Lecture 6 - Epithelial Tissues And Cell Surface Specialisations

Question 1

What is the definition of epithelial tissue?

Answer 1

Sheets of contiguous cells, of varied embryonic origin that cover the external surface of the body and line internal surfaces including the body’s vessels

Question 2

What epithelial tissue is derived from the Ectoderm?

Answer 2

The Epidermis (Skin)

Question 3

What epithelial tissue is derived from the Mesoderm?

Answer 3

Inner linings of boy cavities

Question 4

What epithelial tissue is derived from the Endoderm?

Answer 4

Lining of the respiratory tract
Lining of the GI tract

Question 5

What is the peritoneum?

Answer 5

The sac surrounding the GI tract

Question 6

When classifying Epithelial cell types, what does simple mean?

Answer 6

Only 1 cell thick

Question 7

When classifying Epithelial cell types, what does Stratified/compound mean?

Answer 7

More than 1 cell layer thick

Question 8

What is simple squamous epithelium?

Answer 8

A single layer of flat cells

Question 9

What is the function of simple squamous epithelia?

Answer 9

Lubrication (pericardium, pleural membranes, peritoneum/viscera)

Gas exchange (Type 1 pneumocytes)

Water, nutrient and waste product exchange (endothelial cells lining heart + capilaries

Barrier

Question 10

What is simple cuboidal epithelium?

Answer 10

A single layer of polygonal cells whose height and width are about equal

Question 11

Where are simple cuboidal epithelia found?

Answer 11

Lining pancreatic duct
Bounding thyroid gland follicles (make thyroglobulin)
PCT and collecting duct of nephrons

Question 12

What are the functions of simple cuboidal epithelium?

Answer 12

Absorption and transport (Exocrine glands)
Absorption adn secretion (kidney tubules)
Barrier/covering (ovary)
Hormone synthesis and storage (Thyroid)

Question 13

What are simple columnar cells?

Answer 13

A single layer of cells whose heights are greater than their widths. Taller than they are wide.

Nucleus closest to basement membrane

Question 14

Where are simple columnar cells found?

Answer 14

Stomach lining and gastric glands
Small intestine and colon
Gall bladder

Lining crypts of Lieberkuhn in mucosa of colon

Question 15

What is the main function of the simple columnar epithelial cells lining the crypts of Liberkuhn?

Answer 15

Absorption of nutrients
Movement of lumen contents

Question 16

What do the microvilli do on simple columnar cells?

Answer 16

Increase surface area for absorption

Question 17

What are the 3 functions of simple columnar epithelium?

Answer 17

Absorption
Secretion
Lubrication

Question 18

What is Pseudostratified epithelia?

Answer 18

All cells make contact with he basement membrane but not all reach the epithelial cell surface

Nuclei lie at different levels

Question 19

Where are Pseudostratified epithelia found?

Answer 19

Lining:
Nasal cavity
Trachea
Bronchi

Question 20

What are the functions of Pseudo-stratified epithelium?

Answer 20

Secretion and conduit (respiratory tract)
Mucus secretion (respiratory tract)
Particle trappings and removal

Question 21

What is the mucociliary escalator?

Answer 21

The cilia of Pseudostratified ciliates epithelium of the trachea beating mucus containing pathogens or dirt to the bag of the throat to be swallowed

Question 22

What cell surface specialisation do goblet cells have on their apical surface?

Answer 22

Micro villi

NO CILIA

Question 23

What process do goblet cells use to release Mucins?

Answer 23

Exocytosis

Question 24

What is the function of CFTR in goblet cells?

Answer 24

Release chloride ions from the goblet cell onto its surface

Causes water to be released needed to make good consistency mucus

Question 25

What is cystic fibrosis caused by?

Answer 25

Mutation in the CFTR gene

Question 26

What does a mutation in the CFTR gene cause and how is this bad?

Answer 26

Less chloride ions are released onto surface of goblet cell Less water in mucus Thick sticky, immovable mucus

Question 27

Which tissues are affected in cystic fibrosis?

Answer 27

Tissues that have mucins and cilia

Question 28

Give examples of tissues affected in cystic fibrosis:

Answer 28

Airways - breathing difficulties Liver - small bile duct blocked Pancreas - zymogen secretions not released Small intestines Reproductive tracts Skin - sweat glands malfunction (salty sweat crystals form)

Question 29

What are stratified squamous epithelia?

Answer 29

Multiple layers of cells which the outermost layer are thin flat squamous epithelial cells

Question 30

Where can stratified squamous , non keratinised epithelium be located?

Answer 30

The: -Vagina -Oesophagus - Oral cavity -Part of anal canal

Question 31

In what type of areas are stratified squamous non keratinised epithelium usually located??

Answer 31

Moist areas Usually in areas subject to abrasion

Question 32

What is the function of stratified squamous non keratinised epithelium?

Answer 32

Protect against abrasion Reduce water lost but remains moist

Question 33

How can you tell that stratified squamous epithelium is non keratinised

Answer 33

There are nuclei present in the top layers

Question 34

What is stratified squamous keratinised epithelium?

