Epithelial Cell And Surface Specalisation

Question 1

Where can you find a mucosal membrane?

Answer 1

It lines internal tubes that reach the exterior.

GI tract, respiratory tract, urinary tract

Question 2

What is a mucus membrane made up of?

Answer 2

Epithelium (lines lumen)
Adjacent connective layer (lamina propria)
Smooth muscle (muscularis mucosa)
Blood lymph’s and nerves

Question 3

Where can you find serous membranes?

Answer 3

They line enclosed body cavities and envelop viscera
Peritoneum 
Pleural sac
Pericardial sac
(It excludes lubricating fluid)

Question 4

What is a serous membrane made of?

Answer 4

A simple squamous epithelium
Thin connective layer
Blood,lymph and nerves

Question 5

Name the 2 parts of a serous membrane

Answer 5

Visceral- membrane closest to organs

Parietal- membrane on further/outer edge of cavity

Question 6

Define an epithelium

Answer 6

Sheets of continuous cells, of varied embryonic origin, that cover external surfaces of body + line internal surfaces, including vessels

Question 7

Where do diff epithelium types originate from in an embryo?

Answer 7

Epidermis= from the ectoderm
Inner & outer lining of GI tract= from the endoderm
Inner lining of cavities= from the mesoderm

Question 8

What is the role of a simple squamous cell? And where would you find it?

Answer 8

Fast exchange
Fluid barrier
Tissue lubrication
(Eg lung, brain, CNS, serosa of organ, viscera)

Question 9

What is the role of a simple cuboidal cell and give examples of where t find it

Answer 9

Absorption 
Conduit 
Secretion 
Barrier
Hormone synth
(Exocrine glands, kidney tubule, ovary, thyroid)

Question 10

What are the functions of simple columnar cells and where would you find hem?

Answer 10

Absorption
Secretion
Lubrication
(Stomach lining, gastric gland, SI, colon, gallbladder)

Question 11

What are the roles of a (non-keratinised) stratified squamous cell and where would you find them?

Answer 11

Protect from abrasion
Reduce H2O loss
Keep moisture
(Oral cavity, oesophagus, vagina, anal canal, cornea, inner eyelid)

Question 12

What is the role of a pseudostratified cell and where can it be found?

Answer 12

Secretion
Conduit
Mucus secretion
Trap+remove particles
(Lining of nasal cavity, trachea, bronchi)

Question 13

What is the role of a transitional cell and where is it found?

Answer 13

Cells vary from cuboidal to flat =
Distensible
Protect from toxic chemicals
(Urinry tract)

Question 14

Describe a keratinised cell

Answer 14

Outermost cels are squamous an dhave lost their nuclei. They are dead.

Question 15

What is a Stratum Corneum

Answer 15

The outermost layer of dead cells in a keratinised epithelium can be collectively referred to as a stratum corneum

Question 16

What is the function of keratinised epithelium and where is it found?

Answer 16

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)

Question 17

What are keratinocytes?

Answer 17

They are the stratified squamous keratinised epithelial cells found on the epidermis of the skin.

Question 18

How long does it take a keratinocytes to move from the basal layer to the stratum corneum.

Answer 18

Roughly 28-40 days but in psoriasis it only takes 2-4 days

Hence stratum corneum produced in abundance as silvery scales

Question 19

What are melanocytes

Answer 19

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

Question 20

What are langerhan cells

Answer 20

Another type of epidermis cell.

They present antigens to t-lymphocytes and mediate immune reactions

Question 21

Describe the formation of the dermis.

Answer 21

Dense irregular connective tissue.

Collagen and elastin bundles in all directions

Question 22

Describe a goblet cell and its role?

Answer 22

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

Question 23

List and explain how Cystic Fibrosis effects the body organs.

Answer 23

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

Question 24

Describe club cells and their function

Answer 24

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)

Question 25

Describe and explain function of microfold cells.

Answer 25

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

Question 26

Describe the function of stereocillia

Answer 26

Mechanosensing organelles of hair follicle in ear- fluid motion for hearing and balance
Reabsorb sperm body in vas deferents after spermination

Question 27

Describe symptoms of acute bronchitis

Answer 27

Cough + mucus production
Breathless <3 months
Low lung function due to inflammation
Swelling

Question 28

Describe symptoms of chronic bronchitis

Answer 28

Chronic inflammations
Cough + mucus production
2 cough episodes> 3 months in 2 years
Start irrerable damage

Question 29

Describe symptoms of emphysema

Answer 29

Shortness breath due to permanent widening of airspaces
Damage to air sacs
Loss of recoil
Ermanent change to alveoli size

Question 30

Describe asthma symptoms

Answer 30

Wheeze
Shortness of breath
Tight chest
Cough
Expiratpry flow limitation 
Caused by bronchospasm, mucus and narrow conductive airway