Week 1 Flashcards
(189 cards)
1
Q
=What are the three main functions of skin and examples?
A
2
Q
What is peripheral circulation?
A
Transport of blood around the body allowing the exchange of nutrients in tissues
3
Q
Label this diagram:
A
4
Q
What is the function of the arrector pili?
A
Connected to hair follicle, when contracted causes hair to stand on end creating goosebumps
5
Q
What is the eccrine gland?
A
Major sweat gland abundant in palms and soles.
6
Q
What is the dermal papilla of the hair follicle?
A
Main source of blood for hair follicle, delivers oxygen/nutrients
7
Q
What is the hair follicle composed of?
A
Several layers of epithelial cells
8
Q
Four layers of the epidermis?
A
Stratum basale, spinosum, granulosum and corneum.
9
Q
What is the basement membrane composed of?
A
Extracellular matrix proteins.
10
Q
S+F of stratum basale?
A
Cuboidal, mitotically active stem cells that regenerate other layers of epidermis.
11
Q
Structure of stratum spinosum?
A
Layer of keratinocytes rich in desmosomes giving spiny appearance.
12
Q
S+F of stratum granulosum?
A
Flattened cells contain keratohyalin granules which aggregate keratin filaments
13
Q
Structure of stratum corneum?
A
Flattened cells that have lost their nuclei with keratin and lipids.
14
Q
Function of lipids in epidermis?
A
Act as water barrier
15
Q
Where is stratum lucidum found?
A
Only in thick skin e.g. soles of feet
16
Q
How often is skin shed?
A
1x month
17
Q
How is each layer of epidermis formed?
A
Daughter cells from basal layer migrate upwards and differentiate to form each layer
18
Q
What changes in each layer of epidermis?
A
Type and amount of keratin produced
19
Q
How many keratin types are there?
A
30
20
Q
What is the structure of the dermis?
A
Connective tissue, fibroblasts and immune cells
21
Q
What is connective tissue made up of?
A
Collagen type I, elastin and ground substance
22
Q
Function of fibroblasts?
A
Produce collagen and elastin
23
Q
What fibres allow stretch and what fibres allow tensile strength?
A
Stretch: elastin
Tensile: collagen
24
Q
What are the structures of the two dermal layers?
A
Papillary: thinner and looser, fine collagen fibres, most blood vessels and nerves
Reticular: thicker stronger fibres
25
Functions of dermo-epidermal junction?
- attachment of epidermis to dermis
- aligns cells of epidermis
- base for re-epithelialization in wound healing
- barrier function to and from epidermis
26
Structure and function of subcutis?
Adipose tissue
Energy source, shock absorption, insulation
27
Function and location of meissner's corpuscles?
Mechanoreceptors for touch, papillary dermis of hands and feet
28
Function and location of Pacinian corpuscles?
Detect deep pressure and vibration, subcutis
29
What are adnexal structures?
Hair, nails, glands
30
What are eccrine glands, location?
Sweat glands, everywhere except nails/lips
31
What are apocrine glands, location?
Scent glands, axillae and genitals
32
What are sebaceous glands, location?
Produce sebum, everywhere except palms/soles
33
What type of epthelium is the epidermis?
Stratified squamous keratinised
34
Function of keratinocytes?
Protection/barrier against foreign substances, vit D production
35
Function/location of merkel cell?
Strat basale, sensation
36
Function/location of langerhans cell?
Epidermis, denditic cell (antigen presentation/phagocytosis)
37
How do langerhans cell long processes aid function?
Help detect foreign antigens
38
Function of melanocyte?
Protects from radiation
39
Results of chronic UV exposure?
Loss of skin elasticity/fragility
Abnormal pigmentation
Wrinkles
40
How does melanocytes work with keratinocytes to protect cells from UV damage?
Melanin is transferred into keratinocytes via cytoplasmic processes and protects nucleus from UV damafe
41
What are three keratohyalin granules?
Profillagrin, involucrin, loricrin
42
Function of profilaggrin?
Converted to filaggrin which aggregates keratin into tight bundles
43
Function of involucrin?
Forms cell envelope around corneum cells
44
Function of loricrin?
Cross links to involucrin
45
Function of lymphocytes?
Immunosurveillance
46
Function of mast cells?
Produce inflammatory mediators e.g. histamine and chemotactic factors
47
Which molecules hydrate the dermis?
Proteoglycans, glycosaminoglycans
48
What is a wound?
