TOPIC 3 Flashcards
(113 cards)
1
Q
Is skin an organ
A
Yes
2
Q
Looking at diagram How can you distinguish the glands?
A
Eccrine sweat gland it the worm looking duct, Subaceous gland is lumpy protrusion on follicle
3
Q
What are the layers on the basic skin diagram
A
epidermis,
dermis ( papillary and reticular-made up of dense irregular connective tissue),
subcutaneous tissue ( hypodermics- not part of skin SUB= under)
4
Q
What are the yellow wirey things and spirals on skin diagram?
A
Wirey things nerve endings
Spirals lamellar corpuscles
5
Q
Does the epidermis have a blood supply?
A
No but Dermis has blood supply
6
Q
Does dermis layer have blood supply
A
Dermis has blood supply epidermis does not
7
Q
Does subcutaneous tissue have blood supply?
A
Subcutaneous tissue has a lot of blood supply
8
Q
Layers of epidermis in order deep to superficial
A
‘BSGLC- Beck said go little caterpillar ‘
Stratum basale- produces keratinocytes
Stratum spinosum- Several cell layers thick, with intermediate filaments, keratinocytes and dendritic (Langerhans) cells
Stratum granulosum- consists of one to five cell layers in which keratinocyte appearance changes drastically, and the process of keratinization (in which the cells fill with keratin) begins. These cells flatten, their nuclei and organelles begin to disintegrate, and they accumulate keratohyaline and lamellar granules.
( stratum lucidem -only I thick skin Eg. Palms, soles, fingertips. thin, translucent band consisting of a few rows of flat, dead keratinocytes.)
Stratum corneum - consists of many layers of dead, keratin filled cells.
9
Q
Cells of the epidermis?
A
Keratinocytes which produce keratin.
melanocytes which produce melanin pigment.
dendritic cells which patrols around and look for anything that shouldn’t be there and alert the immune system.
Merkel/ tactile cells also there which detect touch
10
Q
which layer of the epidermis are keratinocytes too far from the dermal capillaries to survive?
A
Stratum granulosum
11
Q
Characteristics of the dermis?
A
friction ridges which are genetically determined.formed in uterus by baby moving around.
Cleavage lines- seperations between underlying collagen fibre bundles in the reticular dermis
Flexure lines from where dermis is closely attached to the underlying structures
12
Q
Cutaneous glands in dermis
A
Eccrine sweat glands
Apocrine sweat glands
Sebaceous glands
13
Q
Eccrine sweat glands function and secretion type/ method / location
A
Eccrine sweat glands - Seperate to hair follicle
function: temperature control, some antibacterial properties
Type of secretions: hypotonic filtrate of blood plasma
Method of secretion: merocrine (exocytosis) at skin surface
Body location- everywhere especially palms, soles and forehead
14
Q
Apocrine sweat glands function and secretion type/ method / location
A
apocrine-attached to hair follicle
Function: may act as sexual scents
Type of secretions: filtrate of blood plasma with added proteins and fatty substances
Method of secretion: merocrine ( exocytosis)
Secretions exiting duct at… usually upper part of hair follicle; rarely, skin surface
Body location: mostly auxiliary and anogenital regions
15
Q
Sebaceous glands function and secretion type/ method / location
A
Functions- lubricants skin and hair, helps prevent water loss, antibacterial properties
Type of secretions: sebum ( an oily secretion) holocrine, with secretions exiting duct usually at upper part of hair follicle; sometimes, skin surface
16
Q
Functions of skin?
A
protection physical ( lots of skin layers, keratinocytes) and chemical barriers ( acidic nature of sweat, chemicals in sebum and sweat. That acts like natural antibiotics)
Temperature regulation- sweat, piloerection -hair standing up
Sensation- touch ( Merkel cell, receptors on hair) , vibration (lamellar corpuscles), pain (nerve endings)
Metabolic function- converting modified epidermal cholesterol to a vitamin D precursor important to calcium metabolism , steroid hormones
Blood reservoir- shunting due to vasoconstriction
Excretion- nitrogen waste products
17
Q
Types of microorganisms/ pathogens?
A
Bacteria
Fungi
Protozoa- single cell organisms
Helminths ( worms)- pretty large and can be seen with the human eye
Viruses
Prions tinyyyyyyy and very rare so don’t need to know in much detail
18
Q
T or f, most microorganisms in body are beneficial
A
True
87% beneficial, 10% are opportunistic ( cause disease if given an opportunity), 3% pathogenic ( can cause disease in a healthy person)
19
Q
What is virulence?
