Physiology of Nervous System presentation.pptx

physiology of nervous system

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2. Physiology of Nervous System Neurophysical therapy Lec 2 Dpt 8 th , batch 4 Dr. AQSA By: Ayesha, Elsa, Fatima, Hanook, Laraib, Sanodia, Sefatullah 2

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4. Nervous system The control center allowing the body to react to environment It functions as Sensory Integrative Motor system Components Brain Spinal cord Nerves 4

5. Neuron The basic structural and functional unit of nervous system Composed of Cell body- contains nucleus Dendrites- receives signals & conducts impulse towards cell body Axons- transmits signals & conducts impulse away from cell body 5

6. Structure 6 Cell body (also known as the soma): - Contains the nucleus, cytoplasm, and cell organelles like mitochondria, Golgi apparatus, and lysosomes - Has Nissl's granules for protein synthesis - Neurofibrils are also present Dendrites: - Short, branching processes that receive incoming impulses - Contain Nissl's granules, mitochondria, and neurofibrils - No myelin sheath or neurilemma- Axon: - Long, slender process that conducts nerve impulses away from the cell body - Contains mitochondria and neurofibrils, but no Nissl's granules - Myelin sheath: Fatty insulating layer that surrounds most axons, Composed of Schwann cells and neurilemma, Interrupted at nodes of Ranvier -

7. Type 7 Based on number of nerve processes: 1. Unipolar neurons (1 process) 2. Bipolar neurons (2 processes: axon and dendrite) 3. Pseudo-unipolar neurons (2 processes arising in a T-shape) 4. Multipolar neurons (many processes: axon and multiple dendrites) Based on axon length: 1. Golgi type 1 neurons (long axons, form fiber tracts or peripheral nerves) 2. Golgi type 2 neurons (short axons, form association fibers within CNS) Based on function: 1. Sensory neurons (afferent, carry impulses from sense organs to CNS) 2. Connector neurons (connect and correlate sensory and motor neurons) 3. Motor neurons (efferent, carry impulses from CNS to effector organs, muscles, and glands)

8. Function Receives and integrate information Transmit signals throughout the body Generate action potential 8

9. Neuroglia 9

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11. Nervous system 11

12. NS 12

13. PNS 13

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15. 15 Division

16. PNS 16 The Autonomic Nervous System (ANS) controls body functions automatically, divided into:- Sympathetic Nervous System (SNS) Parasympathetic Nervous System (PNS) Sympathetic Nervous System Parasympathetic nervous system Consists of three neurons Consists of two neurons Originates in hypothalamus, reticular formation, and medulla oblongata Originates in brain or spinal cord Stimulates "fight or flight" response Stimulates "rest and digest" response Effects: Constricts blood vessels Dilates pupils Increases heart rate and force Inhibits digestion and secretion Relaxes bladder and bowel sphincters Effects: Constricts pupils Increases tear and salivary secretion Decreases heart rate and force Stimulates digestion and secretion Contracts bladder and bowel sphincters

17. Reflex Definition: Automatic responses to stimuli Occur without brain involvement Components: Receptor: detects the stimulus Sensory neuron: transmits the signal to the spinal cord Spinal cord: processes the information and generates a response Motor neuron : transmits the signal to the effector Effector: responds to the stimulus (muscle contraction or gland secretion) Examples: Withdrawal reflex (pain): pulling your hand away from a hot stove knee-jerk response when the patellar tendon is tapped 17

18. Reflex Arc Reflex Arc:- pathway for any reflex action Involves sensory receptors, spinal cord, and effector organs Examples: Vasodilation Increased peristalsis and tone in intestines Relaxation of bladder and bowel sphincters 18

19. Spinal level reflex Spinal reflexes are rapid, involuntary responses to specific stimuli that occur without requiring input from the brain. They follow a neuronal circuit called the reflex arc. Examples of spinal reflexes: Stretch Reflex : This monosynaptic reflex involves the muscle spindle and the alpha motor neuron. When a muscle is stretched (e.g., tapping the patellar tendon), the muscle spindle detects the change in length and triggers a reflexive contraction of the same muscle to resist further stretching Golgi Tendon Reflex: This reflex involves the Golgi tendon organ, which is sensitive to tension in tendons. When tension increases (e.g., during muscle contraction), the Golgi tendon organ inhibits the alpha motor neuron, leading to muscle relaxation and preventing excessive force Crossed Extensor Reflex: A polysynaptic reflex that occurs during withdrawal reflexes (e.g., stepping on a sharp object). It involves both the stimulated limb (flexor muscles) and the opposite limb (extensor muscles) to maintain balance Withdrawal Reflex: When a painful stimulus (e.g., touching a hot surface) activates sensory receptors, it triggers a complex polysynaptic reflex. The flexor muscles of the affected limb contract, pulling it away from the stimulus 19

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22. All spinal reflexes can be voluntarily over ridden 22

23. Summarize 23

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