Somatotropic organization & Nociceptors & Pain Physio Flashcards
In which area of the brain do third order neurons of the sensory pathway project to?
The Parietal cortex
Where specifically does the third order neurons of the sensory pathway project to?
- Somatic Sensory area I (SI) at the post central gyrus
- Somatic Sensory area II (SII) of the anterior parietal lobe
Fill in the blanks. “The various thalamic nuclei receiving somatosensory information project to : ________, _______ & ________.”
- Primary sensory cortex in the postcentral gyrus
- Secondary somatosensory cortex
- Posterior parietal cortex
How is the primary somatosensory cortex organised ?
Somatotopically
In which layer of the cerebral cortex does Afferents end in?
Layer IV (4)
Which layers of the Cerebral cortex generates descending pathways?
Layers V and VI (5&6)
Which layer of the cerebral cortex send axons to related portions of the cerebral cortex on the opposite side of the brain through the corpus callosum?
Layers II & III
Which layer of the cerebral cortex receive diffuse, nonspecific input signals from lower brain centers?
Layers I & II
Where are the columns of proprioception located?
Near the central sulcus
Which layer of the cerebral cortex have corticothalamic neurons?
Layer VI
True or False? The Outer band of Baillarger is located in Layer V of the cerebral cortex.
FALSE!! It is located in Layer IV( 4)
Where is the Line of Gennari located?
In Layer IV(4) in area 17
Local inhibitory neurons are normally found in which layer of the Cerebral cortex?
Layer I ( Molecular layer)
Fill in the blanks. “ The External Granular Layer (Layer II) is associated with __________ neurons while the External Pyramidal layer ( Layer III) is associated with ______ neurons.”
External Granular Layer - Association neurons
External Pyramidal Layer - Commissural neurons
Fill in the blanks . “ The line of Kaes-Bechterew is located in ___________.”
External Pyramidal layer ( Layer III)
True or False? The Inner band of Baillarger
is located in the Internal Pyramidal layer.
TRUE!!
Which layer of the cerebral cortex receives Thalamocrotical projections?
Internal Granular Layer ( Layer IV)
What is the function of the Somatosensory Association cortex?
Synthesizes multiple sensory inputs to create a complete comprehension of the object being felt.
Where is the Primary visual cortex located?
Found in Posterior and Medial Occipital lobe
Where is the Dorsal stream of the Primary visual cortex ?
Parietal cortex ( where : rods, periphery of retina, area 7)
Where is the Ventral stream of the Primary Visual cortex located?
Temporal cortex
Where is the Primary auditory cortex located?
The superior margin of the temporal lobe, next to the lateral sulcus.
What Is the function of the Auditory association area?
The auditory association area which lets us interpret and remember sounds
What is Asterognosia?
The loss of ability to recognize objects by touch in absence of of defects in somatosensation.
What is Asomatognosia?
This is a loss of the ability to recognize parts of one’s own body
What type of cells are located in the Primary Motor cortex?
Pyramidal cells
Where is the Primary Motor cortex located?
Precentral gyrus of each cerebral hemisphere
What are the Afferents for the Primary Motor cortex?
Thalamus
What are the Efferents for the Primary Motor Cortex?
Basal ganglia, thalamus, Reticular Formation, Superior colliculus, pontine, spinal cord
What happens if the Primary Motor cortex becomes damaged?
Damage produces paralysis of contralateral muscles (namely upper limb, tongue, facial muscles)
Where is the Primary Motor cortex located?
In the Precentral Gyrus ( Broadman area 4)
What is the function of the Secondary ( Premotor Area) ?
- Involved in learned or patterned skills.
- Involved in planning movements- influences paravertebral and proximal limb musculature
Which language area is responsible for language comprehension and complex word analysis?
Language prefrontal cortex
Which language area is associated with understanding oral/written words?
Wernicke’s area
What is the function of Broca’s area?
