2.2 The integumentary system Flashcards
What makes up the integumentary system?
The tissues are arranged into an organ
(epidermis + dermis = skin), while together with
its accessory structures (hair follicles, adipose
tissue, sweat glands, nails etc.) form the
integumentary system.
For these accessory structures of the skin, state which types of tissues is it made of:
Accessory structures of skin
Hairs
Arrector pili muscles
Sebaceous glands
Sweat glands
Sensory receptors
Blood vessels
Hairs (E)
Arrector pili muscles (M)
Sebaceous glands (E)
Sweat glands (E)
Sensory receptors (N)
Blood vessels (E-CT-M-N)
For these parts of skin and part of subcutaneous layer, state which types of tissues they are made of:
Skin:
Epidermis –
Dermis -
Subcutaneous layer:
Subcutis/hypodermis
Skin
Epidermis – epithelium (E)
Dermis - connective tissue (CT)
Subcutaneous layer
Subcutis/hypodermis (CT)
What kind of epithelium is the epidermis?
A stratified squamous keratinised epithelium
What kind of tissues makes up the dermis?
Loose and dense connective tissue
What are the two layers of skin?
Epidermis and dermis
What’s beneath the dermis?
more CT in the form of adipose tissue, called the
subcutis or hypodermis
Skin diagram fill in
photos
What are the layers of the dermis and what are they made of?
Papillary layer (Papillary dermis)
* Loose connective tissue
*Reticular layer (Reticular dermis)
*Dense irregular connective tissue
What is the hypodermis layer and what is it made of?
Hypodermis (Subcutaneous tissue/Subcutis)
*Adipose and dense irregular connective tissue
thick skin microscope slide fill in
photos
where can you typically find the dense regular connective tissue?
tendons/ ligaments (only these places)
Which of the following statements about the tissues in the integumentary system is INCORRECT?
The subcutaneous layer (hypodermis) is predominantly connective tissue
Nervous tissue largely exists as sensory receptors in the integumentary system
The epidermis is predominantly made of epithelium
The reticular dermis only contains connective tissue
The papillary layer of the dermis is primarily composed of loose connective tissue
the reticular dermis has glands and hair (epithelium), sensory receptors (nervous) and arrector pili muscles (muscle). It’s not only CT.
What is the classification of the papillary dermis?
Dense regular connective tissue
Dense irregular connective tissue
Loose connective tissue
White adipose tissue
Brown adipose tissue
Loose connective tissue
- not dict: thats reticular dermis
- not drct: that’s only tendons and ligaments
Epidermis is
A layer of stratified squamous keratinised epithelium
sitting on a basement membrane.
Describe the lifespan of a keratinocytes in various situations.
Turnover from basal cell to
keratin layer varies:
* 25-30 days in areas with lots of
friction (e.g. soles)
* 40-50 days in areas of less
friction
* This turnover period is
considerably shortened: 10-15 days in some disease states (e.g.
psoriasis)
- not enough time to form protective layer, sore skin, bleeding)
What are the layers that the epidermis can be subdivided into? Briefly describe their outlook/ functions.
Stratum basale: separates layers from loose connective tissue
Stratum spinosum: spine
Stratum granulosum: granules
Stratum lucidum: dead cells
Stratum corneum: the intermediate layer between living cell layer and dead, consists transitional cell overcoming cell death
When is the stratum lucidum visible?
in thick skin
epidermis layers diagram
photos
What are keratinocytes?
- The cells that constitute the layers of the epidermis.
What do keratinocytes do?
- they play multiple roles essential for skin repair
- They divide (mitosis) in the stratum basale and move upwards towards the
surface.
-> change structure as they do – accumulating more intermediate
filaments, keratohyalin and lamellar granules - Eventually die, their organelles breakdown and the intermediate filaments
and keratohyalin granules fuse to form keratin - Lamellar granules are released to produce waterproofing
describe what keratohyalin is.
a protein that assembles keratin intermediate filaments into keratin.
list the layers of the epidermis and what they do.
- Stratum basale (Basal layer)
* Mitosis of keratinocytes, basal and spot adhering junctions, keratinocytes may
contain melanin granules
* Merkel cells and Melanocytes are found in this layer - Stratum spinosum (Spiny or Prickle cell layer)
* Keratinocytes held together by intercellular bridges and spot adhering
junctions giving them a “spiky” appearance
* Langerhans cells easiest identified in this layer - Stratum granulosum (Granular layer)
* Keratinocytes have accumulated numerous keratohyalin granules,
intermediate filaments, and lamellar bodies
* Cells die – keratohyalin granules combine with intermediate filaments to form
keratin; lamellar bodies are released providing waterproofing substance - Stratum lucidum/corneum (Corny layer)
* Dead keratinocytes filled with keratin
Are all cells found in the epidermis keratinocytes?
No.
Some other cells include:
* Melanocytes
* Tactile epithelial (Merkel) cells
* Intraepidermal macrophages
(Langerhans cells)
epidermal cell layers and non-keratinocytes diagram
photos
What are melanocytes?
dendritic cells that produce melanin and then transfer the
melanin to the keratinocytes.