CONNECTIVE TISSUE MIDTERM Flashcards
are the most widespread and abundant type of tissue in the human body
Connective tissue
provides a matrix that supports and
physically connects other tissues and cells together
to form the organs of the body
Connective tissue
Its function is primarily to ______, ______, and _______
support, anchor, and connect various parts of the body
Connective tissue has three basic structural components: ____, _____ and _____
cell, fibers, and intercellular substance
_______ are derived from embryonic connective tissue or mesenchyme
Connective tissue
_________ is derived primarily from the mesodermal germ layer of the developing embryo
Mesenchyme
________ is known to give rise to some mesenchymal cells (ectomesenchyme)
ectodermal neural crest
a very large and diverse group of tissues that encompasses all organs and body cavities connecting one part with another end
connective tissue proper
very common and generally supports epithelial tissue that is also called _______
Areolar tissue / Loose connective tissue
What are the preponderant cells and preponderant fibers of loose/ areolar connective tissue
fibroblasts and collagen
these tissues are adapted to offer stress resistance and protection.
Dense connective tissue
arranged according to a definite pattern, with fibers and fibroblasts aligned in parallel to resist prolonged and repeated stress exerted in the same direction.
Dense Regular connective tissue
the bundles of collagen fibers appear randomly interwoven with no definite orientation
Dense irregular connective tissue
has abundant ground substance making it jellylike with sparse collagen fibers and scattered fibroblasts.
Mucoid or mucous connective tissue
sparse, with few collagen fibers and undifferentiated mesenchymal cells
Mesenchyme
made up of delicate network of reticular fibers composed mainly type 3 collagen with attached specialized fibroblasts called reticular cells
reticular connective tissue
serves as storage depots for neutral fats and as key regulators of body’s overall energy metabolism
Adipose tissue
what are the preponderant cells and fibers of adipose tissue
adipocytes (fat cells) and reticular, collagen
the hardest connective tissue. It protects body organs and providing support for organs and skeletal muscles
Bone
________ are cells trapped in spaces called______
Osteocytes - lacunae
Small canals called ________ contains blood vessel and are connections to bigger canals
canaliculi
considered a connective tissue because it provides a transport system
Blood
its extracellular matrix is composed of collagen and elastic fibers embedded in a gelatinous ground substance
cartilage
______ are responsible in secreting fibers and ground substance which later become _______
Chondroblasts - chondrocytes
What are the three types of cartilage
hyaline, elastic, and fibrocartilage
are the key cells in connective tissue proper
Fibroblasts
consists largely of viscous ground substance with few collagen fibers
Mesenchyme
are undifferentiated and have large nuclei,
with prominent nucleoli and fine chromatin
Mesenchymal cells
Fibroblasts involved in wound healing, sometimes called ________, have a well-developed contractile function
and are enriched with a form of actin also found in smooth
muscle cells.
myofibroblasts
__________ the most common cells in connective tissue proper, produce and maintain most of the tissue’s
extracellular components
Fibroblasts
storage of lipid as neutral fats, or less commonly for the production of heat.
Adipocytes
Storage of neutral fats
Adipocytes
Extracellular fibers and ground
substance
Fibroblasts (fibrocytes
Antibodies
Plasma cells
Various immune/defense
functions
Lymphocytes (several types)
Modulate allergic/vasoactive
reactions and defense against
parasites
Eosinophilic leukocytes
Phagocytosis of bacteria
Neutrophilic leukocytes
Phagocytosis of ECM
components and debris; antigen
processing and presentation
to immune cells; secretion of
growth factors, cytokines, and
other agents
Macrophages
Pharmacologically active
molecules (eg, histamine)
Mast cells and basophilic
leukocytes
are oval or irregularly shaped cells of connective
tissue, between 7 and 20 μm in diameter, filled with basophilic
secretory granules that often obscure the central nucleus
Mast cells
Macrophages derive from precursor cells called ________
monocytes
Monocytes formed in the
yolk sac during early embryonic development circulate and
become resident in developing organs throughout the body,
comprising a group of related cells called the _______
mononuclear
phagocyte system
________ a sulfated GAG that acts locally as an
anticoagulant
Heparin
which promotes increased vascular permeability and smooth muscle contraction
Histamine
which activate various mediators of
inflammation
Serine proteases
which attract those leukocytes
Eosinophil and neutrophil chemotactic factors
polypeptides directing activities of leukocytes and other cells of the immune system
Cytokines
precursors, which are converted to
prostaglandins, leukotrienes, and other important lipid
mediators of the inflammatory response.
