Bleeding and inflammation stages Flashcards
1
Q
is the process different for different tissues?
A
no, process is the same for all types of tissues
2
Q
what are the three ways tissues are usually damaged due to?
A
excessive ;
- compressive forces
- tensile forces
- shearing/ lacerating forces
3
Q
what are the four phases of tissue repair?
A
- bleeding
- inflammation
- proliferation
- remodelling
4
Q
how long roughly is the bleeding phase?
A
- short phase
- 0 to 10 hours
5
Q
what does the bleeding phase depend on ? (4)
A
- initial injury type
- tissues damaged
- severity of the injury
- person specific factors e.g., smokers, diabetes, haemophilia
6
Q
what does bleeding activate and what does this secrete ?
A
- bleeding activates platelets
- secretes prothrombin
7
Q
what does prothrombin convert to? what is this used for?
A
- prothrombin converted to thrombin
- thrombin binds to fibrinogen to form fibrin cross- linking that aggregates over the wound
8
Q
how long is the inflammation stage? how is it described?
A
- 0-4 days
- described as an essential component of tissue repair process
9
Q
what happens at approximately day 1-3?
A
- rapid onset
- increases in magnitude
10
Q
what are inflamed tissues called?
A
- referred to as ‘itis’
- no inflammatory markers in tendons
11
Q
what are the 5 triggers of inflammation?
A
- bleeding
- trauma
- chemical
- infective
- immunological
12
Q
describe a chemical trigger for inflammation
A
- changes in acid balance
- changes transfer of liquids
13
Q
describe a immunological trigger for inflammation
A
- rheumatoid arthritis ^ inflammation
14
Q
what are the five cardinal signs?
A
- pain
- swelling
- loss of function
- heat
- redness
15
Q
what is pain?
A
- unpleasant sensory and emotional experience associated with, or resembling that associated with actual or potential tissue damage
16
Q
what are the specialised receptors and what do they do?
A
- nociceptors are activated and send an action potential to the spinal cord, transmitted through fibres which depending on their thickness will transduce information fast or slow
17
Q
where is the information sent after the spinal cord?
A
- sent to higher centres
- spinothalamic or spinoreticular tracts in which the brain recognises if the stimuli is damaging or not
18
Q
what are the two main fibres? which one is faster?
A
- A - fibres and C fibres
- A- fibres conducts the action potential fast (large diameter) whereas C fibres conduct the action potential slower (small diameter)
19
Q
is there any conscious involvement?
A
- yes
- perception and cognition
- association areas
20
Q
can you modulate pain?
A
- modulation via pain gate theory involving a - beta fibres and opioids
21
Q
what is the primary mechanism?
A
- markers including macrophage, mast cell, neutrophil accompany the inflammation and cover the damage to activate tissue repair
22
Q
what are produced as a result of inflammatory pain? where from?
A
- chemical mediators
- from the injury itself
23
Q
what are the chemical mediators?
A
- serotonin
- bradykinin
- histamine
- nerve growth factors
24
Q
where are the chemical mediators sent?
A
- sent to the bloodstream
25
what is nociception?
- neural process of encoding, transmitting and processing noxious stimuli
26
is nociception always linked to pain?
- no, nociception doesn't always result in pain; tissue damage not necessary for pain as peripheral factors also influence pain
27
what is a noxious stimulus?
- an actually or potentially tissue damaging event transduced and encoded by nociceptors
28
what are nociceptors?
- sensory receptor that is capable of transducing, encoding and transmitting noxious stimuli
29
what can stimulation of nociceptors result in?
- nociceptive pain
30
where do nociceptors transmit info to and why?
- nociceptors in tissues transmit information to CNS to make you aware of the body
31
what are the four main steps of nociception?
1. transduction of stimulus by nociceptors
2. stimulus conducted to spinal cord
3. transmitted to higher centres
4. encoded by action potential travelling from the nerve
32
what is transduction?
- mechanical, thermal or chemical energy is transduced by specialised endings of Ad and C nerve fibres
33
what do some nociceptors respond to ? give an example
- respond to only one stimulus modality
e.g., mechanoreceptors
34
what are other nociceptors described as?
- polymodal
- responding to multiple stimuli
35
what are some of the nociceptors doing?
- some are silent/ sleeping
- woken up by inflammation
36
what is encoding?
