The divisions of the nervous system

• 3 divisions of the brain

  • Hindbrain
  • Midbrain
  • Forebrain
• Hindbrain is made of medulla, pons and cerebellum
• Medulla, pons and midbrain make up the brainstem
• Brainstem is just the continuation if the spinal cord but within the brain
• Cerebellum is a large structure located on the back surface of the brainstem, major function is the control of movement and damage results in loss of motor coordination
• Forebrain is the largest division of the brain and its divided into 2 major components the diencephalon and telencephalon
• Diencephalon contains 2 main stuctures the thalamus and hypothalamus
• Thalamus is an important sensory structure and it passes sensory information to pathways which go to the spinal cord and brainstem then to the cortex
• Hypothalamus is at the base of the brain and its involved in the body's physiological functions like hunger, thrist, stress related arousal, sexual and reproductive behaviours
• Telencephalon controls high level cognitive and emotional processes. 3 major systems make up telecephalon
• Telencephalon controls high level cognitive and emotional processes and its made up of 3 major systems:

  • Limbic system
  • Basal ganglia
  • Cerebral cortex
• Limbic system consists of a set of interconnected structures, includes the hippocampus, amygdala, septum and cingulate gyrus. Involved in learning memory and emotions
• Basal ganglia have important functions in relation to movement and motor control. Includes the caudate nucleus, the putamen and globus pallidus. Damage to basal ganglia results in movement disorders
• Cerebral cortex contains the highest cognitive functions like planning and problem solving, language, consciousness, personality, perception and control of movement
• The peripheral nervous system is made up of 31 spinal nerves. These contains millions of sensory and motor pathways so the brain is aware of what's going on in the body and outside word. The millions of pathways which make up the spinal nerves can be divided into somatic and autonomic nervous system
• Somatic nervous system is made up of sensory and motor pathways
• SNS is made up of sensory pathways from the sensory receptors in the body. It has specialised sensory receptors in the skin that respond to stimuli by triggering action potentials in sensory neurons.
• SNS is also made up of motor pathways. The axons of motor neurons travel in spinal nerves out to the skeletal muscles of the body so brain can control the body. Commands to move our muscles are made in the cerebral cortex of the forebrain
• Autonomic nervous system play an important role in states of bodily arousal.
• ANS centers are located in the brainstem. From here ANS pathways go through the spinal cord and are distributed throughout the body by the spinal nerves
• ANS takes part in the regulation of the internal environment of out body like heart rate, blood pressure and body temperature, ANS is used for homeostasis.
• ANS has 2 separate branches to carry out its functions. These are called sympathetic and parasympathetic arousal. Nerve fibres from both branches connect with internal structures like glands, heart etc
• Sympathetic arousal is an increase in bodily arousal, increases heart rate and blood pressure and decrease in activity in the digestive system
• Parasympathetic arousal is the opposite of sympathetic arousal with lower heart rate and blood pressure and an increase in activity in the digestive system
• Sympathetic and parasympathetic arousal are usually in balance but under certain circumstances the balance shifts and one branch becomes dominant. These shifts happen depending on the body's physiological needs.