1. Histology

2. Histology Outline
1. Epithelial Tissue a. Simple Squamous b. Simple Columnar c. Simple Cuboidal d. Psuedostratified Columnar e. Stratified Squamous f. Transitional 2. Connective Tissues a. Bone b. Cartilage 1. hyaline 2. elastic 3. fibrocartilage c. Dense CT d. Loose CT 1. Areolar 2. Adipose e. Blood 3. Muscle a. Skeletal b. Smooth c. Cardiac 4. Nervous

3. Epithelial Tissue Info
The lining and covering of all free body surfaces. Forms a boundary between the body and the external environment.
Contains “versatile” cells which function in protection, absorption, filtration, and secretion.
Forms outer layer of the skin and the lining of its body cavities.
General Characteristics of Epithelial Tissues:
1. Cells fit closely together to form continuous sheets.
2. Neighboring cells are bound together are points by cell junctions.
3. Cells have a free surface or edge that is not attached, but is exposed to the exterior of the body or the exterior of the cavity.
4. Exposed surfaces may be smooth, slick, or ciliated.
5. Regenerated themselves easily.
6. Lower surface rests on a basement membrane which is secreted by the epithelium and connective tissues below it.

4. Classification of Epithelium
Each epithelium is given 2 names:
1st name tells the number of cell layers
2nd name tells the shape of the cells
Eg: 1st names: 2nd name:
simple squamous
stratified cuboidal
columnar

5. Examples of Epithelium .

6. Simple Squamous Epithelium
Simple Squamous Epithelia
Flat, thin, single layer resting on a basement membrane.
Cells fit together tightly.
Forms where filtration and exchange by diffusion are needed.
Thin and not useful for protection
*Found in air sacs of lungs
*Forms wall of capillaries
*Form serous membranes that
line ventral body cavity and cover its organs

7. Simple Cuboidal Epithelium
One layer of Cube shaped cells on a basement membrane
Found in glands and their ducts
Forms the walls of kidney tubules
Covers the surface of the ovaries

8. Simple Columnar Epithelium
*Single layer of tall, rectangular cells that fit closely together.
*Lines the length of the digestive tract from the stomach to the anus.
*Line body cavities or mucosae that are open to the body exterior.
Goblet cells are found scattered throughout these cells. They secrete
a lubricating mucus onto the outer layer of the cell
Nucleus of the cell tells where the
base of it is.

9. Psuedostratified Columnar Epithelium
Columnar epithelium of different lengths. Some appear longer than others but all are touching the basement membrane.
Some nuclei are higher up in the cell than others.
This gives the appearance of looking stratified (layered) but is not. (hence the name)

10. Stratified Squamous Epithelium
*Most common in the body *Consists of several layers of *Found in sites that receive a good cells on top of one another.
amount of abuse or friction *Cells at the free edge (top) are squamous while those
near the base are cubiodal/
columnar.

11. Transitional Epithelium
*Highly modified, stratified squamous epithelium.
*Forms the lining of only a few organs – the urinary bladder, uterus, and parts of the urethra.
*Cells at the basement membrane are cuboidal or columnar.
*Cells at the free surface vary in appearance.
*When the organ is not stretched, the membrane is very layered, but when it is stretched, the layers thin and the cells at the surface become squamous-like.
*The cells can stretch and slide past one another and change their shape.

12. Connective Tissue INFO
*Connect Body Parts *Consist of living cells surrounded by a matrix.
*Found everywhere in the body *Most abundant tissue type.
*Examples include bone, cartilage, tendons, ligaments, blood, and dense and loose connective tissues.
Characteristics of Connective Tissues:
~ Variations in blood supply – most have a good blood supply, but tendons and ligaments have a poor blood supply, and cartilages have no blood supply. All heal very slowly when injured.
~ Extracellular Matrix - Substance produced by made up of many different types of cells PLUS varying amounts of nonliving substances found outside of cells called the extracellular matrix.
~ Functions – Connective tissues are able to form soft packing tissue around organs, bear weight, withstand stretching, abrasion, and other abuses.
~ Types – Fat tissue is composed mostly of cells, so the matrix is soft. Bone/cartilage have very few cells, so the matrix is hard and very strong.

