Introduction to Psychology

• Functions of the Nervous System

  • Sensory Output
  • Integration
  • Homeostasis
  • Mental Activity
  • Control of Skeletal Muscles
• Divisions of the Nervous System

  • Central Nervous System (CNS)
  • Peripheral Nervous System (PNS)

  
• Central Nervous System (CNS)


  Consists of the brain and the spinal cord. They interpret incoming sensory information and issue instructions based on past experience and current conditions.

  
• Peripheral Nervous System (PNS)


  Consists of nerves and ganglia which lie outside the CNS. These nerves serve as communication lines.
• Divisions of the Peripheral Nervous System

  • Somatic Nervous System
  • Autonomic Nervous System
• Somatic Nervous System


  Reacts to outside stimuli. Controls voluntary movements, such as the motion of the eyes and the communication of information from the sense organs.

  
• Autonomic Nervous System


  Maintains homeostasis. Concerned with the parts of the body that keep us alive – the heart, blood vessels, glands, lungs and other organs that function or operate voluntarily and continuously without our awareness.
• Divisions of the Autonomic Nervous System

  • Sympathetic Division
  • Parasympathetic Division
• Sympathetic Division


  Acts to prepare the body in stressful emergency situations, engaging all the organism's resources to respond to threat. This response often takes the form of "fight or flight".
• Parasympathetic Division


  Acts to calm the body after the emergency situation is resolved.
• Parts of the Brain

  • Brainstem
  • Diencephalons
  • Cerebrum
  • Ventricles
  • Basal Ganglia
  • Limbic System Structures
  • Cerebellum

  
• Brainstem


  Connects the spinal cord to the remainder of the brain and contains several nuclei involved in body functions such as control of heart and breathing.

  
• Medulla Oblongata


  Regulation of the heart rate and blood vessel diameter, breathing, swallowing, vomiting, coughing, sneezing, balance and coordination.
• Pons


  The term means "bridge". Nuclei in the pons control functions such as chewing and salivation.
• Midbrain


  The smallest region of the brainstem. The midbrain contains nuclei involved in the coordination of the eye movements and in control of pupil diameter and lens shape.

  
• Diencephalons


  Contains the thalamus, hypothalamus, and epithalamus.
• Thalamus


  The largest part of the diencephalons (shaped like a yo-yo). Influencing mood and registering an unlocalized, uncomfortable perception of pain.
• Hypothalamus


  Contains several small nuclei which are essential in maintaining homeostasis. Plays a vital role in the control of body temperature, hunger and thirst. Sensations such as sexual pleasure, feeling relaxed, and "good" after a meal, rage and fear are related to hypothalamic functions. Emotional responses also involve in the hypothalamus.
• Epithalamus


  Represented mainly by the pineal gland, which lies in the midline posterior and posterior to the third ventricle. This gland synthesizes melatonin and enzymes sensitive to daylight. Rhythmic changes in the activity of the pineal gland in response to daylight suggest that the gland serves as a biological clock.
• Pineal Gland


  A small, pinecone-shaped gland of the endocrine system. Produces the hormone melatonin, which influences sexual development and sleep-wake cycles.
• Mamillary Bodies


  Involved in the emotional responses to odors and in memory.
• Cerebrum


  The largest part of the brain. The right hemisphere controls muscular activity and receives sensory input from the left half of the body. The left hemisphere controls muscles and receives input from the right half of the body.

  
• Cerebral Cortex


  The layer of the gray matter that forms the surface of each cerebral hemisphere. Impulses are received and analyzed within the cerebral cortex, forming the basis of knowledge.

  
• Corpus Callosum


  Serves as a bridge to coordinate the activities between the two Cerebral hemispheres.
• Ventricles


  A set of communicating cavities within the brain responsible for the production, transport and removal of cerebrospinal fluid, which bathes the central nervous system.

  
• Lateral Ventricles


  The left and right lateral ventricles located within their respective hemispheres of the cerebrum. They have 'horns' which project into the frontal, occipital and temporal lobes. The volume of the lateral ventricles increases with age.

  
• Third Ventricle


  Situated in between the right and the left thalamus.
• Fourth Ventricle


  The last in the system – it receives CSF from the third ventricle via the cerebral aqueduct. It lies within the brainstem, at the junction between the pons and medulla oblongata.

  
• Basal Ganglia


  A big bundle of nerve fibers and cells leading up to the cerebral cortex. Any damage in this area of the brain causes loss of sensation and movement in the parts of the body. They control movements and posture and are also associated with Parkinson's Disease. Parts of the basal ganglia influence muscle tone and initiate commands to the cerebellum and to higher brain centers.

  
• Limbic System Structures


  • Amygdala
  • Cingulate Gyrus
  • Fornix
  • Hippocampus
  • Hypothalamus
  • Olfactory Cortex
  • Thalamus

  
• Amygdala


  The almond-shaped mass of nuclei involved in emotional responses, hormonal secretions, and memory. Responsible for fear conditioning or the associative learning process by which we learn to fear something.
• Cingulate Gyrus


  A fold in the brain involved with sensory input concerning emotions and the regulation of aggressive behavior.

  
• Fornix


  An arching, band of white matter axons (nerve fibers) that connect the hippocampus to the hypothalamus.
• Hippocampus


  A tiny nub that acts as a memory indexer – sending memories out to the appropriate part of the cerebral hemisphere for long-term storage and retrieving them when necessary.
• Hypothalamus


  About the size of a pearl, this structure directs a multitude of important functions. It wakes you up in the morning and gets the adrenaline flowing. The hypothalamus is also an important emotional center, controlling the molecules that make you feel exhilarated, angry, or unhappy.
• Olfactory Cortex


  Receives sensory information from the olfactory bulb and is involved in the identification of odors.
• Thalamus


  A large, dual lobed mass of gray matter cells that relay sensory signals to and from the spinal cord and the cerebrum.

  
• Cerebellum


  A large structure attached to the back surface of the brain stem. Influences balance, coordination, movement, and single joint actions. Also involved in a number of cognitive operations, including learning.

  
• Lobes of the Brain

  • Parietal Lobe
  • Frontal Lobe
  • Occipital Lobe
  • Temporal Lobe

  
• Parietal Lobe


  Its primary function is to receive sensory information coming from the skin as well as skeletal muscles. It is also responsible for taste sensation.