Epithelium Integument Flashcards
All cells of the body can be classified as one of which FOUR basic tissue types?
Epithelial Connective Nervous Muscle
What are the 5 functions of epithelial?
PTASS Protection, Transport, Absorption, Secretion, Sensation
Is epithelium avascular or vascular?
Avascular
What are three unique characteristics of epithelia that comes as a direct result of their being continuous sheets of cells lining surfaces?
Cell to cell junctions Basement Membrane Polarity
What are the 3 functions of cell to cell junctions?
- Structure 2. Barrier 3. Communication
What types of cell junctions are there in epithelia and what does each of them do?
Tight junctions are barriers between cells, mostly founds in the stratum granulosum. Desmosomes and adhering junctions hold cells together. Hemidesmosomes hold the cells to the BM. Gap junctions open pores bw cells that help signals pass through.
What types of proteins are adhering junctions, desmosomes, and hemidesmosomes made up of?
Cadherins and integrins
In epithelial tissue, what proteins make up intermediate filaments?
Keratin
Where can tonofilaments be found and what do they do?
Connect desmosomes to the cytoskeleton in bundles of keratin.
E-cadherins in desmosomes can only attach to _________
E-cadherins.
Describe the polarization of epithelia.
All epithelia have a distinctive apical and basal side. The apical side is exposed. The basal side secretes extracellular matrix.
How is the basement membrane attached to the basal surface of epithelia?
Hemidesmosomes
What are the three types of epithelia?
Simple - 1 layer Pseudostratified - 1 layer, but looks like many because of cell size and organization. Stratified - 2 or more layers.
What are the 4 apical cell shapes?
Squamous - flat Cuboidal - square Columnar - tall and thin Transitional - specialized domed apical cells
What type of epithelia is this and where can you find it?
Simple squamous. Found in blood vessels and respiratory system because it is good at gas exchange.
What type of epithelia is this and where is it?
Simple cuboidal. In the kidneys because there is room here for active transport.
What type of epithelia is this and where is it?
Simple columnar, digestive system, good at absorption.
What type of epithelia is this and where is it found?
Pseudostratified epithelia, which is found in parts of the respiratory system which do not need to do gas exchange. This is the nasal passages, trachea. This type has goblet cells and cilia.
What type of epithelia is this and where can it be found?
Stratified squamous - because it’s keratinized. Esophagus, oral cavity, vagina. The highly keratinized version of this is the skin. The keratin prevents water loss.
What type of epithelia is this and where is it found?
It’s stratified columnar and is very rare - found in the sweat and mammary glands.
What are the 4 functions of the skin?
Protection
Homeostasis
Sensation
Metabolic (vit D)
PHSM
(Phasm?)
Name the three sections of skin and what they contain.
Epidermis (avascular, epithelium)
Dermis (vascular, conn tissue)
Hypodermis / Subcutaneous (vascular, conn tissue)
What types of cells are in the stratum basale and what do each of the cells do?
Stem Cells - make keratin
Melanocytes - make melanin
Merkel Cells - sensory
What cells are in the stratum spinosum and what do they do?
Langerhan’s - immune system
Keratinocytes w/ desmosomes connected by tonofilaments - connections minimize mechanical stress
What are the defining features of the stratum granulosum?
Keratohyalin granules, lamellar bodies (lipid releasing to keep out water), tight junctions
Name the order of the layers of the epidermis.
Stratum Corneum
Stratum Lucidum
Stratum Granulosum
Stratum Spinosum
Stratum Basale
What is the purpose of the wavy structure of the dermis?
To better fit with the epidermis.
Describe the function of the two layers of the dermis.
Papillary - loose connective tissue, to connect to the epidermis.
Reticular - dense connective tissue for structure and support.
What structures are found in the papillary dermis?
Vascular
Fibroblasts
Hemi-desmosomes - helps to attach pap to BM
Meissner’s corpuscles - texture
What are the main features of the reticular dermis?
Lymphatic vessels
Hair follicles
Sebaceous glands
What are the main features of the hypodermis / subcutaneous layer?
Loose connective tissue + adipose (less supportive, more about cushioning / protection / heat)
Pacinian Corpuscles - pressure
Sweat glands
Describe the Integument Nerve Supply.
Free nerve endings (temp + pain) - in dermis
Merkel Cells (light touch) - basal layer of epidermis
Meissner’s Corpuscles (texture) - papillary dermis
Pacinian Corpuscles (vibration + pressure) - dermis / hypodermis
Ruffini’s Corpuscles (tensile stretching) - dermis/hypodermis
