Histology - Nervous System

Nurons have very distinct regions within the cell

The cell body including the nucleous portion of the nuron

sensory arms

excitation arms

the end of the axon that sends the impulse to the next cell

The classic nuron

• Has dendrites on one end and axons on the other end of the cell body
• used for sensory

• are bipolar during early development
• Sensory
• impulses passes the cell body

• Axons and Dendrites are found on the same stem
• these are found in invertibrates

• No Nissle bodies
• No synapses
• Lower threshhold than other parts of the cell
• Sums up all incoming signals
• increaced amount of voltagegated ion chanelles**

When an axon inervates on the cell body of the next nuron

axon is inervating on a dendrite

inervate on the spine of the next nuron

inervation on the next axon

stains RNA purpilish blue

• soluable NSF atatchment receptors
• aid in membrane targeting

involved in the recycling proceses of membranes

clear and dense cored

• Fusion of the synaptic vesicle membrane with presynaptic membrane
• regulated by SNARs

synaptic vesicle is andhored on top of calcum-selective channels in presynaptic membrane. when Ca²⁺enters a transient pore is formed and the nurotransmitter is released from there. 

• contains a lot of cytoskeliton protiens
• shares them with the membrane so its hard to see the clear line on a slide

microtubules 

actin (they can move slightly)

• consist of channels called connexons which are made up of connexin
• ions travel through these pores
• synchronizes events

Comes off of the dendrite (so the dendrite is the extension and Dendritic Spines are the fingers)

folding in of tissue in the dendritic spine

The folding of an axon into the muscle within a synaptic end plate

do not have microtubule associated protien

in an Axon it is transproted away from the cell body (anterograde)

twards the cell body (retrograde)

• Physical support
• Movement of metabolites
• Some have end feet covering the blood vessels forming tight junctions > help form blood brain barrier

Formation and maintence of myelin in CNS

• Star shaped
• Get rid of potasium > very permiable to potasium

• Gray matter
• numerous, short, branching cytoplasmic processes

• white matter
• few processes, usually straight

• Possess phagocytotic properties > involved in nuro-immune reactions *** 
• Part of the mononuclear phagocytic system; originate from bone marrow monocyte precursor cells
• May mediate neuroimmune reactions, such as those occurring with chronic pain
• Small, contain elongated nuclei
• Processes and cell body appear to be covered with spikes

• Columnar cells **
• Lining the ventricles of the brain and the central canal of the spinal cord**
• Characteristics of fluid transporting cells**1
• Apical microvilli absorb cerebrospinal fluid
• Basal surfaces interdigitate with astrocytic process (ependymal cells have no external lamina)

• Glia in the PNS
• 1 cell to an axon

The jumping of AP from one node to the next

• mylinates the CNS
• multiple axons

The protien that holds the mylin together so it can squeeze itself around 

some cyto gets trapped inside the folds of mylin

• grandular areas in nurons composed of RER
• They stain because of the RNA

The stuff left behind when mylin is fixed

• Mylin basic protien
• proteolipid protein
• myelin oligodendrocyte protein
• oligodendrocyte myelin glycoprotein

• Myelin basic protein
• PO protein
• peripheral myelin protein 22 (PMP-22)

• improtant in compaction
• formed by one gene > 7 forms
• major immunogenic reaction > experimental allergic encephalitis > model for multiple sclerosis

• An autosomal recessive trait
• Causes tremors and convulsions
• five of the six exons for MBP are deleted

• Imparied gaid and other deformities
• Caused by duplication of PMP22 (to much being produced
• Peripheral neuropathy results
• Cycles of myelination and demyelination.

• Disease of the PNS
• Large accumulation of lymphocytes, macrophages and plasma cells around nerve fibers
• Large portions of the myelin sheath are damaged.
• Muscle paralysis, loss of muscle coordination, and loss of cutaneous sensation

• End Feet of Astrocytes
• Basment Membrane
• Endothelial cells > tight junctions
• nothing bigger the 500Daltons gets passed

• CNS outer part is nuronal, inner part is white matter
• SC inner part is nuronal, outer is white matter

• Sends information to the smooth mucles, cardiac mucles, and glandular epithelium
• involentary
• maintains internal inviornment
• three divisions
• >sympathetic > thoracolumbar
• >parasympathtic > craniosacral
• >Enteric > digestive system

• Somatic > volentary system
• efferetn > movement
• one nuron coming from the CNS

• Autonomic > involenray
• there is a nuron junction outside the CNS
• The second lies within the ganglion

• Two trunks running along-side the CNS
• The Autonomic Sympathetic NS make connections there for the Thoracic organs

• Indivdual ganglia
• Nurons of the Autonomic Sympathetic NS make connections there for things that inervate the abdominal aorta
• Exeption: the adrenal gland (goes straight there)

• The Cranial nerves go to ganglia in the head
• The splanklic nerve and the 10th facial nerve do not have ganglia > go straight to the organ (form terminal synaps in the organ) 

dorsal root are pseudounipolar nurons > no synaptic connections > surrounded by stalite cells