■ Phospholipid
Release of certain chemical mediators stored in mast
cells promotes the allergic reactions known as __________
immediate
hypersensitivity reactions
are lymphocyte-derived, antibody-producing
cells. These relatively large, ovoid cells have basophilic cytoplasm rich in RER and a large Golgi apparatus near the
nucleus that may appear pale in routine histologic preparations
Plasma cells
Collagen and reticular fibers are both formed by proteins of the
collagen family, and elastic fibers are composed mainly of the
protein _______
elastin
is the most abundant protein in the human
body, representing 30% of its dry weight
Collagen
are short collagens that
link fibrillar collagens to one another (forming larger
fibers) and to other components of the ECM.
Linking/anchoring collagens
is a local swelling caused by abnormally large
amounts of collagen that form in scars of the skin. Keloids
occur most often in individuals of African descent and can
be a troublesome clinical problem to manage. Not only can
they be disfiguring, but excision is almost always followed by
recurrence.
keloid
) preparations but are characteristically stained
black after impregnation with silver salts (Figure 5–12) and
are thus termed
argyrophilic
are also thinner than the type I collagen fibers
and form sparse networks interspersed with collagen bundles
in many organs, particularly those subject to regular stretching
or bending.
Elastic fibers
In the wall of large blood vessels, especially arteries, elastin also occurs as fenestrated sheets called
elastic lamellae
three
major kinds of macromolecules:
glycosaminoglycans (GAGs),
proteoglycans, and multiadhesive glycoproteins.
are long polymers of repeating disaccharide units, usually a hexosamine and
uronic acid.
GAGs
The
largest and most ubiquitous GAG is
hyaluronan
The four major GAGs found in proteoglycans
dermatan sulfate, chondroitin sulfates, keratan sulfate,
and heparan sulfate
consist of a core protein to which are covalently attached various numbers and combinations of the sulfated GAGs.
Proteoglycans
is the key proteoglycan in all basal laminae.
perlecan
is very
large (250 kDa), having a core protein heavily bound with chondroitin and keratan sulfate chains
aggrecan
is a 235-270 kDa dimer synthesized largely
by fibroblasts, with binding sites for collagens and certain
GAGs, and forms insoluble fibrillar networks throughout connective tissue
fibronectin
Integrin-microfilament complexes are clustered in fibroblasts and other mesenchymal cells to form structures called
focal
adhesions
is the excessive accumulation of interstitial fluid in
connective tissue. This water comes from the blood, passing
through the capillary walls that become more permeable
during inflammation and normally produces at least slight
swelling.
edema
produced by plasma
proteins such as albumin, which draws water back into
the capillaries
osmotic pressure
of the blood caused by the
pumping action of the heart, which forces water out
across the capillary wall
hydrostatic pressure
is common,
forming a layer beneath the epithelial lining of many organs
and filling the spaces between fibers of muscle and nerve
Loose connective tissue
bundles of collagen fibers appear randomly interwoven, with no definite
orientation.
dense irregular connective tissue
is characterized by abundant fibers of type III
collagen
reticular tissue
is the principal
component of the fetal umbilical cord, where it is referred to
as Wharton’s jelly
Mucoid (or mucous) connective tissue
) has relatively more
ground substance than collagen, and it typically surrounds small
blood vessels and occupies areas adjacent to other types of epithelia.
Loose connective tissue
is a gel-like connective tissue with few cells found
most abundantly around blood vessels in the umbilical cord.
Mucoid tissue
are short-lived cells that differentiate from B lymphocytes and are specialized for the abundant secretion of specific antibodies (immunoglobulins)
Plasma cells
also originate from blood cell precursors and are filled
with granules for the release of various vasoactive agents and other
substances during inflammatory and allergic reactions.
■ Mast cells
are short-lived cells that differentiate in connective tissue from precursor cells called monocytes circulating in the
blood; they function in ECM turnover, phagocytosis of dead cells
and debris, and antigen presentation to lymphocytes
Macrophages