13. Bone/Osteocytes/Osteoblasts
*Called Osseous tissue
*Made of bone cells sitting in cavities called Lacunae
*Lacunae is surrounded by layers of hard matrix called Lamella aka canaliculi
*Because of its rock-hard, bones can support and protect other body parts/organs.
Bone cells in Lacunae
Central
(Haversian) Canals
Bone Lecture

14. Sections of Bone

15. Cartilage 1) HYALINE CARTILAGE *Most widespread cartilage
Less hard and more flexible than bone.
Found only a few places in the body.
1) HYALINE CARTILAGE
*Most widespread cartilage
*Has collagen fibers hidden by a rubbery matrix with a glassy, blue-white appearance.
*Forms supporting structures of larynx, nose, attaches ribs to breastbone, covers ends of many bones where they form joints, forms fetal skeletons.
*Lacunae holds cartliage cells called chondrocytes

16. Cartilage Fibrocartilage Highly compressible. Jelly-like.
Forms the cushion-like disks
between vertebrae.

17. Cartilage 3. Elastic Cartilage
Found where a structure needs elasticity.
Forms the external ear, larynx, epiglottis

18. Dense Connective Tissue
-Has collagen fibers as its main matrix element.
-Packed between the collagen fibers are rows of fibroblasts (fiber-forming cells)
-D.C.T. forms strong, ropelike structures, such as tendons and ligaments.
Tendons: attach skeletal muscles to bones
contain less elastic fibers, so they are less stretchy
Ligaments: connect bones to bones at joints
contain more elastic fibers, so they are
more stretchy
Collagen fibers are coarse and lie alongside each
other with small spaces in between.
Between the fibers are fibrocytes which have visible
nuclei.

19. Types of Loose CT include:
Softer and Have More Cells and Fewer Fibers than Any Other CT
Types of Loose CT include:
Areolar Tissue
Most widely distributed
CT in the body.
Soft, pliable, “cobwebby”
tissue wrapped around organs.
Protects and cushions.
“Glue” that holds organs
together and in the right place
Loose and fluid filled
holding water and salt. It can
swell up during inflamation
causing edema.
2. Adipose Tissue AKA Fat
Oil droplet in the cell’s vacuole pushes the nucleus to one side, making cell look empty.
Forms the subcutaneous
tissue beneath the skin.
Insulates the body, protects it from bumps and temperature extremes.
Protects some organs (kidneys & eyeballs)
Fat deposits (hips, breasts) store fat as fuel if needed.

20. Loose CT Pictures
Adipose Tissue
Areolar Tissue

21. Blood/Vascular Tissue
Considered a CT because its made of blood cells surrounded by a non-living matrix called blood plasma.
The fibers of blood are soluble proteins molecules that become visible only during blood clotting.
Serves as the transport vehicle for the cardiovascular system, carrying nutrients, wastes, respiratory gases, and other substances throughout the body.

22. Muscular Tissue Type 1: Skeletal Muscle Tissue
This tissue is packaged by connective tissue sheets into organs called skeletal muscles which are attached to the skeleton for body movements.
Skeletal muscle tissue cells are long, cylindrical, multinucleated, and have obvious striations (stripes)
Voluntary Muscle

23. Muscular Tissue
Type 2: Smooth Muscle Tissue No striations are visible. Cells have a single nucleus and are spindle shaped (pointed at both ends). Found in wall of hollow organs such as stomach, uterus, blood vessels. As the smooth muscle contracts, the organ becomes smaller, and as it relaxes it becomes larger to propel items through the hollow organ. Involuntary muscle

24. Muscular Tissue
Type 3: Cardiac Muscle Tissue Found only in the heart Has striations, has a single nucleus, made of short branching cells, that fit tightly together at junctions called intercalated disks. The disks allow signals to pass through to the next cell. Involuntary muscle tissue.

25. Nervous Tissue
Made of neuron cells which receive and conduct electrochemical impulses from one part of the body to another.
Cytoplasm is drawn out into a long extension (up to 3 ft in the leg) for the impulse to travel down.
Have supporting cells to insulate
and protect the neurons.
Found in the nervous system
(brain, spinal cord, nerves).

26. Name the cell type

32. Check your Knowledge
Tissue Quiz Tissue Slides