Exercise 6: Integumentary System Anatomy Flashcards
Skin
Also called the integument or cutaneous membrane. Makes up the integumentary system.
What are the skin’s accessory organs?
Sweat Glands Sebaceous Glands Hair Sensory Receptors Nails
Hypodermis
A continuous layer of adipose tissue that separates the skin from deeper tissues. Not technically considered part of the skin.
Functions of skin:
Protects against invasion by pathogens, UV damage, loss of body fluids and physical trauma.
Regulating body temperature
Provides sensory information
Excretes waste products
Synthesizes vitamin D
Stores energy in adipose tissue
Two layers of skin:
- ) Epidermis (superficial layer)
2. ) Dermis (deep layer)
Epidermis:
Superficial layer composed of stratified squamous keratinized epithelium
Avascular
Consists of 4 layers in thin skin and 5 layers in thick skin
Dermis:
Deep Layer of the skin
Composed of connective tissue
Highly vascular
Consists of 2 layers
Houses glands, hair and sensory receptors
Hypodermis:
Deep to dermis
Composed of adipose tissue
Also called subcutaneous layer
Layers of the epidermis from surface of skin to deepest layer.
- ) Stratum Corneum
- ) Stratum Lucidum
- ) Stratum granulosum
- ) Stratum spinosum
- ) Stratum basale
Stratum Corneum
Most superficial layer of the skin
15-30 rows
Dead flat keratinocytes continually slough off.
Stratum Lucidum
Found only in thick skin of palm and sole
3-5 layers of flattened, clear, dead keratinocytes
Stratum granulosum
3-5 layers of flattened keratinocytes that are dying and shrinking and becoming filled with keratin
Stratum spinosum
8-10 Layers of many sided keratinocytes
Keratinocytes are dying and shrinking
Have “spiny shape”
Stratum Basale
Deepest layer
Contacts dermis
Single layer of actively dividing cells
Also called status germinativum
Keratinocyte
Found in all epidermal layers
Most abundant skin cell
Produces Keratin
Langerhan’s Cell
Found in stratum spinosum
Migrate from bone marrow
Protect against bacteria
Merkel Cell
Found in stratum germinative (basale)
Touch receptor
Melanocyte
Found in stratum basale
Cell extensions reach into stratum spinosum
Produce melanin
What is the thickest layer of the skin
Dermis
Two layers of dermis
- )Superficial Papillary layer
2. ) Reticular Layer
What fibers make up the dermis?
Collagen and elastic
Dermal papilla
Extensions of papillary layer into epidermis
Papillary Layer of the Dermis
Contacts the stratum basale of the epidermis
Composed or areolar connective tissue
Reticular Layer
Bulk of Dermis
Composed of dense irregular CT
Contacts hypodermis
Two types of skin glands
- ) Sudoriferous Glands
2. ) Sebaceous Glands
Sudoriferous Glands
Produce sweat
Sebaceous Glands
Produce oil called sebum directly onto hair follicle
Two types of Sudoriferous glands
- ) Eccrine
2. )Apocrine
Eccrine Sweat glands
Most common. Secretes watery sweat Sweat evaporation cools skin Sweat contains small amount of waste products Also called merocrine
Apocrine Sweat Glands
Found mainly in axillae and inguinal region
Secretes thick substance responsible for body odor
Usually secretes directly into a hair follicle
Hair Shaft
Portion of hair above skin surface
Contains dead, keratinized cells
Hair Root
Portion of hair below skin surface
Consist of dead, keratinized cells
Arrector Pili muscle
Bundle of smooth muscle fibers
Extends from hair follicle into dermis
Contracts to make hair stand up
Hair follicle
Invagination of epidermal cells
Forms sheath around hair root
Hair Bulb
Group of cells at base of hair root
Matrix is area of hair bulb containing cells dividing to form new hair cells
Hair papilla
CT cells
Extend into hair bulb
Contains blood vessels to bring nutrients to dividing cells
Nociceptors
In papillary layer of dermis and basal layer of epidermis
Free nerve endings
Detect pain as a result of tissue damage
Merkel Disks
In papillary of dermis and basal layer of epidermis
free nerve endings
detect fine touch and pressure
Tactile Corpuscles
Papillary layer of dermis
Encapsulated
Detect light touch and pressure
also called Meissner’s corpuscles
Thermoreceptors
In dermis
Free nerve endings
Cold receptors detect between 10-40 C
Warm receptors between 32-49 C
Hair Root Plexus
Wrapped around hair follicle
Free nerve endings
Detect hair movement
Ruffini’s Corpuscles
In reticular layer of dermis
Encapsulated
Detect stretching
Lamellated Corpuscles
Deep in dermis or hypodermis
Encapsulated
Detect deep pressure
Also called Pacinian corpuscles
First-degree burn
The most superficial. Damages only the epidermis. Redness, swelling and pain. Burned area may become whitened but not blistered
Second-degree burn
Also called partial-thickness burn because damage extends partway through the dermis layer. Red, swollen, painful, plus it blisters
Third-degree burn
Full-thickness burn because damage extends into subcutaneous layer. Not as painful as second-degree because the pain receptors in the dermis have been destroyed. Skin develops a grey to black leathery covering called eschar
