cell biology: cytoskeleton

Question 1

intermediate filament found in epithelial cells (the keratin in desmosomes + hemidesmosomes)

Answer 1

cytokeratin

Question 2

intermediate filament found in all Muscle cells (smooth, skeletal, heart)

Answer 2

desMin

Question 3

intermediate filament found in astrocytes + schwann cells + neuroGlia

Answer 3

glial fibrillary acid proteins (Gfap)

Question 4

intermediate filament in axons

Answer 4

neurofilaments (low, medium, high MW)

Question 5

intermediate filament provides structural framework for the nuclear envelope + DNA

Answer 5

nuclear lamins: A, B, C

Question 6

mutation in nuclear lamins can cause

Answer 6

muscular dystrophy

progenia: advanced cellular aging (wrinkles in kids)

Question 7

intermediate filament found in connective tissue: fibroblasts, leukocytes, endothelium

Answer 7

vimentin: supports cell membrane, keeps organelles fixed in cytoplasm

Question 8

cytokeratin stain used to identify (IF)

Answer 8

carcinoma

Question 9

desmin stain used to identify (IF)

Answer 9

rhabdomyosarcoma

leiomyosarcoma

Question 10

glial fibrillary acid proteins stain used to identify (IF)

Answer 10

glioblastoma

Question 11

neurofilaments stain used to identify (IF)

Answer 11

neuroblastoma (sympathetic ganglion cells in adrenal medulla of kids)

Question 12

nuclear lamins A, B, C stain used to identify (IF)

Answer 12

primitive neuroectodermal tumor

Question 13

vimentin stain used to identify (IF)

Answer 13

sarcomas

Question 14

intermediate filament role

Answer 14

provide structure

Question 15

microtubule role

Answer 15

movement of:
cilia: respiratory tract, bronchioles, paranasal sinus, fallopian tube
flagella: sperm
mitotic spindle: duplicated chromosomes
axonal trafficking: neurons (motor neuron)

Question 16

microfilament contains

Answer 16

polymers of actin

Question 17

actin role

Answer 17

cellular motility:
neutrophil chemotaxis
macrophage
microvilli - brush border
activated PLTs - change shape

Question 18

myosin role

Answer 18

a motor protein that moves along actins

involved in muscle contraction: muscle cells

Question 19

coordinated ciliated contraction due to

Answer 19

gap junctions between ciliated cells

Question 20

cilia + flagella structure: MT architecture

Answer 20

9+2: 9 doublets of MT, 2 MT in center

dynein links peripheral doublets causes bending of cilium via sliding of doublets

Question 21

1° ciliary dyskinesia

Answer 21

immotile cilia due to dynein arm defect:
male (immotile sperm) + female infertility (fallopion tube cilia →↑ risk ectopic pregnancy)
can include triad of sx = Kartagener syndrome

Question 22

triad from what syndrome?
bronchiectasis
recurrent sinusitis: chronic infections + productive cough
situs inversus (50% PCD cases, need cilia for organ placement)
r/o what disease?

Answer 22

Kartagener syndrome = 1° ciliary dyskinesia

r/o TB: cough + infertile + caseating on CXR

Question 23

filaments that make up cytoskeleton from thinnest to thickest

Answer 23

microfilaments
intermediate filaments
myosin
microtubles

Question 24

microtuble structure

Answer 24

cylindrical, helical array of:
heterodimer of αtubulin +ßtubulin → form protofilament
(-) end: ßtubulin
(+) end: αtubulin

Question 25

molecular motor protein that transports cargo anterograde along microtuble (- → +)

Answer 25

kinesin

Question 26

molecular motor protein that transports cargo retrograde along microtuble (+ → -)

Answer 26

dynein