What does the sensory system include?

The classification of sensation: somatic sensation and visceral sensation, including: special visceral sensation: smell and taste; General visceral sensation: sensation caused by swelling, pain, pressure and emptiness of viscera, serosa and blood vessels. Special body feeling: vision, hearing and balance are felt by eyes and ears respectively. General feeling: shallow feeling mainly introduces: the feeling of skin and superficial mucosa. Including: shallow pain, temperature, touch. Deep feeling: that is, proprioception. Including the pressure of subcutaneous tissue, the sense of movement of tendons and joints, the sense of position, deep pain and the sense of vibration felt on bones. Compound sense: sense of orientation, sense of two-point discrimination, sense of entity, sense of re-perception, etc. First, the composition of the sensory system: receptors-receiving stimuli for preliminary analysis and transforming stimuli into nerve impulses. On the left is the baroreceptor, and on the right is the tactile receptor) the conduction part: the central part of the sensory conduction bundle: all kinds of general senses in the sensory cortex center have their own unique receptors and conduction pathways. 1. receptor external receptor: surface sensation, from skin and mucous membrane, to receive various stimuli directly added to body tissues from the outside. Pain: neuropathic pain; Temperature sensation: cold sensation Klaus globular corpuscle, heat sensation Ruffini corpuscle. Touch: Nerve endings around hair follicles, meissner and Merkel. . Pressure: Paccini's annular corpuscle. Proprioceptor: Deep sensation, which receives stimulation from deep tissues such as muscle (neuromuscular spindle), tendon (tendon sheath spindle) and joints, including motor sensation, position sensation, vibration sensation and fine touch. Neuromuscular spindle nerve tendon (Golgi tendon apparatus). Endoreceptor-receives stimuli from internal organs. Sensory conduction system: pain and temperature conduction system (pain and temperature conduction system), lateral spinal cord-thalamic tract-pain and temperature sense, anterior spinal cord-thalamic tract-light tactile sensation, conscious proprioception and fine tactile conduction system: posterior colliculus pathway (thin bundle, wedge bundle)-fine tactile sensation, including external sensation (tactile sensation-barometric sensation), two-point resolution and unconscious proprioception conduction system: posterior cord and. Sensory cortical center: advanced comprehensive analysis of transmitted stimuli: the central posterior gyrus (Brodmann domain 3, 1, 2) and partial parietal gyrus (Brodmann domain 5, 7) 2. Conduction pathway (1) conscious proprioception and subtle tactile conduction system (tactile and vibration sensation), isoauditory receptor → peripheral nerve → spinal ganglion cells (1)→ spinal nerve posterior root → medulla oblongata thin bundle, wedge bundle → nucleus of thin bundle and wedge bundle (2)→ intersection of internal arcuate fibers → medial thalamus (opposite side). 7 domain) (II) Pain and temperature receptors of skin and mucosa → Peripheral nerve → Spinal ganglion cells (1)→ Posterior root of spinal nerve → rolando's glia at the tip of spinal cord (2)→ Anterior commissure of white matter → Lateral bundle of spinal cord and thalamus (contralateral) → Lateral nucleus of thalamus (3)→ The fibers emitted by secondary neurons first rise 2-2 on the same side. 2. Unconscious proprioceptivesystem 1. Lower limbs and trunk: spinal ganglion cells (1)→ posterior cord of spinal cord → Clark column (2)→ spinocerebellar tract → inferior cerebellar peduncle → cerebellar nucleus (3)→ cerebellum. Conduction on the same side, without crossing. 2. Upper limbs and neck: ganglion cells (1)→ posterior funiculus (cuneiform tract) → accessory nucleus of cuneiform tract → cuneiform cerebellar tract → posterior cerebellar tract of spinal cord → cerebellar offal → cerebellar nucleus (3)→ cerebellum. Conduction on the same side, without crossing. Characteristics of sensory conduction system The composition of sensory system: peripheral-receptor, conduction-conduction system, central-cerebral cortex pain and temperature system and proprioception fine tactile conduction system: tertiary conduction: the first neuron is in spinal ganglion cells; The third neuron is in the ventrolateral thalamic nucleus; The second neuron: proprioception is the nucleus tractus gracilis and the nucleus cuneiform, and pain and temperature sensation are the rolando colloid at the tip of the spinal cord posterior horn. Secondary crossing: the medial posterior cord thalamic tract crosses in the medulla oblongata, and the spinal cord crosses at the anterior commissure of the white matter of the spinal cord. The opposite side dominates the unconscious presensory system, which has three levels of conduction and does not cross, and dominates the same side. All sensory conduction bundles are composed of three neuron units. Third, the arrangement and skin distribution of sensory nerve fibers in different parts of the nervous system 1. Peripheral nerve: patch distribution II. Ganglion or posterior root: segmental distribution (the trunk is ring-shaped and the limbs are strip-shaped). Upper limb (enlarged neck) C5-T2; Lower limb (waist swelling) L 1-S2 Trunk: T3-T12; Perineal and perianal parts: S3-S5, head and neck-c1-C4; The medial surface of trigeminal nerve: fine sense of touch and depth; External: