anatonmy

• Reflex activity


  Sudden and involuntary response to stimuli
• Reflex


  • Rapid, predictable motor response and is involuntary response to stimuli
  • Highly specific neural paths
• Components of reflex arc


  • Receptor
  • Sensory neuron
  • Integration centre (interneuron)
  • Motor neuron
  • Effector (muscle/gland)
• Types of reflexes


  • Somatic reflex (skeletal muscle)
  • Autonomic reflex (smooth/cardiac muscle, glands)
• Reflexes are activated based on what a person is doing
• Stretch reflex


  Automatically regulates skeletal muscle length
• Stretch reflex


  1. Muscle stretch activates muscle spindle

  2. Muscle spindle sends impulse to spinal cord

  3. Impulse synapses with motor neuron

  4. Causes muscle contraction
• Muscle spindle


  • Detects changes in muscle length and triggers strength reflexes
  • Prevents over-stretching and injury
• Reciprocal inhibition


  1. Sensory neurons synapse with interneurons

  2. Interneurons inhibit motor neurons of antagonistic muscles

  3. Allows one muscle group to contract while the other relaxes
• Golgi tendon organ


  • Proprioceptors in muscle tendons that detect tension or contraction in the muscle
  • Important for smooth onset and termination of contraction
• Muscle spindle


  • Arranged in parallel with skeletal muscle fibers
  • Encapsulated receptor sensitive to stretch
• Muscle spindle senses


  • Rate of stretch
  • Amount of stretch
  • Degree of stretch
• Muscle contraction


  • Optimal overlap of thin and thick filaments
  • Permits sliding along nearly entire length of thin filaments
• Muscle contraction


  Velocity and duration influenced by muscle fiber type, load, and recruitment
• Muscle fiber types


  • Slow twitch (Type I, red)
  • Fast twitch (Type II, white)
• Slow twitch fibers


  • Contract more slowly but can continue activity for longer duration
  • Have more capillaries and higher oxygen capacity
• Fast twitch fibers


  • Contract more quickly but fatigue faster
  • Have fewer capillaries and lower oxygen capacity
• Muscle load


  • Amount of weight added
  • Greater load results in longer latent period, slower contraction, and shorter duration
• Muscle recruitment


  More motor units contracting results in faster and more prolonged contraction
• Neural tube


  The tube that the central nervous system first appears as during development
• Brain formation


  Begins as the anterior end of the neural tube expands
• Ventricles


  Enlarged chambers in the central canal of the spinal cord
• Brain


  • Soft, wrinkled like a walnut, with a texture of cold oatmeal
  • Approximately 1.4 kg in weight
• Major regions of the brain

  • Cerebral hemispheres
  • Diencephalon
  • Brain stem
  • Cerebellum
• Cerebral hemispheres


  The superior part of the brain, collectively called the cerebrum
• Gyri


  Elevated ridges of tissue (folds and ridges on the surface of cerebral cortex)
• Sulci


  Shallow grooves separating gyri
• Fissures


  Deeper grooves separating the large regions of the brain
• Longitudinal fissure


  Separates the cerebral hemispheres in a single deep fissure
• Lobes of the cerebral hemispheres

  • Frontal lobe
  • Parietal lobe
  • Temporal lobe
  • Occipital lobe
• Frontal lobe


  • Responsible for motor control, problem-solving, speech, writing, concentration and speaking
• Parietal lobe


  • Responsible for sensory processing and perception
• Temporal lobe


  • Responsible for auditory processing such as hearing and memory
• Occipital lobe


  • Responsible for visual information processing such as distance
• Cerebral cortex


  Composed of grey matter where higher cognitive functions such as decision-making, thinking and perception take place
• Cerebral white matter


  Myelinated fibres that facilitate communication between different regions of the brain
• Basal nuclei


  • Important in motor control and learning
  • A tight band of projection fibres called the internal capsule passes between the thalamus and nuclei
• Meninges


  The membranes that protect the central nervous system
• Types of meningeal layers

  • Dura mater (outermost layer)
  • Arachnoid mater (middle layer)
  • Pia mater (innermost layer)
• Meningitis is an inflammation of the meninges that is a serious threat to the brain as it may spread into the nervous tissue of the central nervous system</b>