Answer 34

Multiple layers of cells witht the outermost layer being squamous cells that have lost their nuclei and have become cornfield

Question 35

Where is stratified squamous keratinised epithelium mostly found?

Answer 35

Surface of skin =MAIN Some in oral cavity

Question 36

What is the function of stratified squamous keratinised epithelium?

Answer 36

Protect against abrasion and trauma Prevents water loss Prevents microbial ingress Shields against UV damage

Question 37

What is the layer of skin called where stratified squamous keratinised epithelium is found?

Answer 37

Stratum Corneum Layers called squames

Question 38

What are Tranisitioonal epithelial cells?

Answer 38

Cells which can vary in shape from columnar to cuboidal to flattened

Question 39

Where are transitional epithelium usually found?

Answer 39

Urinary tract (Urothelium)

Question 40

What is the function of Urothelium/Transitiona epithelium?

Answer 40

Protection of underlying tissues from toxic chemicals Distensibility (Can stretch under pressure)

Question 41

What are serous membranes?

Answer 41

Thin 2 part membranes which line certain closed body cavities and envelope the viscera

Question 42

What is the viscera?

Answer 42

The internal organs of the main cavities of the body

Question 43

How are viscera positioned in relation to a serous membrane/cavity?

Answer 43

The organs dont actually lie within the cavity but its is surrounded by it Think of it like a fist being pressed into a balloon, the balloon surrounds the fist but the fist isn’t actually inside the balloon

Question 44

What are the names of the 2 membranes that make up the serous membranes?

Answer 44

Visceral serosa Parietal serosa

Question 45

Where is the visceral serosa located?

Answer 45

The inner membrane which is in contact or close to the organs/viscera

Question 46

Where is the parietal serosa located?

Answer 46

The membrane not in contact with the organs. The membrane that lines the outer edge of the cavity

Question 47

Which cavities do serous membranes line?

Answer 47

Peritoneum Pleural sacs Pericardial sac

Question 48

Which organs does the peritoneum envelope?

Answer 48

Many abdominal organs

Question 49

Which organs does the pleural sacs envelope?

Answer 49

Lungs

Question 50

Which organ does the pericardial sac envelope?

Answer 50

Heart

Question 51

What is the function of serous membranes?

Answer 51

Exude a Lubricating fluid Promotes friction free movement of structures they surround

Question 52

What does a serous membrane consist of?

Answer 52

Simple squamous epithelium (exudes watery lubricating fluid) Thin layer of connective tissue (Blood, Lymph and nerves)

Question 53

What do mucous membranes consist of?

Answer 53

Epithelium lining lumen of tube Lamina propria (connective tissue layer) Muscualaris mucosae (smooth muscle) , blood lymph and nerves

Question 54

Where are mucus membranes found?

Answer 54

Lining certain internal tubes which open to the exterior GI Respiratory tract Urinary tract

Question 55

Where are club cells found?

Answer 55

Terminal Bronchioles

Question 56

What are the functions of club cells?

Answer 56

Protect bronchioles (detoxification, makes protein uteroglobin and surfactant like fluid) Act as stem cells to regenerate bronchioles epithelium HAVE NO CILIA

Question 57

What are micro fold cells? Where are they found?

Answer 57

They are cells that trap pathogens and molecules and present them to dendritic cells They also present to lymphocytes and macrophages Gut Associated Lymphoid Tissue (GALT) of the Payers Patches

Question 58

Where are microfold cells found?

Answer 58

In small intestine near lymph nodes GALT of the Payers Patches

Question 59

What is the importance of microfold cells?

Answer 59

Strong immune response

Question 60

What is the function of Sterocilia?

Answer 60

Convert pressure waves into electrical waves in the auditory system

Question 61

How does smoking damage the lungs in the early stages?

Answer 61

Normal mucus layer thickens Cilia die off Cilia genesis takes place (2-4 days)

Question 62

How does smoking damage cells in the chronic stage?

Answer 62

Goblet cells and basal cells proliferate Club cells die (permenant) Carcinogens undue mutations and malignancy Pneumocytes in alveoli die Fibroblasts lay down scar tissue

Question 63

What is Chronic Bronchitis?

Answer 63

Chronic inflammation of the bronchi

Question 64

What signs does Chronic Bronchitis produce?

Answer 64

A cough and mucus production that has at least 2 episodes of cough lasting 3 months or more during a 2 year period

Question 65

What is the consequences of Chronic Bronchitis?

Answer 65

Reduced lung function and breathlessness Excess mucus Swelling and narrowing of airways Start of or irreparable damage to bronchioles and alveoli

Question 66

What is the cell renewal rate of the trachea??

Answer 66

1-2 months

Question 67

What is the cell renewal rate of alveoli?

Answer 67

8 days

Question 68

What is the cell renewal rate of goblet cells?

Answer 68

10 days

Question 69

What is the cell renewal rate of club cells?

Answer 69

Never Once they die that’s it