Coordination & Response

• how does the sensory neurone look like and which way does the impulse travel?

  receptor cell -> axon

  A)

  
• Electrical impulses travel along..


  neurons
• The mammalian nervous system consists of..

  • CNS (brain and spinal cord)
  • PNS (nerves outside the brain and spinal cord)
• What is the role of the nervous system?


  Coordination and regulating body functions
• What are the two effectors?


  • muscles
  • glands
• How does an impulse travel across a reflex arc?


  1. receptors detect stimulus and generate an impulse
  2. it travels to sensory neurone
  3. it travels to a relay neurone across a synapse
  4. then travels to motor neurone
  5. causes effector to carry out an action
• What is a synapse?


  • junction between two neurones
• What happens at a synapse?


  1. an impulse stimulates the release of neurotransmitters from the vesicles of the first neurone
  2. the neurotransmitters diffuse across the synaptic gap towards the second neurone
  3. the neurotransmitter molecules bind together with the receptor proteins on the second neurone
  4. the impulse is then stimulated in the next neurone
• What makes sure that impulses travel in one direction only?

  synapses
• What does the cornea do?


  refract light
• Which part of the eye refracts light?

  cornea
• What does the iris do?


  controls how much light enters the pupil
• What does the lens do?


  focuses light on the retina
• The retina contains..


  • light receptors
• What is the function of optic nerve?


  transport impulses to the brain
• Define a hormone 


  • a chemical substance
  • produced by a gland and carried by the blood
  • alters the activity of target organs
• Where is adrenaline secreted?


  Adrenal gland
• Where is insulin and glucagon secreted?


  Pancreas
• Where is testosterone secreted?


  Tess Tickle
• What hormone do the ovaries secrete?


  oestrogen
• List the effects of adrenaline.


  • increased breathing rate
  • increased heart rate
  • increased pupil diameter
  • increased blood glucose concentration
• A reflex action is 


  • quick
  • automatic
  • stimuli caused by the response of an effector
• Which two structures in the eye refract light?

  cornea and lens
• What happens to the iris when it is bright?


  • CC
  • RR
• What happens to the iris when it is dark?


  CRRC
• What happens to the lens when there is a far away or near object?

  accomodation
• What happens to the lens when there is a DISTANT object?

  • SL CONTRACT
  • CM relax
• What happens to the lens when there is a near object?

  • SL relax
• Define homeostasis


  The maintenance of a constant internal environment
• Where is auxin made?


  in the shoot tip
• What does auxin do?


  stimulates cell elongation
• Positive gravitropism is when..


  the roots grow towards gravity
• Positive phototropism is when.. 


  a plant shoot grows towards the light
• Is auxin a hormone?


  yuh
• in shoots, auxin _ the elongation of cell


  stimulates
• How does auxin work in a plant stem?

  • stimulates growth in the shoot and makes it curve upwards
  • inhibits growth in the roots and makes them grow downwards

  
• In the roots, auxin is gathered at..

  The lower half of the plant (then it curves downwards)
• what are functions of cones in the retina?


  • enable us to see colours
  • in bright light
  • three different kinds (RGB)
• Describe and explain the changes that occur in the eye when adjusting focus from a distant object to a near object

  • suspensory ligament relax
  • ciliary muscles contract
  • lens become fatter
  • refracts more light
• Describe the function and adaptation of neurones.


  long -> to transmit impulses over a large distance

  mitochondria present -> to release energy

  vesicles -> to release neurotransmitters into the synaptic gap