Tissue and Structures Flashcards
What tissues is the body made up of?
- Epithelium.
- Connective tissue.
- Muscle.
- Nerve.
What elements (tissue) is skin made up of?
- Epithelium.
- Connective tissue.
What is the epithelium of skin called?
Epidermis.
What type of epithelium is the epidermis?
Stratified squamous keratin (variety).
What are the specialised derivatives of the epidermis?
- Sebaceous glands.
- Sweat glands.
- Nails.
- Hair.
What tissue is the dermis made of?
Connective tissue.
What is the origin of the dermis?
Mesodermal (in origin).
What does the dermis consist of?
- Collagen fibres (mainly).
- Elastic tissue.
- Blood vessels.
- Lymphatics.
- Nerve fibres.
(All embedded in ground substance).
What is the uppermost layer of the epidermis called?
Stratum corneum.
What is the stratum corneum also known as?
It’s the cornified or horny layer.
What does the horny layer consist of?
Dead cells (keratin) - these have lost their nuclei. Empty husk.
What happens with the dead cells of the epidermis?
The keratin are constantly being rubbed off and replaced by the cells moving up from the deeper layers.
How is dandruff formed?
Scaly flakes of the horny layer are trapped by the hairs instead of falling out.
How is the horny layer softened?
Greasy secretions of sebaceous glands.
How is the horny layer moistened?
Watery secretions of sweat glands.
What’s the importance of keratin having a husk and being linked up and thick?
It is so that it is impermeable to water.
What happens to keratin when there is prolonged exposure to water?
Keratin is macerated by the water, so it becomes thick, soft and white.
Define thick skin?
Increased thickness of cornified layer of epidermis.
Where do you find thick skin?
Sole of feet.
In thick skin what happens to the dermis?
It is thin.
Define thin skin?
Decreased thickness of cornified layer.
In thin skin what happens to the dermis?
It is thick.
What is the main factor that determines the colour of our skin?
The degree of pigmentation produced by melanocytes.
Where are melanocytes found?
Basal layer of epidermis.