Histology #2 Flashcards

Question

Nuimver of nerves in the Spinal cord

Answer 1

8 Cervical nerves 12 Thoracies nerves 5 Sacral nerces 1. Cocygeal nerve Total - 31 pairs of nerves

Answer 2

Process infomration Found in center of the spinal cord + in cerebral cortext

Answer 3

Contains mylinated and unpmylinated axons Has few nueronalc ell bodies Function - Transmits information

Answer 4

1. Cerebrum 2. Cerebelum 3. Brain stem 4. Spinal cord

Answer 5

Largets part of teh brain Grey matter in cortext + white matter in center Composed of two hemisphere (divided by the medial longitudnal fissure) Function - controls concious thoughts and finction Most common cell types - nuerons + glial cells (Ex Astrocytes)

Answer 6

Function - metabolic and synthetic machinery Stains positive for Nissle stain because of teh riygh ER Has variation in shape (round, oval, triangular (pyrimidal)) and size - Larger in motor nuerons and smaller in granial cells

Answer 7

Function - Transmits signals Axon = constant diameer + usually unbranched - Only branched in Psudounipolar

Answer 8

Boundery between the soma and axon - site of AP initiation IF you have enough depolarizaton in the axon hillock = can open volatge gated Na chanels = depolarizes cells THEN Na chanels will close and delayed K chanels will open K going into the cell and repolarize the cells - end at a hyperpolarization/ refractory period

Answer 9

White matter is white because it is rich in mylinated axons = rich in lipids

Answer 10

Glial cells = preform mylination Schwann cells wtatch to axins --> wind plasma memebranes around teh axon in a helical fashion until it deposites ultiple layers of myline THEn the layers will fuse together to make one myline sheeth Image - can see cross section of mylinated axon (can see layers of myline)

Answer 11

Before Oligiodentries mature they are Oligiodendricyte progentor cells - OPCs ca sense attarrctive and repulsive cues on teh axons IF there is an attarctive cue then the OPCs will extend a limb from the cell body to the cue and begin the wrapping process - Can mylinate multiple nearby axons IF there is a repulsive cue then the OPCs won't extend Product - end with nodes of unmylinated regions = have nodes of Ranvier

Answer 12

Nodes - unmylinated regions of the axon Image 1 - See where the mylin sinches inwards = have nodes of Ranvier Image 2 (right) - myline is blue - see layers and see that myline terminates at the nodes of ranvier

Answer 13

Overall - speeds up the action potential because it is rich in lipids Lipids - not polar = avoids electrical charge = poor conductors of electricty BUT good insulators = retains the strength of the AP doen the axon + creates salatdor conductions were the AP jumps between the nodes - Speed is 100X faster compared to unmylined

Answer 14

Region were electrical or chemical signals are transmitted between nuerons and dendrites How it works - At the presnapse there are vesicles with NT --> NT fuse with the presynamptic membrane --> NT are released into the synaptic cleft --> NT bind with receptors on the post synaptic cleft

Answer 15

Nueron = blue - has vesicles that contain NT (purple circles) + arrow shows teh NT are going to the green + black line is the cleft

Answer 16

Motor nueron connects to the muscle - AP causes the volatged gated Ca chanels to open - Ca causes teh Actylcholine to bind to the presynaptic memebrane - AcH goe sto the cleft --> AcH binds to the ligand gated Na chanels - flow of Na cuases an AP - AP causes the T-tubules to open --> T-tubules opening causes teh SR to release Ca --> Ca binds to the tropinin complex --> casues a confirmation change - actin binds to myosin - During relaxaton = Ca is absorbed and mysine binding sites close

Answer 17

Image 1 - Axon in blue - vesclicles in ellow with AcH --> going to the skelatal muscle on the right Image 2 - See motor nueron connecting to muscle fibers

Answer 18

Image 2 - See motor nueron connecting to muscle fibers

Answer 19

Overall - receotors mediate the membrane Types: 1. Volatge gated chnages 2. Ligand gated chanels 3. GPCRs ALL receptors on post synaptic = result in depolarization or hyperpolarization of the memebrane - Difference = if excitatory or inhibitory

Answer 20

Voltage gated - reulst in local immedtae affect by alowing ions into the membrane Ligand gates ion chanels - Local immediate affect GPCRs - Widesoread affect - Often coupled to effector proteins + produces second messengers

Answer 21

Overall - positive charge flows to the post synpatic = causes depolarization = more likley to generate an AP Example - Glutamate (most common EPSB NT) - Glutamate fuses with the presynaptic memenrane --> GLU goes to the cleft --> Glu binds to the ligand gated chanel (NMDR) --> NMDR allows Na and Ca to post synaptic cell --> Na will depolarize the cell + Ca acts as a secondary messenger ---> because have depolarization you van have AP in ysnapse or in subsquent synpases -