- how many action potentials the nociceptor fires to perceive pain
37
why is stimulus intensity proportional to pain intensity?
- stimulus intensity is encoded to be proportional to nociceptor firing frequency
- nociceptor firing frequency is decoded to be proportional to pain intensity
38
what happens if the nociceptor is stimulated more?
- it produces a larger, more painful response
39
what does repetitive stimulation of nociceptors by chemical mediators and noxious stimuli cause?
- causes nociceptors to lower their activation threshold
- lower stimuli ^ pain experienced
40
what can threshold reduction lead to?
- peripheral sensitisation
41
what does peripheral sensitisation lead to?
- increased responsiveness
- reduced threshold of nociceptive neurons in periphery to stimulation of receptive fields
42
what can nociception cause?
- causes local and remote sensitivity
43
what can peripheral sensitisation transfer to?
- central sensitisation
- CNS more responsive to pain
44
what are the two central sensitisations? what does this cause?
- hyperalgesia
- allodynia
- pain becomes widespread
45
what is hyperalgesia?
- increased pain to a noxious stimulus
e.g., touched with lower pressure ^ pain
46
what is allodynia?
- pain response to innocuous (non- noxious) stimuli
e.g., touched in different place and pain felt
47
what is referred pain?
- intensity and size correlates with CNS excitability
48
what is chronic pain?
- more sensitised
- more pain travels to brain
49
what is conduction?
- axons transmit information via action potentials conducted along nerve fibre axon
50
describe Ad fibres
- greater diameter
- fast
- 5 to 35 ms- 1
- faster than vision
51
describe C fibres
- smaller diameter
- slow
- 0.5 to 2 ms-q
- unmyelinated
52
what are other important afferent fibres ?
- beta fibres, gamma fibres
- sensed in muscle, etc and sent back to spinal cord/ brain
53
what is transmission?
- action potential transmitted to neurons in dorsal horn of spinal cord
54
what are dorsal horns?
- sensory sites in which dynamic activities occur
55
where are Ad fibres transmitted?
- Ad fibres to Lamina I
- Laminae marginalis
56
where are C fibres transmitted?
- C fibres to Lamina II
- Substantia gelatinosa
57
where is the action potential transmitted after the dorsal horn?
- transmitted to higher centres
such as primary somatosensory cortex, sensory homunculus
58
what is the gate theory?
- afferent impulses 'gated' (modulated) within the spinal cord
59
what closes the gate?
- impulses from large, myelinated fibres tend to block nociception
60
what opens the gate?
- impulses in nociceptors facilitate transmission
61
what is descending inhibition?
- inhibitory affect from brain down to spinal cord to inhibit pain pathways, excite inhibitory interneurons which inhibit pain
62
what are the two main reasons for redness and heat production?
- chemical mediators trigger vasodilation
- release of nitric acid
63
what three substances impact redness and heat?
- substance P > short acting vasodilator
- serotonin (5HT) and Bradykinin
64
how does blood flow cause redness?
- blood flow increases
- hyperaemia
- generates localised heat
65
does swelling occur immediately? does this change meaning?
- may not occur immediately and may take serval hours to develop
- when swelling is immediate it indicates substanial injury
66
what indicates inflammatory injury? why does this occur?
- inflammatory exudate
- occurs due to alteration of hydrostatic an osmotic pressures in capillaries
- if pressure is higher than oedema and swelling produced as fluid forced out
67
how does functional loss of mobility occur?
- due to pain, fear of movement, swelling and tissue damage
- should assess limping
68
what alters permeability of capillary walls? what does this allow?
- chemical mediators
- bradykinin and histamine
- alteration allows plasma proteins to move from capillaries to interstitial space
69
what gradient is altered and what does this cause?
- osmotic gradient altered
- net flow of fluids is greater into interstitial space
70
what happens as blood flow slows down?
- white blood cells move towards margin of blood vessels
- via process of margination
71
where do white blood cells emigrate to and how? what are they guided by?
- emigrate into interstitial spaces by pseudoposis
- guided by chemical mediators via chemotaxis
72
what does inflammatory exudate dilute and allow?
- dilutes toxins
- allows passage of antibodies and plasma proteins
73
what happens in inflammatory exudate?
- neutrophils and macrophages engulf debris and bacteria via phagocytosis
