4 Epithelial Cells And Surface Specialisation Flashcards
Mucous membranes structure
Epithelium lining lumen of tube
Layer of connective tissue - lamina propria
Layer of smooth muscle cells - muscularis mucosae
Carries blood and lymphatic vessels and nerves
Serous membranes
Line closed body cavities and envelop viscera
Line peritoneum, plural sacs, pericardial sac
Exude lubricating fluid, allows friction free movement of structures
Serous membranes structure
Simple squamous epithelium
Layer of connective tissue that attaches epithelium to adjacent tissues
Carries blood and lymphatic vessels and nerves
Serous membrane pericardial sac
Surrounds heart
Visceral serosa membrane closest to heart
Parietal serosa membrane outside of sac
Epithelium definition
Sheets of continuous cells that cover external surface of body and line internal surfaces
E.g. skin, GI, respiratory and genitourinary tract, pericardial sac, pleural sac
Simple squamous epithelium
One layer thick Squashed Fast material change Barrier to fluids Tissue lubrication
Simple cuboidal epithelium
Absorption and conduit (exocrine)
Absorption and secretion (kidney)
Barrier/covering (ovary)
Hormone synthesis, storage and mobilisation (thyroid)
Simple columnar epithelium
Absorption
Secretion
Lubrication
Simple psuedostratified epithelium
Columns but looked stratified
Secretion and conduit
Mucus secretion
Particle trapping and removal
Stratified squamous (keratinised) epithelium
Outermost cells lost nuclei and cornfield In epidermis of skin Protection against abrasion Prevent water loss and microbial ingress Shield against UV light damage
Stratified/compound epithelium
Squamous keratinised Squamous non-keratinised Cuboidal Columnar Transitional
Epidermis
Stratified squamous keratinised epithelium (keratinocytes)
Mitosis occurs mainly in basal layer
Melanocytes occur at intervals and produce melanin
Langerhans cells, present antigens to T lymphocytes, mediate immune reactions
Goblet cells
No cilia on apical surface
Microvilli
Release mucins
Water release increased by release of ions
Club cells
In bronchioles Club like apical surfaces No cilia Secrete uterglobin and similar solution to pulmonary surfactant Detoxify harmful substances inhaled Act as stem cell
Microfold clls
In small intestine
Folded extension that samples lumen by endocytosis
Exploited by pathogens as portal of entry
Trap pathogens, present to dendritic cells, present to lymphocytes and macrophages
Stereocilia
In inner ear
Mechanosensing organelles of hair cells, hearing and balance
Contain actin and myosin filaments
Effects of smoking early stage
Normal mucus layer thickens
Cilia die off
Ciliagenesis (2-4 days, cilia regenerate if stop smoking)
Effects of smoking chronic stage
Goblet cells and basal cells proliferate
Club cells abnormally change or die
Carcinogens induce mutations and malignancy
Pneumocytes in alveoli die
Cell renewal rates
Trachea 1-2 months
Alveoli 8 days
Goblet cells 10 days
Club cells never
Conditions linked to smoking
Acute bronchitis Chronic bronchitis Emphysema COPD (emphysema and chronic bronchitis) Asthma
