Quarter Three

Neuron Anatomy & Function

Neuron Anatomy

• Neurons

  • Function as core nervous system components, enabling rapid & efficient communication; is responsible for various bodily functions.

• MT Relevance: Neurons’ responses to therapeutic touch can influence relaxation, sensory feedback, and pain modulation. Massage may alter neuron activity by affecting neurotransmitter release, stimulating sensory neurons, and affecting muscle tone.

• Anatomical Overview

• Dendrites: Recieve signals from neurons/sensory receptors, translating them into electrical signals within the neuron

• Cell Body (Soma): Maintains neuron health by housing nucleus & key organelles, & processes information

• Axon: A long, slender projection that transmits electrical signals away from the cell body to neurons, muscles, or glands

• Synaptic Terminal: Endpoints of axon that store & release neurotransmitters into the synapse, enabling communication with other cells

• Axon Hillock: Specialized region between soma & axon, responsible for integrating signals & determining whether to initiate an action potential

• Neuron Histology

• Microscopic Features: Includes soma with organelles, as well as dendrites & axons

• Synaptic Vesicles: Located in axon terminals, they store neurotransmitters for release upon an action potential

• Dendrites: Receivers

• Structure: Short, branching structures that create extensive surface area for receiving signals

• Receptors:

  • Mechanoreceptors: Touch & Pressure

  • Theromoreceptors: Detecting Temperature

  • Nociceptors: Pain Sensation

• Synaptic Input: Receive presynaptic neurons at specialized synapses

• Cell Body (Soma): Processing

• Structure: Houses nucleus & organelles

• Function: Synthesizes proteins & neurotransmitters required for neuron function & maintaining cellular metabolism

  • Soma processes input signals from dendrites & contributes to action potential generation.

• Nucleus: Contains DNA, directing protein synthesis for maintenance, repair, & responses to changes

• Axon: Transmission

• Structure: Varies in length from a few micrometres to over a meter. Its diameter also influences conduction speed: the larger reduces resistance to electrical flow.

• Axon Hillock: Neuron “Trigger Zone” where the decision to fire an action potential is made based on the sum of excitatory & inhibitory inputs

• Myelinated vs. Unmyelinated Axons: Myelination significantly increases conduction speed, particularly in long axons that transmit signals over distances.

• Myelin Sheath

• Structure: Lipid-rich layer surrounding axons, produced by Shcwann Cells (PNS) & Oligodendrocytes (CNS)

• Function: Insulates axons, preventing electrical leakage and allowing for faster impulse conduction

• Nodes of Ranvier: Small gaps that allow ions to enter & exit the axon, enabling saltatory conduction

• Neurolia: Support Cells

• Roles of Neuroglia:

• Types in CNS:

  • Astrocytes: Forms blood-brain barrier & neurotransmitters balance

  • Oligodendrocytes: Create myelin sheaths around CNS axons, increase transmission speed & provide insulation

  • Microglia: Immune cells; that clean up debris & respond to injury

  • Ependymal Cells: Line brain ventricles & spinal cord central canal, producing & circulating CSF

• Types in PNS:

  • Schwann Cells: Form Myelin Sheath around PNS axons & assist with regeneration after injury

  • Satellite Cells: Support neuron cell bodies in peripheral ganglia, regulating the chemical environment

Types of Neurons

• By Structure

• Arranged by number & processes extending from the cell body

  • Multipolar Neurons: Most common in CNS, have multiple dendrites & a single axon; well suited for integrating large amounts of information

    • Facilitate integration of information from multiple sources & play a role in motor coordination & higher-order processing

  • Bipolar Neurons: One dendrite & one axon; found in sensory organs

    • Found in PNS & are sensory; offer direct & rapid transmission of specific sensory signals of the peripheral nervous system

  • Unipolar Neurons: One process which splits into a dendrite & axon

    • Sensory pathways in PNS where relay sensory information from the body to the CNS. Allows for rapid transmission of sensory information, which is critical for quick reflexes & responses to environmental changes

• By Function

  • Sensory (Afferent) Neurons: Transmit sensory information from receptors to CNS; play a critical role in detecting touch, temperature, & pain

  • Motor (Efferent) Neurons: Carry commands from CNS to rest of body; enables movement & secretion

  • Interneurons: Facilitates communication between sensory & motor neurons within CNS, processing complex information & coordinating responses