A
capacity to cause disease
20
Q
What is resident flora
A
Flora residing/ living in body, replicating etc
21
Q
What are transient flora
A
come across by touching others, soil and environment. Usually don’t replicate. They come and go but if they start replicating and decide to become resident it is called COLONISATION
22
Q
How are bacteria named
A
Shape, colour
Shape, location
Who discovered it, location
23
Q
T or false, species can have different strains, some good some bad?
A
True
24
Q
Are bacteria prokaryotes or eukaryotes?
A
Prokaryotes, they have no nucleus
25
Do bacteria have a cell wall
Yes, some also have a capsule
26
How can bacteria protect themselves from hostile environments?
Can form an endospore which is like a copy of the bacteria within the bacteria that can survive tough hostile conditions
27
Different cell shapes include...
Cocci Eg. Staphylococcal
Rods Eg. E. coli
Spiral
28
Difference between gram positive and negative bacteria
Gram positive - have thick double wall/ peptidoglycan, pick up colour and show as purple/ violet in dye
Gram negative - have thin peptidoglycan, show pink/ red in dye
29
Importance of knowing whether gram positive or negative
Significant as if we want to treat a patient, we need to find what sort of bacteria we are dealing with as some antibiotics work better for gram positive and some work better for gram negative.
30
Bacteria ‘growth cycle’
Bacteria multiply very quickly, then go into stationary stage ( as only so many nutrients) then start dying off when they’ve run out of nutrients
31
Factors that help bacteria grow?
water, they are temperature dependant ( depending on the type of bacteria), they like specific PH ( depending on the bacteria), specific pressure, oxygen for some/ no oxygen for some
32
What are fungi?
yeasts
Mould
Mycosis
Can happen in various areas of the body.
Eg. Athletes foot
33
What are Protozoa
Protozoa
single cell organisms
Have a nucleus (eucaryote)
Eg. Malaria
34
What are helminths
Helminths
tapeworm
Roundworms
Many types, weird life cycles, can cause a lot of damage but easily treatable
35
What are viruses?
Viruses
RNA or DNA as genetic material
Can not replicate or synthesise proteins by themselves
Need a host cell to replicate
Many different ones Eg. Influenza, HIV, hepatitis
Some preventable with vaccinations
Viruses do not react to antibiotics
Most respiratory tract infections are viral
Host cells are SPECIFIC most of the time
36
What is the chain of infection
1. Aetiological agent (Microorganism)
2. Reservoir (Source)
3. Portal of exit from reservoir
4. Method of transmission
5. Portal of entry to the susceptibile host
6. Susceptible host
All steps required for an infection to occur
37
Factors increasing susceptiblity to infection
Age- young and old
Hereditary - genetic predisposition and race
Stress- cortisol release, altered immune response
Nutrition- micronutrient deficiency and metabolic derangement
Treatment- immunodeficiency drugs and breaching defensive barriers
Disease- altered immune response and metabolic derangement
38
Methods of transmission of communicable disease
Direct- skin to skin touch, droplets, vertical ( mother to baby)
Indirect- airborne, vehicle Bourne( finite transmission), vector Bourne- mechanical( agent doesn’t multiply of undergo any change in vector) or biological ( agent undergoes change in vector)
39
Standard precautions of infection control
```
hand hygine
PPE when risk of bodily fluid exposure
Use and dispose of sharps safely
Perform routine environmental cleaning
Clean and reprocess shared patient equipment
Respiratory hygine and cough etiquette
Aseptic technique
Handle and dispose of waste and used linen safely
```
...Standard precaution assumes that every patient is infectious ...
40
5 moments of hand hygine
5 moments of hand hygine
Before touching patient ( including file)
Before procedure.
After procedure or body fluid exposure risk
After touching a patient
After touching a patients surroundings
41
What is a Parasite relationship?
one partner benefits from the other one.
| Parasites are different to normal flora
42
What is colonisation
Colonisation: microorganisms are multiplying on host but not causing disease
43
What is chronic infection
Chronic infection - slow and not eliminated
44
What is a Mutualistic relationship
- both partners benefitting
| Eg. Normal flora feed from you who’s also defending you
45
Is the immune system an anatomical system or a functional system
Immune system is not an anatomical system but is a functional system
46
2 big divisions of the immune system
innate / non specific defences and adaptive / specific defences
47
Innate non specific divisions innate...
