Somatic Senses & Motor Control PDF 2025

16.2 Nervous System Organization (pg. 592) spinal cord, brain * integration ALL * interneurons afferent efferent * c...

16.2 Nervous System Organization (pg. 592) spinal cord, brain * integration ALL * interneurons afferent efferent * cranial & * cranial & *dual spinal nerves innervation spinal nerves SNS, ANS, ENS sensory receptors and neurons * * general effectors senses Somatic Nervous System (SNS) → exteroceptors (skin, muscles, joints, special senses) Autonomic Nervous System (ANS) → interoceptors (viscera – organs) Enteric Nervous System (ENS) → interoceptors (chemical changes, stretch: GI tract) © D.M. Andrews, 2025  16.2 Nervous System Organization (pg. 592) spinal cord, brain * integration ALL * interneurons afferent efferent * cranial & * cranial & *dual spinal nerves innervation spinal nerves SNS, ANS, ENS sensory receptors and neurons * * special effectors senses Somatic Nervous System (SNS) → exteroceptors (skin, muscles, joints, special senses) Autonomic Nervous System (ANS) → interoceptors (viscera – organs) Enteric Nervous System (ENS) → interoceptors (chemical changes, stretch: GI tract) © D.M. Andrews, 2025  Sensation (pg. 719) * adaptation * perception Sensory CNS sensation receptor * sensory stimulus transduction impulse integration modalities conduction © D.M. Andrews, 2025  20.1 Sensory Receptors: Skin (also Tab. 20.1 pg. 721; Tab. 20.2 pg. 726) ALL Classification/Types: 1. features Meissner 2. stimulus detected 3. location/activation Ruffini - free nerve endings - encapsulated nerve endings - separate cells* Pacinian (lamellar) * special senses © D.M. Andrews, 2025  20.1 Sensory Receptors: Skin (also Tab. 20.1 pg. 721; Tab. 20.2 pg. 726) ALL Classification/Types: 1. features Meissner 2. stimulus detected 3. location/activation Ruffini - photoreceptors - mechanoreceptors - thermoreceptors - osmoreceptors Pacinian - chemoreceptors (lamellar) - nociceptors © D.M. Andrews, 2025  20.1 Sensory Receptors: Skin (also Tab. 20.1 pg. 721; Tab. 20.2 pg. 726) ALL Classification/Types: 1. features Meissner 2. stimulus detected 3. location/activation Ruffini - exteroceptors - interoceptors - proprioceptors Pacinian * density/ (lamellar) distribution © D.M. Andrews, 2025  20.1 Sensory Receptors: Skin (also Tab. 20.1 pg. 721; Tab. 20.2 pg. 726) ALL Somatic Sensations 1. tactile Meissner 2. thermal 3. pain 4. proprioception Ruffini - touch - pressure - vibration Pacinian - itch* and tickle (lamellar) * chemical stimuli © D.M. Andrews, 2025  20.1 Sensory Receptors: Skin (also Tab. 20.1 pg. 721; Tab. 20.2 pg. 726) ALL Somatic Sensations 1. tactile Meissner 2. thermal 3. pain 4. proprioception Ruffini - coldness * vs. pain - warmth Pacinian (lamellar) © D.M. Andrews, 2025  20.1 Sensory Receptors: Skin (also Tab. 20.1 pg. 721; Tab. 20.2 pg. 726) ALL Somatic Sensations 1. tactile Meissner 2. thermal 3. pain 4. proprioception Ruffini - nociceptors* * X brain Pacinian * mechanical, thermal, chemical (lamellar) © D.M. Andrews, 2025  20.1 Sensory Receptors: Skin (also Tab. 20.1 pg. 721; Tab. 20.2 pg. 726) ALL Somatic Sensations 1. tactile Meissner 2. thermal 3. pain 4. proprioception Ruffini - muscle spindles - tendon organs - joint kinesthetic Pacinian receptors (lamellar) © D.M. Andrews, 2025  20.3 Muscle Spindles & Tendon Organs ALL * reflexes Muscle Spindles 1. intrafusal fibres 2. length change/stretch 3. muscle tone Tendon Organs 1. muscle/tendon junction 2. tendon fascicles 3. muscle tension * collagen bundles © D.M. Andrews, 2025  17.11 Sensory & Motor Tracts (pg. 634) * pathways interneuron (association) e.g., posterior spinocerebellar tract * name // direction © D.M. Andrews, 2025  20.4 Somatic Sensory Pathways: Posterior posterior column – * perception ALL medial lemniscus * decussation * post-central gyrus * projection tracts * brainstem first-order second-order (funiculus) third-order * spinal cord (somatic receptors) © D.M. Andrews, 2025  20.4 Somatic Sensory Pathways: Anterolateral spinothalamic * perception ALL * decussation * post-central gyrus * projection tracts first-order second-order third-order * posterior gray horns (neck, trunk, limbs) © D.M. Andrews, 2025  20.6 Somatic Motor Pathways: Corticospinal * direct (cortex) ALL * decussation * projection tracts 90% UMNs LMNs * anterior & lateral white funiculi 10% (decussation) * limb and trunk muscles © D.M. Andrews, 2025  Reminder: Movement Influencers (pg. 735; Ch. 18) Corpus striatum Cerebellum Colliculi 1. initiates/terminates 1. monitors intended & 1. movements of eyes, movements actual movements head, body 2. regulates muscle tone 2. provides corrective 2. centres for visual 3. subconsciously controls feedback and auditory reflexes muscle contractions © D.M. Andrews, 2025