COM1 Physiology C49 week4 Flashcards
1
Q
What type of receptors are pain receptors
A
- Free nerve endings
2
Q
Where is pain receptors found
A
- Skin, periosteum, arterial walls
3
Q
Name the types of Pain stimuli + examples
A
- Mechanical- Pressure, cuts
-Thermal- heat above 45C
-Chemical - acids
4
Q
What is the affect of prostaglandin on the body
A
Increases sensitivity
5
Q
Do pain receptors adapt
A
No
6
Q
What is hyperalgesia
A
- Where pain receptors become more sensitive over time
7
Q
When does skin pain begin
A
When heated over 45C
8
Q
What else is pain triggered by
A
- Infection
-Ischemia
-Contusion
9
Q
What do damaged tissues release
A
- Pain inducing chemicals
10
Q
Name a chemical that is released form damaged tissues
A
- Bradykinin
11
Q
What does pain intenisty correlate with
A
- It correlates with the increases in potassium or increase in proteolytic enzyme activity
12
Q
When blood flow to the tissue is blocked, why is it painful
A
- Due to the lack of oxygen
13
Q
When the blood flow to the tissue is blocked, when does the pain appear faster
A
- With exercise
14
Q
WHat is the main cause of pain when blood flow is blocked
A
- Accumulation of lactic acid, bradykinin and enzymes
15
Q
How does Muscle spasm cause pain
A
- By:
-Direct stimulation of mechonreceptors
-Compressing vessles, causing ischemia
-Increased metabolism, which worsens ischemia
16
Q
What are characteristics of fast pain
A
- Sharp
- pricking
17
Q
Give an example of fast pain
A
Knife cut
18
Q
Where is the location of fast pain
A
Mostly in the skin and not felt in deep tissues
19
Q
What is the function of fast pain
A
- Protection and prompts immediate withdrawal
20
Q
What are characteristics of slow pain
A
- Throbbing
Chronic
Aching
21
Q
What is the location of slow pain
A
In the skin and deep tissues/organs
22
Q
What is the name of the Fast pain pathway.
A
Neospinothalamic Tract
23
Q
How does the neospinothwlamic tract cart fast pain
A
Via Alpha delta fibers
24
Q
Where do the alpha delta fibers in the neospinothalamic tract terminate
A
Lamina 1
25
Explain the process in neospinothalamic tract stating from second order neurons
-The second order neurons cross to the opposite side of the spinal cord and ascend into the anterolateral column
- most fibers go to the thalamus
- from the thalamus the signals are relayed to the somatosensory cortex
26
Is fast pain wide spread or localised
Well localised
27
Give an example of a neurotransmitter of the Type Alpha delta fast pain fibers
Glutamate
28
What is the name for the Slow chronic pain pathway
Paleospinothalamic Pathwwy
29
What and how does the Paleospinothalamic pathway transmit
- Slow , chronic pain via Type C fibers
30
Explain the process of Paleospinothalamic pathway
- c fibers enter the spinal cord and terminate in laminae II and III
- Signals pass through interneurons to lamina V
- Then cross over and ascend in the anterolateral column
31
How does glutamate act as a neurotransmitter
Acts fats and for a short duration
32
How does substance P act as a neurotransmitter
+ what is it involved in
- It had a slower release and it builds up over seconds or minutes
- involved in prolonged or dull pain
33
In the Paleospinothalamic tract most fibers where do most fibers terminate
- Reticular nuclei
- Tectal Area
- Periaqueductal gray
34
Explain the localisation tipw of the paleospinalthalamic tract (slow pain pathway)
It has a poor localisation
35
In the Paleospinothalamic pathway what it’s the function of the cortex
Helps interpret pain quality
36
How does pain signals prevent sleep and enhance alertness
- By arousing brain activity
37
What is the name of the system that suppress pain
Analgesia system
38
What is the overall function of the Analgesia system
Allows the brain to suppress pain signals entering the nervous system
39
Name the 3 major components of the Analgesia system
1.Periaqueductal gray (PAG) and the periventricular areas( Mesencephalon + upper pons)
2. Raphe magnus nucleus and nucles reticularis paragigantocellularis
3. Pain inhibitory complex in the dorsa; horns of the spinal cord
40
How does the Analgesia system work
-Periaqueductal gray and periventricular areas( mesencephalon and upper pons) - SEND SIGNALS to the raphe nuclei then to the dorsolateral spinal cord, which inhibits pain at the spinal cord
- Blocks pain before it reaches the spinal cord
41
Name the 2 key neurotransmitters involved in the Analgesia system
- Enkephalin
-Serotonin
42