• Presynaptic vs. Postsynaptic Neurons

  • Presynaptic Neuron: Releases neurotranmisttters into synaptic cleft; action potential traveling down axon prompts release of neurotransmitter-filled vesicles into synapse

  • Postsynaptic Neuron: Contains receptors that bind to neurotransmitter released by presynapitc neuron; biding causes ion channels to open potentially generating action potential

  • Synaptic Cleft: Small gap between pre & post synaptic neurons where neurotranmitters exchange occurs

Conduction

• Atoms & Ions

• Atoms: Basic particles of chemical elements; consists of protons, neutrons, & electrons

  • Distingusihed by the number of protos that are in their atoms

• Ion: Atom or group of atoms that have an electrical charge

• Reseting Membrane Potential

• RMP: The electrical charge difference across the neuron’s cell membrane when the neuron is not actvely transmitting a signal

  • Baseline voltage is around -70 millivolts (mV) meaning the inside is more negative to the outside

  • Difference in charge is membrane potential

• Resting Potential Basics: Inside the neuron, it's more negative compared to the outside

  • Happens because there are more sodium (Na⁺) ions outside the cell and more potassium (K⁺) ions with negatively charged proteins inside.

• Ion Distribution: Imbalance in ion placement creates a difference in charge, polarizing the neuron and storing potential energy, this uneven ion distribution is managed by the cell membrane’s selective permeability and active transport.

• Membrane Permeability: Allows a lot of K⁺ to leak out through potassium channels; some Na⁺ ions leak in through sodium channels.

  • To stay negative inside, the cell uses a special pump.

• Sodium-Potassium Pump: Pump uses energy (ATP) to move 3 Na⁺ out and 2 K⁺ in.

  • Critical for keeping the resting potential steady and fixing any ion imbalances after disruptions like nerve signals.

• Importance of RMP in Neuronal Function

  • Neuronal Excitability: RMP allows the neuron to be “primed” & ready for activation. If membrane potential reaches a certain threshold, it can trigger an action potential

  • Threshold Potential: Level of depoloarization needed to generate action potential; RMP is essential in maintaining the neuron at a state where it can reach this threshold quickly when stimulated

• Stages of Action Potential

  • Resting State: Neurons polarized with negatuve interior

  • Depolarization: Sodium channels open, allowing Na+ to enter & make interior more +

  • Repolarization: Potassium channels open, allowing K+ to exit & restoring the negative charge

  • Hyperpolarization: Temporary period of increased negativity before returning to resting potential

• Refractory Period: The Reset

  • Absolute Refractory Period: After action potential, the neuron cannot initiate another, preventing signal overlap & ensuring unidirectional impulse flow

  • Relative Refractory Period: During this phase, a stronger-than-usual stimulus is required to generate a new action potential, providing control over signal frequency

• Continuous vs Saltatory Conduction

  • Continuous Conduction: Occurs in unmyelinated axons where the action potential must travel along the entire length of the membrane, leading to slower conduction.

  • Saltatory Conduction: In myelinated neurons, impulses “jump” from node to node between myelinated sections, dramatically increasing speed.

  • Efficiency: Saltatory conduction conserves energy and accelerates response times in reflex and motor pathways.

• Continuous vs Saltatory Conduction

  • Continuous Conduction: Occurs in unmyelinated axons where the action potential must travel along the entire length of the membrane, leading to slower conduction.

  • Saltatory Conduction: In myelinated neurons, impulses “jump” from node to node between myelinated sections, dramatically increasing speed.

  • Efficiency: Saltatory conduction conserves energy and accelerates response times in reflex and motor pathways.

  • Unmyelinated: Why? We often don’t need speed. Sometimes we need time to scrutinize, process, THEN act/react as needed; Examples are temperature, pain (nociception), etc

Growth, Repair, Adaptability

• Neuron Growth & Regeneration

  • Neurogenesis: Limited new neuron formattion, primarily in the hippocampus, supporting memory & learning

  • Nerve Growth Factor: Protein that helps regulate growth, survival, & maintenance of neurons: essential for the develoment of neurons in the PNS & CNS

    • Shpwn to be released with touch proprioception, especially when combined with visual input; called Haptic Learning

    • Haptic Learning rewires the CNS & PNS through releaae of NGF; new pathway result in improved awarness, proprioception, & impaired movement

  • Regeneration in PNS: Shcwann cells assist in axonal regrowth, forming a guide for damaged fibers

