The change of linear momentum of an object of mass, m.
F = ma
What is stress?
The force over a unit area. MPa = N/m^2
What is strain?
The relative ratio between the change in length of the original length
What is the ultimate tensile strength?
"Stress at failure" - from notes.
However, it is truly the point at which the failure begins and necking occurs.
What is the ultimate strain?
"The strain at failure" - from notes.
However, it is truly the point at which the failure begins and necking occurs.
What is the modulus of elasticity?
"Extent of deformation" - from notes.
Mathematical expression describing the object's tendency to be deformed elastically.
What is the cell type "primary cell type" referring to?
A cell that is harvested directly from a living organism.
Primary cells are cultured cells freshly derived from a living organism. Once in culture they undergo a limited, predetermined number of cell divisions. For this reason, primary cells can be passaged a finite number of times and are considered to be very delicate and sensitive.
Cell lines, in contrast to primary cells, typically undergo unlimited cell division and have an infinite lifespan. These are in contrast to immortal cell types.
What is the cell type "immortal cell type" referring to?
An immortalised cell line is population of cells from a multicellular organism which would normally not proliferate indefinitely but, due to mutation, have evaded normal cellular senescence and instead can keep undergoing division.
This is in contrast to primary cell types which have a limited number of cell divisions.
Cytokine/Growth factor delivery for modulation of cellular activities:
What are the three types of growth factor delivery? Where are the intended targets?
Endocrine - Target cells located away from the site of synthesis, transported via vasculature
Paracrine - Target cells are nearby and factors diffuse readily
Autocrine - Target cells are the synthesis cells
What are endocrine cells?
Cells that create growth factors that are intended for target cells that are located away from the site of synthesis, transported via vasculature.
What are paracrine cells?
Cells that create growth factors that are intended for target cells nearby where the factors that may diffue readily
What are autocrine cells?
Cells the create growth factors that the target cells are the same as the cells synthesizing the factors.
What is vascularization?
Tissue engineered structures need nutrition and waste removal from the system. Vascularization (or neovascularization) includes the creation of vessels to achieve those functions.
The minimum distance for diffusion is 200 microns.
What is hypoxia?
Hypoxia is a condition in which the body as a whole or a general region of the body is deprived of adequate oxygensupply.
This is the driving force for vascularization leads to increased angiogenesis (production of blood vessels).
Hypoxia, or hypoxiation, is a pathological condition in which the body as a whole (generalized hypoxia) or a region of the body (tissue hypoxia) is deprived of adequate oxygensupply. Variations in arterial oxygen concentrations can be part of thenormal physiology, for example, during strenuous physical exercise. A mismatch between oxygen supply and its demand at the cellular level may result in a hypoxic condition. Hypoxia in which there is complete deprivation of oxygen supply is referred to as anoxia.
What is angiogenesis? What are some growth factors? What does the process include?
Angiogenesis is the physiological process involving the growth of new blood vessels from pre-existing vessels. This includes splitting off of existing vessels.
Angiogenic factors include:
The process includes vasodilation (widening of vessels) and the proliferation of endothelial cells, pericytes, smooth muscle cells prior to migration.
List three angiogenic factors.
VEGF - Angiogenesis
PDGF - Mitogen for fibroblasts, granulation tissue, chemotactic
TGF-Beta - Stimulates matrix deposition
How is inflammation brought about by chemical mediators? Is it local?
It is a local response by chemical mediators.
The triple response of Lewis is a superficial scratch.
Red scratch mark
Red flare around the scratch mark
Red swollen area ("wheal") around the flare
Cutting the autonomic nerve supple prevent the "axon reflex" which led to the discovery of hisamine (chemical in inflammatory response)
What is a leukocyte?
A white blood cell in the immune response.
There are some types of white blood cells that have a role in the early stages of inflammation .
What is acute inflammation?
Response to recent or ongoing injury with the principal feature of dilation and leaking of vessels, and involvement of circulating leukocytes
What is chronic inflammation?
Response to prolong problems and orchestrated by T-help lymphocytes. It may feature recruitment and activation of T- and B-lymphocytes, macrophages, eosinophils, and or fibroblasts. This process is very complex, as well as acute inflammation.
What are granulomas?
An organized group of macrophages.
Granulomas are seen in certain chronic inflammation situations. They are clustors of macrophages that have stuck tightly together, typically to wall something off. Such are called epithelioid cells.
You will recognize granulomas in tissue sections by their characteristic appearance, or the presence of giant cells.
What is fibrin?
A fibrous, non-globular protein involved in the clotting of blood.
Released as fibrinogen from damaged vessels, and activated by the clotting cascades when blood meets tissue juices.
Fibrin forms the meshwork that controls bleeding and then becomes the framework for fibroblasts and angioblasts that form the scar.
Until the new scar is complete, the whole meshwork of the immature scar is called granulation tissue.
When the scar has matured, it contracts.
What is the advantage of vasodilation?
Leads to greater blood flow to the area of inflammation, resulting redness and heat.
What is vascular permeability's role in the inflammation response?
Endothelial cells become "leaky" from either direct endothelial cell injury or via chemical mediators. This allows for leukocytes to pass through if necessary.
What is exudation?
The process in which fluid, proteins, red blood cells, and white blood cells escape from the intravascular space as a result of increased osmotic pressure extravascularly and increased hydrostatic pressure intravascularly.
What is vascular stasis?
Slowing of the blood in the bloodstream with vasodilation and fluid exudation to allow chemical mediators and inflammatory cells to collect and response to the stimulus.
War is the metaphor for inflammation. Both are necessary evils that are more-or-less sterotyped responses to outside threads.
There are specialized troops (____________) that include suicide-commandos (____________), long-term siege armies (___________) and many others.
There are supply routes (______), communications and intelligence (mediators) and a huge array of lethal weapons (inflammatory enzymes).
White blood cells
Neutrophils - high percentage of these are found in pus
Granulomas - organized groups of macrophages
blood vessels - modes of transportation
(T/F) Inflammation and infection are the same.
What are the differences?
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the
injurious stimuli and to initiate the healing process. Inflammation is not a synonym for infection, even in cases where inflammation is caused by infection. Although infection is caused by a microorganism, inflammation is one of the responses of the organism to the pathogen.
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease. Colloquially, infections are usually considered to be caused by microscopic organisms or microparasites like viruses, prions, bacteria, and viroids, though larger organisms like macroparasites and fungi can also infect.
What are the differences between acute and chronic inflammation?
Acute inflammation - intial response of the body to farmful stimuli and is achieved by the increased movement of plasma and leukocytes (especially granulocytes) from the blood to the tissue.
Prolonged inflammation, known as chronic inflammation, leads to a progressive shift in the type of cells present at the site of inflammation and is characterized by simultaneous destruction and healing of the tissue from the inflammatory process.
What are the most predominat cells in pus from an inflammation reaction?
Neutrophils are phagocytes, capable of ingesting microorganisms or particles attracted by chemotaxis.
Neutrophils are recruited to the site of injury within minutes following trauma and are the hallmark of acute inflammation. They are the predominant cell in pus.