Epithelial Cell And Surface Specalisation Flashcards
Where can you find a mucosal membrane?
It lines internal tubes that reach the exterior.
GI tract, respiratory tract, urinary tract
What is a mucus membrane made up of?
Epithelium (lines lumen)
Adjacent connective layer (lamina propria)
Smooth muscle (muscularis mucosa)
Blood lymph’s and nerves
Where can you find serous membranes?
They line enclosed body cavities and envelop viscera Peritoneum Pleural sac Pericardial sac (It excludes lubricating fluid)
What is a serous membrane made of?
A simple squamous epithelium
Thin connective layer
Blood,lymph and nerves
Name the 2 parts of a serous membrane
Visceral- membrane closest to organs
Parietal- membrane on further/outer edge of cavity
Define an epithelium
Sheets of continuous cells, of varied embryonic origin, that cover external surfaces of body + line internal surfaces, including vessels
Where do diff epithelium types originate from in an embryo?
Epidermis= from the ectoderm
Inner & outer lining of GI tract= from the endoderm
Inner lining of cavities= from the mesoderm
What is the role of a simple squamous cell? And where would you find it?
Fast exchange
Fluid barrier
Tissue lubrication
(Eg lung, brain, CNS, serosa of organ, viscera)
What is the role of a simple cuboidal cell and give examples of where t find it
Absorption Conduit Secretion Barrier Hormone synth (Exocrine glands, kidney tubule, ovary, thyroid)
What are the functions of simple columnar cells and where would you find hem?
Absorption
Secretion
Lubrication
(Stomach lining, gastric gland, SI, colon, gallbladder)
What are the roles of a (non-keratinised) stratified squamous cell and where would you find them?
Protect from abrasion
Reduce H2O loss
Keep moisture
(Oral cavity, oesophagus, vagina, anal canal, cornea, inner eyelid)
What is the role of a pseudostratified cell and where can it be found?
Secretion Conduit Mucus secretion Trap+remove particles (Lining of nasal cavity, trachea, bronchi)
What is the role of a transitional cell and where is it found?
Cells vary from cuboidal to flat =
Distensible
Protect from toxic chemicals
(Urinry tract)
Describe a keratinised cell
Outermost cels are squamous an dhave lost their nuclei. They are dead.
What is a Stratum Corneum
The outermost layer of dead cells in a keratinised epithelium can be collectively referred to as a stratum corneum
What is the function of keratinised epithelium and where is it found?
Reduce H2O loss and ingress Hold oils Prevent toxin ingress Protect from abrasion Reduce microbial colonisation (Sin surface, oral cavity, but primarily epidermis of skin)
What are keratinocytes?
They are the stratified squamous keratinised epithelial cells found on the epidermis of the skin.
How long does it take a keratinocytes to move from the basal layer to the stratum corneum.
Roughly 28-40 days but in psoriasis it only takes 2-4 days
Hence stratum corneum produced in abundance as silvery scales
What are melanocytes
Another form of epidermal cell.
They occur at intervals and produce the melanin that pigments skin. Individuals of any skin colour have the same number but more tanned people produce more melanin
What are langerhan cells
Another type of epidermis cell.
They present antigens to t-lymphocytes and mediate immune reactions
Describe the formation of the dermis.
Dense irregular connective tissue.
Collagen and elastin bundles in all directions
Describe a goblet cell and its role?
No cilia on apical surface
Produce musings in exocytosis
Increase H2O release by releasing Cl ions.
A deficiency in this ions results in thick, immovable mucus
List and explain how Cystic Fibrosis effects the body organs.
Airway-clog,infect bronchial passage, obstruct breathing, lung damage
Liver-block small bile duct, disrupts digestion in 5%
Pancreas-zymogen secretions blocked in 85%
SI-thick, non-motile stool (10% neonates need surgery)
Reproductive tract-absence fine ducts like vas derferns make 95% men in fertile, thick mucus plug in cervix effect females
Skin-malfunction glans=salty crystals on skin
Describe club cells and their function
On airway of terminal bronchiole
No cilia or basal body
They secrete uteroglobin and a pulmonary surfactant
Detoxify armful inhales using cytochrome P45 enzyme (SER)
Act as stem cells for cilated cells (regenerate bronchiole epithelium)
Describe and explain function of microfold cells.
Only in SI near lymphatic nodules
Trap a pathogen and present to underlying dendritic cells to process
Present to lymphocytes and macrophages in basal pocket to raise immune response
Folded mushroom cap extension -samples lumen by endocytosis
Pathogens may exploit as entry portal
Describe the function of stereocillia
Mechanosensing organelles of hair follicle in ear- fluid motion for hearing and balance
Reabsorb sperm body in vas deferents after spermination
Describe symptoms of acute bronchitis
Cough + mucus production
Breathless <3 months
Low lung function due to inflammation
Swelling
Describe symptoms of chronic bronchitis
Chronic inflammations
Cough + mucus production
2 cough episodes> 3 months in 2 years
Start irrerable damage
Describe symptoms of emphysema
Shortness breath due to permanent widening of airspaces
Damage to air sacs
Loss of recoil
Ermanent change to alveoli size
Describe asthma symptoms
Wheeze Shortness of breath Tight chest Cough Expiratpry flow limitation Caused by bronchospasm, mucus and narrow conductive airway