  • Challenges in CNS Regeneration: Inhibitory proteins & glial scar formation limit CNS repair

• Neuroplasticity

• Neuroplasticity: The brain & neuron’s ability to recognize synaptic connections in response to learning or injury

  • Include synaptic plasticity (strenghtening/weakening of synapse), axonal sprouting, & dendritic growth
    

Nerve Plexuses

Plexus Overview

• Nerve Plexus

• Nerve Plexus: Complex networks of interconnected spinal nerves that merge & split to form specific peripheral nerves

  • Formed by the anterior (ventral) rami of spinal nerves, except in the thoracic region (T2-T12; no plexus, intercostal nerves)

• Purpose: Allow for redistribution of nerve fibres, ensuring that damage to one spinal nerve does not result in complete loss of function in a region

• Major Plexus:

  • Cervical: C1-C4

  • Brachial: C5-T1

  • Lumbar: L1-L4

  • Sacral: L4-S4

  • Coccygeal: S4-S5 & Coccygeal Nerves

• Cervical Plexus

• Overview:

  • Roots Involved: Anterior rami of C1-C4, with contributions from C5

  • Location: Situated deep in the neck, alongside the first four cervical vertebrae

• Regions Innervated:

  • Skin: Head, neck, superior chest

  • Muscles: Neck & portions of the shoulder & chest

• Major Nerves

  • Phrenic Nerve (C3-C5)

    • Function: C3,4,5 keeps Diaphragm alive

    • Motor: Diaphragm

    • Sensory: Provides sensation to parts of the heart, heart coverings, diaphragmatic coverings (Pleura)

  • Greater & Lesser Occipital Nerves (C2)

    • Provides sensation to the skin of the posterior scalp, near the ear

  • Supraclavicular Nerves (C3-C4)

    • Provides sensation to the skin over the clavicle, upper chest, & shoulder

• Brachial Plexus C5-T1

• Structure

  • Divided into roots, trunks, divisions, cords, & terminal branches

• Regions Innervated:

  • Sensory: Skin of the shoulder & upper limb

  • Motor: Muscles of the shoulder, arm, forearm, & hand

• Major Nerves

  • Musculocutaneous Nerve (C5-C7)

    • Function: Mixed (motor & sensory)

    • Motor: Innervates the biceps brachii, brachialis, & coracobrachialis, enabling elbow flexion

    • Sensory: Provides sensation to the lateral forearm

  • Axillary Nerve (C5-C6)

    • Controls the deltoid & teres minor, facilitating shoulder abduction & rotation; suppliers sensation to the skin over the deltoid

  • Radial Nerve (C5-T1)

    • Innervates triceps brachii, wrist extensors & finger extensors, enabling extension of the elbow, wrist, & fingers

  • Median Nerve (C5-T1)

    • Controls forearm flexors & thumb muscles, essential for gripping & precision

    • Provides sensation to lateral palm & fingers (thumb to middle finger)

  • Ulnar Nerve (C8-T1)

    • Innervates intrinsic hand muscles & forearm flexors; aiding fine motor control

    • Supplies the medial hand including the little finger & hald of the ring finger

• Lumbar Plexus (L1-L4)

• Location: Along the psoas muscle

• Regions Innervated:

  • Skin: Anterior thigh, medial leg, & foot

  • Muscles: Anterior & medial thigh muscles

• Major Nerves:

  • Femoral Nerves (L2-L4)

    • Controls quadriceps & sartorius, enabling knee extension & hip flexion

    • Supplies sensation to anterior thigh & medial leg & foot

  • Obturator Nerve (L2-L4)

    • Innervated adductor muscles of the thigh, including adductor longus, adductor brevis, adductor magnus, & gracillis

    • Provides sensation to medial thigh

  • Lateral Femoral Cutaneuos Nerve (L2-L3)

    • Supplies the skin of lateral thigh; sensory

  • Sephaneous Nerve (Branch of Femoral Nerve)

  • Supplies sensation to medial side of leg & foot

• Sacral Plexus (L4–S4)

• Location: Anterior to the sacrum

• Regions Innervated:

  • Skin: Buttocks, perineum, posterior thigh, most of the leg and foot

  • Muscles: Lower limb muscles

• Major Nerves:

• Sciatic Nerve (L4–S3):

  • Function: Mixed

  • Motor: Hamstrings (biceps femoris, semitendinosus, semimembranosus); knee flexion

  • Sensory: Posterior thigh

  • Branches:

    • Tibial Nerve: Posterior leg muscles (e.g., gastrocnemius, soleus); sole sensation

    • Common Fibular Nerve: Anterior/lateral leg muscles; lateral leg and dorsum sensation

• Superior Gluteal Nerve (L4–S1):

  • Function: Motor

  • Motor: Gluteus medius, gluteus minimus, tensor fasciae latae; hip abduction and medial rotation

• Inferior Gluteal Nerve (L5–S2):

  • Function: Motor.

