ANIMAL TISSUES
Humans and other large multicellular animals are made up of four basic type of tissues:
1) Epithelial tissue
2) Connective tissue
3) Muscular tissue
4) Nervous tissue
1- Epithelial Tissue:
Epithelial tissues cover the surface of the body, line its cavities, and form glands. The lining of small intestines and
other organs are made up of epithelial tissues.
Epithelial cells are polarized, meaning they have a top and a bottom side.
There are different types of epithelial tissue depending on the number of layers.
1. Simple Epithelium: Single layer of cells.
2. Stratified Epithelium: Two or more layers of cells.
Types based on shape:
a) Squamous (flat)
b) Cuboidal (cube-shaped)
c) Columnar (tall)
Examples:
- Simple Squamous Epithelium: Found in alveoli of lungs and kidneys for diffusion of gases( the exchange of
gases between the blood and lungs).
- Simple Cuboidal Epithelium: Found in lumen of collecting ducts in the kidney(kidney tubules) and present in
thyroid glands around the follicles that secretes thyroid hormones.
- Simple Columnar Epithelium: Found in digestive and reproductive tracts.
- Stratified Squamous Epithelium: Found in skin, mouth, and esophagus, with many dead keratinized cells
provide protection against water and nutrient loss.
Stratified cuboidal epithelia: are found surrounding the ducts of many glands, including mammary glands in the
breast and salivary glands in the mouth.
- Stratified Columnar Epithelium: rare , found predominantly in some organs of the reproductive system.
-Transitional epithelia: Special subset of stratified epithelia. They are exclusively found in the excretory system.
2- CONNECTIVE TISSUE: Connective tissue connects or binds different types of cells. It supports and protects body
organs and binds other tissues together. It has a flexible matrix and includes cartilage, bone, blood, and adipose
Humans and other large multicellular animals are made up of four basic type of tissues:
1) Epithelial tissue
2) Connective tissue
3) Muscular tissue
4) Nervous tissue
1- Epithelial Tissue:
Epithelial tissues cover the surface of the body, line its cavities, and form glands. The lining of small intestines and
other organs are made up of epithelial tissues.
Epithelial cells are polarized, meaning they have a top and a bottom side.
There are different types of epithelial tissue depending on the number of layers.
1. Simple Epithelium: Single layer of cells.
2. Stratified Epithelium: Two or more layers of cells.
Types based on shape:
a) Squamous (flat)
b) Cuboidal (cube-shaped)
c) Columnar (tall)
Examples:
- Simple Squamous Epithelium: Found in alveoli of lungs and kidneys for diffusion of gases( the exchange of
gases between the blood and lungs).
- Simple Cuboidal Epithelium: Found in lumen of collecting ducts in the kidney(kidney tubules) and present in
thyroid glands around the follicles that secretes thyroid hormones.
- Simple Columnar Epithelium: Found in digestive and reproductive tracts.
- Stratified Squamous Epithelium: Found in skin, mouth, and esophagus, with many dead keratinized cells
provide protection against water and nutrient loss.
Stratified cuboidal epithelia: are found surrounding the ducts of many glands, including mammary glands in the
breast and salivary glands in the mouth.
- Stratified Columnar Epithelium: rare , found predominantly in some organs of the reproductive system.
-Transitional epithelia: Special subset of stratified epithelia. They are exclusively found in the excretory system.
2- CONNECTIVE TISSUE: Connective tissue connects or binds different types of cells. It supports and protects body
organs and binds other tissues together. It has a flexible matrix and includes cartilage, bone, blood, and adipose
