Theory + Application of Cell Mechanics Flashcards
What is stress relaxation?
the stress induced in the body deceases with time under a constant deformation
Creep
Applying a constant force to the body, the body will continue to deform and this increases over time
Hysteresis
a body subjected to cyclic loading, experiences a different stress strain relationship during loading and unloading
What is bacterial motion?
very swift and agile
What happens to a viscoelastic material under high frequency excitation?
It becomes stronger
What do viscoelastic properties depend on?
frequency
Name 3 examples of single cell motion in viscous physiological flow and what do they all have in common?
1 - RBC moving in capillary
2 - bacteria swim with bodies + flagella
3 - sperm cells swimming around the interstitial fluid
LOWWWW reynolds flow Re «_space;1
What is the function of a erythrocyte?
Exchange co2 + return to lung to unload co2 and soak up o2 again
What is the shape of a erythocyte?
disk shaped with almost perfect symmetry
Explain the growth process of a erythrocyte
- RBC grow in the bone marrow and have a nuclei and irregular shape
- As they mature they expel their nuclei and enter the blood
- Circulate body for 120 days then SWELL into spherical shape
What is the ratio of Leukocytes to Erythrocytes?
1:1000
What is the function of a Leukocyte?
key role in immune system + protecting the body against diseases
What are the two types of Leukocytes and what compromises these subgroups
- Non-granular
- Monocytes & Lymphocytes (20-40%) - Granulocyte - characterised by granules in the cytoplasm
- Neutrophils (50-70%)
- Basophils
- Eosinophils
What is the function of the monocytes?
functions in the ingestion of bacteria & other foreign particles
What is the function and percentage of Lymphocytes found in the body?
25% of leukocyte count but increase the presence of infection
- B cells
- T cells
What are neutrophils
remember - granulocytes
they are professional phagocytes > primary function to kill and eat bacteria and arrive quickly ON SITEEEEEEEEEE
oi neutrophils are on beef
Describe what basophils are
- remember - granulocytes*
- coarse granules
- stain blue when exposed to dye
- less than 1% of leukocyte count
Describe eosinophils and their function
- readily stained with eosin
- 1-3% of leukocyte count
- function in allergic responses and resisting some infections
What are fibroblasts and what do they play an important role in?
The most common cells of connective tissue
- important role in WOUND HEALING
What is the importance of cell mechanics in fibroblast migration + contraction?
- tissue regeneration
- cancer genesis
- corneal fibroblasts determining corneal clarity, mechanical integrity & refractive properties
How thin is the cell membrane of a RBC?
< 10 nm
(RBC) What does the cell membrane consist of?
2 layers of phospholipid molecules
- hydrophilic heads facing out
- hydrophobic tail locking into each other on the interior
(RBC) What does the lipid bilayer contribute to the cell membrane?
Fluidity or viscosity
liquid-like behaviours
(RBC) What are the 3 types of proteins found in the cell membrane?
- INTEGRAL proteins - embedded in membrane
- SKELETAL proteins - a network linking the endoface parallel to the membrane
- SPECTRIN contributes elasticity (solid-like behaviours) of the membrane
