Histology Flashcards
List the layers of the epidermis from deep to superficial. What are their functions?
- Stratum basale = stem cells creating new keratinocytes
- Stratum Spinosum = keratinocytes (water-proof) and melanocytes (melanin protection against UVB)
- Stratum Granulosum = keratonization of keratinocytes
- Statum Lucidum = dead keratinocytes of thick skin
- Stratum Corneum = shedding dead cells
List the layers of the dermis from deep to superficial. What do they contain?
- Reticular layer = fibroblasts, blood vessels, nerves, Pacinian corpuscle, macrophages, accessory structures (sweat/oil glands, hair follicles)
- Papillary layer = fibroblasts, blood vessels, nerves, Meissner corpuscle, free nerve endings, macrophages
What specialized cells are found in the skin and what layers are they located in? (9)
- Merkel cells –> stratum basale of epidermis
- Melanocytes –> stratum spinosum of epidermis
- Fibroblasts –> papillary and reticular layer of dermis, hypodermis
- Meissner corpuscle –> papillary layer of dermis
- Free nerve endings –> papillary layer of dermis
- Macrophages –> reticular and papillary layer of dermis, hypodermis
- Pacinian corpuscle –> reticular layer of dermis
- Adipocytes –> hypodermis
- Dendritic cells (Langerhans) –> stratum spinosum of epidermis
What part of the skin has blood vessels? Lymphatics?
Blood = dermis and hypodermis
Lymphatics = hypodermis
What does the hypodermis contain?
Adipoctyes, fibroblasts, blood vessels, nerves, lymphatics, macrophages
What layer of the skin is responsible for:
- Insulation
- Padding
- Termperature regulation
- Fingerprints
- Production of vitamin B
- Hypodermis
- Hypodermis
- Reticular layer of dermis
- Papillary layer of dermis
- Epidermis
Neutrophils - what are some characterisitics?
- The most abundant circulating leukocyte
- The first immune cell to get to a site of interest
- Short lived
What is the name for resident macrophages in:
- The brain
- The lungs
- The subcutaneous tissue
- The liver
- Microglia
- Alveolar macrophages
- Histiocytes
- Kupffer cells
Eosinophils:
- What is their function?
- What do they play a role in?
- Weak phagocytes, parasite killers, mediate inflammation
- Parasitic infection, allergic reactions
Basophils:
- What is their function?
- What do they play a role in?
- Liberate heparin into the blood, release histamine/bradykinin/serotonin
- Allergic reactions
Where in the skin does most of our normal skin bacterial flora reside?
Stratum corneum (and upper parts of hair follicles)
What are the two layers within a lymph node? How they are each organized and what cells do they contain?
Outer = stroma = supportive connective tissue
- Capsule covers the nade with trabeculae extensions dividing the node into compartments
- Contains reticular fibers and fibroblasts
Inner = parenchyma = functional part of the node
- Outer cortex contains primary lymphatic nodules (naive T cells), secondary lymphatic nodules (B cells becoming plasma/memory), germinal center (B cells, TFH, macrophages)
- Inner cortex contains T cells, DCs, and macrophages
- Medulla contains B cells, plasma cells, and macrophages
Describe the structure of the blood brain barrier
- Endothelial cells of brain’s capillaries are connected with tight junctions
- Thick basement membrane surrounding capillaries
- Pericytes (contractile cells) embedded in basement membrane and wrapping around endothelial cells
- Astrocyte cell projections (glia limitans) surrounding basement membrane