  • Motor: Controls the gluteus maximus, essential for hip extension.

• Pudendal Nerve (S2–S4):

  • Function: Mixed.

  • Motor: Innervates perineal muscles and the external anal sphincter.

  • Sensory: Supplies sensation to the external genitalia and perineum.

• Coccygeal Plexus (S4, S5, Coccygeal Nerves)

• Location: Adjacent to the coccyx

• Regions Innervated:

  • Skin: Small area around the coccyx

  • Muscles: Minor contributions to the pelvic floor

• Clinical Relevance:

  • Discomfort in the coccygeal region may respond to targeted massage or manual therapy

• Intercostal Nerves: Overview

  • Roots Involved: T2–T12.

  • Regions Innervated:

    • Intercostal muscles and overlying skin of the chest wall.

  • Clinical Relevance: Intercostal nerve irritation or compression can cause rib pain, which may be alleviated by addressing surrounding musculature through massage.

Entrapments

• Cervical Plexus: Common Entrapment Sites

  • Greater & Lesser Occipital Nerves

    • Fasia of conjoin tendon, semispinalis, or inferior oblique muscles

    • Posterior aspect of proximal SCM & surronding fascia

  • Supraclavicular Nerve

    • Scalenes

    • Posteriorly between mid-superior SCM & anterior fibres UFT

    • Platsyma

• Brachial Plexus: Common Entrapment Sites

• Musculocutaneous Nerve

  • In or just distal to coracobrachialis muscle

  • Between the biceps brachii and brachioradialis muscles

• Axillary Nerve

  • Quadrilateral space; intersection of inferior border of teres minor, lateral border of superior long head tricep, medial border of superior humerus, superior border of teres major

• Radial Nerve

  • Arcade of Frohse; located at lower edge of supinator muscle

  • Proximal: Extensor carpi radialis brevis (ECRB), spiral groove/intermuscular septum of the humerus

  • Distal: Radial tunnel (just distal to the elbow)

  • Muscles: Supinator, extensor carpi radialis longus, extensor carpi radialis brevis, brachioradialis

  • Other Structures: Fibrous tissue (forms the tunnel floor, originating from the radial head)

• Ulnar Nerve

  • Guyon’s Canal; palmar aspect of medial wrist

  • Cubital Tunnel, narrow fascial passageway on inner elbow

  • Subscapularis

• Brachial Plexus: Common Entrapment Sites

  • Median Nerve

  • Elbow: Between superficial and deep heads of the pronator teres muscle

  • Ligament of Struthers: Proximal medial elbow

  • Forearm: The proximal edge of the flexor digitorum superficialis (FDS) muscle. 

  • Wrist: At Carpal Tunnel (commonly overdiagnosed)

• Lumbar Plexus: Common Entrapment Sites

• Saphenous Nerve

  • Hunter’s Canal: Between vastus medialis, adductor longus/magnus, subsartorial fascia

  • Fascia medial/inferomedial knee

  • Fascia medial/distal shin & ankle

• Femoral Nerve

  • Femoral Triangle: Inguinial Ligament, Adductor Longus, Sartorius

• Obturator Nerve

  • Obturator foramen/canal/membrane

  • Obturator externus

  • Between Adductor Longus/Brevis

    
    

• Sacral Plexus

• Tibial Nerve

  • Fascia & musculature of Gastrochnemius

  • Popliteal Fossa

  • Tarsal Tunnel

• Common, Superficial, and Deep Peroneal/Fibular Nerves

• Superficial Peroneal Nerve (SPN):

  • Location: Enters the lateral compartment of the leg at the fibular head

• Deep Peroneal Nerve (DPN):

  • Location: Crosses underneath the extensor retinaculum

• Sciatic Nerve

  • Piriformis/Deep 6:

    • Located beneath or within the piriformis muscle and deep external rotators

    • Commonly overdiagnosed along with disc-related conditions

    Ischiofemoral Space:

    • Location: Between the ischium and lesser trochanter

    Ischial Tunnel:

    • Location: Proximal hamstring (biceps femoris) at the level of the ischium

Dermatomes & Myotomes

• Dermatomes

• Definition: Specific areas of skin supplied by sensory fibers from a single spinal nerve root.

