Nerve Cells Flashcards
Central Sulcus separates:
Precentral gyrus AKA Frontal Lobe (memory, higher thinking, motor control)
-from Postcentral AKA Parietal Lobe (sensory cortex)
Lateral Fissure defines
Lateral Lobe (auditory) and in the back, Occipital
Brain Stem Compositions:
Diencephalon (relay of sensory to thalums)
Midbrain
Pons (relay between celebellum and cerebral cortex)
Medulla (breathing and heart rate)
Substantia nigra
nucleus in Midbrain that degenerates in Parkinsons Disease
6 layers of Gray Matter
I. Molecular Layer
- neurophils
2. External Granular
3. External Pyramidal - pyramidal neurons giving corticocortical connections
4. Internal Granular Layer - IMPORTANT, receives sensory info from Thalmus via stellate neurons
5. Ganglionic Layer
6. Multiform (polymorphic) cell layer - pyramidal neurons whose axons leave the cortex
Cerebellum Layers
- Molecular
- Purkinje
- Granule
Purkinje Layer is Important because:
only output cells. receive info from brain stem, accumulates it, and sends it to the deep nuclear cellular layer
Nissl substance is in high concentration in what kind of neurons?
Motor Cell
-large amount of nissl substance = large cell size when compared to glia
Motor neuron pathway
- Cortico spinal signal (signal from upper spinal cord to lower spinal cord) travels via white matter axons
- Signal sent out from VENTRAL root of spinal cord
- Motor neuron axon transduces signal from CNS to PNS
- From PNS to muscle fibers
4 Categories of Peripheral Nerves:
8 Cervical (3, 4, 5 important for breathing) , 12 Thoracic, 5 Lumbar (4,5 = Sciatic), 5 Sacral
ALS Amyotrophic Lateral Sclerosis
Upper Motor Neurons cannot communicate with Lower Motor Neurons = paralysis
4 Parts of the Neuron
Dendrite -Receive information (input) Cell body -Sort information (integratge) Axon -propagates electrical info transfer (conduct) Synapse -sends signal to the next cell (electrically or chemically) (output)
Ependyma Cells
(in CNS -> specifically the central canal) Protect CSF (has cilia)
Microglia
(in CNS) Phagocytize
Oligodendrocyte
(in CNS) Form myelin in CNS (NOT SCHWANN)
–> What is attacked in MS
Protoplasmic Astrocytes
vs. Fibrous Astrocytes:
Protoplasmic are Present in Gray Matter of CNS
Fibrous are in White Matter of CNS
Both:
- FORM BLOOD BRAIN BARRIER by telling capillary endothelial cells to form zona occludins
- KEEP CNS STRUCTURE
- Regulate PH
- Regulate immune response by contact w/ capillary endothelium (again, BBB!)
- Sequester Neurotransmitters
Meninges are Made of:
- Dura Mater: Dense Connective Tissue around CNS to protect brain
- Acrachnoid Matter: Web-like fibers
- Sub Arachnoid Space: Filled with CSF made in Choroid Plexus by special Ependymal cells
- Pia Matter: thin clear covering of cerebral cortex
How are the ventricular systems of the cerebral cortex and the central canal connected?
3rd and 4th ventricles of the cerebral cortex connect to choroid plexus which connects to the central canal
Dorsal Root Ganglion
pseudopolar cells. These motor axons branch from PNS and send signals to CNS via Dorsal root
Sympathetic Ganglia Chain
Part of Automatic Nervous system of PNS. Runs parallel spinal cord in THORACIC column. Signals for fight or flight
-Each Ganglia has lots of synapses
Parasympathetic
Part of PNS. Axons originate from Cranial and Sacral regions of spine and actually go within organs to innervate them. “Rest and Digest”
How does the anatomy of innervation differ in Parasympathetic vs. Sympathetic
Sympathetic:
- SHORT Preganglionic located in thoracic spine
- then innervate sympathetic ganglion
- Which innervates the post synaptic ganglion
- which then goes out close to target
Parasympathetic:
- LONG Preganglionic located in Cranial and Sacral Spine
- then have axons that extend to post synpatic neuron located within to target
Submucosal Plexus of Enteric System
Sense PH, regulate glands of the ducts
Myenteric Plexus of Enteric System
Regulate Gut muscle movement
Why is enteric system part of automatic system?
Enteric system is connected to the sympathetic nervous system (however when these are cut can still function to a certain degree)
How do Dorsal Root Ganglion and Sympathetic Ganglions differ?
Sympathetic ganglions have synapses
Dorsal Root Ganglions have cell bodies which make them Pseudounipolar neurons!
Peripheral Nerve Myelination vs. CNS Nerve Myelination
PNS = Schwann cells. Each axon gets myelinated
CNS = Oligodendrites
multiple axons myelinated together
Charcot-Marie-Tooth Disease
Damage of Schwann Cell myelination in PNS
Wallerian degeneration
intentional axon destruction
