Ch 5: Connective Tissue Flashcards
Connective Tissue serves what purpose?
: provides supportive and connective framework for all tissues in body
CLASSIFICATION OF CONNECTION TISSUE:
what are the 4 types?
1. Connective Tissue Proper
– Loose connective tissue
*Areolar
* Adipose
* Reticular
– Dense connective tissue
* Regular
* Irregular
* Elastic
- *2. Cartilage**
- Hyaline cartilage
- Elastic cartilage
- Fibrocartilage
- *3. Bone Tissue**
- Compact bone
- Spongy bone
4. Blood
Which are considered specialized connective tissue?
Adipose
Blood
Bone
cartilage
hemoportic
lymphatic
Define Mucous tissue / the umbilical cord
most of the connective tissue between the vessels consists of collagen fibers.
- Between the collagen fibers are small cells staining red, they are fibrocytes and fibroblasts.
- white space is ground substance.
Loose Connective Tissue
characterized by a loose irregular arrangement of connective tissue fibers and
abundant ground substance. Collagen fibers, fibroblasts(most numerous), mast cells and macrophages
predominate in loose connective tissue.
- thickest lighter staining strands are
collagen fibers.
- thinner darker staining fibers is elastic
fibers.
- fibroblasts lie along the length of collagen
fibers.
Stain: H&
Dense Connective tissue / Tendon
- Dense regular connective tissue is present in ligaments and tendons.
- consists of long collagen fibers (typically type I)
- between the densely packed collagen fibers are flatten nuclei of
- *fibroblasts.**
Adipose Tissue:
Adipose cells are closely packed and separated by thin strips of connective tissue septa in which are found compressed fibroblasts, arterioles, venules, nerves and capillaries
(non is visible in slide).
- the adipose cell nuclei are located peripherally. (not visible in slide).
- adipocytes are derived from lipoblasts that are derived from mesenchymal cells.
- lipid droplets are present inside the adipose cell.
Unlike the other tissue types (epithelium, muscle, and nerve), which consist mainly of cells, what makes up most of Connective tissue?
composed of fibroblasts and other cells that make up the
extracellular matrix (ECM) of various protein fibers,
all of which are surrounded by watery ground substance
Where does Connective Tissue come from?
Mesenchyme, which are undifferentiated cells with large nuclei, with prominent nucleoli and fine chromatin and are spindle shaped.
What do Fibroblast do in Connective Tissue? other cells found in here, such as macrophages , plasma cells , and mast cells.
originate locally from mesenchymal cells and are permanent residents of connective tissue; and are the most common cells in connective tissue, produce and maintain most of the tissue’s extracellular components. Fibroblasts synthesize and secrete collagen (the most abundant protein of the body) and elastin, which form large fibers, as well as the GAGs, proteoglycans, and multi adhesive glycoproteins that comprise the ground substance.
What else does Fibroblast do for connective tissues?
They are targets of many families of proteins called growth factors that influence cell growth and differentiation.
-involved in wound healing, sometimes called myofibroblasts, have a well-developed contractile function and are enriched with a form of actin also found in smooth muscle cells.
Adipocytes
These large,
mesenchymally derived cells are specialized for cytoplasmic
storage of lipid as neutral fats, or less commonly for the production
of heat. The large deposits of fat in the cells of adipose
connective tissue also serve to cushion and insulate
the skin and other organs.
Macrophages & the Mononuclear
Phagocyte System
phagocytic ability and specialize in turnover of protein fibers
and removal of dead cells, tissue debris, or other particulate
material.
A typical macrophage measures between
10 and 30 μm in diameter and has an eccentrically located,
oval or kidney-shaped nucleus.
Macrophages are also secretory cells producing an
array of substances, including various enzymes for
ECM breakdown and various growth factors or cytokines
that help regulate immune cells and reparative
functions.
What else does Macrophages able to do in the system?
Macrophages derive from bone marrow precursor cells
that divide, producing monocytes that circulate in the blood.
These cells cross the epithelial wall of venules to penetrate connective
tissue, where they differentiate further, mature, and
acquire the morphologic features of phagocytic cells. Therefore,
monocytes and macrophages are the same cell at different
stages of maturation.
Mast cells are
oval or irregularly shaped connective tissue cells,
between 7 and 20 μm in diameter, whose cytoplasm is filled with
basophilic secretory granules.
Because of their high content of
acidic radicals in their sulfated GAGs, mast cell granules display
metachromasia, which means that they can change the color of
some basic dyes
Mast cells release numerous bioactive substances with the roles in the inflammatory response. Below are 6 of them.
Heparin, a sulfated GAG that acts locally as an anticoagulant
■■ Histamine, which promotes increased vascular permeability
and smooth muscle contraction
■■ Serine proteases, which activate various mediators of
inflammation
■■ Eosinophil and neutrophil chemotactic factors,
which attract those leukocytes
■■ Cytokines, polypeptides directing activities of leukocytes
and other cells of the immune system
■■ Phospholipid precursors for conversion to prostaglandins,
leukotrienes, and other important lipid mediators
of the inflammatory response.
mast cells are especially numerous near small blood vessels in the skin and
mesenteries (perivascular mast cells) and in the tissue that lines
digestive and respiratory tracts.
mast cells place themselves strategically
to function as sentinels detecting invasion by microorganisms.
Mast cells originate from progenitor cells in the bone
marrow. The progenitor cells circulate in the blood, cross
the wall of venules and capillaries, and penetrate connective
tissues, where they differentiate.
Release of certain chemical mediators stored in mast cells
also promotes the allergic reactions, also known as
immediate
hypersensitivity reactionsbecause they occur within a
few minutes after the appearance of an antigen in an individual
previously sensitized to the same or a very similar antigen.
Plasma cells are:
are B-lymphocyte–derived, antibody-producing
cells.
These large, ovoid cells have basophilic cytoplasm due
to their richness in RER
They have a clock like face.
They are also specific antibodies.
White blood cells: Leukocytes
Leukocytes, or white blood cells, make up
a population of wandering cells in connective tissue. They
leave blood by migrating between the endothelial cells lining
venules to enter connective tissue by a process called diapedesis.