Nervous system

• Divisions of the Peripheral Nervous System

  • Somatic Nervous System
  • Autonomic Nervous System

  
• Somatic Nervous System


  Nerves that convey messages from the sense organs to the CNS (Afferent) and from the CNS to the muscles and glands (Efferent)

  
• Autonomic Nervous System


  A set of neurons that control the heart, the intestines, and other organs
• Types of Neurons


  • Sensory Neuron
  • Interneuron
  • Motor Neuron

  
• Sensory Neuron


  • Transmit sensory information from receptors of PNS towards the CNS
  • Most are unipolar, a few are bipolar
• Interneuron


  • Transmit information between neurons within the CNS
  • Analyze inputs, coordinate outputs from sensory to motor neurons
  • Are the most common type of neuron (20 billion)
  • Are all multipolar

  
• Motor Neuron


  • Transmit motor information from the CNS to effectors (muscles/glands/adipose tissue) in the periphery of the body (CNS to PNS)
  • All are multipolar

  
• Reflex Arc


  1. Stimulus

  2. Sensory neuron

  3. Interneuron

  4. Motor neuron

  5. Effector

  
• Neurones conduct impulses from one part of the body to another

  
• A stimulus is something that human sensory receptors are able to detect, e.g. sounds, physical contact, tastes, visual sensation

  
• The human brain controls nearly every aspect of the human body ranging from physiological functions to cognitive abilities
• The human brain, just like most other mammals, has the same basic structure, but it is better developed than any other

  
• On average, an adult brain weighs between 1.0 kg – 1.5 kg
• The brain, along with the spinal cord, constitutes the central nervous system. It is responsible for thoughts, interpretation, and origin of control for body movements

  
• Cerebrospinal Fluid (CSF)


  A fluid that circulates within the skull and spinal cord, filling up hollow spaces on the surface of the brain

  
• Functions of Cerebrospinal Fluid (CSF)

  • Acts as a buffer for the brain, cushioning mechanical shocks and dampening minor jolts
  • Provides basic immunological protection to the brain
  • Provides buoyancy for the brain
• Parts of the Human Brain

  • Forebrain
  • Midbrain
  • Hindbrain

  
• Forebrain


  • Controls the reproductive functions, body temperature, emotions, hunger, and sleep
  • The largest part of the brain, including the cerebrum, hypothalamus, and thalamus
• Midbrain


  • Smallest and central part of the brain, consisting of the tectum and tegmentum

  
• Hindbrain


  • Coordinates all processes necessary for survival, including breathing, heartbeat, sleep, wakefulness, and motor learning
  • Composed of the cerebellum, medulla, and pons
• All behaviors & Mental processes are influenced by or based on body biology
• Principles & Assumptions


  • Everything psychological is simultaneously biological
  • The nervous system is complexity built from simplicity
  • The brain is both specialized and integrated
  • The nervous system is "plastic" (change/modeled) especially at early ages of development