nervous and endocrine system

• the nervous system 


  a complex network of nerve cells that carry messages to and from the brain and spinal cord to different parts of the body

  allows different parts of body to communicate with each other

  -controlled by the brain , divided into the Central Nervous System and Peripheral Nervous System
• central nervous system 


  brain and spinal cord
• neurons 


  nervous system carries messages from one part of the body to another using individual nerve cells - neurons

  they transmit nerve impulses in the form of electrical signals
• CNS 2 main functions

  the control of behaviour ad regulation of the body's physiological processes
• the brain


  responsible for coordinating sensation, intellectual and nervous activity

  the centre of all conscious awareness

  brains outer later = cerebral cortex , highly developed in humans - distinguishes our higher mental functions from animals

  brain also regulates automatic functions that are essential for life
• the spinal cord 


  relays information from the brain to rest of the body

  allows brain to regulate bodily processes and to coordinate voluntary movements

  contains circuit of nerve cells that enable us yo perform some simple reflex's without the direct involvement of the brain
• peripheral nervous system 


  transmits messages to whole body to and from the brain
• PNS 2 main divisions

  somatic = transmits and receives messages from the senses & directs muscles to react and move

  autonomic nervous system = regulates bodily actions without conscious awareness
• ANS - sympathetic 


  activated in situations that require energy

  causes increase in heart rate and breathing, decrease in digestion, blood flow is diverted to muscles, pupils dilate - fight or flight
• ANS - parasympathetic 


  activated when body is trying to conserve energy and store resources

  heart rate and breathing decreases, blood flow diverted to digestive function
• the endocrine system 


  the endocrine and nervous system work together ti regulate the physiological processes of the human body

  endocrine system uses blood vessels to deliver hormones to their target
• what is the endocrine system

  a network of glands throughout the body that manufacture and secrete hormones

  hormones are chemical messengers that regulate the activity of cells in the body

  they are secreted directly into the blood stream where they travel to their 'target cells'
• glands and hormones 


  target cells respond to a particular hormone because they have receptors for that hormone

  cells that don't have a receptor cannot be influenced directly by that hormone

  when enough receptor sites are stimulated by hormones - it results in physiological reaction in the target cell
• hypothalamus 


  brain region controlling the pituitary gland
• pituitary gland 


  secretes many different hormones, some of which affect other glands

  'master gland'

  2 parts - anterior (front) releases ACTH as a response to stress , stimulates the adrenal glands to produce cortisol. produces LH and FSH - stimulate the ovaries/testis to produce oestrogen and progesterone / testosterone and sperm

  posterior (back) releases oxytocin which stimulates bonding between mother and infant
• thyroid gland 


  affects metabolism and other things
• adrenal glands 


  helps trigger fight or flight response

  2 adrenal glands sit on top of the kidneys

  outer part - adrenal cortex = releases hormones necessary for life (cortisol)

  inner part - adrenal medulla = releases hormones that aren't necessary for life (adrenaline and noradrenaline)
• pancreas


  regulates the level of sugar in the blood
• ovary and testis 


  secretes female and male sex hormone