Cell Mechanobiology (9/3b) Flashcards Preview

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Flashcards in Cell Mechanobiology (9/3b) Deck (33)
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1

Connective tissue (CT)

made up of cells and extracellular matrix

2

Tendon

type of connective tissue

conveys the tension created by muscles onto the bones, and also provide support

3

Fibroblasts

cells in a tendon that separate the components of extracellular matrix

4

Extracellular Matrix (ECM)

made up of ground substance and fibers

5

Ground substance (ECM)

Proteins: Proteoglycans and glycosaminoglycans - strongly hydrophilic, attract water

Glycoproteins link ECM components

6

Fibers (ECM)

Collagen (primarily type 1), elastin

In tendon, collagen bundles arranged in parallel to resist tension

7

Fibroblast structure

Cytoskeleton provides structure and aids in mechanotransduction

Microtubules (MTs), Intermediate Filaments (IFs), Microfilaments (MFs)

Desmosomal cadherins and integrins

Continuous chain of communication (EX: gap junctions) from outside of the cell to nucleus

8

Gap junction

specialized intercellular connection between the cytoplasms of two cells, allowing messages to be relayed

9

Microtubules (MTs)

polymers of tubulin that form part of the cytoskeleton

provide structure and shape to the cytoplasm

10

Intermediate Filaments (IFs)

provide mechanical support for the plasma membrane where it comes into contact with other cells or with the extracellular matrix

do not participate in cell motility

11

Microfilaments (MFs)

mostly composed of actin, also called actin filaments

the smallest filaments of the cytoskeleton. aids in cell movement, muscle contraction, cell division

12

Cadherins

calcium-dependent cell adhesion molecules that play a role in cell-cell adhesion and maintaining integrity of multicellular structures

a main component of zonula adherens

13

Integrins

transmembrane receptors that facilitate cell-extracellular matrix adhesion

14

Mechanotransduction

transduction of mechanical stimuli into a cellular signal and a response

mechanical stimulus>tissue forces>cellular forces>molecular response

15

Types of Forces (Forces)

Tension
Shear
Vibration
Compression
Hydrostatic Pressure
Fluid Shear

16

Tension (Forces)

force pulling away from point

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Shear (Forces)

unaligned forces pushing one part of a body one way and another part of the body an opposite way

18

Vibration (Forces)

forces moving quickly and repeatedly around an equilibrium point

19

Compression (Forces)

force pushing down on point

20

Hydrostatic Pressure (Forces)

pressure exerted by a fluid at equilibrium at a given point within the fluid, due to gravity force

21

Fluid Shear (Forces)

shear stress developed due to particles in fluid moving relative to one another

22

How are mechanical stimuli sensed

Collagen fibers in ECM linked to cytoskeleton via integrin proteins

Stretch-activated ion channels

G-protein coupled receptors

Growth-factor receptors

Integrins

23

Signal Transduction

by direct structural links between cytoskeleton and nucleus, and intracellular signaling cascades

24

Physical Stress Theory (PST)

Changes in the relative level of physical stress cause a predictable response in all biological tissue

25

Physical stress (PST)

force applied to an area of tissue

Force = mass * acceleration

Stress = force/area of tissue

26

5 Characteristic Responses to Stress

Death
Decreased tolerance
Maintenance
Increased tolerance
Injury

27

Stress level is a composite of these 3 things

Magnitude
Time
Direction

28

Excessive stress can be

1) high magnitude brief duration

2) low magnitude long duration

3) moderate magnitude many times

29

What can increase thresholds for stress

Overload

Progression of exercise stimulus

30

What can decrease thresholds for stress

inflammation

prolonged low stress