Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

FRCA > Physiology > Flashcards

Physiology Flashcards

1
Q

Draw and explain the oxygen cascade

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define and classify pain

A

Pain is an unpleasant sensory and emotional experience with actual or potential tissue damage

It can be classified according to its acuity or its nature:

Acute - recent onset and limited duration. Identifiable cause
Chronic - Persists beyond time of healing. No clearly identifiable cause

Nociceptive - results from stimulation of nociceptors
Neuropathic - results from dysfunction of the nervous system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe the pain pathway that are activated when injury occurs

A
  1. Nociceptors within the damage tissue are activated
  2. An action potential is generated and travels down afferent sensory neurones (Abeta, Adelta, C)
  3. Synapses in dorsal horn within the rexed laminae
  4. Interneurones (secondary neurones ) decussate the spinal cord and travel within the ascending pain pathways (spine thalamic tracts)
  5. The ascending tracts travel up the spinal cord and synapse within the thalamus (specifically the intralaminar nuclei and the ventral posterior nucleus)
  6. Tertiary neurones project into the somatosensory cortex
  7. Some ascending spinal pathways project directly into the reticular-activating system and then into higher centres which affect memory/emotion
  8. Descending fibres from the cortex/thalamus/brain stem exert an inhibitory effect on pain transmission in the dorsal horn
  9. An immediate polysynaptic withdrawal reflex occurs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe the ascending pain pathways (4x)

A

There are multiple ascending pathways. The most important are:

  1. SPINOTHALAMIC TRACT
    - Anterior (light touch) and lateral (pain and temperature)
    - Made of both fast and slow fibres
    - FAST - travel directly in STT to brain stem & synapse in ventral posterior nucleus of thalamus before projecting into the somatosensory cortex - involved in conscious perception and memory of pain
    - SLOW - synapse in the brain stems reticular formation and in intralaminar nuclei in the thalamus before projecting into hypothalamus/lambic system and autonomic centres
  2. SPINORETICULAR TRACT
    - slow fibres that terminate the reticular formation and thalamus
  3. SPINOMESENCEPHALIC TRACT
    - terminate in the midbrain and periaqueductal grey mater
  4. DORSAL COLUMNS
    - Pressure/vibration/proprioception carried by Abeta fibres
    - Not involved in pain transmission
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe the descending inhibitor pain pathways (2x)

A

There are 2 main descending pathways - the periaqueductal grey and the locus caeruleus

The periaqueductal grey is the main descending pathway, it gets projections from the thalamus/hypothalamus/amygdala/cortex and projects into the NUCLEUS RAPHE MAGNUS in the medulla whose fibres synapse with the substantia gelatinosa of the dorsal horn. It’s transmitters include endorphins and enkephalins (MOP opioid receptors) and serotonin

The locus caeruleus is an important brain stem nucleus projecting descending inhibitory pathways to the dorsal horn via adrenaline receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are nociceptors and how are they classified?

A

Nociceptors are unmyelinated nerve endings that respond to thermal, mechanical and chemical stimuli

They are classified according to their sensitivity to different stimuli.

  1. Unimodal (thermo-mechanoreceptors) - respond to pin-prick and sudden heat
  2. Polymodal - respond to pressure, heat, cold, chemicals and tissue damage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do noxious stimuli activate pain transmission?

A

Tissue damage leads to release of endogenous chemicals that stimulate nociceptors such as:
- bradykinin, histamine, seratonin, acetylcholine, H+ & K+

Other chemical mediators lower the threshold for excitation - eg prostaglandins, leukotrienes, substance P, neurogenic A and calcitonin gene-related peptide

Stimulation causes an influx of sodium and calcium which causes depolarisation and the generation of an action potential

This then propagates down pain pathways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the substantia gelatinosa?

A

Otherwise known as the laminae II and III in the dorsal horn

A point of significant pain modulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the main neurotransmitters at the primary afferent sensory neurone?

A

Excitability neurotransmitters - glutamate, aspartate and substance P

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the main neurotransmitters of the interneurones or secondary afferent neurones?