Explain the role of Enkephalin in the Analgesia system
Causes pre and postsynaptic inhibitoon of pain fibers( C and alpha delta)
43
Where is Enkephalin released
- Released in Periaqueductal gray, raphe nucleus, and spinal cord
44
Where is Serotonin released
- Released in spinal cord by descending fibers
45
What is the role of Serotonin in the Analgesia system
- Stimulates local enkephalin
46
How can pain be suppresed
By activating high brain areas that stimulate periaqueductal gray inclduing:
-Periventricular nuclei
-Medial forebrain bundle
47
What drug can be injected in PAG or periventricular nucleus whcih causes string analgesia
Morphine
48
Name 4 important opiate-like compounds
- B- endorphin
-Met-Enkephalin
-Leu-Enkephalin
-Dynorphin
49
Where is Enkephalin found
- Brain stem and spinal cord
50
Where is B-Endoprhin found
Hypothalamus and pituitary gland
51
Where is Dynorphin found
- In similar areas as enkephalin( brinstem and spinal cord) just in smaller amounts
52
What is the function fo the Opiate system when activated
- They can suppres pain signals
53
What can the opiate systme be triggered by
- Nervous input to specific brain areas
-Morphine like drugs
54
What is referred pain
Pain felt in a different area than its actual source
55
Explain the mechanism of referred pain
- Visceral and skin pain fibers converge on the same spinal neurons
-The brain misinterprets visceral pain as coming from the skin
56
Give charcateristc of visceral pain
- Highy localised damage, causing little or no pain
-Diffuse stimuli causes stretching
-Pain is dull, aching and chroning, transmitted by type C fibers
57
Name the 5 causes of viseceral pain
- Ischemia
-Chemical irritation
-Smooth muscle cramps
Overdistention
-Insensitive viscera
58
Explain Overdistention as a cuase of visceral pain
- Stretching of a hollow organ which causes pain
59
Explain insensitive viscera as a cause of visceral pain
-Where organs like the liver parenchyma and lung alveoli are nearly pain sensisitve BUT suroudnignj areas like bronchi are pain sensitive
60
When does Parietal pain occur
Occurs when Visceral disease spreads to the parietal linings
61
Give characterisitcs of Parietal pain
- Sharp and localized
62
Name the 2 pain transmission pathways
- Visceral pathway
-Paietal pathway
63
Name the type of nerves Vsiceral pathway uses
- Autonomic nerves
64
Name the type of nerves Parietal pathway uses
- Spinal somatic nerves
65
What type of pain does the visceral pathway contain
- Dull, cramping , aching pain
66
What type of pain does Parietal pathway result in
- Sharp and localised
67
Where does the parietal pathway come from
- Parietal peritoneum, pleura or pericardium
68
In the visceral pathway where is pain referred to
Surface areas
69
If the pain is in the heart where is it felt
left chest, neck , shoulder and arm
70
If the pain is in the stomach whre is it felt
- Epigastric region
71
Name the 3 types of thermal receptors
- Cold receptors
-Warmth receptors
-Pain receptors
72
Where are the cold and warmth receptors located
- Just under the skin
73
What type of fibers are warmth signals carried by
unmyelinated Type C fibers
74
What type of fibers are cold signals carred by
Mainy Alpha delta fibers but some Type C fibers
75
How are thermal receptors( cold and warmth) stimulated
By changes in metabolic rate
76
Why is it harder to detect temperature changes in small skin areas
- Due to fewer thermal receptors
77
Why is it easier to detect temperate changes in larger skin areas
- Due to cumulative signals
78
Explain the neural pathway for thermal sensations
Enter spinal cord → tract of Lissauer
Terminate in laminae I, II, III of dorsal horn
Cross to opposite side and ascend in the anterolateral sensory tract
Terminate in:
Reticular areas of the brainstem
Ventrobasal complex of the thalamus
79
What is the effect of the removal of the somatosensory cortex
- Reduces temperature discrimination
80
What is primary Hyperalgesia
Incrased sensitivity of pain receptors
81
What is second hyperalgesia
- Increased sensory transmission due to spinal cord
82
What is herpes Zoster( shingles) caused by
Herpesvirus infection fo a dorsal root ganglion
83
What does herpes Zoster( Shingles) results in
- Segmental pain
84
What is Tic Doulourex
Sharp pain on one side of the face
85
What is Tic Doulourex triggered by
Mild touch
86
What is Brwon sequard syndrome caused by
-Hemisection of spinal cord resulting in weakness or paralysis
87
What are headaches
Referred pain from deeper structures