Breakdown in protective function of the skin, loss of epithlium continuity with/without loss of underlying connective tissue
49
What is an erosion injury?
Only epidermis lost
50
What is an ulceration injury?
Structures deep to epidermis
51
What is a partial thickness injury?
Epidermis and some dermis
52
What is a full thickness wound?
Epidermis, dermis and deeper structuresm only wound edge cells left
53
What cells are involved in wound healing?
Inflammatory cells, keratinocytes are replaced, fibroblasts, endothelial cells for angiogenesis
54
How long is each phase of wound healing?
Inflammation: 24-48 hrs
Proliferative: 4-21 days
Remodelling: several months
55
What happens in the inflammatory phase?
Platelets initiate hemostasis/blood clot and healing cascade and attract neutrophils/macrophages to site
56
Function of neutrophils/macrophages in wound healing?
Phagocytsoe dead tissue and microorganisms
57
What happens in proliferative phase?
58
What cells are involved in the proliferative pgase?
Keratinocytes: reepithelialsation
Fibroblasts: ecm formation
Endothelial cells: angiogenesis
59
2 methods of keratinocyte migration?
60
What happens in the remodelling phase?
Granulation tissue become mature scar tissue, collagen cross linked to form mature scar, switch from type III to type I collagen
61
Function of epidermal growth factor signal?
Re-epithelialisation (keratinocyte proliferation and migration)
62
Function of platelet derived growth factor signal?
Matrix formation (inc number and activiy of fibroblasts)
63
Function of vascular endothelial growth factor signal?
Angiogenesis (endothelial cell proliferation and migration)
64
What 3 molecules signal inflammation?
IL-1, IL-6, TNF
65
Local factors affecting wound healing?
Infection, foreign body, oxygenation, vascular supply
66
Systemic factors affecting wound healing?
Age, disease, alcohol/smoking, obesity, medication
67
What is the definition of cells?
Basic structural and functional unit of all living organisms
68
What are the three points of cell theory?
1. all living things are composed of one/more cells
2. cells are basic unit of life
3. new cells arise from pre-existing cells
69
What is cytosol?
Intracellular fluid of cytoplasm
70
What is tissue defined as?
Groups of similar cells working together to carry out common function
71
What is parenchyma?
Working tissue
72
What is stroma?
Scaffold and nutritional tissue
73
What is an organ defined as?
Several tissue types comprised in morphologically recognizable structure performing specific set of functions
74
What is tissue composed of?
cells +ECM
75
Four types of tissue and function?
Connective: supports and protects e.g. fat, blood
Epithelial: covers/lines body surfaces
Muscle: cells contract to generate force
Nervous: generate electrical signals in response to environment
76
Four stages of tissue processing?
Fixation, embedding, sectioning, staining
77
How are tissues fixated and why?
Freezing with dry ice/nitorgen or chemically with aldehyde
Preserves the tissue
78
How are tissues embedded and why?
Frozen samples or paraffin wax
Provides support when sectioning
79
How are tissues sectioned?
Microtome
80
What type of dye is haemotoxylin?
Basic so stains negatively charged structure bluish purple e.g. nucleus
81
What type of dye is eosin?
Acidic so stains positively charged structures reddish pink e.g. cytopkasm
82
What is PAS stain used for?
Staining complex carbohydrates and glycogen e.g. mucus, basement membranes, brush borders of intestines
83
How do lipids stain?
Optically empty
84
Why is electron microscopy used over light microscopy sometimes?
Electron microscopy is used to see very small structures and has increased resolution
85
Functions of epithelial tissue?
Covers and protects body surfaces
Lines internal cavities, blood vessels, respiratory and reproductive organs
86
Function of covering epithelia?
Covers/lines all body surfaces, cavities, tubes
87
Function of glandular epithelia?
Secretory epithelial
Produces and releases secretory products: sweat, saliva, mucus, digestive enzymes, hormones etc.
88
How do exocrine glands secrete?
Via duct, retain continuity w/ surface
89
How do endocrine glands secrete?
Into bloodstream, lose contact with surface
90
Where is simple squamous epithelia found? Function?
Blood vessel/heart lining
Alveoli
Lining of kidney tubules
For diffusion/filtration
91
Location/function of simple cuboidal epithelium?
Kidney tubules, glands, terminal bronchiole lining
Diffusion/secretion
92
Location/function of simple columnar epithelium?
Glands, bronchioles, auditory tubes, uterus, stomach
Movement of substances, absoprtion
93
Function/location of stratified squamous epithelium?
