Epithelial Cells and Surface Specialisation Flashcards

Question

What is the location of SIMPLE COLUMNAR epithelium

Answer 1

Locations include: Stomach lining & gastric glands Small intestine & colon Gallbladder

Answer 2

Functions include: Absorption (small intestine and colon, gallbladder) Secretion (stomach lining & gastric glands, small intestine and colon) Lubrication (small intestine and colon)

Answer 3

Pseudostratified epithelia are tissues in which all cells make contact with the basement membrane, but not all of the cells reach the epithelial cell surface. This results in nuclei lying at different levels giving the impression of multiple cell layers.

Answer 4

In the Upper repository tract there is Pseudostratified ciliated epithelium of the trachea. The cilia beat at 12 Hz within a watery solution exuded by the epithelium. Above this is a viscoelastic mucous blanket, secreted by the goblet cells, which immobilises particles and lubricates their passage to the pharynx, where they are swallowed.

Answer 5

Mucins are glycoproteins that represent the major secreted products of the gastrointestinal tract

Answer 6

* Goblet cells lack of cilia on the apical surface * Instead have microvilli * Release of mucins through exocytocis * Water release increased by release of ions

Answer 7

Deficiency of chloride ion release results in very sticky and immovable mucous – characteristic of cystic fibrosis due to mutation in CFTR gene

Answer 8

The job of the CFTR is to put chloride ions onto the surface of the cell. As It does this it takes water with it Water + Mucus = less Stickiness With Cystic fibrosis, less Chloride ions thus less water thus more sticky immovable mucus

Answer 9

1. medicines to make the mucus in the lungs thinner and easier to cough up. 2. Physiotherapists bangs on chest to move mucus up to mouth where it can be swallowed or spit out.

Answer 10

Airways * clogging and infection of bronchial passage with thick sticky mucus obstructs breathing, progressively damages lungs – major cause of mortality in CF patients Liver * the small bile duct becomes blocked, disrupts digestion in 5% of CF patients Pancreas * zymogen secretions not released in 85% of patients (no lipid digestion) Small intestine * thick, non-motile stools in 10% of CF neonates - requires surgery Reproductive tracts * absence of fine ducts such as vas deferens renders 95% of CF males infertile. Occasionally, a thick mucous plug in cervix prevent semen transit and results in female infertility Skin * malfunctioning of sweat glands results in very salty sweat and crystals on the surface of the skin

Answer 11

Locations include: Lining of nasal cavity, trachea and bronchi

Answer 12

Functions include: Secretion and conduit (respiratory tract, ductus deferens) Mucus secretion (respiratory tract) Particle trapping and removal (respiratory tract)

Answer 13

Stratified squamous epithelia contain multiple layers of cells, the outermost of which are thin squamous epithelial cells

Answer 14

Desmisomes

Answer 15

Stratified squamous non-keratinised epithelia are found in areas that are moist and subject to varying degrees of abrasion

Answer 16

The cells are rich in glycogen, a substrate for lactobacilli, which produce lactic acid and thereby maintain a suitably low pH - helps to destroy non-native bacteria and viruses

Answer 17

Locations include: Oral cavity Oesophagus Vagina Part of anal canal Surface of cornea Inner surface of eyelid

Answer 18

Functions include: Protection against abrasion (all sites) Reduces water loss but remains moist (all sites)

Answer 19

Stratified squamous keratinised epithelium contains multiple layers of cells, the outermost of which are squamous cells that have lost their nuclei and cornified (i.e. become ‘squames’ of keratin).

Answer 20

The outermost dead cells of this epithelium are collectively called the Stratum Corneum This layer - greatly reduces water loss and ingress - prevents ingress of toxins - protects against abrasion - reduces microbial colonisation

Answer 21

The epidermis of the skin is the primary site of stratified squamous keratinised epithelium

Answer 22

Yes, (like all epithelia epidermis contains no blood vessels – it is avascular)

Answer 23

Dense irregular connective tissue, consisting of collagen and elastin bundles orientated in all directions; leather is made out of dermis

Answer 24

Locations include: Surface of skin Limited distribution in oral cavity

Answer 25

1.Protection against abrasion and physical trauma 2.Prevention of water loss 3.Prevention of microbial ingress 4.Shielding against UV light damage

Answer 26

urothelium

Answer 27

surface cells vary in shape from columnar/cuboidal to flattened

Answer 28

Urinary tract: from renal calyces --> ureters --> bladder --> Proximal urethra

Answer 29

Distensibility (The capability of being distended or stretched under pressure) Protection of underlying tissue from toxic chemicals (Urea dentures proteins)

Answer 30

During embryonic development the heart, lungs, and gut develop next to a bag-like cavity into which they invaginate. So they each become surrounded by serous membrane that has an inner (Visceral Serosa) and outer part (Parietal Serosa). It allows the frictionless movement of the heart and lungs, as well as the organs of the abdominal cavity.

Answer 31

Visceral serosal membrane closest to organs in cavity

Answer 32

Parietal serosal membrane lines outer edge of cavity

Answer 33

The pleural cavity is a space between the visceral and parietal pleura. The space contains a tiny amount of serous fluid. The serous fluid continuously lubricates the pleural surface and makes it easy for them to slide over each other during lung inflation and deflation.

