Module 2 - Integument Flashcards
What the the two parts of the integument
Cutaneous membrane (skin) and accessory structure
Two components of the cutaneous membrane (skin)
Outer epidermis which contains superficial epithelium and the inner dermis which contains connective tissues
What are accessory structures in the integument
Structures that originate in the dermis extend through the epidermis to skin surface such as hair, nails and multicellular exocrine glands
What two others systems does the integumentary system link to and how
Cardiovascular system - blood vessels in the dermis
Nervous system - sensory receptors for pain touch and temp
What is the hypodermis (superficial fascia or subcutaneous layer)
The hypodermis is the loose connective tissue below the dermis (site for hypodermic injections)
Two layers of the dermis from the surface to deeper
Papillary layer and the reticular layer
All four components of system from surface down
Epidermis, papillary layer and reticular layer (both in the dermis) and the hypodermis
What two things does the skin produce
Melanin and keratin
What does the skin excrete
Salts, water
What does the skin protect against
Abrasions, water loss, bacteria and UV Radiation
What is synthesised in the skin
Vitamin D3
What is stored in the skin
Lipids
The epidermis is ….
Avascular stratified squamous epithelium
Nutrients and oxygen ….
diffuse from capillaries in the dermis
What are keratinocytes
A type of cell in the epidermis that produces keratin
What are melanocytes
Cells in the epidermis that produce melanin that is transferred to nearby keratinocytes
What are dendrocytes
Macrophages in the epidermis that interact with lymphocytes to assist in the immune response
What do Merkel cells do
They’re associated with a sensory nerve ending for fine touch and pressure
Is the epidermis vascularised
NO
How do nutrients in the epidermis reach epidermal cells
Diffusion
What is thin skin
Skin that covers most of the body and consists of four layers of keratinocytes
What is thick skin
Skin that covers the palms of the hands and soles of the feet, has five layers of keratinocytes
List the five strata of keratinocytes in thick skin from basal Lamina to free surface (deep to surface)
Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum
What is the stratum basale attached to and by what
Basement membrane by hemidesmosomes
What is the function of the stratum basale
Forms a strong bond between epidermis and dermis and forms epidermal ridges (fingerprints)
What are the two functions of dermal papillae
Increase the area of basement membrane and strengthen attachment between epidermis and dermis
Where are Merkel cells found
In hairless skin
Where are melanocytes found
Scattered throughout stratum basale
What is the stratum spinosum produced by
Division of stratum basale
What is the stratum spinosum made of
Eight to ten layers of keratinocytes bound by desmosomes
Why is the stratum spinosum considered the “spiny layer”
The cells shrink until the cytoskeletons stick out
What happens as the stratum spinosum continues to divide
Increases the thickness of the epithelium
What type of cells does the stratum spinosum contain
Dendritic (Langerhans) cells, active in immune response
What two things does the stratum granulosum produce
Keratin and keratohyalin
What happens to the cells of stratum granulosum
Produce protein fibres, dehydrate and die creating tightly interlocked layer of keratin surrounded by keratohyalin
What does the stratum lucidum do
Covers stratum Granulosum in thick skin only
What is the stratum corneum
Exposed layer of the skin, consist of 15-30 layers of keratinised cells, is water resistant, sheds and replaced every 2 weeks
Main function of the dermis
Anchors epidermal accessory structures
Location of the dermis
Between the epidermis and the subcutaneous layer
What does the papillary layer of the dermis consist of
Areolar tissue
what 3 things does the papillary layer of the dermis contain
smaller capillaries, lymphatics and sensory neurons
What does the reticular layer of the dermis consist of
Dense irregular connective tissue
What six things does the reticular layer of the dermis contain
Larger blood vessels, lymphatic vessels, nerve fibres, collagen, elastic fibres and connective tissue proper
Two Types of fibres
Collagen and elastic
What are collagen fibres
Very Flexible but very strong fibres (resist stretching but bend easily)
What are elastic fibres
Fibres that permit stretching but then recoil to original length, they limit the flexibility of collagen fibres to prevent damage to tissue
What is skin turgor
Properties of flexibility and resilience
What are sagging and wrinkles caused by
Dehydration, age, hormonal changes and/or UV exposure
What are stretch Marks caused by
Thickened tissue resulting from excessive stretching of skin due to either pregnancy or weight gain
What makes cleavage lines
Collagen and elastic fibers in the dermis
What do cleavage lines do
Resist force in a specific direction
What happens if a parallel cleavage Line is cut
Remains shut and heals well
What happens if there’s a cut across a cleavage line
Pulls open and scars
Three things nerve fibers in the skin control
Blood flow, gland secretions and sensory receptors
What is and where the sensory receptor for light touch located
Tactile corpuscles located in the dermal papillae
What is and where is the sensory receptor for deep pressure and vibration located
Lamellated corpuscles in the reticular layer
Where are the integumentary accessory structures such as hair, hair follicles, sebaceous glands, sweat glands and nails derived from
Embryonic epidermis
Where isn’t there hair on the body
Palms, soles, lips, portions of external genitalia
2 functions of hair
Protects and insulates, guards openings against particles and insects,
What is the function of the hair follicle
Produces non living hairs
What is wrapped around hair follicles
Dense connective tissue sheath
What surrounds the base of the hair follicle
Sensory nerves (root hair plexus)
What is arrector pill and what does it do
An involuntary smooth muscle that causes hair to stand up and produces “goose bumps”
What do sebaceous glands do
Lubricate the hair, control bacteria
What does sebum contain and what’s its function
Contains lipids, lubricates and protects the epidermis and inhibits bacteria
List two types of sweat glands
Apocrine glands, merocrine (eccrine) glands (watery secretions)
Where are apocrine sweat glands found
Armpits, around nipples and groin
What are apocrine sweat glands surrounded by
Myoepithelial cells
Where are merocrine sweat glands
Widely distributed on body surface, especially on palms and soles
Functions of merocrine sweat gland activity
Cools skin, excretes water and electrolytes and flushes microorganisms and harmful chemicals from skin
Function of mammary glands
Produce milks
Ceremonious glands
Cerumen (ear wax), protects the eardrum
What controls the sebaceous and aporcrine sweat glands
Autonomic nervous system
How are merocrine sweat glands controlled
Independently
What is the main function of sensible perspiration
Thermoregulation
Functions of nails
Protects fingers and toes
What are nails made of
Dead cells packed with keratin
What can change nail structure
Metabolic disorders
Where does nail production occur
In a deep epidermal fold near the bone called the nail root
Effect of aging on skin
Epidermal thinning, decreased number of dendritic cells, decreased Vitamin D3 production, decreased melanocyte activity, decreased glandular activity
