Wk 3- Epithelial Tissue & The Integument Flashcards
The integumentary system
The I. System is comprised of
1. C- membrane = the Epi- and D?
- Accessory structures = hair, ? exo- glands
Cutaneous membrane - epidermis and dermis
nails, exocrine glands
Epidermis
The epidermis = - - - epithelium
Epidermis is made up of 4 cells and 5 layers
Keratinised stratified squamous
Epidermis cells:
- Keratinocytes: tough fibrous protein, -0% epidermis
- Melanocytes: pigment m?, 8% epidermis ( protect from - -)
- Intraepidermal macrophages: I? cells
- Tactile epithelial cells: form sensory structures
- 90%
- Melanin , 8% UV
- Immune
Epidermis layers
- Stratum basale: single base layer of cuboidal /columnar cells. Contains germination cells to produce more k?
- Stratum spinosum: spiny appearance, contains - to 10 layers of k?
- Stratum granulosum: - to 5 flattened layers of k?transitioning live to dead (apoptosis)
- Stratum lucidum: 4 to 6 layers clear, flat, dead k?
- Stratum corneum: surface layer of 25 to -0 layers dead, flat k? shedding and r?
- keratinocytes
- 8, keratinocytes
- 3-5 , keratinocytes
- keratinocytes
- 25 - 30 , keratinocytes , replacing
The Dermis
The dermis is divided into 2 layers
- Papillary : l? connective tissue = replacing
- Reticular: d? connective tissue= stable base
Loose
Dense
The Dermis consists of;
Collagen fibres: strong and - stretching
Elastic fibres: permit - and recoil
Epidermal pigments: carotene orange/yellow and melanin (brown to -) made by melanocytes
resist
Stretching
black
Epithelial cells
Epithelial cells must maintain structure to function well
Their epithelial function is either to ;
- Cover and l? (selectively permeable barrier to protect and cushion)
- G? (secret)
- line
2. Glandular
Epithelial cells
Epithelial cells are tightly connected by 1 of 3 junctions.
- Tight junctions: fusion / st? of cells together
- Desmosomes: sticky - pads together
- Gap junctions: riveted cells allowing tiny - through
- stitch
- Velcro
- ions
Epithelial cells
Epithelial contain
1. Germinative cells: used in cell division to produce cells
2. Gland cells: exocrine (secrete - surface)
Endocrine (secrete - bloodstream)
The pancreas produces exo- gland cells (digestive enzymes) and releases endo- gland cells (hormones in bloodstream)
- Onto , into , exocrine ,endocrine
Epithelial cells
Epithelial cells are 1 of 3 shapes 1. Flat/thin: ? 2. Cubes: ? 3. Long columns: ? These shaped cells will always sit on top of a basement membrane
- Squamous
- Cuboidal
- Columnar
Epithelial cells
Epithelial cells are classified into 2 layers;
- Simple single layer
Squamous: for diffusion and ab?
Cuboidal: for secretion and ab?
Columnar: self cleansing for ? and ab? - Stratified multiple layers
Squamous : stronger structure to - stresses
Squamous: diffusion and absorption
Cuboidal: absorption
Columnar: secretion and absorption
2. Resist
Accessory structures
Hair - insulate , provide sen? information on - surface
Nails- tightly packed - epidermal cells, protect ends of fingers / toes
Sensory , Skin
Keratinised
Cell junctions
What are the 3 types of cell junctions ?
- T? Junctions (fusion of cell membrane)
- D? (Molecular Velcro )
- G? (Special structures allow passage of ions)
Tight junctions
Desmosomes
Gap junctions
Gland cells
? Gland cells
Release secretions ? surface of cell (sweat)
? Gland cells
Release secretion ? interstitual fluid (hormones)
Exocrine, onto
Endocrine, into
What are the 5 Functions of epithelium:
- P? =Barrier to mechanical /chemical/ biological attack
- Excretion= Water/ salts /waste products
- H? =Body temperature control via insulation/evaporation
- Manufacture= Contributes to synthesis vitamin D
- S? =Touch /pressure /temperature
Protection
Excretion
Homeostasis
Sensation
