Transcript Tissues Part B - Thinkport.org

Tissues Part B
Connective Tissues
• 12 different tissues
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Embryonic
Alveolar
Adipose
Reticular
Dense regular
Dense irregular
Hyaline cartilage
Elastic Cartilage
Fibrocartilage
Osseous
Blood
Common Characteristics of
Connective Tissues
1. All originate from mesenchyme tissue in
the embryo
2. Can be avascular or vasculated;
cartilage is avascular while loose
connective tissue is vascular
3. Extracellular matrix of nonliving
chemicals plus the cells
Characteristics of Connective
Tissue
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Weight bearing (bone)
Withstand great amount of tension
Endure abuse of physical trauma and abrasion
Binds cells together as a group
Can form “ropes” to hold muscle to bone
Insulates organs as packing
Permits transportation of cells and chemicals
from one set of cells to another through ground
substance
Connective Tissue – Physical
Characteristics
• Contains cells that are widely spaced
apart
• Located in a loose or dense structure that
can consist of one or both of the following
– Fibers
– Ground substance – a semisolid gel of water,
glycoproteins (sugar-protein molecule that is
gluey), adhesion proteins and other chemicals
to hold everything together and provide a
transportation medium
Connective Tissue
• Connective tissue supports epithelium
– Reticular lamina under the basal lamina
contains collagen
– Both basal lamina and reticular lamina form
the “basement membrane”
– Basement membrane protects epithelium
from stretching out of shape or tearing; define
epithelial boundary
Vocabulary
• Lamina - layer; a thin, flat plate of a larger
composite structure.
• Reticular - Resembling a net in form;
netlike.
• Lucida – clear
• Desmosomes – proteins that “spot weld”
cells together or to other tissues
Terminology
• - blast – cells that form tissues or other
cells
• - cyte – cell
• -clast – break down tissues
• Chondro – cartilage
• Osteo - bone
• Lacunae - A cavity, space, or depression,
especially in a bone, containing cartilage
or bone cells.
Epithelial cells
Basement membrane
• Basement membrane
is the clear region
between the two lines
at the point of the
green arrow
Ground Substance
The amorphous intercellular material in
which the cells and fibers of connective
tissue are embedded; composed of
proteoglycans, plasma constituents,
metabolites, water, and ions present
between cells and fibers. Also called matrix.
Ground Substance with fibers and
cells
Ground Substance
The amorphous intercellular material in
which the cells and fibers of connective
tissue are embedded; composed of
proteoglycans, plasma constituents,
metabolites, water, and ions present
between cells and fibers. Also called matrix.
Fibers
• Collagen Fibers
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Made of collagen
Crosslinked
Highly tensile
Resist longitudinal stress
• Stand up and do a side
bend
– When fresh are a glistening
white; called white fibers
• Elastic fibers
– Branching networks
– Made of elastin, which is
rubbery and stretchy
– Good recoil to original
shape
• Pull skin out from back of
hand – does it “snap
back”?
– Found in skin, blood
vessels and lungs
– When fresh are yellow:
called yellow fibers
Collagen fibers (thicker)
Elastic fibers (darker
blues and blacks)
Fibers
• Reticular fibers
– fine collagenous fibers
– highly branched network (hence reticula;
means “maze” or “pattern”)
– surround blood vessels, support soft organ
tissue
– Seen between different tissues; form a fuzzy
“nest” that allows for give with the organs
Embryonic or Mesenchyme Tissue
• Found in embryo
• Gives rise to all other
connective tissues
• Contains lots of
ground substance,
mesenchymal cells
that give rise to all
four types of
connective tissue
What gives rise to what?
Mesenchymal tissue
Fibroblasts
Chondroblasts
Connective tissue
proper
Cartilage
Loose
Dense
areolar
regular
adipose
irregular
reticular
elastic
Hyaline
Osteoblast
Compact
bone
Spongy
bone
Fibrocartilage
Elastic cartilage
Hematopoietic
stem cell
Blood cells
Erythrocytes (RBC)
Leucocytes (WBC)
Thrombocytes
(platelets)
Areolar Tissue (Loose)
• Lots of ground
substance (clear)
• Thin elastic and thick
collagen fibers
• Various cells
(fibroblasts,
macrophages, mast
cells, white blood
cells)
Adipose Tissues (loose)
• Aka ‘fat cells’
Brown fat
Brown vs. White
• Brown fat - A dark-colored, mitochondrionrich adipose tissue in many mammals that
generates heat to regulate body
temperature, especially in hibernating
animals.
• White/yellow fat - contains stored cellular
fat. Good for cushioning bones, insulation,
gives “shape” to human females.
Reticular Tissue (Loose)
• Reticular fibers,
ground substance,
reticular cells,
macrophages, mast
cells
• Supports other cells
like an internal
skeleton
Dense regular (Dense connective)
• Tissues are fairly
straight and run in
one plane
• Interspersed with
various cells
• Notice how evenly the
cells are lined up
• Found in tendons and
ligaments, where
regularity is a must
Dense Irregular (Dense connective)
• Notice how irregular
or “all over” this tissue
is
• Contains fibroblasts
and collagen fibers
• Found in skin dermis
and around some
organs that move
multidirectionally
Elastic (Dense connective)
• Consists of ground
substance and elastic
fibers
• Where stretch is
needed
• Under the skin,
surrounding aorta and
arteries, veins, lungs,
elastic cartilage and
other parts
Osseous (Compact and Spongy)
• Compact bone forms the
outer edge of the bones,
making a hard outer
coating that gives
strength
• Spongy (cancellous)
bone is found in the long
bones and in the
sternum; it provides a
supporting internal
scaffold while helping
make bones lighter
Cartilage
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Three types of tissues
Hyaline
Elastic
Fibrocartilage
Hyaline cartilage
• Firm matrix
• Collagen fibers present,
but imperceptible
• Chondroblasts produce
matrix
• Chondrocytes (mature
chondroblasts) lie in
lacunae
• Long bone covers; costal
cartilage; cartilage of
nose, trachea, larynx
• Is the embryonic skeleton
constituent
Elastic Cartilage
• Similar to hyaline,
with prominent elastic
tissue
• Maintains shape with
greater flexibility
• External ear and
epiglottis
Fibrocartilage
• Less firm matrix,
preponderance of
thick collagen fibers in
a regular pattern
• Ability to absorb
compressive shock
• Intervertebral discs,
symphysis pubis,
discs of knee joints
Fibrocartilage – Symphysis pubis
Fibrocartilage
Squishy center to allow
“give” and absorb shock
Location of fibrocartilage
Blood
• Blood is a connective tissue
• Aids in oxygen transport, immune
response, blood clotting
Macrophages
• Purple cell
surrounded by red
blood cells
• Stained – usually
clear or buffy colored
• Active part of immune
system
• Looks for intruders to
“eat” and tell rest of
immune system about
Mast Cells
• Highly granular
• Located in matrix
• Contain histamine (an
inflammatory
chemical) and heparin
(a anti-clotting
chemical)
• Open up when you
are wounded to cause
swelling of the tissue
Plasma cells
• “B” white blood cells
that create antibodies
against previously
contracted infections
• Antibodies attack
invading organisms to
immobilize until
macrophage can
show up to eat the
invader
Plasma cells
Erythrocytes
• Red blood cells
• Biconcave, permits
O2/CO2 perfusion
across membrane