Week 1- Cells and Tissues Flashcards
State what layers E, D and SC are and how they appear in a histological image (Find card on Anki)
E- epidermis- darkly stained outer layer
D- dermis- thicker paler layer
SC- subcutis/hypodermis- very pale, almost clear layer
Label the diagram ( skin structure saved to computer)
Saved to computer
Briefly describe how the skin is involved in providing sensation
Network of nerve cells that detect and relay in changes in the environment (heat,cold, touch and pain)
Define ‘amphipathic’
A molecule that has a polar and a non-polar end
Define ‘cell’
Basic structural and functional unit of all living systems, consisting of an aqueous solution of organic molecules enclosed by a membrane
Define ‘compound tissue’
A compound tissue is made up of cells that are structurally and functionally different- made up of multiple cell types
Define ‘eukaryotic cell’
A cell with a nucleus and other membrane bound organelles
Define ‘filipodia’
Very small spikes of microfilament based potrusions of plasma membranes based in cell motility
Define ‘lamellipodia’
Microfilament based membrane protrusions that help cells move
Define ‘magnification’
A measure of how much larger a microscope causes an object to appear in comparison to the actual size
Define ‘metastasis’
Spread of disease producing agency (such as cancer cells) from initial or primary site of disease to another part of the body
Define ‘organelles’
Sub-cellular structure in eukaryotic cells to compartmentalise specific cell function(s)
Define ‘phospholipid’
A lipid made of a phosphate polar head group and two fatty acid chains (one saturated, one unsaturated)
Define ‘resolution’
Smallest distance by which two points can be separated and still be distinguished as two separate entities/objects
Define ‘section’
A 2D representation of a 3D object
Define ‘tissues’
Group of similar cells working together to carry out a common function
Define endocrine gland
Glands which have no duct system so release their contents directly into the blood stream and can act on distant tissues
Define exocrine glands
Glands which secrete their contents directly onto an epithelial surface or via a duct
Define organ
An organ is made up of several tissue types comprise in a morphologically recognisable structure which performs a specific set of functions
Define prokaryotic cells
A cell with no membrane bound nucleus or organelles
Define simple epithelia
Surface epithelia consisting of one layer
Define simple tissue
A tissue that is made up of cells that are strucurally and functionally the same- one type of cell
Define stratified epithelia
Epithelium consisting of two or more layers of cells
Describe how antibiotics that target the peptidyl transferease centre on the large subunit work
Prevents polypeptide chain elongation
Describe the 3 step process of how proteins get to the right location within a cell
- Protein needs to be synthesised- process starts in the cystol (on ribosomes- multicomponent of complex of RNA and proteins)
- Proteins are dispatched to different locations which is coded in their amino acid sequence
- Correct address protein enters the organelle
Describe the 3 step process of proteasomal degredation of ubiquitinated proteins
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
Describe the changes in epidermal keratinisation
Basal- scattered tonofilaments
Spinous- tonofibrils (keratin bundles)
Granular- keratohyalin granules
Corneum- keratin fibres
Describe the lay out of the Golgi Apparatus
Cis cisternae - medial and trans cisternae- trans network
Describe the location and function of keratinocytes in the epidermis
Location: Keratinised stratified squamous epithelium
Function: protection and barrier, vitamin D production
Describe the location and function of stem cells in the epidermis
Location: stratum basale
Function: self renewal and repopulation of epidermal layers
Describe the process of a protein entering a lysosome
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
Describe the process of exocytosis from a transport vesicle
Proteins remain anchored to the ER membrane
Vesicles from the ER fuse with the plasma membrane
Describe the process of the signal peptide going to the ER
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
Describe the process of wound healing if only the epidermal layer has been damaged
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
Describe the process that occur during remodelling
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
Describe the structure of the dermis
A type of connective tissue
Composed of mostly fibroblasts, collagen type 1, elastin and other molecules that are reffered to as ground substances
Describe the structure of the papillary layer
Loose and contains very fine interlacing collagen fibres
Most concentrated area of blood vessels
Describe the structure of the reticular layer
Collagen bundles are stronger
Elastin fibres larger
Contains minimal blood vessels
Describe what may occur with defective tight junctions
No gate:
Intestinal/renal permeability is disrupted
Hypomagnesaemia
Infections: enteric pathogens
Obesity
Coeliac disease
No fence:
Loss of polarity can cause cancer
Discuss the layer of skin that isn’t always present
Stratum lucidium- only found in thicker layers of skin such as the palms of hands and soles of feet
Draw the summary of protein pathways flow chart
Answer on computer
