Dermis & Hypodermis Flashcards
Dermis is located between
epidermis and hypodermis
Two components of dermis
Superficial papillary layer
Deep reticular layer
Dermis
It is the thick sensitive layer of skin or connective tissue beneath the epidermis.
Structural components of dermis
Collagen and Elastin
Protein responsible for skin strength
Collagen
Protein responsible for skin elasticity
Elastin
Collagen and Elastin are obtained from
Fibroblast cells
Tissue found in papillary layer
Areolar tissue
Dermal papillae projects between
epidermal ridges
Tissue found in reticular layer
Dense irregular connective tissue
Inflammation of the papillary layer are caused by
Infection
Radiation
Mechanical irritation
Chemicals
Inflammation of the papillary layer are characterized by
Pain and itch
Characteristics of skin
Strong( due to collagen fibers)
Elastic( due to elastic fibers)
Flexible
Tissues in hypodermis
Elastic areolar and adipose tissues
Hair Follicles
Organs that form the hairs.
Location of hair follicles
Deep in the dermis.
Hair follicles are wrapped in
Dense connective tissue sheath.
Base of hair follicle surrounded by
Root hair plexus (sensory nerves)
Accessory structures of hair
Arrector pili and sebaceous glands.
Arrector pili
Involuntary smooth muscle
Function of arrector pili
- Causes hairs to stand up.
- Produces goosebumps.
Function of sebaceous glands
secrete sebum
Regions of the Hair Structure
Hair root and Hair shaft
Hair root
Lower part of the hair which is attached to the integument.
Hair shaft
Upper part of the hair which is not attached to the integument.
Hair shaft structures
Medulla
Cortex
Cuticle
Medulla of hair shaft
- It is the Core
- The dead cells contain soft keratin and air to provide flexibility.
Cortex of hair shaft
- It is the Middle layer
- The dead cells contain hard keratin to provide stiffness.
Cuticle of hair shaft
- It is the Outermost layer
- The overlapping dead keratinized cells form shiny surface.
Function of the Hair
- Head : -UV protection
- Cushion from trauma
- Insulation. - Nostrils, Ear canals, Eyelashes : -Prevent entry of foreign material.
- Body Hair : -Sensory detection.
Structure of Nails
Made of dead cells packed with keratin.
Function of Nails
Protect fingers and toes.
Where is Nail produced?
Occurs in a deep epidermal fold near the bone called the nail root.
Describe the nail body.
The visible portion of the nail which covers the nail bed.
Describe the lunula.
It is a pale crescent at the base of the nail.
Describe the side of nails.
They lie in lateral nail grooves which are surrounded by lateral nail folds.
About how many sweat glands does an adult has?
Between 1.6 to 4 million.
Types of sweat glands
Eccrine sweat glands and Apocrine sweat glands
Location of Eccrine sweat glands
They are found almost all over the surface of the body, and are most numerous on the palms and soles.
Location of Apocrine sweat glands
They are located mainly in the armpit, genital area and around the nipples of the breasts.
Location of sebaceous glands
They are found all over the body except on the palms, the soles, and the top of the feet.
Where are sebaceous glands most numerous?
On the face and scalp.
Sebaceous glands secrete
Sebum
Function of Sebum
It lubricates the skin and hair and inhibits the growth of certain harmful bacteria.
