The Nervous System & the control of movement Chapter 6

Q: What is the main role of the Nervous System? A: To “assemble info about conditions external & internal to the body, to analyze this information and initiate an appropriate response”. “COMMUNICATION NETWORK” A: To “assemble info about conditions external & internal to the body, to analyze this information and initiate an appropriate response”. “COMMUNICATION NETWORK”

What are the 2 Major Components of the Nervous System? 1. The Central Nervous System 2. The Peripheral Nervous System 1. The Central Nervous System 2. The Peripheral Nervous System

CNS (Central Nervous System)  Two Parts: A) The Brain B) The Spinal Cord (& vertebral column)  Two Parts: A) The Brain B) The Spinal Cord (& vertebral column)

CNS ‘A’ - The Brain  Main control center for survival  Emotions  The brain is made up of 6 parts:  Main control center for survival  Emotions  The brain is made up of 6 parts:

The 6 Brain Segments 1) Cerebrum: -largest section -controls sensory, motor & intelligence functions -2 hemispheres / 8 ‘lobes’ 1) Cerebrum: -largest section -controls sensory, motor & intelligence functions -2 hemispheres / 8 ‘lobes’

The 6 Brain Segments (continued) 2) Cerebellum - coordinates balance & muscle movement 3) Brain Stem - links cerebrum to the spinal cord ---> Autonomic functions like “muscle tone” 2) Cerebellum - coordinates balance & muscle movement 3) Brain Stem - links cerebrum to the spinal cord ---> Autonomic functions like “muscle tone”

The 6 Brain Segments (continued) 4. Diencephalon -divided into the: 4. Diencephalon -divided into the: i)Thalemus -pain & attention ii) Hypothalemus -appetite -emotions -body temperature

The 6 Brain Segments (continued) 5. Limbic System: -regulates basic drives like hunger, emotions, aggression 6. Reticular Activating System -crucial for maintaining consciousness 5. Limbic System: -regulates basic drives like hunger, emotions, aggression 6. Reticular Activating System -crucial for maintaining consciousness

CNS ‘B’ - Spinal Cord (& Vertebral Column)  Main info pathway between brain & PNS  Spinal Cord - 45cm (brain stem to L2)  Spinal Nerves carry: -sensory info to CNS & -motor commands away from CNS  Main info pathway between brain & PNS  Spinal Cord - 45cm (brain stem to L2)  Spinal Nerves carry: -sensory info to CNS & -motor commands away from CNS

What are the 2 Major Components of the Nervous System? 1. The Central Nervous System 2. The Peripheral Nervous System 1. The Central Nervous System 2. The Peripheral Nervous System

PNS (Peripheral Nervous System)  12 Cranial Nerves / 31 Spinal Nerves (sensory fibers)  Responsible for voluntary actions & bodily functions  Eg heart beat, muscle control  Made of Autonomic NS & Somatic NS  Efferent nerves (motor) - carry info from CNS to organs ( E fferent-->muscles)  Afferent nerves (sensory)- carry info to brain --> A fferent-->br a in)  12 Cranial Nerves / 31 Spinal Nerves (sensory fibers)  Responsible for voluntary actions & bodily functions  Eg heart beat, muscle control  Made of Autonomic NS & Somatic NS  Efferent nerves (motor) - carry info from CNS to organs ( E fferent-->muscles)  Afferent nerves (sensory)- carry info to brain --> A fferent-->br a in)

PNS ‘A’- Autonomic Nervous System  Involuntary i) Sympathetic System: -prepares body for emergencies (fight or flight response) ii) Parasympathetic System: -returns boy to normal after ‘emergency’  Involuntary i) Sympathetic System: -prepares body for emergencies (fight or flight response) ii) Parasympathetic System: -returns boy to normal after ‘emergency’

PNS ‘B’- Somatic Nervous System Components: -afferent & efferent nerve fibers -PNS controls and knows what our muscles/tendons are doing & feeling (ie pain, cold, balance, etc.) Components: -afferent & efferent nerve fibers -PNS controls and knows what our muscles/tendons are doing & feeling (ie pain, cold, balance, etc.)

REFLEX ARC -Automatic response to stimulation -if command center for the flex is: a)the brain ---> cerebral reflex arc b)the spinal cord --->spinal reflex arc -Automatic response to stimulation -if command center for the flex is: a)the brain ---> cerebral reflex arc b)the spinal cord --->spinal reflex arc

Autonomic Reflexes -some involve smooth muscle, cardiac muscle, glands -regulates digestion, blood pressure, sweating -some involve smooth muscle, cardiac muscle, glands -regulates digestion, blood pressure, sweating

Somatic Reflexes -involve stimulation of skeletal muscle ie -stretch reflex, withdrawl reflex -involve stimulation of skeletal muscle ie -stretch reflex, withdrawl reflex

Basic Reflex Arc  The components of a basic reflex include; i) receptor ii) adjustor iii) effector  The components of a basic reflex include; i) receptor ii) adjustor iii) effector

Reflex Arc The components of a reflex arc include; i) receptor ii) sensory or AFFERENT nerve (brain) iii) intermediate nerve fibers (adjustor) which interprets the signal & issues an appropriate response iii) motor or Efferent nerve (muscle) v) effector organ (muscle) -if command center for the flex is: a)the brain ---> cerebral reflex arc b)the spinal cord --->spinal reflex arc The components of a reflex arc include; i) receptor ii) sensory or AFFERENT nerve (brain) iii) intermediate nerve fibers (adjustor) which interprets the signal & issues an appropriate response iii) motor or Efferent nerve (muscle) v) effector organ (muscle) -if command center for the flex is: a)the brain ---> cerebral reflex arc b)the spinal cord --->spinal reflex arc

Proprioceptors Provide info re: - muscle contraction - position of limbs - body posture - balance Provide info re: - muscle contraction - position of limbs - body posture - balance

Proprioceptors There are 2 receptors: i) Golgi Tendon Organs (GTO) ii) Muscle Spindles There are 2 receptors: i) Golgi Tendon Organs (GTO) ii) Muscle Spindles

Golgi Tendon Organs - tension detectors - In the tendon of the muscle - Tension Reflex: GTO, Afferent Neuron, CNS, Efferent Neuron, Motor unit - tension detectors - In the tendon of the muscle - Tension Reflex: GTO, Afferent Neuron, CNS, Efferent Neuron, Motor unit

Muscle Spindles -senses changes in muscle length -2 afferent neurons & 1 efferent neuron -very sensitive “Stretch Reflex” (see table 6.1 on pg. 101 in text) -senses changes in muscle length -2 afferent neurons & 1 efferent neuron -very sensitive “Stretch Reflex” (see table 6.1 on pg. 101 in text)