Speech production
Fill in the blanks.” ____________ integrates visual and auditory stimulate”
Lateral and ventral temporal cortex
Fill in the blanks. “Information is projected to Wernicke’s area through _____________.”
Arcuate fasciculus
What are the different manifestations of pain?
Hyperalgesia
Paresthesia
Allodynia
Hyperpathia
What is Pain?
Pain is the perception of an aversive or unpleasant sensation that originates from a specific region of the body
What is the term given to the pain from a stimulus that would not normally cause pain ?
Allodynia
What is the term given to unpleasant or painful feelings e.g. pins and needles with no apparent stimulus?
Paresthesia
What is Hyperalgesia?
This is severe pain from a stimulus that would normally cause only slight discomfort
What is Hyperpathia ?
Exaggerated and prolonged reactions to painful stimuli.
What are factors that can modify pain?
- past experiences
- suggestion
- emotion – particularly by anxiety
- simultanneous activation of other sensorymodalities
- different state of attention
How can pain protect the body?
- Remove body from danger
- Promote healing by preventing further damage
- Avoid noxious stimuli
Why does one feel pain?
- Gives conscious awareness of tissue damage
- Protection:
- Remove body from danger
- Promote healing by preventing further damage
- Avoid noxious stimuli
- Elicits behavioural and emotional responses
What systems are activated by pain?
- Sympathetic neuronal system
- Parasympathetic neuronal system
- Respiratory & Cardiovascular system
- Motor system
- Endocrine system
What are the different classifications of pain?
- By perception: Fast/sharp pain and slow/dull pain.
- Somatic and visceral pain
- Superficial and deep pain
- Physiological sharp pain and pathological pain (inflammatory, neuropathic pain).
Where are pain receptors normally located?
- In the skin
- Periosteum
- Arterial walls
- The joint surfaces
- Falx and tentorium in cranial vault
Fill in the blanks. “ A delta fibres only project to laminae _____ &______.”
I & V
Fill in the blanks. “C fibres project to laminae __________. “
I , II & V
Fill in the blanks. “ Harmful stimuli activate peripheral endings of primary sensory neurons whose cell bodies are located in the _____________”
Dorsal root ganglia and Trigeminal ganglia
Which nociceptor is associated with a burning sensation associated with spicy food?
Capsaicin (from chili peppers) receptor
What do Polymodal nociceptiors travel via?
Non- myelinated C fibres
Which nociceptor has ASIC like channels or mediation via ATP?
Mechanical nociceptors
What are the stimulants for Polymodal nociceptors?
Noxious mechanical stimuli, noxious heat / cold, irritant chemicals.
What type of pain is associated with Polymodal nociceptors ?
Slow burning pain or aching pain
What are the names given to the receptors that are members of the transient receptor potential (TRP) family of ligand-gated ion channels that detect a variety of painful stimuli ?
- Vanilloid receptor-1 (VR-1/TRPV1)
- Vanilloid like receptor-1 (VRL-1/TRPV2)
What are the TRP receptors stimulated by?
- Noxious heat (≥ 45oC)
- Capsaicin (ingredient in chili peppers
What are substances that have a direct influence on the free - nerve endings?
Potassium
Histamine
Bradykinin
Serotonin
What substance is released from activated free- nerve endings?
P- substance
Which substances causes a sensitisation of nociceptors?
Prostagoandins especially PgE2, interleukin-1, interleukin-6, cyclooxygenases (COX-1, COX-2)
Which substances evoke inflammation ?
- Histamine
- Bradykinin
- Serotonin
Where does Central sensitisation occur?
In the dorsal horn
What is the enzyme involved in the synthesis of Serotonin?
Tryptophan hydroxylase
What is the enzyme involved in the synthesis of Bradykinin?
Kallikrein
What is the source of Serotonin?
Platelets
What is the source for Prostaglandins and Leukotrines?
Arachadonic acid and damaged cells