94
Structure/function/location of pseudostratified epithelium?
95
Structure/function/location of transitional epithelium?
96
What are intracellular processes?
Processes that take place within a cell
97
What are two strategies to segregate molecules?
Multicomponent complexes e.g. ribosome
Compartmentalization into organelles
98
What are organelles?
Cellular subunit performing specific function in cell
99
Where are proteins synthesised?
In cytosol on ribosomes
100
What is ribosome composed of?
Proteins and rRNA , two subunits
101
What is svedberg?
Non-linear measurement measuring sedimentation rate (how quickly it will settle at the bottom after centrifugation)
102
Why is ribosome main antibiotic target of bacterial cell?
It is larger than human ribosome so easy target: bacteria will die if it cannot make more proteins
103
3 methods of proteins imported into organelles?
Nuclear pores: selective gates for nuclear proteins
Protein translocators: for proteins moving from cytosol to ER, mitochondria, peroxisomes
Transport vesicles: for proteins moving from ER onwards
104
How do ribosomes know to go to the ER?
signal peptide on protein being made
105
What is a signal peptide?
Specific sequence on N-terminal amino acid.
106
How is the signal peptide guided to the ER?
Signal recognition particle in cytosol binds to signal peptide
107
What do vesicles that carry proeteins from ER to golgi become?
Fuse to become cis cisterna
108
What happens as proteins move through golgi stack?
Undergo enzymatic modification
109
Function of phosphorylation?
Alters activity of protein
110
Function of acetylation?
Regulates gene expression in histones
111
Function of farnelysation?
Targets proteins to cytoplasmic face of plasma membrane
112
Function of ubiquitination?
Targets protein for degregation
113
When is protein degregation required?
Faulty proteins, proteins past sell by date, foregn proteins
114
Two methods of protein degradation?
Lysosomal degradation
Proteasomal degradation
115
What are the two outcomes for transport vesicles in golgi apparatus?
Exocytosis: vesicles from ER fuse with plasma membrane
Endocytosis: mannose-6-phosphate address label targets them to become endosome then matures to lysosome
116
What is lysosomal degregation carried out by and activated by?
Lysosomal enzymes e.g. lipases/proteases
Lysosomal acidic environment
117
When is lysosomal degregation used?
Proteins with long half life >20 hrs
Mmebrane proteins
118
Where does proteasomal degregation happen? Dependent on?
In cytosol at proteasomes
ATP
119
What is proteasomal degregation used for?
Proteins with short half life
120
What is the nuclear lamina?
Strong Mesh that supports nuclear membrane
- organises nucleus and chromatin
121
What is chromatin?
DNA combined with histone proteins
122
What is the nucleoleus function?
Site of rRNA and ribosome synthesis
123
Which things can you view under a light microscope?
Eukaryotes, bacteria, organelles
124
Which things can you view only under electron microscope?
Virus, proteins lipids
125
Which organeles are not membrane bound?
Ribosomes
126
Size of prokaryotic vs eukaryotic cells?
Pro: 1-10 microns
Eukaryote: 5-100 microns
127
Organelle definition?
Subcellular structures that carry out different functions
128
Where are nuclear pores found, function?
Nuclear membrane
Allows certain molecules to pass through
129
Nucleus functions?
Chromosomes replicated
Genetic information found
Dna transcribed into RNA
130
Function of plasma membrane?
Regulates what moves in and out of cell
Detects signals from outside of cells
131
Function of cholesterol in plasma membrane?
Maintains fluidity of membrane
132
Function of carbohydrates in plasma membrane?
Stabikises membrane and maintains fluidity
133
Function of lipid rafts in plasma membrane?
Cholesterol rich
Concentrate proteins and signalling receptors for specific functions
134
Where are proteins for energy production found in mitochondria?
Genome
135
What is the structure and function of the inner membrane of mitochondria
Cristae: invaginate cell to increase surface area
136
Function of mitochondria?
ATP production and apoptosis
137
Which 3 ways does mitochondria produce ATP?
- krebs cycle
- electron transport chain
- oxidative phosphorylation
138
Which molecules does the electron transport chain require?
Cytochrome c
139
How is apoptosis initiated in the mitochondria?
cytochrome c is released from mitochondria into cytosol
140
Functions of RER?
- protein synthesis
- protein folding
- protein modifications
141
Functions of SER?
- lipid synthesis
- ca storage
142
Structure + Function of lysosomes?
