psychology revision

• The nervous system regulates and coordinates activities within the body. it detects, interprets and responds to changes that occur internally and externally. Sensory receptors gather information and send electrical impulses to the central nervous system (CNS - spinal cord and brain). Electrical impulses are processed and generate appropriate reactions by sending electrical impulses via nerves to effector organs such as muscle and glands.
• Brain

  The control center of the CNS, responsible for processing and integrating information. It consists of the cerebrum, cerebellum, and brainstem.
• Cerebrum

  The largest part of the brain, responsible for controlling movement, sensation, and perception. It is divided into two hemispheres: left and right.
• Cerebellum

  A structure at the base of the brain, responsible for coordinating muscle movements, balance, and posture.
• Brainstem

  A part of the brain connecting the cerebrum to the spinal cord, controlling functions such as breathing, heart rate, and blood pressure.
• Spinal Cord

  A long, thin, tube-like structure extending from the base of the brain down to the lower back, transmitting messages between the brain and the body.
• Nerve

  A bundle of fibers outside and inside the spinal cord that transmit signals between the brain and the rest of the body.
• Sensory Nerve Fibers

  Transmit sensory information from the body to the brain, allowing us to perceive the environment.
• Motor Nerve Fibers

  Transmit signals from the brain to muscles and glands, controlling movements and bodily functions.
• Interneuron Fibers


  Connect neurons within the CNS, processing and integrating information.
• The peripheral nervous system (PNS)

  The portion of the nervous system lying

  outside the brain and spinal cord.

  It extends from the top of the head to the

  very tips of the toes and all over the skin.

  The PNS can be subdivided into two distinct

  branches:

  ▪the somatic nervous system (SNS) and

  ▪the autonomic nervous system (ANS).
• The somatic nervous system

  (SNS)

  The SNS has both a sensory and a motor

  function.

  • transmits messages from the sensory

  receptors (receptors that detect light, touch,

  smell, taste and sound) to the CNS,

  • controls voluntary movements of skeletal

  muscles (muscles attached to the skeleton).
• The human nervous system

  The human nervous system is organised into

  two branches:

  ▪the central nervous system (CNS) and

  ▪the peripheral nervous system (PNS).
• The CNS is comprised of:

  ▪the brain and spinal cord.

  ▪The spinal cord connects the brain to the

  peripheral nervous system.
• The autonomic nervous system  (ANS) 

  Regulates key involuntary functions of the body. Connects the brain with body's internal organs  and glands 

  It does this via its two branches:  

  ▪the sympathetic nervous system and  ▪the parasympathetic nervous system.  ▪These two systems work in opposition to one  

  another, as the sympathetic system works to activate the internal muscles, organs and glands, and the parasympathetic system works to calm them down.
• The sympathetic nervous system 

  The sympathetic nervous system activates internal muscles, organs and 

  glands to prepare the body for vigorous activity, or to deal with a stressful or 

  threatening situation. It increases the chances of survival by providing a split second response to any kind of emergency. Fight or flight 

  A hormone called adrenalin plays a big part in arousal.  Adrenalin is made by the adrenal glands (situated just above the kidneys). 
• The sympathetic nervous system 

  When someone is frightened or nervous, the  sympathetic nervous system is activated and causes the  adrenal glands to squirt adrenalin into the bloodstream.  This has several physiological or ‘bodily’ effects.  

  Examples of responses associated with this sympathetic  nervous 

  system activity include: 

  ▪increased heart and breathing rates,  

  ▪increased blood pressure,  

  ▪enlarged pupils,  

  ▪increased perspiration,  

  ▪slowing of the digestive process.
• Reflex arc?

  • R: electrical impulse created by receptor S: travels through sensory neuron R: joins the relay neuron in the spinal cord M: travels along motor neuron E: reaches an effector that starts a response