Week 1- Cells and Tissues

Question 1

State what layers E, D and SC are and how they appear in a histological image (Find card on Anki)

Answer 1

E- epidermis- darkly stained outer layer
D- dermis- thicker paler layer
SC- subcutis/hypodermis- very pale, almost clear layer

Question 2

Label the diagram ( skin structure saved to computer)

Answer 2

Saved to computer

Question 3

Briefly describe how the skin is involved in providing sensation

Answer 3

Network of nerve cells that detect and relay in changes in the environment (heat,cold, touch and pain)

Question 4

Define ‘amphipathic’

Answer 4

A molecule that has a polar and a non-polar end

Question 5

Define ‘cell’

Answer 5

Basic structural and functional unit of all living systems, consisting of an aqueous solution of organic molecules enclosed by a membrane

Question 6

Define ‘compound tissue’

Answer 6

A compound tissue is made up of cells that are structurally and functionally different- made up of multiple cell types

Question 7

Define ‘eukaryotic cell’

Answer 7

A cell with a nucleus and other membrane bound organelles

Question 8

Define ‘filipodia’

Answer 8

Very small spikes of microfilament based potrusions of plasma membranes based in cell motility

Question 9

Define ‘lamellipodia’

Answer 9

Microfilament based membrane protrusions that help cells move

Question 10

Define ‘magnification’

Answer 10

A measure of how much larger a microscope causes an object to appear in comparison to the actual size

Question 11

Define ‘metastasis’

Answer 11

Spread of disease producing agency (such as cancer cells) from initial or primary site of disease to another part of the body

Question 12

Define ‘organelles’

Answer 12

Sub-cellular structure in eukaryotic cells to compartmentalise specific cell function(s)

Question 13

Define ‘phospholipid’

Answer 13

A lipid made of a phosphate polar head group and two fatty acid chains (one saturated, one unsaturated)

Question 14

Define ‘resolution’

Answer 14

Smallest distance by which two points can be separated and still be distinguished as two separate entities/objects

Question 15

Define ‘section’

Answer 15

A 2D representation of a 3D object

Question 16

Define ‘tissues’

Answer 16

Group of similar cells working together to carry out a common function

Question 17

Define endocrine gland

Answer 17

Glands which have no duct system so release their contents directly into the blood stream and can act on distant tissues

Question 18

Define exocrine glands

Answer 18

Glands which secrete their contents directly onto an epithelial surface or via a duct

Question 19

Define organ

Answer 19

An organ is made up of several tissue types comprise in a morphologically recognisable structure which performs a specific set of functions

Question 20

Define prokaryotic cells

Answer 20

A cell with no membrane bound nucleus or organelles

Question 21

Define simple epithelia

Answer 21

Surface epithelia consisting of one layer

Question 22

Define simple tissue

Answer 22

A tissue that is made up of cells that are strucurally and functionally the same- one type of cell

Question 23

Define stratified epithelia

Answer 23

Epithelium consisting of two or more layers of cells

Question 24

Describe how antibiotics that target the peptidyl transferease centre on the large subunit work

Answer 24

Prevents polypeptide chain elongation

Question 25

Describe the 3 step process of how proteins get to the right location within a cell

Answer 25

1. Protein needs to be synthesised- process starts in the cystol (on ribosomes- multicomponent of complex of RNA and proteins)
2. Proteins are dispatched to different locations which is coded in their amino acid sequence
3. Correct address protein enters the organelle

Question 26

Describe the 3 step process of proteasomal degredation of ubiquitinated proteins

Answer 26

Shuttling proteins take ubiquitinated protein to proteasome
Tagged proteins recognised, unfolded and translocated
Degraded in proteasome to give peptides which are extruded and digested by cytosolic peptidases

Question 27

Describe the changes in epidermal keratinisation

Answer 27

Basal- scattered tonofilaments
Spinous- tonofibrils (keratin bundles)
Granular- keratohyalin granules
Corneum- keratin fibres

Question 28

Describe the lay out of the Golgi Apparatus

Answer 28

Cis cisternae - medial and trans cisternae- trans network

Question 29

Describe the location and function of keratinocytes in the epidermis

Answer 29

Location: Keratinised stratified squamous epithelium
Function: protection and barrier, vitamin D production

Question 30

Describe the location and function of stem cells in the epidermis

Answer 30

Location: stratum basale
Function: self renewal and repopulation of epidermal layers

Question 31

Describe the process of a protein entering a lysosome

Answer 31

Directed by a specific address label that is added in the Golgi Apparatus eg. mannose-6- phosphate
Proteins with new specific site chain bind to a specific receptor in the Golgi membrane
Initally go to an endosome which will mature to a lysosome
Endosome contains pathogenic material that has been endocytosed for the protein that has been targeted to destroy

Question 32

Describe the process of exocytosis from a transport vesicle

Answer 32

Proteins remain anchored to the ER membrane
Vesicles from the ER fuse with the plasma membrane

Question 33

Describe the process of the signal peptide going to the ER

Answer 33

Signal recognition particle in cystol binds to ER signal peptide when it is exposed on ribosome
SRP receptor embedded on ER membrane binds to the SRP
Polypeptide continues to be formed
Polypeptide is threaded through the translocon (protein channel) in ER membrane
Signal peptide is cleaved by signal peptidase
Protein enters into ER lumen and encapsulated into transport vesicle

Question 34

Describe the process of wound healing if only the epidermal layer has been damaged

Answer 34

Simple process of re-epithelialisation and cell migration
Keratinocytes losen cell-cell junctions from any available source eg. sebaceous glands and left over hair follicules
Keratinocytes migrate to the wound site and cover granulation tissue via two mechanisms ( leap frog method and train method)
They meet in the middle of this covering process

Question 35

Describe the process that occur during remodelling

Answer 35

Longest phase- can last several months
Granulation tissue is replaced by type 1 collagen which is stronger and organised into thick bundles which is extensively cross linked- produced by fibroblasts
Fibroblasts may differentiate into myofibroblasts which generate contractile force to close the wound
Granulation tissue becomes mature scar tissu

Question 36

Describe the structure of the dermis

Answer 36

A type of connective tissue
Composed of mostly fibroblasts, collagen type 1, elastin and other molecules that are reffered to as ground substances

Question 37

Describe the structure of the papillary layer

Answer 37

Loose and contains very fine interlacing collagen fibres
Most concentrated area of blood vessels

Question 38

Describe the structure of the reticular layer

Answer 38

Collagen bundles are stronger
Elastin fibres larger
Contains minimal blood vessels

Question 39

Describe what may occur with defective tight junctions

Answer 39

No gate:
Intestinal/renal permeability is disrupted
Hypomagnesaemia
Infections: enteric pathogens
Obesity
Coeliac disease
No fence:
Loss of polarity can cause cancer

Question 40

Discuss the layer of skin that isn’t always present

Answer 40

Stratum lucidium- only found in thicker layers of skin such as the palms of hands and soles of feet

Question 41

Draw the summary of protein pathways flow chart

Answer 41

Answer on computer