- degrade unwanted molecules
50 degregative enzymes - acid hydrolyses
pH 5
143
Structure + Function of peroxisomes?
- membrane bound organelle
- biochemical reactions
- oxidative enzymes e.g. catalase
- breakdown fatty acids
144
Examples of reasons to localise different functions of the cell?
cytochrome c in mitochondira
lysosome degregation
peroxisome
145
Glycocalyx structure and function ?
-layer of carbohydrate covering cells
- cell recognition
- prominent in gut
146
Which molecules determine ABO blood grouping?
carbohydrates
147
Four compartments of mitochondria?
Outer membrane
Inner membrane
Matrix
Intermembrane space
148
Function of mitochondria outer membrane?
selective permeability
149
Function of mitochondria inner membrane ?
Electron transport chain
150
Function of mitochondria matrix?
Enzymes for citric acid cycle
151
Function of mitochondria inter membrane space?
location of cytochrome c
152
Functions of the cytoskeleton?
Organises cell structure
Maintains cell shape
Supports plasma membrane
Allows organelle movement
Allows growth, division, motility
153
Three types of cytoskeleton?
- microtubules
- microfilaments
- intermediate filaments
154
Function of intermediate filaments?
Provide strength and structure in a cell
155
Examples of intermediate filaments?
Keratin in skin epithelial cells
Vimentin in fibroblasts
Lamins in nuclei of eukaryotes
156
Structure + Functions of microtubules?
Constantly assembling and disassembling
A and b tubulin
Cell movement, intracellular organelle transport, mitotic spindle
157
How do microtubules move organelles intracellularly ?
Kinesins: move cargo away from centrosome
Dyneins: move cargo towards centrosome
158
Structure and Function of axonomes?
Microtubule and dynein composition
Cytoskeletal component of cilia and flagella
Allow bending
159
Composition of microfilaments?
polymers of actin
160
Functions of microfilaments?
Cell projections: microvilli, stereocillia
Cytoplasm: cell contraction, shape change
Membrane extensions for motility: lamellopodia, filopodia
Contractile ring: cytokenesis
161
Functions of cell junctions?
Connect plasma membrane to adjacent cells, basement membrane, cytoskeleton of other cell
162
Functions of anchoring junctions?
Anchor cells to other cells or the ECM
163
Which junctions are cell-cell junctions?
Adherens, desmosomes
164
Which type of cytoskeleton is adherens and focal adhesions?
actin
165
Which junctions are cell-ecm junctions?
Focal adhesions, hemidesmosomes
166
Which type of cytoskeleton is desmosomes and hemidesmosomes?
intermediate filaments
167
Function of gate in tight junction?
Regulates paracellular permeability (what can enter cell)
168
Function of fence in tight junction?
Forms apical and basolateral inter membrane diffusion barrier
169
Which type of junction is paracellular?
tight
170
Function of GAP junctions?
Allows passage of small molcules
171
Structure of GAP junctions? Where are they found?
cell-cell contact
hexamers and connexins
cardiac tissue
172
Which structures are composed from microtubules?
Flagella and cillia
173
Function of hepatocytes?
Liver cells
Lipid biosynthesis
174
Location and function of leydig cells?
Testes
Steroid hormone biosynthesis
175
Which molecule do muscle cells rely on?
Calcium
176
What is epidermolysis bullosa?
Defects in hemidesmosome
Causes fragile skin
Skin blistering, tearing upon touch
177
What is kartegeners syndrome?
Defective cilia - effects mucus clearance, circulation of CSF and fertility as sperm aren't motile
178
How are microtubules stabilised?
Presence of proteins tat bind to them
179
Effect of Tau protein not being present in microtubules?
Alzheimers
Microtubules dissassemble
180
What is tay-sacks disease?
Mutation in genes that encode lysosomal enzymes
Genetic
build up of gangliosides in brain and spinal cord
181
Where is E-cadherin found?
Adherens junction
182
What happens when adherens junctions are defective?
Cancer as E-cadherin is lost so carcinomas can metastasise
183
Function of tight junctions and where are they found?
barrier - selectively permeable, cell polarity
epidermis
184
What are tight junctions composed of?
Claudins
185
What are adherens junctions composed of?
cadherins
186
What are desmosomes composed of?
desmosomal cadherins
187
What are focal adhesions and hemidesmsomes composed of?
integrins
188
What cytoskeleton does focal adhesions have?
actin
189
