Tissues, Organs And Systems

Question 1

What holds cells together (4)

Answer 1

Cell adhesion molecules, extracellular matrix proteins (fibres), Internal/external scaffolding, close proximity

Question 2

Connective tissue

Answer 2

Extracellular matrix plentiful, cells sparse(as full of fibres), matrix is rich in fibres (collagen) direct attachments between cells

Question 3

Epithelial tissue

Answer 3

Cells tightly bound in sheets (epithelia), no extracellular matrix (just basal lamina underlying) cells attached via adhesions (lots of stress), strong intracellular protein filaments, junctions proteins

Question 4

Features of connective tissue

Answer 4

Primary cell - mesenchymal stem cells: Interconvert between cell types, produces most of extracellular fibres.

Question 5

What does mesenchymal stem cell do in culture

Answer 5

Quickly converts to mature fibroblast, allows cells to adhere to plastic/glass surfaces (fibroblasts divide faster than tissue)

Question 6

Epithelial tissue function

Answer 6

Line cavities and free surfaces of body, tissue barriers, rest on basement membrane - attaches epithelial layer to other tissues

Question 7

What is an organ

Answer 7

More than 1 type of tissue together

Question 8

Epithelial adherence systems in lateral surface

Answer 8

Adherens, tight junctions, gap junctions, desmosome, cell adhesion molecules

Question 9

Epithelial adherence system in basal surface

Answer 9

Focal adhesions, cell adhesion molecules, hemidesmosome, integrins, proteoglycans

Question 10

Tight junctions

Answer 10

Very top, prevent movement of larger molcules to deeper tissue layers (bladder). In gut can open to allow paracellular transport of small molecules.

Question 11

Adhesion junctions

Answer 11

1/3 from top, found in pairs, formed from actin, linked to E-cadherin proteins (form bridges). Transport barrier and stabilising factor

Question 12

Desmosome

Answer 12

Strongest(found in tissues undergoing intense mechanical stress) , 1/2 way down, randomly distributed. Mechanical strength, prevent tissue destruction (only cell to cell in skin)

Question 13

Gap junctions

Answer 13

Close to base, cardiac and smooth muscle. Allows wave of electrical impulse (contraction) and movement of small molecules

Question 14

Hemi-desmosome

Answer 14

Basal surface, attach to extracellular matrix. Anchor epithelial cells to basal lamina (via integrins attached to cytokeratin inside cell)

Question 15

Focal adhesions (basal)

Answer 15

Attach to basal lamina, uses actin and integrins, binds to fibronectin - then binds to collagen

Question 16

Integrins

Answer 16

Alpha beta dimer, dimers come together (focal adhesion kinase) to form stronger bonds (skin/blastocyst attachment to endometrium)

Question 17

Mucosal membrane

Answer 17

Lines moist and hollow internal organs of body, secretes mucus (thick), stop pathogens, lubricate, hydrate.

Question 18

3 examples of mucosal membranes

Answer 18

GI tract, Respiratory tract, Urinary tract

Question 19

Mucosal membrane layers

Answer 19

Epithelial, lamina propria, muscularis mucosae (submucosa, musclularis externa, serosa)

Question 20

Oesophagus structure layers

Answer 20

Epithelium - stratified squamous (withstand abrasion). Submucosa - contains mucus secreting glands (goblet cells) Muscularis externa - two layers (circular and longitudinal) allows food to be moved via peristalsis

Question 21

Stomach layers and structure

Answer 21

Epithelial mucosa - secretes acid, digestive enzymes, Rugae (folds increase SA). Muscularis externa - 3 layers (oblique, circular, longitudinal) allows mixing.

Question 22

Jejunum

Answer 22

Simple columnar epithelium. Pilcae circulares - folds of mucosa projects into gut lumen

Question 23

Large intestine

Answer 23

Crypts of lieberkuhn produce lots of mucus, surface epithelia absorb water and electrolytes

Question 24

Overall GI tract function

Answer 24

Absorb substances, prevent pathogen ingress, move contents and expel water

Question 25

How is the GI tract modified for its function

Answer 25

Folds of mucosa/ microvilli help substances be absorbed. Peristaltic actions from layers of muscularis externa allow for contents to be moved. Lamina propria connects to lymphatic system allowing prevention of pathogens.

Question 26

Urinary tract structure - epithelial

Answer 26

Squamous epithelial in bowman capsule, cuboidal in ducts.

Question 27

Where do muscle layers appear in urinary tract

Answer 27

Ureter and bladder - 2 layers (inner and longitudinal) allowing stability and control

Question 28

Epithelium in ureter and bladder

Answer 28

Uroepithelium (transitional) - produce mucus(protection from acidic urine) with tight junctions to prevent leakage.

Question 29

Bladder features

Answer 29

Fat acts as shop absorber, umbrella cells protect epithelium from acidic urine, transitional epithelium flatten when bladder is filled with urine.

Question 30

Urethra

Answer 30

Similar to bladder, mucus glands produce lots of sticky mucus to protect ingress of pathogens from outside of body.

Question 31

Urinary tract summary

Answer 31

Similar to GI tract - absorb nutrients, prevent pathogens (especially in lower), remove waste products

Question 32

Respiratory function and parts

Answer 32

Gas transport and exchange. 2 parts: conducting (nasal to bronchioles) and respiratory(bronchioles to alveoli)

Question 33

Trachea and primary bronchi mucosa

Answer 33

Epithelial - pseudo-stratified covered in cilia (moves debris and bacteria towards mouth). Lamina propria - thin. Muscularis Mucosae - no longitudinal

Question 34

Submucosa trachea and primary bronchi

Answer 34

Collagen and elastin fibres (connective tissue layer) seromucous glands (watery mucus secretions that thicken during infection)

Question 35

C shaped Hyaline cartilage

Answer 35

Two layers - perichondrium(collagen fibres), chrondrogenic (cartilage formed)

Question 36

Cartilage feature

Answer 36

Cells can interconvert between chrondroblasts and chondrocytes to make hyalin and elastic cartilage

Question 37

How is Resp tract different to GI and Urinary

Answer 37

No muscularis externa in respiratory

Question 38

Secretions from Trachea and bronchi

Answer 38

From epithelial and submucosa - mucins (sticky mucus) serum proteins (lubricate) lysozyme (destroys bacteria) anti proteases (inactivate bacterial enzymes)

Question 39

How is movement of debris aided in trachea

Answer 39

Mucociliary escalator - goblet cells and cilia. Thick basement membrane, lamina propria rich with immune cells, elastic fibres.

Question 40

Secondary and tertiary bronchi

Answer 40

Similar to primary(pseudostratified, ciliated, seromucous glands) but cartilage is not full circles of rings. Instead crescent shaped to keep airway open

Question 41

Alveolus structure

Answer 41

Flattened (squamous) specialised epithelial (endothelium), folds in basal lamina allow for expansion when air is drawn in. Connective tissue - Collagen and Elastin fibres allow recoil.

Question 42

What is definition of tissue

Answer 42

Collection of cells adapted for specific function

Question 43

4 types of tissue

Answer 43

Epithelial, connective(blood, cartilage, bone, fat), muscle, nerve

Question 44

What is an organ

Answer 44

Two or more tissues combined to create a structural unit that has a particular function

Question 45

3 cell types that are not part of organs

Answer 45

Ova, spermatozoa, corpuscles of blood

Question 46

What cells are derived from ectoderm

Answer 46

In contract with environment - nerve cells, skin.

Question 47

What cells derived from mesoderm

Answer 47

Muscle and connective tissue

Question 48

What cells are derived from endoderm

Answer 48

Mucosae - GI tract, respiratory tract