Chapter 6 – The Integumentary System – Skin
The Largest Organ of the Body.
Consists of two major Sections :
1. Epidermis
A. Approximately 90 to 100 layers of Keratinized Stratified Squamous
Epithelial Cells.
B. A Major Function is Protection.
C. At Minimum, consists of 4 “Strata” of Cells – i.e. “Thin Skin” that
covers most of the surface of the body.
D. “Thick Skin” consists of 5 Strata of Cells and is found only in the
Palms of the Hands and the Soles of the Feet. Protection.
E. Stratum Basale – the Basal Cell layer of the Epidermis. These
Cells are right next to the Dermis where there are blood vessels,
and so, these cells are alive and regularly divide by Mitosis.
These cells stack on top of each other and are pushed upwards,
away from the blood supply. They begin to die.
F. The Epidermis is Thin – approximately 1/16 th of an inch thick.
G. The Epidermis is Avascular – there is no direct blood supply into
the Epidermis. Consequently, most of the cells of the Epidermis
are in the Process of dying, or, are dead.
H. Stratum Corneum – the outermost Strata of cells that can be seen;
2 to 4 layers of these dead cells are sloughed off daily so the
skin can cleanse itself on a regular basis. This outer layer of
flat, dried out, dead cells act like microscopic bony plates or
“armor” that Protect the body from external factors. Protection.
I. Keratin – a protein found only in the Epidermis that waterproofs the
skin; when the cell dies, the Keratin dries out and hardens,
along with the dried cellular cytoplasm, and helps Protect
against invading Antigens (i.e. Viruses, Bacteria, Mold, Mildew,
Fungi, etc.), scratches, scrapes, abrasions, etc. Protection.
J. Melanin – a second protein, found only in the Outer Epidermis;
Melanin is a pigmented protein that gives skin its color and acts
as the body’s natural sunscreen, protecting the skin from the
harmful UV rays of the sun. Protection.
The Largest Organ of the Body.
Consists of two major Sections :
1. Epidermis
A. Approximately 90 to 100 layers of Keratinized Stratified Squamous
Epithelial Cells.
B. A Major Function is Protection.
C. At Minimum, consists of 4 “Strata” of Cells – i.e. “Thin Skin” that
covers most of the surface of the body.
D. “Thick Skin” consists of 5 Strata of Cells and is found only in the
Palms of the Hands and the Soles of the Feet. Protection.
E. Stratum Basale – the Basal Cell layer of the Epidermis. These
Cells are right next to the Dermis where there are blood vessels,
and so, these cells are alive and regularly divide by Mitosis.
These cells stack on top of each other and are pushed upwards,
away from the blood supply. They begin to die.
F. The Epidermis is Thin – approximately 1/16 th of an inch thick.
G. The Epidermis is Avascular – there is no direct blood supply into
the Epidermis. Consequently, most of the cells of the Epidermis
are in the Process of dying, or, are dead.
H. Stratum Corneum – the outermost Strata of cells that can be seen;
2 to 4 layers of these dead cells are sloughed off daily so the
skin can cleanse itself on a regular basis. This outer layer of
flat, dried out, dead cells act like microscopic bony plates or
“armor” that Protect the body from external factors. Protection.
I. Keratin – a protein found only in the Epidermis that waterproofs the
skin; when the cell dies, the Keratin dries out and hardens,
along with the dried cellular cytoplasm, and helps Protect
against invading Antigens (i.e. Viruses, Bacteria, Mold, Mildew,
Fungi, etc.), scratches, scrapes, abrasions, etc. Protection.
J. Melanin – a second protein, found only in the Outer Epidermis;
Melanin is a pigmented protein that gives skin its color and acts
as the body’s natural sunscreen, protecting the skin from the
harmful UV rays of the sun. Protection.
