What should be included in your tissue text book …
1. The images taken during lab. Be sure to title them
or make sure they appear in the correct context of
your book. Example – areolar picture appears in
the areolar section of your book.
2. An introductory paragraph for epithelial tissues
in your book. Describe the general characteristics
for epithelial.
3. The body of the epithelial section should include a
description of each tissue type from your
observations in the lab. You don’t have to be
“technical”. Use your words, not the text book’s
description! Describe 2 locations of the specific
tissue type and link it to the function. Do not list
functions and locations separately.
4. Another “don’t”: bullet points/outline form
Below is a sample of book.
Connective Tissue
Connective tissue is characterized by having its cells isolated from one another. The spaces
between are often filled with blood vessels, making them highly vascular and involved with
tissue repair. Cells are highly specialized and produce an extra-cellular matrix. The form of the
matrix is what is used in categorizing connective tissues as fluid connective tissue, connective
tissue proper or supportive connective tissue.
Bone and cartilage are both supportive connective tissue. The matrix for bone is very hard, made
of calcium salts and ground substance. On the microscopic level, the tissue contains open circles
(Haversian canals) with dark, tick-like structures
concentrically arranged around the canals. Narrow,
Osseous (bone)
thread-like structures radiate through the concentric
rings like spokes on a wheel. Osseous, or bone, tissue
can be found in all 206 bones of the adult body.
Examples would include the femur, scapula, and
parietal bones. Osseous tissue stores calcium which
can be used for other body processes when needed.
Because it is so hard, bone tissue functions in
protection and support of other tissues. Muscles
attach to bone which causes movement of the body.
The matrix of cartilage can be described as tough,
rubbery and resilient. Under the microscope, hyaline
Hyaline cartilage
cartilage has the appearance of “cream of eyeball” soup.
The cells (chondrocytes) reside in lacunae that seem to
float in a sea of a smooth matrix. One can find hyaline
cartilage at the ends of long bones, forming the rings in
the trachea and making up the larynx. Hyaline cartilage is
smooth and rubbery. This makes it ideal for reducing
friction at joints which are made where long bones meet.
In the trachea, hyaline cartilage keeps the passageway
open for air to enter the lungs. Elastic cartilage is found
in the outer ear and pinna. It can also be found in the epiglottis which covers the trachea when
one swallows. Under the microscope, it looks similar to hyaline cartilage, but the lacunae are
closer together and one can see fibers within the
matrix. This makes the matrix look “rougher” than
the matrix of hyaline. This gives elastic cartilage
its name. It allows the tissue to return to its original
shape and size.
Elastic Cartilage
Adipose, Areolar (loose), and fibrous connective tissues are classified as “connective tissue
proper. These tissues are characterized as having fibers (elastic and/or collagen) laid down in
fluid-filled matrix. Adipose tissue looks like soap bubbles clinging together when viewed under a
microscope. The “open” area of the cell is the fat droplet. As fat molecules are stored in the cell,
it pushes the cytoplasm and its contents out to the side. Adipose tissue can be found in the subdermal layer of the skin and surrounding organs such as
the eyeballs, the kidneys, or the heart. Adipose assists in
thermoregulation by insulating the body and organ. It
also provides a means of energy storage. Cushioning
organs is yet another function of this tissue. Areolar
tissue looks like a mish-mash of fibers, thick and thin,
criss-crossing the field of the microscopic view. The
thin, dark strands are elastic fibers while the thicker,
light pink fibers are collagen. The dark splotches are the
fibroblasts.
Adipose
Areolar tissue can
be found surrounding other tissues or organs such as blood
vessels, nerves and muscles. Areolar tissue acts as a sort of
“organ glue”, adhering things together. They protect and
nourish other organs and can act like a sponge, storing
body fluids.
Areolar Tissue
Epithelial Tissue
The unique characteristics of epithelial tissue include closely packed cells, avascular, highly
mitotic, and free apical surfaces. Epithelial tissue often covers and lines organs and structures.
General functions include secretion, absorption, excretion, and filtration. If arranged in multiple
layers, they function in protection from friction and abrasion. Cells are sacrificed in this process.
Squamous tissue can be found in single layers (simple) or
multiple layers (stratified). Both are important components of Simple squamous; cheek smear
body membranes. Simple squamous tissue forms serous and
mucous membranes and resembles a cluster of pink fried
eggs. Stratified squamous epithelium form the skin and lines
the digestive tract.
Simple squamous also
lines blood vessels and
are
the
only
component in the
walls of capillaries, facilitating diffusion. For the same
reason, it also composes the walls of the alveoli in the
lungs. The outer layers of stratified squamous epithelium
are made of dead, flattened cells. They are sloughed off as
Stratified squamous
these surfaces experience abrasion. Cells are constantly being replaced along the basement
membrane. The skin is waterproof because the outer layers become keratinized. Stratified
squamous lining the mouth and esophagus are not keratinized.
Cells of columnar epithelium look like fence posts
standing side-by-side with their nuclei close to the
ground. The image on the left shows mottled looking
goblet cells which secrete mucous. In the respiratory
tract mucous helps trap and remove dust and debris.
In the stomach and intestines, the mucous coats the
inner lining and protects those organs from digestive
enzymes and hydrochloric acid. Columnar epithelium
also is responsible for nutrient absorption by the
Pseudostratified columnar
small intestine.