spinal trunk dorsal root dorsal root ganglion dorsal root dorsal rootlets spinal cord preganglionic neuron (mylenated) ventral rootlets ventral root spinal trunk ventral ramus parasympathetic pelvic splanchnic nerve postganglionic motor neuron (efferent) not mylenated viscera --->acetylcholine
Parasympathetic Neuronal Pathway from Cranial Origin
***trace
viscera of stomach cranial nerve cranial nerve ganglion cranial nerve brainstem preganglionic motor neuron (efferent) mylenated cranial nerve cranial nerve ganglion cranial nerve postganglionic motor neuron (efferent) non mylenated viscera ---> acetylcholine
Autonomic Pathways to Somatic Viscera
Sympathetic Neuronal Pathways
From lower limb
***trace
in white
out gray
anterior popliteal artery visceral sensory neuron (afferent) ventral ramus spinal trunk dorsal root dorsal root ganglion dorsal root dorsal rootlets spinal cord interneuron up spinal cord preganglionic neuron (efferent) ventral rootlet ventral ramus spinal trunk ventral ramus white communicating rami sympathetic trunk ganglion sympathetic trunk down sympathetic trunk ganglion postganglionic neuron (efferent) gray communicating rami ventral ramus
Autonomic Pathways to Somatic Viscera
Sympathetic Neuronal Pathways
From upper limb
in white
out gray
ulnar artery visceral sensory neuron (afferent) ventral ramus spinal trunk dorsal root dorsal root ganglion dorsal root dorsal rootlets spinal cord preganglionic neuron efferent ventral rootlets ventral root spinal trunk ventral ramus white communicating rami symp trunk ganglion postganglionic neuron efferent gray communicating rami ventral ramus viscera prob: norepinephrine