light perception (internal: rough touch; Medium: temperature perception; Exterior: pain) 3. Spinal cord: posterior cord: thin bundle: medial-lower limbs (only below T4 or T6). Wedge bundle: lateral upper limb. Inside? Exterior: sacrum-waist-chest-neck (because the fibers entering the posterior cable do not cross, the posterior cable fiber-wedge bundle from the upper segment pushes the posterior cable fiber-thin bundle from the lower segment to the inside one after another) back to the ventral side: fine touch, position, movement, vibration and pressure. Lateral and anterior bundles of spinal cord and thalamus: medial-upper limb, middle trunk, lateral-lower limb; Outside? Internal: The hierarchical arrangement of the sacral-lumbar-thoracic-cervical conduction bundle (caused by the fibers of the upper spinal cord-thalamus bundle pushing the fibers of the lower spinal cord-thalamus bundle outward) is of great significance for the differential diagnosis of intramedullary tumors and extramedullary tumors, especially in the case of pain and temperature sense's disorder. For example, for cervical intramedullary tumors, pain and temperature sense's disorder develop in the order of neck-chest-waist-sacrum, that is, from the focus level to the bottom; For cervical extramedullary tumors, the development order of pain and temperature sense's disorder is opposite. Back to abdomen: sense of temperature, pain, rough touch and pressure 5. Brain stem: medial thalamus (posterior cord) medulla oblongata-headless people stand back; Pont- lower part: headless people sit on their backs; The upper part: headless people lie on their backs; Midbrain-a headless man standing upside down, with his lower limbs on his back and his upper limbs on his ventral side; Medulla oblongata-upper limbs on the inside, lower limbs on the outside. Pontine: located outside the medial colliculus, the upper limbs are inside and the lower limbs are outside. Midbrain: located at the back of medial colliculus, with upper limbs on the back and lower limbs on the ventral side. The medial colliculus and the spinal colliculus are closely connected behind the superior pontine, so there are obstacles in depth and sensation during the lesion, and there is no change in dissociative sensory disturbance. 6. Thalamus: ventrolateral nucleus of thalamus, surface sensation: lateral; Deep sleep: inside 7. Internal capsule: posterior limb 1/3, anterior upper limb, posterior lower limb 8. Sensory cortex: central posterior gyrus (brod Mann 3, 1, 2 domain), inverted humanoid. The upper and lower limbs, middle trunk, upper limbs and lower head and face intersect, and the representative area is not proportional to the body surface area, which is related to the distribution of receptors. Fourth, the symptoms of sensory disorders are divided into "degree": sensory loss, anesthesia, and hypersensitivity (slight stimulation causes strong feelings). Divided by "nature": sense of separation: one sensory obstacle, the other reserved. Such as pain tactile separation: pain disorder, tactile preservation. Schizophrenia sensory disturbance. Hyperpathia: the threshold of excitement is increased, the reaction time is prolonged, the nature and location are difficult to determine, there is a strong discomfort, and the stimulation site has spread. Such as thalamic injury and peripheral neuritis. Abnormal sensation: numbness, dullness, itching, acupuncture, ant walking, and no external stimulation on the belt. Spontaneous pain: such as root pain. Inhibitory symptoms: anesthesia-sensory pathway is destroyed. Integrity-all senses (shallow and deep) are missing in the same place; Separation-only some sensory disorders and other senses remain in the same place. Insensitivity-sensory function is inhibited. Irritation symptoms: Allergy-slight irritation causes strong feeling. Sensory inversion-pain is induced by non-pain stimuli, or cold stimuli are regarded as hot stimuli. Hyperpathia-a strong uncomfortable feeling caused by various stimuli, such as pain after herpes zoster, thalamic angiopathy (cerebral hemorrhage), and recovery period of peripheral nerve trauma. Abnormal sensation-numbness, numbness, itching, tingling, ant walking, swelling and trembling when there is no external stimulus. Pain-local pain, radiation pain (when the nerve trunk, nerve root or central nerve is stimulated by the lesion, the pain not only occurs in the stimulated part, but also extends to the dominant area of the affected sensory nerve. Such as disc herniation), diffuse pain (pain caused by stimulation spreading from one nerve branch to another). Such as angina pectoris caused by involvement pain, left chest and left upper limb pain). According to "distribution", there are peripheral type, segmental type and conduction beam type. 5. Location diagnosis of sensory disturbance: sensory disturbance caused by lesions in various parts of the sensory system 1. Peripheral nerve: single: patchy distribution, various sensory disorders. Such as lateral femoral cutaneous neuritis: symmetrical glove-sock distribution at the distal ends of limbs, multiple sensory disorders; That is, peripheral sensory disturbance. For example, polyneuritis is mostly caused by poisoning (arsenic-pyridine cream, furacilin-Paeonsulin) or metabolic disorder (vitamin B 1 deficiency, diabetes, alcoholism). Posterior root sensory disturbance: segmental (the trunk is ring-shaped and the limbs are strip-shaped), and various sensory disturbances. There will be root