A

NMDA, AMPA, Neurokinin 1 and adenosine 1& 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the inhibitory neurotransmitters of the pain pathways?

A

Enkephalins (MOP) and GABA A receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the gate control theory of pain

A

The gate control theory pain is an aspect of pain modulation. It postulates that transmission from primary afferent to secondary afferent neurones is “gated” by interneurones in the substantia gelatinosa. This can be pre or post synaptic

The pain pathway - ie what opens the gate - is the C nerve fibre and substance P synapsing within the SG to secondary afferent neurones. This is aided by Adelta fibres that inhibit ENKEPALINERGIC interneurones that would otherwise post-synaptically inhibit neurotransmission

There are a number of mechanisms to inhibit pain transmission.
1. Noradrenergic & serotonergic Descending pathways (LC/NRM/PAG) activate ENKEPHALINERGIC interneurones (MOP) that inhibit post-synaptic transmission of pain pathways
2. Abeta fibres inhibit C fibre pre-synaptically via GABA receptor stimulation.
A-Beta fibres are activated by touch and pressure and explain how rubbing it better works
3. A-delta fibres also ascend to the PAG and stimulate it to, perhaps paradoxically, exert its inhibitory effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the actions of commonly used painkillers on the pain pathway:

  • Paracetamol
  • NSAIDs
  • Opioids
  • Tramadol/pethidine
  • TCAs
  • Anticonvulsants
  • Gabapentin
  • Local anaesthetic
  • Ketamine
  • Clonidine
  • TENs machine
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

N

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the different types of neurone?

A

There are A, B & C nerve fibres

A fibres are sub classified into A alpha, beta, gamma, delta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Tell me about A alpha neurones

A

A-alpha neurones

  • somatic motor and proprioception
  • diameter 12-20 micrometers (largest)
  • conduction velocity 70-120 m/s (fastest)
17
Q

Tell me about A-beta nerve fibres

A

A-beta

Transmit touch and pressure
Diameter 5-12 micrometers
conduction speed 50-70 m/s

18
Q

Tell me about A gamma nerve fibres

A

A gamma

Motor fibres to muscle spindles

Diameter 3-6 micrometers
Conduction speed 30-50 m/s

19
Q

Tell me about A delta nerve fibres

A

A delta

Pain, temperature and touch
Diameter 1-3 micrometers
conduction speed <30 m/s

20
Q

Tell me about B nerve fibres

A

B fibres

Myelinated pre-ganglionic autonomic fibres
Diameter 1-3 micrometers
Conduction speed <15 m/s

21
Q

Tell me about C nerve fibres

A

C fibres

Unmyelinated, post ganglionic autonomic fibres AND pain/temperature
Diameter <1 micrometer
conduction speed <2 m/s

22
Q

Demonstrate the relationship between PO2, PCO2 and cerebral blood flow

A

Linear relationship between CBF and PCO2

Above PO2 8 there is little difference in CBF but below it there is increased CBF

23
Q

Draw the lung volumes

A
24
Q

What is the closing volume?

A

The volume of gas over the residual volume that remains in the lungs when the small airways begin to close

25
Q

What is the closing capacity?

A

The lung capacity at which the small airways begin to close. It is a combination of residual volume and closing volume

It increases with age - it reaches supine FRC at 40 years and standing FRC at 70 years

26
Q

What are the functions of the liver

A 
Biosynthetic 
- Formation of plasma proteins incl. albumin
- Formation of clotting factors 
Metabolic 
- Carbohydrate/protein/lipid metabolism
- Drug metabolism 
Energy production and storage
- gluconeogenesis/glycogenolysis
- glycogen storage 
Digestive
- Bile acid formation 
Immunological 
- Kumphner cells 
Blood volume storage
27
Q

What are the functions of the kidney

A

Filtration & reabsorption

BP/blood volume/electrolyte/osmolarity regulation

  • RAAS
  • Effect of ADH

pH homeostasis

Calcium and phosphate homeostasis
- Activates vitamin D

Hormonal
- EPO

FRCA (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions