Histology Integument Flashcards
What type of epithelium can be found in the epidermis?
stratified squamous epithelium
What are the 2 layer of the dermis?
- papillary layer
- reticular layer
What are the components of the papillary layer of the dermis?
small blood vessels, lymph & nerves
fine collagen and elastic fibers
What are the components of the reticular layer of the skin?
vasular plexus
lymph, nerves
compact collagen fibers and thick elastic fibers
List the layers of the epidermis from bottom to top?
S. basale (germinal)
S. spinosum (desmosomes)
S. granulosum (keratohyaline granules)
Stratum lucidium
S. corneum (squames)
What are the distinct cell types found in the epidermis?
1) Keratinocyte,
2) Melanocyte,
3) Langerhans cell,
4) Merkel cell
Label the special cells in the image.
What type of cells are in the stratum basale? (cuboidal, squamous, or columnar?
cuboidal cells
Which layer of the epidermis contains basophilic cells that synthesize keratin?
stratum basale
What layer of the epidermis are melanocytes and Merkel cells contained?
stratum basale
What are the 2 main functions of keratinocytes?
to produce keratin and contain melanin
as a water barrier
How often do keratinocytes renew themselves?
every 15-30s
What are desmosomes? Where are they located in the layers of the epidermis?
Desmosomes are a junction complex for cell anchorage
Stratum spinosum
What does the term “spinosum” in stratum spinosum come from?
Because of the many FALSE cytoplasmic extensions (hence “spinosum”)
Where are Langerhans cells found in the epidermis?
In the stratum spinosum
The “prickle cell layer” of the epidermis?
stratum spinosum
What is the purpose of keratin filaments?
crucial for maintaining structural integrity stability, and continuity of the epithelium
What are the keratin filaments of the keratinocytes cross linked bye?
filaggrin (keratohyalin granules)
Keratin filaments form large aggregates within the keratinocyte called what?
tonofilaments
What substance are the keratohyaline granules (filaggrin) rich in?
sulfated amino acids (cysteine)
What are keratosomes? What layer of the epidermis are they in?
Membranous lamellar bodies/vesicles/ granules
Found in the S. granulosum
Are keratohyalin granules eosinophilic or basophilic?
basophilic
Another name for keratosomes?
Olland bodies?
What is the purpose of keratosomes?
Act as a waterproofing cement
What does the stratum granulosum consist of?
glycophospholipids
What areas of the body is the stratum lucidum more prominent in?
thick skin only (palms and soles only)
The cells of the S. lucidum are described as flattened cells with desmosomes. Do these flattened cells contain a nucleus?
They are non-nucleated.
T/F. The stratum corneum contains layers of living cells?
False; dead and dying cells
About how many layers thick is the stratum corneum in thick skin? Thin skin?
15-20 layers thick
3-5 layers in thin skin
Understand this slide.
Understand slide
What are hemidesmosomes? What do they do?
stud-like structures found in keratinocytes that
act in the signal transduction process via a integrin and regulate cellular activities such as gene expression and cell proliferation and differentiation
Difference between orthokeratinization and parakeratinization?
Orthokeratinization process by which cells in S. corneum are flat and lose nuclei and cytoplasmic organelles
In parakeratinization the cells keep nuclei, considered incomplete keratinization
What are some conditions parakeratinization may be observed in?
- actinic keratosis
- psoriasis
What layer of the epidermis are Langerhan’s cells located?
in stratum spinosum
What is the embryonic origin of Merkel’s cells?
the neural crest
Describe the color of the melanocyte cells?
Pale cells with brown granules in them.
How do the melanocytes function?
Transfer the melanin to cells in str. Basale & Spinosum via cytoplasmic extensions – CYTOCRINE SECRETION
Do the melanocytes have desmosomes?
no
Color of skin depends on concentration of granules in melanocytes or number of the melanocytes?
depends on concentration of granules not on the number of melanocytes.
What are langerhans cells? Where are they found? What do they do?
Star shaped cells found in epidermis, specially around str. Spinosum and around blood vessels in the papillary dermis.
Present antigens to lymphoid cells in the epidermis and dermis (APC)
What are Birbeck’s granules?
Racquet shaped granules found in langerhans cells.
Where do Langerhan’s cells arise from?
bone marrow stem cells
Langerhans cells present antigens to what? Would this be considered an adaptive or innate response?
T cells in regional lymph nodes – adaptive response
Difference between dendritic cells and Langerhans cells? Where are dendrocytes located in the skin?
Dendritic cells (DCs) are professional APCs that play a crucial role in activating adaptive immune responses. Langerhans cells (LCs) are a subset of immature DCs that reside in the epidermis
Dendrocytes are located in dermis
Papillary layer of dermis contains what type of connective tissue?
Loose CT
Reticular layer of the dermis contains what type of CT?
dense irregular
What type of connective tissue is found in the hypodermis?
loose connective tissue/adipose tissue
What is the subcutaneous tissue of the skin also known as?
Hypodermis or superficial fascia
What type of glands are sebaceous glands?
Simple acinar glands (HOLOCRINE GLANDS)
What is sebum and what is it secreted from in the skin?
Sebum is a complex mixture of triglycerides, waxes, cholesterol & its ester.
sebaceous glands
What is the function of sebaceous glands?
antibacterial and moisturizing
Where are sebaceous glands found in the body?
in only areas where there is hairy skin
When the sebaceous glands are infected what condition can be caused?
acne
Function of eccrine sweat glands specifically?
excretion: provide a significant excretory route for water and electrolytes.
protection: aids in preserving the skin’s acid mantle, which helps protect the skin from colonisation from bacteria and other pathogenic organisms
Secretory portion of the sweat glands has what type of epithelium?
simple cuboidal epithelium
The excretory portion of the sweat glands contain what type of epithelium?
stratified cuboidal epithelium
Describe clear cells of the sweat glands.
pale cells resting on BM. Secrete watery sweat
Describe dark (mucoid) cells of the sweat glands.
few, pyramidal cells contain granules of glycoproteins
Describe myoepithelial cells of the sweat glands.
contractile cells located at BM
Describe duct cells of the sweat glands.
– stratified cuboidal, cells smaller & darker. Absorb NaCl & glycoproteins.
Secretions of the sweat glands include what? (merocrine) (What do they secrete?)
NaCl, ammonia, urea & uric acid.
Are secretions of the sweat gland hypertonic or hypotonic?
hypotonic
What are the functions of the sweat glands?
thermoregulation and waste secretion
What are the functions of the sweat glands?
thermoregulation and waste secretion
Where are the apocrine sweat glands typically located?
axillary, anal & areolar regions of the body
Where do the apocrine sweat glands secrete sweat into?
hair follicle
What are the secretory substance that come from apocrine sweat glands?
proteins, carbs, lipids
Bacteria act on lipids from apocrine sweat glands to produce what?
produce odoriferous compounds. (Pheromones)
When do apocrine sweat glands become functional?
at puberty
Apocrine sweat glands are under what type of autonomic control?
adrenergic sympathetic control
What do apocrine sweat gland respond to? (Heat or emotional and sensory stimuli?)
emotional and ssensory
The bulb of the hair follicle sits in what tissue layer of the skin?
subcutaneous (adipose fat) tissue layer
What is the hair papilla?
projection of dermis into center of the bulb
BE able to differentiate between 1st, 2nd, and 3rd degree burns.
View Chart
BE able to differentiate between 1st, 2nd, and 3rd degree burns.
View chart
Describe nail root.
buried in fold of epidermis
and covers cells of germinative zone
Describe nail matrix.
cells of matrix divide regularly
migrate toward root
Differentiate
produce keratin of nail
What parts of the skin is the nail bed continuous with?
stratum basale and stratum spinosum of epidermis
Function of free nerve endings.
basic sensations like pain, touch, temp & pressure
Functions of Merkel’s discs?
sense pressure and touch
What layers of the skin can Merkel’s discs be found in?
epidermis and dermis
Where can Meissners corpuscles be found?
dermal papillae?
What are the functions of the Meissner’s corpuscles?
two point or discriminative touch
What is the function of the Pacinian corpuscle?
pressure, touch and vibration
What is the purpose of the Ruffini’s sensory receptor?
pressure and touch
Where are the Ruffini’s sensory receptors found?
dermis, hypodermis and joint capsules
What is the purpose of Krause end bulbs?
receptors for cold
What is the purpose of the muscle spindle?
change in muscle length
What is the purpose of the Golgi tendon organ?
Responds to muscle tension
Label these sensory receptors.
Label