Answer 22

High Glutamate = overactivation of nuerons = get seizures

Answer 23

Overall - influx of negativley charged ions = get hyperpolarization --> less likley to fire AP = inhibits cell Example - GABA fuses to the preseynapyic emmebrane --> GABA goes to the cleft ---> Ligang gated chanels A and C --> Chnages let Cl into the cell --> Cell becomes hyperpolarized --> cell is less likley to have AP

Answer 24

Low GABA = no inhibition of nervous system = can get seizures

Answer 25

Overall - muscle control + sensory preception + cogntion + homeostatss 1. Sensory input 2. Infomration processnig 3. Coordination of repsnes 4. Enabling complex behaviors 5. Maintaining homeostasis

Answer 26

MG - Have disruption of the NMJ ALS (nuerodegentive disorder) - Have degeneration of the motor nueron that impairs motor control Alzheimers -Accumilation of amyloid plaques and tai tangles that lead to cognitive disfunctions

Answer 27

Overall - Autoimmune disorder - affects the connection between nerves and muscles Progressive = volentary muscle weakness gets worse over time

Answer 28

Overall - Muscle weakness + tired Affects the eye muscles (causes drooping of eylid + double vision) Can have chnages in facial + diffuclty swallowing + weakness in upper and lower limbs - If affcets diaphram = can lead to difficulty breathing

Answer 29

Overall Issues in teh NMJ --> leads to muscle weakness - Caused by production of antibodies againt AcH receports + overactive compartment pathway + Disruption of the thalymus Have AcH and AcH recpotores in NMJ + have Mask in NMJ (stimulates epxression of AcH receptors) In MG - immune syste prdoduces AB that destor or block teh AcH receptors = AcH can't bind - ALSO have AB that will go to Mask receptor - ALSO can have overactive complement protein = promotes immune function + enhances function of AB Complement protein + mask receptors = reduces AcH

Answer 30

See Normal vs. Nuscles in MG MG - sixe and shape of muscle are vraible vs. normal are very unifrom + MG has space between muscle fibers + accumularion of nucleo

Answer 31

MG = have chnages in the junctional folds (more wide + shallow + few folds) + have widening of the synaptic cleft

Answer 32

Overall - causes degernation of motor nuerons in the CNS = have muscle twitching + issues chewing/swallowing + pain in feet andhands + eye movement abnormailities + progressive weakness + issues speack + trouble with daily acitivities + cognoive and behavioral imporment Leads to death 2-5 years upon onset of symptoms due to failure of basic activities (failure to move + breath + swallow)

Answer 33

5% = family history --> has some genetic compenent 95% = No family history --> could be due to protein degredation + oxidarve distress + glial cell disfunction

Answer 34

Have loss of motor nuerons in motor cortxt + spinal anterior horn _ loss of mulination in spine Image 1 - Thoracis and lumbar spin in normal vs. ALS - Top = blue dye for nuerons --> ALS have loss of normal compared to normal

Answer 35

Motor nuerons in control is defined vs. less in ALS and deformed and stain differentley in ALS Have purple dots around ALS - glial cells come to supoirt the nueron but fail = marker of nuerodenegeration

Answer 36

Umbreela term for groups of symotms that affect conginotive abilities + memeory + thinkning + behavior

Answer 37

Most common cause of dimmensioa (casues 60-70% of cases) progressive nuerdegenerative disorder that affecst memory and cognitive functions - Progressive for 3-11 years

Answer 38

Symptoms: 1. Mild - little memery loss (lose ability to cound + cognotive difficulties + might get lost + personlaity/ behavioral chnages 2. Moderate = affects concious thoughts + worse ememory loss + can't mutli task + might have halicenous 3. Severe - lose bodily functions + can't talk/walk/swallow + bedridden

Answer 39

Unknown - combination of age related chnages in the brain + genetic alterations + envrinemnts and life sytel factors Can have below age of 65 - have genetic alterations ( Genetic alteractons = APP + PSEN1 + PSEN2)

Answer 40

1. See formation of amaloid plaques (biildup and clumps of amaplod beta fragmnets between nuerons 2. Nuerofibulary taregts - twisted strand of tau inside nuerons = stick together 3. Loss of nuerons - loss of function and connections to otehr nuerons 3. Brain atrophy - brain tissue srhinks Loss of nuerons - due to plaques + tangles --> lose communication + nuerons die Plaqus and tangles form in happocampus first --> then spread to other areas as disease progress Image - Top right - see plaques and tangles Lower left - see different tyoes of plaques in brain (not all plaques look the same) Lower right = tangles and plaques in frontal lobe

Answer 41

Have Brain atrophy - Brain shrinks as age BUT shrinks dramatically in alzheimers Image - see atrophy in brian oin the left vs. healthy brain on the right

Answer 42

A and B on left = single amploid plauqes Bottom = tangles Bottom left = pretangles that lead to tangles