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Intermediate filaments: fxn and classes

Fxn: resist mechanical stress (most durbale of all filaments)
Classes: nuclear lamins, keratin filaments, vimentin filaments, neurofilaments


Role of nuclear lamins (3)

found in nucleus of ALL cells. Play a role in gene expression, differentiation, cell cycle


Progeria: cause, symptoms

mutation in nuclear lamins (Lamin A). wrinkling of skin, kidney issues, MSK degeneration (Benjamin button)


Microtubule Fxn: 2

movement within cell, cilia/flagella


MT have a + end and - end. whats the difference?

(+): beta tubulin, more likely to grow

(-): alpha tubulin, more likely to shrink


Motor proteins associated with MT? which is used in flagella and cilia movements?

Dynein (move towards - end, towards centrosome/nucleus), seen in flagella and cilia

Kinesin (move toward + end, cell periphery)


what is the role of basa bodies?

serve as MT organizing center for cilia


dynamic instability is associated with..role

MT. they can grow or shrink at + end (GTP=grow, GDP=shrink), helps "search" for proteint to bind to


Taxol: effects? use?

cancer treatment; stabilizes MTs


B/c MT play a major role in cell division (separates chromosomes) they are often targets of....

cancer treatments


Colchicine: effects? use?

prevents MT polymerization; cancer treatment


Vinblastine: effects? use?

prevents MT polymerization


Actin is composed of...ATP bound?

actin monomers combined to form 2-stranded helix. free actin is ATP bound. Actin monomers in filaments are ADP bound


Actin filaments play a role in making what 5 structures?

Stress fibers, microvilli, contractile ring, lamellipodia, filopodia


Congential Myopathy: cause? symptoms?

skeletal muscle weakness caused by mutation in muscle-specific actin


Insulin triggers glucose uptake in what three cell types?

adipose, liver, muscle


describe insulin signaling

Insulin=>RTK=>IRS-1=>PI-3K=>GLUT4 containing vesicle exocytosed


describe the process of insulin production

1. pre-proinsulin: [signal peptide-BCA]--> produced in rER

2. proinsulin: loss of signal peptide and formation of sulfide bonds (2 between B and A, one within A) produced in rER

3. mature insulin: Cleavage of C-peptide within vesicle


describe the storage form of insulin. where is this seen? when is it undone?

3 AB/AB dimers of insulin surrounding a Zn ion. seen in storage vesicles. undone once contents of vesicle are released


compare half-life of insulin vs. C-peptide

insulin has a short half life, but C-peptide is very stable and can be used as a measure of insulin production


pro-enzyme convertase and insulin: role, location

used to convert pro-insulin to insulin. located within vesicle


what is the difference between GLUT2 and GLUT4

GLUT4 is the only insulin sensitive glucose transporter (seen in muscle cells, liver cells, adipocytes). GLUT2 is located in Beta cells (insulin producing) of pancreas and play an important role in insulin release


describe the signal cascade associated with insulin release from beta cell

1. Alpha and beta cells of pancreas are highly vascularized
2. increase in blood glucose increases the amount of glucose entering beta cells through GLUT2
3. increased glucose increased ATP
4. ATP inactivates K channels
5. B cell depolarizes
6. Voltage gated calcium channels open
7. Ca binds insulin vesicle and insulin released


describe insulin release over time?

biphasic. insulin is released in two phases: phase 1=short burst, phase 2=prolonged

(glucagon release is also biphasic)


In ultrasound: high f gives? low f gives?

high f=better resolution
low f= better depth/penetration


what are the four ultrasound probes? uses?

-phased array: adbomen, cardiac
-endoluminal: vaginal, oral, rectal
-linear: superficial
-curvilinear: abdomen


what is attenuation? what is the attenuation of water? air?

how much an object decreases a sound wave (higher attenuation = less signal)
water: 0
air: 12


what are the modes of US?

-A mode: out dated
-B mode: babies!
-M mode: beach
-Pulsed Wave Doppler
-Color doppler: red=towards, blue=going away
-Power doppler: tells if you have flow


what is the piezoelectric effect

this is how ultrasound works. the crystal in the US converts electrical signal to sound waves and a sound waves back to electrical signal


does Type I or II diabetes have a stronger familial correlation? genetic?

type II

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