Transcript Tissuesx

Tissues
Chapter 5
Objectives:
1. List and describe the four major tissue
types, and provide examples of where
each occurs in the body.
2. Name the types of epithelium, and
identify an organ in which each is
found.
3. Distinguish different types of
connective and muscular tissues.
Tissue:
• Def.: a group of similar cells that performs a
specialized function
• 4 major types of tissues:
A. Epithelial Tissues
•
•
Forms linings throughout the body
Anchored to underlying connective tissue by a
nonliving layer called basement membrane
1. Simple Squamous Epithelium - a single layer of
thin, flattened cells
–
–
–
–
Fit together tightly
Broad, thin nuclei
Substances pass through easily; easily damaged
Found in lung air sacs, capillary walls, and
membranes lining body cavities
– ???
Epithelial Tissues (cont.)
2. Simple Cuboidal Epithelium – single layer of
cube-shaped cells
– Centrally located, spherical nuclei
– Ovaries, kidney tubules, ducts of some glands
– Adds in secretion and absorption
Epithelial Tissues (cont.)
3. Simple Columnar Epithelium – longer than
they are wide (elongated, like columns)
– Thicker
– Nuclei located near the basement membrane
– Ciliated – found in female reproductive tubes
– Nonciliated – lining of uterus, stomach, intestines
Epithelial Tissues (cont.)
4. Pseudostratified Columnar Epithelium –
appear to be stratified (layered), but are not
– Why? Nuclei are found at different levels in the
cells, instead of only near the basement
membrane.
– Many are ciliated.
– Found lining respiratory passages
Epithelial Tissues (cont.)
5. Stratified Squamous Epithelium
– Many layers = thick (for protection) ???
– Outer layer of skin (“epidermis”)
– Lining of mouth, throat, vagina, and anal canal
6. Stratified Cuboidal Epithelium
– 2-3 layers of cuboidal cells lining a lumen
– Lines large ducts of glands (mammary, sweat,
salivary, pancreas) and of ovarian follicles and
seminiferous tubules
7. Stratified Columnar Epithelium
– Top layer elongated; base layer cube-shaped
– Found in male urethra, vas deferens, and pharynx
???
Epithelial Tissues (cont.)
8. Transitional Epithelium – changes in response
to tension
– Found lining the bladder, ureters, and part of the
urethra
– Contracted – thicker; many layers **
– Relaxed – stretches and appears thinner
• See Table 5.3, p. 99!!
B. Connective Tissues
• Made up of:
– Cells, which are further apart than epithelial cells
– Fibers
– Matrix: intercellular material
• Major cell types:
1. Fibroblasts – large, fixed, star-shaped cell that
secretes fibers
2. Macrophages – wandering scavenger cells that
defend against infection
3. Mast cells – large cells, located near blood
vessels, that secrete heparin and histamine
Fibroblast
http://www.cimaging.net/applications/
examples/images/fibroblast3.jpg
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Macrophage &
Mast Cell
http://upload.wikimedia.org/wikipedia/
commons/7/73/Macrophage_in_the_al
veolus_Lung_-_TEM.jpg
http://www.bu.edu/histology/
i/22602ooa.jpg
http://www.healthsystem.virginia.edu/
internet/hematology/images/Mastcell-and-basophil-100x-websitearrow.jpg
Connective Tissues (cont.)
• Connective tissue fibers:
1. Strong, collagenous fiber (white fiber), made of
the protein collagen; adds strength
2. Stretchy, elastic fiber (yellow fiber), made of
the protein elastin; adds ____________.
3. Reticular fibers – thin collagenous fibers that
form supportive networks in tissue
Connective Tissues (cont.)
1. Loose Connective Tissue (“areolar tissue”)
– Cells are some distance apart; separated by gellike matrix
– Forms delicate, thin membranes
– Binds skin to underlying organs, fills space
between muscles
Connective Tissues (cont.)
2. Adipose Tissue – fat
– Large fat droplets in cells push nuclei close to the
cell membranes.
– Beneath the skin, between muscles, around
kidneys, behind eyeballs, on heart, around joints
Connective Tissues (cont.)
3. Dense Connective Tissue – closely packed,
thick collagenous fibers + elastic fibers
– Strong!
– Binds organs together
– Found in tendons, ligaments, deep skin layers
Connective Tissues (cont.)
4. Cartilage – a rigid connective tissue
– Chondrocyte: cartilage cell
– Perichondrium: around cartilage; membrane
surrounding cartilage; contains blood vessels to
supply nutrients
– Three types of cartilage, distinguished by
intercellular (???) matrix:
a) Hyaline cartilage
b) Elastic cartilage
c) Fibrocartilage
Connective Tissue (cont.)
a) Hyaline cartilage
– Very fine collagenous fibers in matrix
– White glass appearance
– Ends of bones in joints, soft part of nose
b) Elastic Cartilage
– Dense network of elastic fibers = more flexible
– Framework for external ears and parts of larynx
c) Fibrocartilage
– Very tough; many collagenous fibers
– Forms intervertebral discs and pads between
bones in knees and pelvic girdle
Hyaline cartilage cells
Elastic cartilage cells
Fibrocartilage
http://www.bartleby.com
/107/Images/small/image
295.jpg
http://cellbio.utmb.edu/microanatomy/bone
/fcartilage.jpg
Connective Tissue (cont.)
5. Bone – the most rigid connective tissue
– Matrix made of mineral salts and collagen fibers
– Osteocyte: bone cell
6. Blood
• See Table 5.4, p.105!!!
???
C. Muscle Tissues
1. Skeletal muscle tissue (“voluntary”)
– Long, threadlike cells
– Striations: alternating light and dark crossmarkings
– Each cell has many nuclei just beneath the cell
membrane.
Muscle Tissues (cont.)
2. Smooth muscle tissue (“involuntary”)
– No striations
– Cells are shorter than skeletal muscle, spindleshaped, and have one, centrally located nucleus.
– Line walls of internal organs
Muscle Tissues (cont.)
3. Cardiac muscle tissue – heart
– Striated and joined end-to-end
– Each cell has only one nucleus.
???
D. Nervous Tissue
• Nervous tissue is
– found in the brain, spinal cord, and nerves.
– made up of:
• Neurons: nerve cells
• Neuroglial cells: helper cells
– “glia” = glue
– Support and bind components of nervous tissue to each
other and to blood vessels
• See Table 5.5, p.107!!!