Squamous epithelium

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Squamous epithelium

In anatomy

Anatomy

Anatomy is a branch of biology that is the consideration of the body plan. It is a general term that includes human anatomy, animal anatomy and plant anatomy ....
, squamous epithelium (from Latin squama, "scale") is an epithelium

Epithelium

In biology and medicine, epithelium is a Biological tissue composed of cell s that line the cavities and surfaces of structures throughout the body....
characterised by its most superficial layer consisting of flat, scale-like cells

Cell (biology)

The cell is the structural and functional unit of all known Life organisms. It is the smallest unit of an organism that is classified as living, and is often called the building bricks of life....
called squamous cell. Epithelium may possess only one layer of these cells, in which case it is referred to as simple squamous epithelium; or it may possess multiple layers, referred to then as stratified squamous epithelium. Both types perform differing functions, ranging from nutrient exchange to protection.

mple squamous epithelium is a single layer of flat squamous cells that are all in contact with the basement membrane

Basement membrane

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Encyclopedia

In anatomy

Anatomy

Epithelium

Cell (biology)

Simple squamous epithelia

A simple squamous epithelium is a single layer of flat squamous cells that are all in contact with the basement membrane

Basement membrane

Cell nucleus

In cell biology, the nucleus , also sometimes referred to as the "control center", is a membrane-enclosed organelle found in all eukaryote cell ....
sometimes creates a bump in the surface of the cell

Stratified squamous epithelia

A stratified squamous epithelium consists of squamous (flattened) epithelial cells arranged in layers upon a basement membrane

Basement membrane

The basement membrane is a sheet of cells and fibers that covers two other kinds of cells -- the epithelium, which lines the cavities and surfaces of organs, and the endothelium, which lines the interior surface of blood vessels....
. Only one layer is in contact with the basement membrane; the other layers adhere to one another to maintain structural integrity. Although this epithelium is referred to as squamous, many cells within the layers may not be flattened; this is due to the convention of naming epithelia according to the cell type at the end.

This type of epithelium is well suited to areas in the body subject to constant abrasion, as the layers can be sequentially sloughed off and replaced before the basement membrane is exposed.

Stratified squamous epithelium is further classified by the presence or absence of keratin

Keratin

Keratins are a family of fibrous protein; tough and insoluble, they form the hard but mineral structures found in reptiles, birds, amphibians and mammals....
at the apical

Apical

Apical, from the Latin apex meaning to be at the apex or tip, may refer to:*Apical consonant, a consonant produced with the tip of the tongue...
surface. Non-keratinised surfaces must be kept moist by bodily secretions to prevent them drying out and dying, whereas keratinised surfaces are kept hydrated and protected by keratin.

Non-keratinizing stratified squamous epithelium (SSNKE): cornea
Cornea

The cornea is the transparency front part of the eye that covers the Iris , pupil, and anterior chamber. Together with the cilliary muscles, the cornea reflects light, and as a result helps the eye to dilate, accounting for approximately two-thirds of the eye's total optical power....
(see also corneal epithelium
Corneal epithelium

The corneal epithelium is made up of epithelial tissue and covers the front of the cornea. It consists of several layers of cells.The cells of the deepest layer are columnar; then follow two or three layers of polyhedral cells, the majority of which are prickle cells similar to those found in the stratum mucosum of the cuticle....
), oral cavity, esophagus
Esophagus

The esophagus or oesophagus , sometimes known as the gullet, is an Organ in vertebrates which consists of a Muscle tube through which food passes from the pharynx to the stomach....
, rectum
Rectum

The rectum is the final straight portion of the large intestine in some mammals, and the Gastrointestinal tract in others, terminating in the anus....
, vagina
Vagina

The vagina is a fibromuscular cylinder tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles....
, and the internal portion of the lip
Lip

Lips are a visible body part at the mouth of humans and many animals. Lips are soft, movable, and serve as the opening for food intake, as an erogenous organ used in kissing and other acts of intimacy, as a tactile sensory organ, and in the articulation of speech....
s
Keratinizing stratified squamous epithelium (SSKE): skin
Skin

The skin is the outer covering of the body, also known as the epidermis. It is the largest organ of the integumentary system made up of multiple layers of epithelial biological tissue, and guards the underlying muscles, bones, ligaments and organ s....
, tongue
Tongue

The tongue is skeletal muscle on the floor of the mouth that manipulates food for chewing . It is the primary organ of taste. Much of the upper surface of the tongue is covered in papillae and taste buds....
(partially keratinised), and the external portion of the lip
Lip

Lips are a visible body part at the mouth of humans and many animals. Lips are soft, movable, and serve as the opening for food intake, as an erogenous organ used in kissing and other acts of intimacy, as a tactile sensory organ, and in the articulation of speech....
s

Cancers of the squamous cell epithelium

These include squamous cell carcinoma

Squamous cell carcinoma

In medicine, squamous cell carcinoma is a form of cancer of the carcinoma type that may occur in many different organs, including the skin, lips, mouth, esophagus, urinary bladder, prostate, lungs, vagina, and cervix....
, basal cell carcinoma

Basal cell carcinoma

Basal cell carcinoma is the most common of all types of skin cancer. Statistically speaking, approximately 3 out of 10 caucasians develop a basal cell cancer within their lifetime....
, and other adnexal tumors. mj

Additional images

External links

Simple squamous epithelium of the glomerulus
Glomerulus

A glomerulus is a capillary tuft surrounded by Bowman's capsule in nephrons of the vertebrate kidney. It receives its blood supply from an afferent arteriole of the renal circulation....
(kidney)
Stratified squamous epithelium of the vagina
Stratified squamous epithelium of the skin (thin skin)
Stratified squamous epithelium of the skin (thick skin)