Surface and internal barriers
48
Surface barriers include...
skin Eg. Acidic sweat with low PH and natural antibiotics ( defensins), dermcidin, cathelicidins
Mucus membranes Eg. Sticky mucus producing goblet cells, cilia
49
Internal fences innate defences include?
phagocytes
Natural killer cells
Inflammation
Antimicrobal proteins
Fever
50
Adaptive specific immunity divisions include...
humoral immunity ( B cells)
Cellular immunity ( T cells)
51
What does innate defences target
Anything foreign as non specific
52
What do adaptive defences target?
Specific antigens
53
What is the phagocytes mobilisation process?
leukocytosis- neutrophils enter blood from bone marrow (increased no. Of WBC in blood)
Marginalisation -neutrophils Cling to capillary wall
Diapedesis- neutrophils flatten and squeeze out of capillary walls to go to place of injury
Chemotaxis- neutrophils follows/ are attracted by chemical trail to site of injury and start phagocytosis
54
What is a neutrophil?
A neutrophil is a type of phagocyte and are a white blood cell,
55
What are macrophages?
- Large very efficient phagocyte
- free macrophages that travel around the various tissues,
- resident macrophages that live in specific organs all the time,
- They are a specific type of white blood cell that derives From monocytes, turning into macrophages when they leave the blood stream.
- Destroy microorganisms by digesting them with the help of lysosomes
56
What are natural killer cells
- destroy intruders by use of chemicals that induce cell death
- Recognise and eliminate cells infected with viruses and some function in eliminating cancer cells
- attack cells that lack ‘self’ cell surface receptors (MHC proteins) by Inducing apoptosis
- Secrete chemicals that enhance inflammatory response
57
How do killer cells recognise non self infected cells and eliminate them?
Killer cells recognise infected cells by activation receptors being matching with cancer cells.
They don’t target body cells as body cells recognize inhibiting receptors on the natural killer cells.
58
What happens in inflammation?
- Tissue injury triggers host of inflammatory mediators/ chemicals
1) arterioles will dilate so there is increased blood flow causing heat and redness
2) increased permeability of vessels means more fluid with nutrients and protein to needed site , can cause swelling. Some of fluid is also clotting proteins = stop bleeding
3) attract neutrophils, monocytes and lymphocytes to area ( chemotaxis)
- Pain is mainly from prostaglandins
Inflammation helps...
role of preventing spread of further damaging antigen
Get rid of dead pathogens
Alerts adaptive immune system and sets the scene for further healing
59
What is the first stage of healing?
Inflammation is first stage of healing
60
What are the types of antimicrobal proteins
Cytokines and the complement system
61
What are are cytokines?
Cytokines- group of antimicrobial proteins that includes.. interferons, interleukins, tumblr necrosis factors
Cytokines are chemical signals that guide your immune system. Cytokines they themselves are not really involved in the killing, they guide. They have two functions 1) they boost (increase) your immune system Eg. Increase no. Of white blood cells 2) they will coordinate the attack.
62
What are interferons?
A type of cytokines...
Interferons- protect against viral infections
....interferon alpha & beta- is released into Extracellular space and can attach to specific receptors in neighbouring cells alerting them that their is a virus around. Alerted cells, then put antiviral proteins on the cell wall that will block viruses from entering
....gamma interferons- increases activity of macrophages)
63
What are interleukins?
Type of cytokines...
Interleukins are produced by T cells,
are inflammatory mediators pro inflammatory ones and anti inflammatory ones
They activate CD8 T cells which proliferate/ produce into cytotoxic T cells
which target viral infected cells. They also activate plasma cells (
antibodies)
64
What are tumor necrosis factors?
Type of cytokines...
| tumor necrosis factors alpha- inflammatory mediators
65
What is the complement system?
system that can be activated in various ways and is a cascade of various changes usually enzyme related changes of proteins changing shape and doing different things.
It causes... causes opsonisation
It activates/ forms... the membrane attack complexes
66
What is opsonisation?
Coating of antigen with compliment proteins to enhance phagocytosis.
pathogens (particularly bacteria) that have entered out bodies and have cell wall characteristics making it difficult for our body to recognise get coated by complement system with proteins, showing it off to our immune system as foreign stuff
67
What are the membrane attack complexes?
Compliment system activates/ forms the membrane attack complexes, which infiltrate the cell wall of infected cells. Macs will form a big hole allowing a lot of water in so the cell swells and destroys itself
68
What does fever do?
