Histo Lab: Skin and Glands Flashcards
How do you differentiate between thick and thin skin
Thick skin doesn’t have hair on it, it has more prominent stratum corneum and stratum lucidum
What is the function of stratum basale
Contains keratinocyte stem cells that move up and add cells to the other layers of the skin
What do the spines in the spinous layer represent
I think it is desmosomes but she said cytoplasmic extensions of the cells
What is the function of stratum granulosum cells
They have keratohyalin granules in cytoplasm which are released into interstitial space and help epidermis maintain barrier against external environment.
What cellular process occurs in the stratum granulosum and the stratum corneum
Water permeability barrier formation
Where are epidermis and dermis derived from
Ectoderm and dermatome (derived from somites that are from paraxial mesoderm)
Where are melanocytes derived from
Neural Crest cells
Are there more melanocytes in pigmented skin
No
What mode of secretion is used by sabecous glands
Holocrine
What is the composition of sebum
Trglycerides, wax esters, squalene and free fatty acids
How do you identify sebaceous glands and sweat glands
Sebaceous glands are light staining, next to the hair follicle whereas sweat glands are dark staining and lined by stratified cuboidal epithelium.
Also sweat glands are deeper into the skin and exhibit merocrine mode of secretion
What is the sweat duct misfunction if cystic fibrosis
Unable to absorb Cloride ion back
What structures of hair do we need to know
What is the one structure we may see
- Erector pilli muscle
- Internal Root Sheath
- External root sheath (it has nuclei)
Sebaceous glands which are light staining may also be seen
Also know how the smooth muscles look like
What are Meissner corpuscles? How do you identify them? Where are they found and where are they found in abundance?
They are found in areas of hairless skin areas such as the lips, skin and toes.
They are low frequency, FINE TOUCH receptors, they are found in abundance in the finger tips and highly sensitive region of the body.
Also they look like a spiral arrangement of a single layered cell.
These occur right underneath the basale layer, at the dermal papillae
What are the 2 main types of glands
Exocrine and Endocrine, endocrine are ductless, mainly for hormones
What are the 2 glands in the duodenum
The dark staining glands right underneath the “base” are known as crypts of glands of glands of Lieberkuhn which are simple tubular glands.
Underneath these glands is a layer that has lighter staining glands called the Brunner’s glands.
What does the bruners glands secrete
Bicarbonate and mucus
What are the 3 salivary glands
Parotid, sublingual and submandibular
What kind of cells does glands consist of
Parenchymal (secreting) and stroma cells (supporting cells)
What are the two types of glands
Tubulor and acinar
What are the dark staining cells that form the acinar structure in the parotid glands
Serous cells, they have grape-like structures
Expalin the cells in the sublingual gland
Here we see that there are mucous cells that are light pink staining and are capped by demi lune serous cells that are slightly dark staining
How does the stroma and parenchyma cells arrange themselves in sublingual cells
The connecttive tissue which is the stroma partitions the parenchyma cells into lobs or lobules
Inter and Intra lobular ducts
The interlobular ducts runs in the connective tissue in the stroma cells in these glands (these ducts have large lumens) whereas the intralobular duct runs between the parenchyma cells.
Types of intra lobular ducts
There are 2 types: intercalated and striated.
Intercalated ducts have either simple or squamous epithelium and they drain the acinar whereas the striated ducts have simple columnar epithelium and are more round shaped
Explain the features of Psoriasis
- One of the most obvious features if the Rete ridges or Rete pegs which emerge from test tube acanthosis
- Hyperkeratosis and acanthosis (thickened) of the epidermis
- These rete pegs or some of these rete pegs can form Munro’s microabscess. They showed us a high power EM which of one of the microabscess. It contained several neutrophils.
What is Koebner phenomenon
It is in Psoriasis patients, psoriasis of the skin is observed after injury where there was previously healthy tissue. This is because the injury activates an inflammatory response that causes the symptoms of psoriasis in that part of the skin
What is lichenoid infilterate
It is a lymphytic infilterate that is just underneath the epidermis (in the dermal layer) and it is the one that secretes the cytokines
What structures are affected in pemphigus vulgaris
desmosomes (desmoglein 3)
What antibodies are directed towards these structures in pemphigus vulgaris and pemphigus foliaceous
IgG
What layer is sloughed off in pemphigus vulgaris
Spinosum
What is suprabasal acyntholysis
It is the destruction of the skin layers just above the basal layer of the skin, this is observed in pephigus vulgaris
How do you differentiate Bullous Pemphigoid from Pemphigus Vulgaris
It is especially obvious in immunofluorescent stain as in BP the IgG bodies are only at the basal layers, affecting the BP180 protein
