Lecture 4 Epithelial Cells And Surface Specilisations Flashcards
(39 cards)
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.
-
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