• Key Features:

  • Organized in overlapping patterns for redundancy.

  • Damage to a spinal nerve causes sensory deficits in its dermatome.

• Dermatome Regions:

  • Cervical (C2–C8): Head, neck, shoulders, parts of upper limbs

  • Thoracic (T1–T12): Chest and abdomen

  • Lumbar (L1–L5): Lower back, anterior thighs, medial legs

  • Sacral (S1–S5): Buttocks, posterior thighs, most of the feet

• Clinical Applications:

  • Localize nerve or spinal cord injuries via sensory changes.

  • Guide massage therapy (e.g., S1 for sciatica).

  • Conditions like shingles follow dermatome patterns.

• Myotomes: Motor Regions of Muscle Control

• Definition: Groups of muscles innervated by motor fibers from a single spinal nerve root.

• Key Features:

  • Essential for voluntary muscle control and reflexes.

  • Testing myotomes identifies motor deficits or nerve injuries.

• Cervical Myotomes:

  • C5: Shoulder abduction (deltoid)

  • C6: Elbow flexion, wrist extension (biceps brachii, brachioradialis)

  • C7: Elbow extension, wrist flexion (triceps brachii, wrist flexors)

  • C8: Finger flexion (flexor digitorum profundus), thumb extension (extensor pollicis brevis/longus)

• Lumbar Myotomes:

  • L2: Hip flexion (iliopsoas).

  • L3: Knee extension (quadriceps).

  • L4: Ankle dorsiflexion (tibialis anterior).

  • L5: Big toe extension (extensor hallucis longus).

• Sacral Myotomes:

  • S1: Plantar flexion (gastrocnemius, soleus).

  • S2: Toe flexion (flexor digitorum longus) or Knee Flexion (hamstrings).

Reflexes & Reflex Arcs

Reflexes

• Reflexes: Rapid, automatic responses to specific stimuli that occur without concious control; rely on reflex arcs

• Functions

  1. Protective Role: Immediate withdrawal fro. harmful stimuli

  2. Homeostasis: Regulation of internal processes like BP & Respiration

  3. Postural Support

• Types

• By Function:

  • Somatic Reflexes; Involve skeletal muscles, such as withdrawal reflexes or stretch reflexes

  • Autonomic Reflexes: Regulate involuntary functions

• By Complexity:

  • Monosynaptic Reflexes: Single synapse between sensory & motor neurons

  • Polysnaptic Reflexes: Involve interneurons for more complex integration

• Spindle Anatomy

  • Composed of intrafusal (Sensory) fibres embedded within Extrafusal (Contractile) fibres

  • Spindles will synapse directly with motor neurons in the spinal cords

• Autogenic vs Reciprocal Inhibition

• Autogenic Inhibition

  • A protective reflex inhibits muscle contraction when excessive tension is detected in the muscle tendon

• Mechanism

  • GTO sense tension in a contracting muscle

  • Signals from the GTOs are sent to the spinal cord via afferent neurons

  • Inhibitory interneurons suppress the motor neuron activity of the same muscle, causing it to relax

• Purpose

  • Protects muscles & tendons from excessive force/tension

• Reciprocal Inhibition

  • Where the contraction of one muscle inhibits the activity of the agonist muscle

• Mechanism

  • Muscle spindles detect stretch in the agonist muscle

  • Signals travel via afferent neurons in the spinal cord

  • Excitatory interneurons activate the motor neurons of the agonist muscke

  • Inhibitory interneurons suppress the motor neurons of the antagonist muscles causing it to relax

• Purpose

  • Facilitates smooth & coordinated movement by preventing resistance from opposing muscles

• Withdrawal (Polysynaptic) Reflex

• Mechanism:

  • Thermo/Nociceptors detect a threatening stimulus

  • Sensory neurons synapse with interneurons within spinal cord

  • Interneurons activate motor neurons to flexor muscles while inhibiting extensors

• Purpose: Protects body from harm by rapidly withdrawing the affected part

• Physiological: Nocieptive signals ascend to the brain for concious processing via spinothalmaic tract