Enhance the immune response
69
What are The General concepts of all adaptive defences
General concepts of all adaptive defences
- specificity
- Diversity
- Memory
- Antigens
- Cells off the immune system (lymphocytes)- B cells, T cell ( effector and memory)
- Antigen presenting cells ( APCs)+ macrophages and dendritic cells
70
What does it mean to say adaptive defences are specific?
They respond to specific antigens and allow the immune response to discover what is body owned and what foreign things it’s dealing with
71
What does it mean to say adaptive defences are diverse?
It can react to millions of different antigens and in theory can react to all of them
72
What does it mean to say that Adaptive immune systems have memory?
If a specific antigen comes into the body, subsequent responses will happen muchhh faster and has specific cells in place that will react straight away
73
What does the immune system respond to?
Antigens
74
What are the basic 2 categories for cells of the adaptive immune system?
(lymphocytes)- B cells, T cell ( effector and memory)
Specific cells involved
Effectors- do something or memory recognise antigens
Memory- remember antigens for secondary exposures
75
What are types of antigen presenting cells?
Dendritic cells ( mostly)
Macrophages
Some B cells
76
What are Major Histocompatibility complex (MHC) proteins
Flag/ signal on each cell in our body that help our body’s tell what is our own body cells and what isn’t.
- cell surface proteins ( glycoproteins), like little pockets
- May present ‘self’ or ‘foreign’ antigen
- Helps immune system to detect ‘foreign’
- Class 1 and 2
- an infected cell would display something ,on MHC proteins , from the infected cell and signal to immune system that it is foreign and infected.
- class 1 MHC proteins are found on every cell in the body apart from red blood cells
- class 2 are not common and usually only found on B cells and antigen presenting cells
77
What is an antigen?
- Foreign substance in the body that causes an immune response.
- can be Complex or incomplete ( hapten- difficult for immune system to detect and may bind to other proteins to be recognised in body)
- can have Immunologenicity- ability to stimulate lymphocytes
- can have Reactivity- ability to be affected by the immune response Eg. Bind to antibodies
78
What is a hapten?
Tiny molecule but it does not cause an immune response by itself alone. Eg. Most vaccines are hapten ( hapten+ protein= makes it large making it cause an immune response)
79
What are antigen presenting cells?
- Antigens need to be shown to cells of adaptive immune system in order to be acted on
- dendritic cells, macrophages and B lymphocytes
- work by Internalising antigens via phagocytosis, Travelling to lymph nodes and Presenting an antigen fragment ( determinant) on their own MHC proteins to T lymphocytes
80
Lymphocyte ‘ cycle’?
Lymphocytes ( white blood cells)
1) Origin- red bone marrow
2) Maturation- T lymphocytes mature in thymus, B cells mature in red bone marrow. Develop immune competency ( know what so t of antigen they are suppose to identified- genetically determined) and learn how to recognise self from foreign (self tolerance)
3) Seeding secondary lymphoid organs and circulation
4] Antigen encounter and activation
While travelling around body, before meeting antigen are known as NAIVE ANTIGENS
5) Proliferation and differentiation
Turning into effector cells and memory cells once met with antigen
81
Where does humoral response occur? And what does it target?
Extracellular fluid.
| Specific for bacteria mostly but can pick up some viruses that haven’t affected cells yet
82
Mechanism for humoral response
Antibodies
83
Humoral response process?
- Naive B cells recognise antigens with receptors and bind to them
- Activated and grow and proliferate into clones, some which will become plasma b cells and some memory B cells.
- Plasma cells produce antibodies
(Antibodies don’t kill pathogens just prepare them so easier for phagocytes and macrophages to engulf them)
- Memory cells last long and recognise antigens in subsequent exposures so Secondary response will therefore be faster
84
What are antibodies made up of and what do they bind to?
Specific antigens bind to specific antibodies
Made up of Heavy chains ( inner region) and light chains ( 2 smaller outside parts)
85
Different types of antibodies ?
IgM- first one that gets produced in primary response
IgG- most common, long term one that gets produced during second response
IgA- floats around in body secretions like saliva
IgE- binds to mast cells and triggers release of histamine
IgD- sitting on B cells itself (as receptors) to recognise those antigens
86
Igm antibody
IgM- first one that gets produced in primary response
87
IgG antibody?
IgG- most common, long term one that gets produced during second response
88
IgA antibody?
IgA- floats around in body secretions like saliva
89
IgE antibody
IgE- binds to mast cells and triggers release of histamine
90
IgD antibody?
IgD- sitting on B cells itself (as receptors) to recognise those antigens
91
Antigen, antibody complex triggers....
