Histology 2 Flashcards
arachnoid matter
loose areolar connective tissue
lubricated with cranial spinal fluid
dura mater
outer cord coat
adherent to bone
dense fibrous irregularly arranged connective tissue
arachnoid grnaulation
buds out of arachnoid matter and reaches spaces in the dura.
pia mater
inner coat at brain interface
CSF
cerebrospinal fluid, produced by ependymal epithelial cells or brain ventricles
ependymal cells
few tight junctions fluid pressure drives CSF to brain across arachnoid grnaulations
CSF from brain ventricles
Through tight junctions, fluid made by capillary filtration
connective tissue in brain
there isn’t any! just astrocytes (star shaped glial cells)
nissl bodies
granulars of RER with rosettes of free ribosomes found in cell bodies of neurons. (some in dendrites)
stains blue.
axons don’t contain
ribosomes, much ER or RNA
transport from body to axon
microtubules and kynesin (toward +)
transport from axon to body
microtubules and dynein (toward -)
Tau
links MT bundles in axon
Map 2
links MT bundles in dendrites
tubulin type in neurons
beta 3 tubulin
initial segment
axon region closes to cell body: where APs start
glial fibrillary acid protein
composes IF filaments in astrocytes
tensile strength
collagen in brain
there isn’t any!
microglia
main CNS immune system
macrophages from bone marrow
oligodendroglia
cells that insulate axons in the brain.
each can insulate more than one
schwann cells
mylinate axons. each cell can insulate just one axon
nodes of Ranvier
open spaces in axon between mylination. where Ca channels open to perpetuate an AP
SAME DAVE
sensory afferent, motor efferent
dorsal afferent, ventral efferent
(therefore: sensory dorsal, motor ventral)
latency period due to
Na channel inactivation, K channels open
hyperpolarization
due to open voltage-gated K channels
proteolipid protein
holds together layers of the myelin sheath. very hydrophobic
schmidt-lanterman lines
small amounts of schwann cell cytoplasm
subdivide myelinated axon into irregular portions
electrical gap junctions
made of connexons, no synaptic delay.
e.g: brainstem neurons that control breathing
fusion of synaptic vesicles signaled by
Ca current signaled by AP
small molecule transmitters are made
in synaptic terminal
40-60 nm
peptide vesicles are made
in the golgi (cell body)
120-250 nm
synapsin
tethers vesicles to actin near active site
Ca triggers fusion how?
Ca-Calmodulin activates v-snares to interact w/ syntaxin
synaptobrevin
type of v-snare in synapse. interact w/syntaxin
acetyl choline is made
in the bouton! (end of axon)
vesicles are recycled by
clathrin coat and dynamin pinch-off
botulism toxin
a protease, cleaves snare proteins, inhibits vesicle fusion
acetyl choline esterase
degrades released Ach in the synapse
ionotropic receptors
ligand gated, nicotinic achR, fast
metabotropic receptors
g-protein coupled, muscarinic AchR
MAP kinase to other ion channels, slow
motor unit
nerve and the muscle it innervates
muscle pool
many motor neurons innervating many muscle fibers
cholinergic
activated by Ach
RBCs
terminally differentiated
have hemoglobin, lactate dehydrogenate, K+
deliver O2, remove CO2
8 microns
RBCs have no
nucleus, ER, golgi, mitochondria, protein synthesis
WBC types
neutrophil (poly, seg or PMN) monocytes lymphocytes eosinophils basophils platelets
neutrophil appearance
multilobed nuclei, neutral stains. 50% of all WBCs
neutrophil function
phagocytosis, granule release, PUS!
respond to gram +/- bacteria, dead tissue
monocytes look like:
nonsegmented, horseshoe or oval nucleus, not grainy.
5-9% of WBCs
monocytes are:
macrophage precursors (e.g. Kupffer cells in liver). As macrophages, they eat parasites and foreign RBCs
lymphocytes have:
a big round nucleus, little cytoplasm.
20-30% of WBCs
lymphocytes do:
aquired immunity, viral and bacterial infections.
Ts: reg, cytotoxic, helper
Bs: antibody production after antigen presentation
autoimmune thyroidosis
one example of lymphocytes infiltrating organs
eosinoophils have:
segmented nuclei, RED granules. Are terminally differentiated
eosinophils do:
recruit to inflammation sites. parasitic infection (eg, river blindness) or allergic response.
basophils look like this:
purple, grainy, hard to determine nucleus.
basophils do this:
contain heparin, histidine.
turned on by IgE receptors bound to allergens.
become mast cells and release histidine
platelets
derive from megakaryocytes. squeezed off by induced actin fibers.
WAS-Arp2/3
induced actin to squeeze platelets off megakaryocytes.
blood serum
NO coagulation factors. after blood coagulated in tube, serum is left on top.
blood plasma
has coagulation factors, and fibrin, and fibronogen
coagulation factors
12 factors, will be activated by Ca++
consumptive coagulopathy
overactive coagulation pathways.
corrected by tranfusion (?)
coagulation factors regulated
thrombosis (clotting) and fibrinolysis (unclotting)
stable useful clotting requires
platelet activation
and coagulation cascade
coagulation cascade
7 steps
breach of epithelia factor VIII prothrombin thrombin fibrinogen fibrin clot
clot is broken down by
plasmin
tPA
tissue plasminogen activator, activates plasmin to break down clots
hemophilia locus
factor VIII
therapeutic heparin infusion activates
antiprothrombin III
albumin carries
drugs, water to give volume to vascular structures
lipoproteins carry
cholesterol
transferrin carries
iron
ceruloplasmin carries
carries copper in the blood, plays a role in iron metabolism
cytokines carry
short distance hormones
haptoglobin carries
leaked hemoglobin (to prevent it from oxidating)
hemoplexin carries
leaked heme
hemoglobin carries
O2, CO2
vWF
von Willebrand factor. clotting component made by endothelial cells (most others made in liver)
cell leak and disease (3)
PSA: prostate specific antibody, in prostate cancer
amylase in pancreatitis
troponin in heart attack
blood cell renewal and proliferation
from pluripotent stem cells
first differentiate as myeloid or lymphoid.
leukemia
overproliferation of blood stem cells
aplastic anemia
failure of stem cells to proliferate
killed by antibodies, meds, chemotherapy
blood stem cells isolated by
fluorescence activated cell sorting
CD34+CD38-Kit+Lin-
stem cell markers
CDs are antibodies,
Kit is receptor for stem cell factor
Lin- means not yet differentiated
erythropoetin hormone
activates TFs (GATA1) to cue blood stem cell differentiation
where does hematopoesis happen?
yolk sac, then liver and spleen, then bone marrow.
can revert to liver and spleen in blood system emergency
RBC lineage (9)
SBCPBPNRM
stem cell burst-forming unit erythroid colony-forming unit erythroid proerythroblast basophilic erythroblast polychromatophilic normalblast reticulocyte mature RBC!
colony forming unit erythroid expresses
GATA1 and EpoR
proerythrocyte expresses
transferrin receptor
heme and globin synthesis
aquaporin transporters
glycoporin A
normoblast is:
reddish
last phase before nucleus is removed
RBC organelles go where?
they get eaten! autophagy.
niches
macrophages surrounded by RBC progenitors. macrophage destroys nucleus, supplies iro-transferrin.
sickle cell anemia
hemoglobin mutation makes sickled RBCs
clump with WBCs + activate inflammation response
need sickle RBCs under 30% to prevent
stroke, acute chest syndrome(clumps in lungs), pain crisis
