Lecture 4 Epithelial Cells And Surface Specilisations Flashcards
What are 4 differences between serous and mucous membranes ?
1) mucous membranes line internal tubes which open to exterior , whereas serous membranes line closed body cavities than do not open to the exterior.
2) serous membranes exude watery , lubricating fluid , whereas mucous membranes secrete mucins onto the epithelial surface that then produce mucus.
3) serous membranes do not have
A visible lumen , whereas mucus membranes do.
4) mucous membranes have muscularis mucosa , whereas serous membranes do not.
What type of epithelium do serous membranes have ?
Simple squamous
Give 3 examples of where mucus membranes line ?
L1) respiratory
2) urinary
3) GI tract
Give three examples of what serous membranes line
1) plural sacs ( lungs)
2) peritoneum sacs ( abdominal organs)
3) pericardial ( heart)
How do serous membranes surround organs ?
- during embryological development
- heart , abdominal organs , lungs develop near a bag like cavity in which they then invaginate.
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What is the inner part of the bag like cavity called during embryological development ?
Visceral serosa
What is the outer part of the bag like cavity called during embryological development ?
- parietal serosa
Define epithelia
Sheets or continueous cells that have varied embryonic origins ; line external surfaces and internal surfaces.
What is an example of what pseudostratfied epithelium lines ?
- respiratory tract eg trachea , bronchi , nasal cavity
What is an example of what transitional epithelium line?
Only the bladder are lined with transitional epithelium
What is an example of what simple squamous epithelial cells line ?
- serous membranes
- bowman capsule wall
- lymphatic vessels and blood vessels
- air sacs of the lungs and lining of the heart
What is an example of what simple cuboidal epithelium line ?
- collecting ducts of kidneys
- thyroid glands follicles
- pancreatic duct
What is an example of simple columnar epithelium ?
- Agi tract eg stomach , small intestine , colon
What is an example of stratified squamous epithelial?
OseopHague m vagina , anal
Inside the mouth
To protect against abrasion
What is the function of simple squamous epithelium !
Fast exchange of materials and barrier to fluids
What is keratinised stratified squamous epithelium ?
Found on the epidermis of the skin
- made up of keratinocytes
- keratincyte mitosis occurs at the basal layer where daughter cells then move to the surface.
- transit time is around 28-40 days.
What occurs to the
Keratinocytes in psiarious ?
- transit time is 2-4 days.
- stratum Corneum is produced in abdundance but slivery scales.
Name two other cells that are found in epidermis cells
1) melanocytes
2) langerhan cells
What are melanocytes
- produce melanin
- everyone has the same number melanocytes but darker people more melanin.
- occur at 1:8 intervals of basal layer
What are langerhans and where in epidermal cells are they found ?
- found in the middle so they can have greater access to pathogens
- they have a specialised capacity to present antigens to T lymphocytes
What is one cause for cystic fibrosis ?
- mutation in the CTFR gene
- this causes the absence of CTFR ion channel in apical membranes in epithelial cells.
- Cl- ions cannot be transported out of the cell and usually wherever chloride goes , water follows. So water does not move out by osmosis to lubricate mucus. This results in mucus being really sticky and thick.
What are Clara ( club cells)
They are found in the bronchioles of the lungs.
- they protect the lungs
- they secrete a secretory substance from themselves called uteroglobin which represses an allergy induced inflammatory response
.
What are microfold cells ?
- found in small intestine
- trap pathogens
- however some pathogens use them as a portal of entry
Define the characteristics of the early stage of smoking
- mucus thickens
- cilia dies off
What happens when the person stops smoking for 2-4 days at an early stage of smoking ?
Ciliogensis occurs , that’s what may cause itching.
Describe the characteristics of a smoker during the chronic stage
- club cells that are found on the linings of bronchioles metaplasia or die.
- goblet cells and basal cells profilerate.
- type 11 cells in alveoli profilerate into type 1 and type 11 pneumocytes.
- fibroblasts in alveoli lay down scar tissue.
Do club cells every renew once a long term smoker stops smoking ?
No.
What is outline features of acute bronchitis
- occurs when smoking is less than 3 months
- occurs because airways and lungs narrow and swell.
- characterised by breathlessness , cough , mucus production
Out,one features of chronic bronchitis
- occurs when two episodes of cough last more than 3 months in a 2 year period.
- chronic inflammation of bronchi / bronchioles
- breathlessness
- excess mucus production and coughing
Outline features of emphysema
- shortness of breath
- damaged air sacs as alveoli fuse and enlarge so their recoiling ability fails
What does COPD stand for and what is it an umbrella term for?
Chronic obstructive pulmonary disease and chronic bronchitis and emphysema
What is asthma caused by?
Bronchospas, - tightening of the smooth muscle layer in the bronchi and bronchioles.
What are featuredof asthma
-shortness of breath ,
Chest tightness
Wheezing
Coughing
What are the effects of cystic fibrosis on the airways ?
Blocks the passages of the bronchial passage with sticky mucus.
- this obstructs breathing
What are the effects of cystic fibrosis on the liver ?
The small bile duct becomes blocked which causes problems with digestion as the bile usually emulsifies fats.
What is an effect of cystic fibrosis on the skin ?
- malfunctioning of the sweat glands which causes really salty sweat.
Where is stratified columnar epithelium found ?
- the male urethra and ducts of some glands
Where are stratified cuboidal epithelium found ?
- sweat glands
- salivary glands
- mammary glands
Where are simple squamous epithelium found ?
- serous membranes ( air sacs of the lungs , lining of the heart
) - bowmans capsule
- blood vessels
- lymphatic vessels
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