pain. For example, radiculitis, disc herniation and extramedullary tumor of spinal cord, because the dominant areas of adjacent roots overlap, it is impossible to find a root lesion, but there may be a root irritation-root pain. Gangliopathy: the distribution is similar to that of root, and there may be herpes zoster. See the damage to the ponytail. Upper limb (cervical enlargement: C5-T2)C5- deltoid muscle; C6- thumb; C7-middle finger and ring finger; C8- little finger; T 1- ulnar forearm (part), medial upper arm; T2- armpit. Chest T3-T6, male nipple T4; Abdomen: upper abdomen T7-T8, xiphoid process T7; Navel T9-T 10, navel t10; Lower abdomen T 1 1-T 12, groin t12; Lower extremity: l1-S2; Perineum: S3-S5. Spinal cord: gray matter: segmental distribution, dissociative sensory disturbance A posterior horn: unilateral segmental distribution, dissociative sensory disturbance-painful tactile separation, dysalgesia, tactile preservation. Such as syringomyelia, occurs in the central canal and posterior horn of the spinal cord. The cone is damaged. B anterior gray matter commissure: segmental distribution on both sides, dissociative sensory disturbance-separation of pain and touch, dysalgesia and tactile retention. The injury of the fibers in front of the thalamic tract of the spinal cord leads to the "jacket-like" distribution of cervical spinal cord and thoracic spinal cord injuries, and the "underwear-like" distribution of lumbar spinal cord injuries. Such as syringomyelia, intramedullary tumors of the spinal cord (with more longitudinal development) and spinal hemorrhage. White matter: sensory disturbance of conduction bundle distribution below the lesion plane A posterior cord: deep sensory disturbance of conduction bundle distribution below the lesion plane, ipsilateral, sensory ataxia (walking unsteadily, especially when there is no visual adjustment-at night or with eyes closed, walking loudly, feeling of stepping on cotton, wearing shoes to bed, easy to fall when washing face), Rhomberg sign positive. Such as spinal tuberculosis, true syphilis and pseudodiabetes; Subacute combined degeneration (vitamin B 12 deficiency after subtotal gastrectomy). Decreased sense of oppression, inability to feel the ground under your feet, and instability in standing or walking, especially in the absence of visual adjustment (such as at night and with your eyes closed); And have the feeling of stepping on cotton; The signs in Rhomberg are positive. Obstacles in position perception and motion perception cannot explain the position of his limbs after closing his eyes. The sense of vibration is lost, and the tuning fork placed on its bone cannot feel vibration. Lose the ability to distinguish between two points on the skin. Compound sensory loss, after closing his eyes, he could not distinguish the words written on his skin and describe the shape and nature of the objects he touched. B Anterior commissure of white matter: The fibers cross the lateral tract of spinal cord and thalamus and the anterior tract of spinal cord and thalamus, and the sensory disturbance, bilateral pain and temperature sense's disturbance are separated in segments, but the sense of touch is preserved, and the pain and the sense of touch are separated. Ipsilateral hemispinal cord injury (Brown-Secard syndrome): posterior spinal cord-deep sensory disturbance; Contralateral: lateral bundle of spinal cord and anterior bundle of spinal cord and thalamus-pain and temperature sense's disorder, but the sense of touch remains, and pain and touch are separated. Transverse damage of spinal cord in dissociative sensory impairment: posterior spinal cord bundle, lateral spinal cord bundle, anterior spinal cord bundle and thalamus, bilateral. Various senses are damaged. Brain stem and medulla oblongata: cross sensory loss, ipsilateral part (nucleus of trigeminal spinal tract), pain and temperature loss of contralateral limb (spinal cord mound system). Clinical diseases: thrombosis of posterior inferior cerebellar artery (Wallenberg syndrome, posterolateral lesion of upper middle level of medulla oblongata). Pontine and midbrain: sensory disturbance extends to the lateral side and limbs, sensory fibers have crossed to the opposite side, and there are motor neuron paralysis under the ipsilateral cranial nerve in the damaged plane, which is more common in cerebrovascular diseases. Thalamic sensory disturbance: various sensory disturbances of contralateral oblique conduction tract of thalamic triad. The distal limbs are obvious and feel heavy. Partial ataxia. Isotopic hemianopia (lateral geniculate body) thalamic spontaneous pain, hypersensitivity, sensory inversion, etc. Such as thalamic tumor, cerebrovascular disease-thrombosis of posterior cerebral artery, and sensory disturbance of internal capsule: three-deviation sign of internal capsule, such as cerebral hemorrhage, sensory disturbance of contralateral side of internal capsule and sensory disturbance of conduction bundle. Hemiplegia with cerebral palsy (lateral geniculate body) 6. Cortical sensory disturbance: stimulation symptoms: stimulation of sensory cortex can cause sensory localized seizures. Symptoms of damage: (1) sensory disturbance of one limb, especially the hand or foot; Compound sensory disorders: somatic sensory disorders such as orientation perception, two-point discrimination perception, entity perception and heavy perception. And it is impossible to distinguish the size, shape and texture of objects by touch.