• Crossed Extensor Reflex (Polysynaptic)

• Mechanism:

  • Threat detected by nociceptors

  • Sensory neurons activate interneurons, which stimulate motor neurons

  • Withdrawal occurs in affected leg, while opposite leg extends to maintain balance

• Purpose: Ensures postural stability during reflexive movements

  
  

• Abnormal Reflexes

• Hyperflexxia:

  • Caused by UMN lesions leading to exaggerated reflexes

  • Mechanism: Loss of descending inhibitory signals from the brainstem or cortex

• Hyporflexia:

  • Caused by peripheral nerve damage or LMN lesions

  • Mechanism: Impaired transmission of sensory or motor signals in reflex arcs

• Areflexia:

  • Absence of reflexes indicating severe neural impairment

Muscle Tone

• Regulation:

  • Muscle spindles detect changes in length & adjust tone via stretch reflex

  • Gamma motor neuron modulate spindle sensitivity

    • GMN’s control muscle contraction at muscular level

    • Innervate the muscle spindle & allow contraction of intrafusal fibers, increasing their sensitivity to stretch

    • They work with Alpha Motor Neurons to maintain muscle lenght & velocity

    • AMN’s initiate contraction of extrafusal muscle fibers, which are the primary muscle fubers used for skeletal movement

Intervention

• Hypertonicity

  • Friction, Stripping, Local Cross Fibering

    • Increases tension on GTO’s & reduces tension on spindles

  • Effluerage, Petrissage, Goading, General Cross Fibering

    • Stimulates mechanoreceptors

• Hypotonicity

  • Tapotment

  • Fast Techniques

• GTO’s

  • Passive Stretching

  • Sustained Compression

  • Proprioceptive Neuromuscular Fasicilitation

  • Soft Tissue / Active Release

  • Myofascial Release

• Spindle

  • Static Stretching

  • Reciprocal Inhibition Stretching

  • Joint Mobilization

Proprioception & Exteroception

Proprioception

• A sense which allows us to perceive where we are in space

• Key Receptors:

  • Muscle Spindles

  • GTO

  • Joint Kinesthetic Receptors

  • Fascial Mechanoreceptors

• Spindles

• Function: Provide continuous feedback to NS about muscle position, movement, & tone

• Proprioception:

  • Detects Length Change

  • Inhibites Stretch Reflex

  • Provides Continuous Sensory Feedback to CNS

  • Fine-Tunes Muscle Tone & Coordination

• Annulospiral vs. Flower Spray Endings

• Location: Within skeletal muscles

• Function: Detects muscle stretch & rate of length change

• Annulospiral Endings (Primary Endings)

  • In intrafusal muscle fibres within a muscle spindle; detects dynamic stretch

  • Activated by quick stretches or rapid muscle contraction

  • More sensitive to rate of muscle length change

• Flower Spray Endings (Secondary Endings)

  • Located on ends of intrafusal fibers; concerned with realtive muscle length & slow stretch

• Gamma Gain

• The level of sensitivity of the spindle to stretch, controlled by the activity of GMN that innervate

• GTO

• Function: Provides feedback on amount of force being generated in a muslce

• Proprioception:

  • Montiors tension

  • Autogenic Inhibition

  • Fine-Tuning Motor Control

  • Postural Stability & Load Managment

Joints & Ligaments

• Joint & Ligament Kinesthetic Receptors

• Function:

  • Detec pressure, angle, movement, speed

  • Reflexively adjust muscle activation for joint stability

• Types:

  • Ruffini Endings (Capsule)

  • Pacinian Corpuscles

  • Goligi Ligament Endings (Ligaments)

  • Free Nerve Endings

Exteroception

• Common Mechanoreceptors

  • Pacinian Corpuscles

  • Meissner’s Corpuscles

  • Merkel Discs

  • Ruffini Endings

  • Low Thershold Mechanoreceptors

  • Free Nerve Endings / CT Fibers / Nociceptors

• Thermo, Chemo, Nociception

• Nociceptors:

  • Mechanical: Pressure, stretch

  • Thermal

  • Chemical: Inflammation

• Chemoreceptors

  • Polymodal: Chemical changes due to injurry

  • Hstamine-Sensitive Receptors: Detect inflammation & allergic responses

  • Tactile: Respond to topical agents

• Thermoreceptors