Integumentum Flashcards
What is the function of the skin?
Barrier Water/temperature homeostasis PNS receptor Vitamin D production Excretion Immunologic function Endocrine
How many layers in the epidermis of thick skin?
Five layer
Thick S. cornermen;
Thick S. granulosom
What kind of skin has hair follicles and where?
Thin: Most areas, except lips, labia minora, glans penis
What are the glands of thick skin?
No sebaceous glands
What are the glands of thin skin?
Many sebaceous glands
Fewer eccrine sweat glands
What kind of skin has more sensory receptors?
Thick
Where is thick skin located?
Palms of the hands
Soles of the feet
Where is thin skin located?
Entire body except thick skin areas
What is an arrest or pili muscle?
Force sebum out of sebaceous gland
Creates an acidic muscles
Erects hair
Smooth muscle
What kind of secretion do sebaceous glands have?
Holocrine
What kind of secretion do excreciones sweat glands have?
Merocrine
Where is the supply of the skin located?
In the dermis and epidermis
Where are the subpapillary plexus, cutaneous plexus, and subcutaneous plexus located?
- In papillary layer of Dermis
- In dermis
- In hypodermis
What are the two layers of the dermis?
Papillary layer composed of loose CT
Reticular layer composed of dense irregular CT
What are the layers of thick skin?
Superficial
- Stratum corneum (largest and cells without nuclei(
- Stratum lucidum
- Stratum granulosum
- Stratum spinosum
- Stratum Basale
Where re the desmosomes located in the thick skin?
Stratum spinosum
When is it a big deal for cancer cell on the skin?
Whenever they break through the basement membrane
What layer of the skin has hemidesmosomes and is connected to the basal lamina?
The stratum basale ( they have cuboidal cells)
What are keratinocytes (prickle cells)?
Cells that become skin
What is pemphigus vulgaris?
An autoimmune disease of desmosomes
What happens in pemphigus vulgaris?
Autoantibodies target desmosomes protein
Blisters form in mouth and skin
Treated with oral corticosteroid
What happens in the stratum basale?
Contains mitotically active stem cells
Keratin 5 and 14
Hemidesmosomes and desmosomes
What happens in stratum spinosum?
Cells start to differentiate from stratum basale
Keratin 1 and 10
Desmosomes
What happens in stratum granulosom?
Lamellae bodies (lipids)
Keratohyaline granules (filaggrin, involucran, loricrin)
Desmosomes
What’s in the stratum lucidum and corneum?
Proteins deposited on inside of plasma membrane form the cornfield cell envelope
Extrusion of lipid from lamellar bodies forms water permeability barrier
Keratinocytes undergo apoptosis
How does skin pigmentation occur?
(For melanocytes)
- Premelanosomes contain melanin derived from DOPA
- Melanosomes with mature melanin are transported along microtubules in melanocytes processes (dendrite)
- Keratinocytes internalize melanin granules by phagocytizings tips of melanocytes processes
What is lentigo simplex?
Local increased number of melanocytes
What are ephelis?
(Freckles)
Increased melanin production
What are melanocytic nevus?
(Moles)
Pigmented growth of melanocytes
What are Verruca vulgaris?
(Common warts)
Thickening of S corneum and spinosum due to HPV (papilloma)
What are the 3 types of common skin tumors?
- Squamous cell carcinoma
- Melanoma
- Basal cell carcinoma
Where are langerhans cells?
In the stratum spinosum
What do Langerhans cells do?
Are dentritic antigen presenting cells derived from monocytes
After phagocytizing antigen they leave the epidermis and migrate to lymph nodes to present antigen to T lymphocytes. They have rod-shaped Birbeck granules (grab antigen) containing antigen-trapping lectins
Where are merkel cells located?
In the stratum basale, they resemble modified karatinocytes
What are merkel cells?
Mechanoreceptors cells connecting to unmyelinated nerve fibers. The nucleus is irregularly shaped and the cytoplasm contains abundant vesicles containing neurotransmitter.
What do free nerve endings feel?
Temperature
What do pacinian corpuscle feel?
Deep Pressure, vibration
What do Ruffini corpuscles feel?
Stretch and torque
What do Meissner’s corpuscle feel?
Touch receptors
Dermal papillae, thick skin
Note: in papillary layer of hairless skin
Unmyelinated nerve fibers surround by Schwann cells
What does a merkel cell feel?
It’s a mechanoreceptor in thick skin
How do pacinian corpuscles look like?
Ovoid, encapsulated, over 1 mm in size
Concentric Lamellae of Schwann cells
Central nerve fibers
What kind of secretion do eccrine sweat glands have?
Merocrine secretion and are simple tubular in design
What kind of secretion do sebaceous glands have?
Holocrine secretion
What kind of secretion do apocrine sweat glands have?
Merocrine secretion a simple tubular duct
Where is NaCl absorbed in an eccrine sweat gland?
In the resorptive duct
Where are apocrine sweat glands located?
Axilla, mons pubis circumanal
Opens into hair follicle
When does apocrine sweat gland activity start?
Art puberty
Why does apocrine sweat gland produce a smell?
Odor is produced by bacterial breakdown of secretion
What are the characteristics of sebum secreting cells
Store oily secretion
Undergo apoptosis
Release sebum by disintegrating
What does 5 Fluorouracil topical treatment do?
Inhibits DNA replication in neoplastic cells
What pathway does 5 fluorouracil take in order to inhibit DNA replication?
5FU inhibits the enzyme thymidylate synthase
Thymidilate synthase enables Deocyuridine to be converted to thymidine
Thymidine is a nucleoside required for DNA replication
