Epithelial Cells Flashcards
Epithelia definition
Sheets of contiguous cells of various embryonic origin, that cover the external surface of the body and line internal surfaces
What are epithelial tissue derived from?
Give detail
The germ layer
Ectoderm - epidermis (outer layer of skin)
Endoderm - GI tract
Mesoderm - inner body cavities
What is the basement membrane made of?
Function? (3)
Basal lamina and reticular layer
Filter, cell attachment, physical support
What do goblet cells have on them?
What do they release?
Microvilli - NOT cilia
Mucins - through exocytosis
What causes more water to be in the mucin released by goblet cells?
Increased release of ions
How do you identify keratin in an image?
No nucleus
Lateral surface
What is the stratum corneum?
Outermost layer of the epidermis
How do goblet cells release mucin?
Exocytosis
What gene is mutated for a patient with cystic fibrosis? What does this cause?
CFTR
Cl- not released, sticky immovable mucus
What is the membrane that some organs are surrounded by?
Serous membrane
What is the name of the serous membrane closest to organs?
Visceral
What is the name of the serous membrane that lines the outer edge?
Parietal
Why are the lungs shiny?
They are covered by moist pleura (thin layer of tissue)
What do the mucous and serous membranes line?
M - internal tubes which open to the exterior
S - closed body cavities !which do not open to the exterior!
Give examples of what mucous and serous membranes line
M - GI tract, respiratory tract, urinary tract
S - peritoneum (abdominal organs), pleural sacs (lungs), pericardial sacs (heart)
What is a similarity mucous and serous membranes
Both carry blood and lymphatic vessels + nerves
Role of keratin
Prevents water loss
Protects against abrasion
Role of cilia
Control micro movements of luminal contents
Role of goblet cells
Secrete mucus
Moisten
Lubricate
Role of microvilli
Increase surface area for absorption and secretion
Role of club cells
Protect bronchioles
Act as stem cells for respiratory epithelium
Role of micro fold cells
Allow rapid sampling of gut micro flora
Role of stereocilia
Convert pressure waves into electrical signals - in the auditory system
Where are club cells found?
Airway side of the terminal bronchioles
How do club cells protect the bronchioles?
Secrete a variety of products - like uteroglobin
Detoxify harmful substances inhaled - using cytochrome P450 enzymes
Where are microfold cells found?
Small intestines, close to lymphatic nodules
Describe how microfold cells function
- Trap pathogens and molecules
- Present to dendritic cells
- Present to lymphocytes and macrophages - immune response or digestion occur
Key downside of microfold cells
Pathogens use them as a point of entry
What specific type of organelles are stereocilia, for hair cells?
Mechanosensing
How do stereocilia assist hearing and balance?
They respond to fluid motion
How are stereocilia linked to sperm?
Facilitate absorption of the residual sperm body after spermiation has completed
What do stereocilia contain that assists them with movement?
Actin and myosin
Which cells do not renew for smokers?
Club cells
What are the three early stages of smoking damage?
- Thickened mucus layer
- Cilia die
- Ciliagenesis
What are the four steps to chronic damage when smoking?
- Goblet and basal cells proliferate
- Club cells die
- Carcinogens induce mutations
- Pneumocytes in the alveoli die
Name four common conditions related to smoking
Asthma
Chronic bronchitis
Emphysema
COPD
What is COPD?
Emphysema and chronic bronchitis
What is acute bronchitis?
Reduced lung function due to inflammation, excess mucus and swelling
What is chronic bronchitis?
Start of or irreparable damage to the bronchioles and alveoli
What is emphysema?
Permanent widening of airspaces distal to the terminal bronchiole without fibrosis - loss of elastic recoil
What is asthma?
Caused by bronchospasm, obstruction form mucus and narrowing of airways
Leads to variable expiratory airflow - amongst other symptoms!
When are epithelial cells polarised?
When at surfaces
What are epithelial cells held together by?
Anchoring proteins
What is a contractile epithelial cell?
Myoepithelial
