Body tissues are divided into 4 categories:
1. Connective
2. Nerve
3. Muscle
4. Epithelial
-Functions: Connect, support,
transportation (blood), defense, and
storage (fat)
-cells are surrounded by some type
of non-living matrix
-classified by their structure and
the type of matrix
-there are four major classes of
connective tissue with
subcategories
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I. Fibrous, II. Bone, III. Cartilage, IV. Blood
a)
Loose- the stretchable fascia between organslike an elastic glue spread between organs
b)
Adipose- fat storage under the skin
-important for protection and insulation
c)
reticular- web like fibers of the lymphatic
(immune) system
- helps filter blood
- contains white blood cells to destroy
dangerous invaders
d)
dense- tendons and ligaments –flexible but
strong
-tendon- connects muscle to bone
-ligament- connects bone to bone
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bone cells are called osteocytes
-osteoblast- bone building cell
-osteoclast- bone destroying cell
the 2 cells above work together and can reshape
bone
a “unit” of bone is known as the Haversian
System (see fig 5-20)
the cells are squeezed between the hard matrix
of mineral salts (mostly calcium)
flat bones are called membranous bones (skull,
pelvis)
Osteocytes
Cross-section of long bone
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chondrocytes are cartilage producing cells
cartilage is avascular (no blood vessels)
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there are 3 subcategories of cartilage

a)
hyaline cartilage- shiny and smooth, at the
ends of bones (linings of joints)
chondrocytes
b)
Fibrocartilage- strongest and most durable,
“shock absorbers” (intervertebral discs,
meniscus of the knee joint)
c)
Elastic cartilage- most flexible cartilage
(ears, nose, larynx)
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Considered a connective tissue because it is made in
the bones
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Hematopoiesis- the process of blood production in the

has a liquid matrix called plasma
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red marrow of the bones
There are 3 main types of blood cells:
1) Erythrocytes- red blood cells: carry O2 (some CO2)
2) Leukocytes- white cells: kill invaders
3) Thrombocytes- responsible for blood clotting by
producing platelets
All are responsible for movement
-May be voluntary or involuntary
-May be striated or non-striated
Voluntary= may be
“willed” to move
Involuntary= not
controlled by thought or
will
Striated= visible
“stripes” on tissue
Non-striated= no
visible “stripes

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Striated and voluntary
Cells are very long and thin with multiple
nuclei
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Non-striated and involuntary
Cells are shorter and each with one nucleus
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Striated and involuntary
Cells connect at dark “disks” and only one
nucleus per cell.
-Rapidly regulate and
integrate body activities
-2 basic kinds of cells
1. neurons=conducting cells
2. glial cells= support cells
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Soma: main body of cell (nucleus is here)
Dendrites: short thin branches that carry signal
towards the soma
Axon: long thin “wire” carrying signal away from
the soma
Synapse: where neurons connect to transmit
signal
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Schwann Cells- wrap around the axon to
insulate the “wiring” to speed nerve signal
transmision
- Responsible for the
fatty white matter of
the nervous system
-Cells are tightly packed into
sheets with no “matrix”
between cells
-sheets of cells attached to a
“basement membrane”
-cells are attached to each
other by “tight junction”
making a tight seal
- one side is “exposed” to
either internal or external
environment
-2 main types:
membranous
glandular
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Classification is based on shapes and layers:
Description of Cell Shapes:
Squamous -(flat and scaly)
Cuboidal -(cubic)
Columnar -(tall narrow column)
Pseudostratified columnar -(odd columns, not
all reach the surface)
Description of Layers:
Simple (one layer)
Stratified (several layer of same cell type)
Transitional (many layers transitioning to
different cell types)
Simple Squamous
- VERY thin. Where quick diffusion is necessary
lining of blood vessels, tiny air sacs in
lungs, parts of kidney, etc.
“flat”
Cross-section
Stratified Squamous
- areas that receive friction
skin, mouth, esophagus
Cross-section
Cuboidal
- lines many ducts and tubules
Cross-section
Columnar epithelium
- may be ciliated with tiny “hairs” (cilia)
Non ciliated
- lines gastrointestinal
tract
Ciliated
- lines respiratory tract
Transitional
- bladder – allows for expansion
Cross-section
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Synthesizes and secretes a chemical product
oEndocrine gland- secrete
directly to bloodstream
oExocrine gland- secrete
into collecting ducts
oUnicellular gland- single
cells called goblet cells
that produce mucous
Pituitary: Example of an
endocrine gland
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Exocrine glands come in a wide variety of shapes:
Exocrine Secretion:

Merocrine- hormones
released through cell
membrane (sweat & salivary glands,
mucous producing goblet cells)
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Apocrine- part of cell
containing hormones
pinches off (mammary gland)
Holocrine- cell bursts to
secrete products and
must be replaced
(sebaceous gland)