Neutralisation- masks dangerous parts of bacterial exotoxins ( which enhances phagocytosis)
Agglutination- cell bound antigens( which enhances phagocytosis)
Precipitation- soluble antigens ( which enhances phagocytosis and inflammation
Complement activation which leads to inflammation and cell lysis
92
difference between innate and adaptive immunity.
Innate immunity is the natural defence against infections. It is the type of immunity that you are born with, there are surface barriers and internal defences (white blood cells). Immunity you get after infection or immunisation, it is specific and there tare 2 types: humeral Eg. Vaccines Eg. and cellular immunity Eg. T lymphocytes.
93
Cellular immunity target?
targets cells that have been infected by pathogens
| Mainly works on viruses, some bacteria and also parasites
94
Cellular immunity mode of action?
Doesn’t produce antigens
| Acts by having specific specialised cells that kill affected cells
95
Cellular immunity process?
- T cells mature in thymus glands and go out as naive T lymphocytes (CD4 or CD8) into lymphoid and blood stream
```
- APCs ( most likely dendritic cells, which have both class 1 and class 2 MHC proteins ) pick up antigen and display it on their MHC proteins.
CD4 recognise antigens on class 2 and display, CD8 recognise class 1 MHCs display
```
- Naive T CD4 cells activated by binding to specific antigen grow and proliferate producing 2 types of effector cells. T Helper cells or regulatory T cells and memory cells.
- Naive T CD8 cells activated by binding to specific antigens grow and proliferate producing cytoxic T cells/ T killer cells and memory cells
- All these cells go into the blood and travel to the affected tissues.
96
In the cellular immune response which Naive T lymphocytes recognise which MHC class protein ( 1 &2)
- CD4 recognise antigens on class 2MHCs
| - CD8 recognise class 1 MHCs
97
How do cytotoxic T cells kill affected cells?
Cytotoxic T cells - kill affected cells
How?
By latching on to affected target cell, drill a hole into it and release some digestive enzymes into it.
98
Importance of helper T cells?
Helper T cells ( from CD4) play an important role for both arms ( humoral and cellular immunity) by attaching to and activating B cells and making them start multiplying and producing antibodies. They also activate CD8 cells to multiply and make cytotoxic T cells.
99
What do regulatory T cells do?
regulatory T (TReg) cells dampen the immune response. They act either by direct contact or by releasing inhibitory cytokines.
100
Discuss how the immune system differentiates between self and non-self cells.
Body cells have protein on their surface. That protein is called Major comparability complex (MHC) proteins, there are 2 classes. Class 1 and class 2. All cells in your body have class 1 MHC, except 2 types of cells ( red blood cells and antigen presenting cells- macrophages, dendrite cells).
101
What do dendritic cells do?
In epidermis ingest foreign substances and activate the immune system ( are APCs)
102
Which stratum layer contains stem stem cells responsible for regeneration more superficial layers?
Stratum basale
103
T or F, cells of the epidermis protect against evaporative water loss, ur radiation and infection
True
Keratinocytes protect against evaporative water loss, melanocytes and keratinocytes protect against UV light and the dendritic cells protect against infection
104
What is cyanosis?
Bluish discolouration of skin caused by deoxygenated hemoglobin
105
What is the ph of the blood like?
Slightly alkaline
106
What sign of inflammation is the result of exudate ( mass of cells and fluid that has seeped out of blood vessels or an organ) in the tissue space?
Edema ( swelling)
107
What chemicals can directly trigger inflammation?
Prostaglandins
Histamines
Kin kins
108
Unless attached to protein carriers Haptens have reactiviy but not immunogenicity. T of f
T
Immunogenicity is the ability to stimulate specific lymphocytes to proliferate. ( haptens cant)
Reactivity is ability to react with activated lymphocytes and The antibodies released by immunogenic reactions (haptens can if attached to protein)
109
Primary vs secondary immune response
Secondary faster
Also
In primary naive lymphocytes activated but in secondary , memory lymphocytes are activated
110
Which antibody is most abundant in the body?
IgG
111
Wha type of at cell will recognise antigens associated with an organ transplant
Cytotoxic T cells can distinguish between self cells and those from transplanted tissue. If a cytotoxic T cell recognises it’s own antigen on a transplanted cell, the T cell will destroy it, leading to organ rejection
112
T or f the dermis contains blood vessels and nerve endings while the epidermis does not?
False
113
What protects us from excessive water loss through skin?
Glycolipids that are secreted by keratinocytes into EXtracellular spaces
