Histology Connective Tissues Flashcards
What is a mesenteric spread?
A emsentery is a sandwich were the bread is simple squamous epithelium and the filling is loose connective tissue
In a spread, the mesentery is not sectioned, but is simply stretched and dried on a slide.
What is the role of a fibroblast in a mesentery spread?
Describe the fibrobast?
In a mesentary it is a branching cell with a pale oval nucleus and pale cytoplasm.
What is the function of the macrophage?
Phagocytosis of damaged tissue , worn out cells, bacteria, foreign antigens.
**Contains debris in the cytoplasm
Are macrophages antigen presenting cells?
Yes, digested material present digested fragments on their surface bound to the major histocompatibility complex (MHC).
Lymphocytes can interact with this coplex via the T-Cell receptor.
What are macrophagtes derived from?
What system do they belong to?
Do macrophages ingest ferrotin?
Monocytes
Reticuloendothelial system
Yes it is useful in identiying them in a stain
What is the function of a lymphocyte?
Where are lymphocytes present?
Interat with macrophages when foreign particles are presented in the complex with the MHC complex.
Present in loose connective tissue adjacent to the epithelium of the skin and the GI tract.
What do plasma cells produce?
Circulating antibodies
What does the nucleus of a plasma cell look like?
Clock-like heterochromatin
What do the granules of mast cells contain?
Heparin (anticoagulant), Histimine and slow reactive substances of anaphylaxsis
What is the purpose of histamine?
What happens to endothelial cells in the presence of histamine?
Causes vasodilation and increaes the permeability of capillaries and venules
In the presence of histamine endothelial cells develop gaps between them and leak fluid from the vasculature to the tissue.
What is the mechanism of degranulation of mast cells
Antigen binds to the IgE-receptor causing crosslinking and coupeling.
Increased intracellular Ca+ causes fusion and release of granules.
Where do Myofibroblasts appear?
What do they do?
In wounds and intermediate between fibroblasts and smooth muscle.
They cause wound contraction
What are the two main types of connective tissue?
Collagen
Elastin
What aminoacids make up collagen?
Which gets modified with an o-Glycosidic linkage?
Glycine, Hydroxyserine, Hydroxylysine
Hydroxylysine
How is the normal state of collagen content in the cell mantained?
A balance between collagen degradation and collagen metabolism
What are reticular fibers? What are they made of?
Reticular fibers form a net like reticulum,
Made of fibroblasts and are abundant in blood forming organs
Where are elastin fibers located?
Dermis, Lungs, Large ateries, elastic cartlidge
How is elastin different from collagen?
It forms branches
They anastomose freely
They stretch
What is marfan syndrome?
What will patients present with clnically?
Genetic defect in the fibrillin gene that Causes abnormal elastic fibers
Patients will present with externally tall stature with disproportionate arms and legs.
What is a ground substance?
What is it composed of?
Where is it found?
A colloidal gel of variable viscosity
Proteoglycans
In most connective tissues it is removed by processing but it remains in cartlidge and bone.
What sugers make up chondroitin sulfate (GAG)?
1,4 glucuronic acid
1,3 galacrosamine
How does Hyaluronic acid differ from other GAG’s?
It does not form proteoglycans but associates with proteoglycans through link proteins.
Contributes to the viscosity of ground substance.
It is much larger
What is a multiadhesive glycoprotein?
What is an example of one?
multidomain, multifunctional molecule that binds cells to the extracelllular matrix proteins.
Fibronectin
Where is fibronectin produced?
It is produced by fibroblasts (cell surface FN) and is also produced in the liver and secred into the blood (Plasma FN)
What are some major functions of FN?
FN is linked to fibrin during clot formation.
The FN coating on the fibrin strands allows fibroblasts to migrate into the clot and make new connective tissue.
What is mesenchyme?
Embryonic connective tissue. Contains mesenchymal cells that form all the cells of the connective tissue
What does mesenchyme contain?
Ground substances and sparse reticular fibers.
What is a pericyte?
What does a pericyte arise from?
Gives rise to many different fibroblasts and participate in new vessed formation during wound healing.
Mesenchymal cells.
What is an example of mucous connective tissue?
What is it made of?
Whartons jelly, found in the umbilical cord. Mix of fibroblasts mixed with small collagen fibers
What is connective tissue proper?
Loose connective tissue, composes the mesentary and forms the stroma of most tissues
What characterizes dense connective tissue?
What is an example of dense irregular?
Closely packed fibers, differentiated from loose connective tissue by the larger fiber size.
Dermis of the skin and periosteum, perichondrum
What is an example of dense regular?
What composes it?
Tendons, ligaments, aponeurosises.
Composed of fibroblasts and parallel orientated collagen fibers.
What is adipose tissue composed of?
Each cell contains one large fat droplet.
Very little extracellular material separates adipose cells.
Mainly found in subcutaneous tissue, around the kidneys and in the mesentary.
What is another name for reticular connective tissue?
What is lymphatic tissue composed of?
Lymphatic tissue
Consists of reticular fibers and reticular cells.
Processes of the cells wrap around the fibers
What differentiates white adipose tissue from brown adipose tissue?
White, contain one huge fat droplet that is not membrain bound.
Brown, contain several fat droplets and is present in infants and hibernating animals. Functions to mantain body temperature.
What are keloids?
Exuberant scar tissue formation that extends far from the site of the injury. .
**Due to an overproduction of collagen
Most common in africo carribeno races.
