Lecture 7- Integument Flashcards
A 44 year old female is told that she has skin cancer. Some type of carcinoma! This would be cancer of what part of the skin?
Epidermis
What is the outermost epithelial layer?
Epidermis
What is the layer of connective tissue under the epidermis?
Dermis
What is the layer of connective tissue under the dermis?
Hypodermis
Where are keratinocytes found?
In the dead and alive tissue of the stratified squamous epithelial cells.
As basal cells divide, they move toward which surface?
the apical surface to slough off
Does the thickness of the epidermal layer change?
no, it is a very orderly process
What are melanocytes?
Dendritic processes that make melanin. Found in the basement membrane.
What are Langerhans cells
Dendritic processes that are immune cells
Where are Tacticle (Merkel) cells found?
In the basement membrane connecting to a sensory nerve ending
There is thick skin and think skin. How do they differ?
The epidermis is thicker in thicker in skin
What characterizes the stratum basale? (5)
- one cell layer thick
- cuboidal or columnar cells
- contains hemidesmosomes
- mitotic cells
- contains desmosomes
What characterizes the stratum spinosum? (5)
- does not contain hemidesmosomes
- contains desmosomes
- has some mitotic cells
- thicker in thick skin than in thin skin
- Active cells
How are tonofibrils formed?
Keritanocytes in the stratum spinosum produce keratin that forms the intermediate filaments or tonofibrils in the epidermis.
Intermediate filaments are involved in intercellular adhesion. Is this via adherent junctions, desmosomes, or tight junctions?
Desmosomes
How would you describe the nuclei in keratinocytes in the stratum spinosum?
Euchromatic nucleus producing a lot of protein
Describe the outer cell body of the stratum spinosum.
prickly or spiny
What characterizes the stratum granulosum? (4)
- squamous
- Only 3-5 layers of cells
- Cells develop a lipid envelope
- Cytoplasm has basophilic masses
How does profilaggrin stain?
intensely blue has a lot of phosphate groups that are very acidic, basophilic and stain blue. Exception to proteins staining pink*
Where are the lamellar granules produced and what is their function?
Lipids produced in the cells and are exocytosed to form a layer around the plasma membrane to act as part of the water barrier of skin
What is the purpose of filaggrin?
Fillagrin brings keratin and tonofilaments together to condense them.
What is keratinization?
The process of binding keratin to filaggrin
What characterizes the stratum lucidum? (3)
- see only in thick skin
- cells have lost their nuclei and organelles
- have desmosomes
How thick is stratum lucidum?
only a couple cell layers
What is the stratum corneum?
Nonnucleated, keratinized cells called squames or cornified cells that have lost their desmosomes and will slough off
Having fair skin increases your risk of skin cancer because there is:
Less melanin in keratinocytes
How do melanocytes stain?
Stains much clearer around the nucleus than other basal cell layers
How do melanocytes orient themselves in the keratinocyte?
In the supranuclear cap to protect DNA from UV radiation
Where are Langerhans cells and how do they stain?
Stratum spinosum and stain brown
What do langerhans cells do?
They are immune cells that phagocytize antigens. They exit the skin and move to lymph nodes.
What can you find in the dermis of the skin? (6)
- blood vessels
- connective tissue
- hair
- sebaceous and sweat glands
- sensory receptors
What is the purpose of the epidermal ridges and dermal papilla?
Strength- to reinforce the dermal- epidermal junction. The dermal layer provides nutrients for the epidermis.
What are the two layers of the dermis?
- papillary layer (top)
- reticular layer
What type of collagen is found in the derms?
Type 1- lots in the reticular layer
How does the papillary and reticular layers differ?
- More fine collagen, elastin fibers, and more cells in papillary layer.
- Course collagen, elastin, less cells in reticular
a 34 year old female is stung by a bee, she develops hives and itchiness. What is going on in the skin to cause this reaction?
Mast cells degranulate and release histamine
What will cause the itching?
Free nerve endings
What do the free nerve endings sense?
Itch, light touch, temperature
What is the merkel disc?
The end of the process of an axon.
What do merkel discs sense?
light touch
What does the root hair plexus sense?
movement of hair
What type of structures are the merkel discs, free nerve endings and root hair plexuses?
Simple nerve endings without a cover
What is a meissner corpuscle?
Unmyelinated nerve ending surrounded by modified schwann cells and capsule that is adjacent to epithelial cells.
Where are Meissner corpuscles found?
Concentrated in the finger tips, hands, soles of feet, lips, and tongue. No hair on this skin. Senses light touch.
What is a Pacinian corpuscle?
An axon surrounded by layers of modified Schwann cells and outer CT capsule that may be near adipocytes.
Where are Pacinian corpuscle’s found?
Either deep in the dermis or the hypodermis
What type of touch would Pacinian corpuscles sense?
Course touch, pressure and vibrations
What is the shaft of hair?
The portion you can see
What is the root of hair?
The portion within the skin
What is the hair bulb?
The base of the hair follicle
That kind of tissue is hair?
epithelial tissue, located in the dermis but comes from epithelial origin.
What makes up the invagination of the epidermis for the hair follicle?
The external root sheath surrounded by the Matrix
What muscle attaches to hair?
Arrector pilli muscle
What is the dermal papilla?
CT with blood vessels. Damage to the dermal papilla that impairs flood supply can prevent hair growth.
What makes up the matrix?
Dividing epithelial cells and melanocytes which give hair its color.
How does cells move in hair cells?
Cells move up and are keratinzed to form hair root and then shaft
Where do the hair and internal root sheath come from?
Matrix cells
What does the external root sheath come from?
Invaginated epidermal cells
What is the glassy membrane?
Similar to the basement membrane
What surrounds the glassy membrane?
The connective tissue sheath
What cells are found in sebaceous glands?
sebocytes
Why are the sebocytes not stained?
- Cytoplasm is filled with fat droplets
- sebum is a waxy mix of cholesterol and fats that coat the skin and hair
Where do you not find sebaceous glands?
- palms of hands
- soles of feet
How is sebum secreted into the hair follicle?
Holocrine secretion
Where are eccrine sweat glands found?
All over
Where are apocrine sweat glands found?
axillary and perineal regions
What are the main characteristics of eccrine sweat glands?
- small lumen
- stratified cuboidal epithelium
- duct
What are the main characteristics of an apocrine sweat gland?
- large lumen
- cuboidal epithelium with underlying myoepithelial cells
- lumens are fuller and more empty
A 14 year old male presents to the emergency department after consuming some jimson weed. His body temperature is elevated and his skin, in general, appears hot and dry. Which is not functioning properly because of the jimsom weed?
Eccrine glands