Answer 34

MUCOUS MEMBRANES line certain internal tubes which open to the exterior, for example: * the gastrointestinal tract * the respiratory tract * the urinary tract (these mucosae bear mucus-secreting cells to varying degrees) A MUCOUS MEMBRANE consists of: * an epithelium lining the lumen of a tube (type depends on site) * an adjacent layer of connective tissue often referred to as the lamina propria (literally ‘one’s own layer ’) * a third layer consisting of smooth muscle cells, referred to as the muscularis mucosae * (also carries blood and lymphatic vessels and nerves) SEROUS MEMBRANES are thin, two-part membranes which line certain closed body cavities (spaces which do not open to the exterior) and envelop the viscera They line: * the peritoneum......which envelops many abdominal organs. * the pleural sacs........which envelop the lungs. * the pericardial sac.....which envelops the heart. These serous membranes (or serosae) exude a lubricating fluid that promotes relatively friction-free movement of the structures they surround. A SEROUS MEMBRANE consists of: * a simple squamous epithelium (mesothelium) that exudes the watery lubricating fluid * a thin layer of connective tissue that attaches the epithelium to adjacent tissues * (also carries blood and lymphatic vessels and nerves)

Answer 35

* Keratin – prevents water loss and protects against abrasion * Cilia – controls micro-movement of luminal contents * Goblet cells – mucus secretions, moistens and lubricates * Microvilli – increases surface area for absorption and secretion * Club cells – (previously known as Clara cells) protect bronchioles and acts as stem cells for respiratory epithelium * Microfold cells – allows rapid sampling of gut microflora * Stereocilia – in the auditory system coverts pressure waves into electrical signals

Answer 36

On the airway side of the terminal bronchioles and have club like apical surfaces, no cilia and no basal bodies

Answer 37

To protect the bronchiolar epithelium * Secretion of a small variety of products, including club cell secretory protein uteroglobin, and a solution similar in composition to pulmonary surfactant Detoxification of harmful substances inhaled into the lungs * Accomplish this with cytochrome P450 enzymes found in their smooth endoplasmic reticulum Act as a stem cell, multiplying and differentiating into ciliated cells to regenerate the bronchiolar epithelium

Answer 38

Found only in the small intestine and very close to lymphatic nodules

Answer 39

1. Trap pathogens and other molecules 2. Present to underlying dendritic cells that process material and 3. Present to lymphocytes and macrophages that reside in a basal ‘pocket’ that is not linked to the basement membrane to raise an immune response or digestions, respectively

Answer 40

Although M cells are important for the generation of a strong immune response, they also represent a weak point in the intestinal epithelium as many pathogens exploit them as a portal of entry they are not attached to the basement membrane.

Answer 41

* In the inner ear, stereocilia are the mechanosensing organelles of hair cells, which respond to fluid motion for hearing and balance * In the epididymis and vas deferens (sperm duct) , stereocilia facilitate absorption of the residual sperm body after spermiation has completed * Stereocilia contain actin and myosin filaments (just like cilia) and so could be involved in sperm movement along these ejaculatory ducts

Answer 42

Early stage 1. Normal mucus layer thickens 2. Cilia die off 3. Ciliagenesis – 2 to 4 days

Answer 43

Chronic stage 1. Goblet cells and basal cells proliferate 2. Club cells (metaplasia- cancer) or die 3. Carcinogens induce mutations and malignancy 4. Pneumocytes in the alveoli die * Remaining type II cells proliferate to make both type I and II pneumocytes * Fibroblasts lay down scar tissue

Answer 44

Cell renewal rates: Trachea - 1 to 2 months Alveoli - 8 days Goblet cells - 10 days Club cells - never (once they die or undergo morphogenesis)

Answer 45

Acute bronchitis Chronic bronchitis Emphysema COPD Asthma

Answer 46

Acute bronchitis – cough and mucus production, breathlessness < 3 months Reduced lung function and breathlessness due to inflammation, swelling and narrowing of the lung airways and excess mucus in the lung passages Later stage - Increased risk of serious respiratory diseases

Answer 47

Chronic bronchitis - chronic inflammation of the bronchi that produces a cough and mucus production that has at least 2 episodes of cough lasting 3 months or more during a 2 year period (smoker’s cough) * Reduced lung function and breathlessness due to inflammation, swelling and narrowing of the lung airways and excess mucus in the lung passages * Start of or irreparable damage to the bronchioles and alveoli

Answer 48

Emphysema – shortness of breath due to permanent widening of the airspaces distal to the terminal bronchiole without fibrosis (i.e. destruction of the air sacs) * Damage to air sac, loss of elastic recoil and permanent changes to the size of the alveoli (fuse and enlarge)

Answer 49

COPD – chronic obstructive pulmonary disease – umbrella condition that includes both emphysema and chronic bronchitis

Answer 50

Asthma - wheeze, shortness of breath, chest tightness and cough that may vary over time and in intensity, with a variable expiratory airflow limitation * often has a trigger (e.g. cold, exercise, allergens, stress, etc.) Caused by bronchospasm (tightening of the smooth muscle layer in the bronchi and bronchioles), obstruction from mucus and narrowing of the conducting airways

Epithelial Cells and Surface Specialisation Flashcards

(74 cards)