coordination and response

• 2.80 understand how organisms are able to respond to changes in their environment


  All living organisms need to respond to changes in environment for survival

  
  

  Organisms additionally have reflexes for fast involuntary actions that protect body from damage
• coordinated response


  Process in which a reaction is carried out in response to a change in environment (stimuli)
• 2.81 understand that homeostasis is the maintenance of a constant internal environment, and that body water content and body temperature are both examples of homeostasis


  regulations of conditions inside body, including temperature, water levels and blood glucose concentration
• Thermoregulation:


  Keeping the body at optimum body temperature (37°C)
• osmoregulation


  Control of water levels in body
• water content


  balance between water you gain and lose part of homeostasis
• body temperature


  the amount of heat in the body that is a balance between the amount of heat produced and the amount lost by the body part of homeostasis
• Homeostasis


  the maintenance of a constant internal environment/regulations of conditions inside body
• 2.82 understand that a co-ordinated response requires a stimulus


  Change in environment (internal/external)

  
• 2.82 understand that a co-ordinated response process

  -Receptor cells detect a stimuli

  -Coordination center receives and processes the information from the receptor

  -Effector brings a response to the stimuli which restores optimum levels
• 2.82 understand that a co-ordinated response requires a receptor


  Specialised cells that detect stimuli
• 2.82 understand that a co-ordinated response requires an effector


  Part of the body that produced the response

  
• 2.86 describe how nervous communication control responses and understand the differences between the two systems


  -Stimulation of receptors in sensory organs sends electrical impulses around the body-Messages are carried by electrical impulses-Electrical impulses are fast but short-lived
• 2.86 describe how hormonal communication control responses and understand the differences between the two systems

  -Endocrine glands produce specific Hormones, which cause a change to the body

  -Hormones are transported to target organs

  -Chemical signals are slow but long-lived as they are transported by plasma
• 2.87 understand that the central nervous system consists of the brain and spinal cord and is linked to sense organs by nerves

  Stimuli detected by receptors,

  
  

  stimulating Sensory Neurons that send electrical impulses to the Central Nervous System - Brain and Spinal cord

  
  

  Central Nervous System relays impulse across the synpase to Relay Neurons

  
  

  Relay Neurons relays impulse to Motor Neurons in the Effector, which will quickly carry out rapid response

  
• 2.88 understand that stimulation of receptors in the sense organs sends electrical impulses along nerves into and out of the central nervous system, resulting in rapid responses


  -When stimuli is detected, sensory neurons send electrical impulses to the CNS-CNS relays impulse from sensory neurons, across the synapse to relay neurons-Relay neurons give an impulse to the motor neurons in the effector, carrying out the rapid response
• 2.88 understand that


  stimulation of receptors in the sense organs sends electrical impulses along nerves into and out of the central nervous system, resulting in rapid responses

  
• 2.89 understand the role of neurotransmitters at synapses(Sensory Neurones)


  afferent neurones, take nerve impulses from receptors to CNS.
• 2.89 understand the role of neurotransmitters at synapses (Relay Neurones)


  found within CNS, link sensory neurones to motor neurones.
• 2.89 understand the role of neurotransmitters at synapses (Motor Neurones)


  efferent neurones, take nerve impulses from the CNS to muscle or gland.
• 2.90 describe the structure and functioning of a simple reflex arc illustrated by the withdrawal of a finger from a hot object

  heat (Stimulus) is detected by the finger (receptor) and will stimulate sensory neurones to carry electrical impulses to CNS

  
  

  electrical impulses will be carried from CNS to relay neurons which will carry it through the CNS (where a response is decided) and carried to motor neurons

  
  

  motor neuron will carry electrical impulses to muscles in the arm (effector)

  
  

  muscles (effector) will contract and will withdraw finger away from the hot object (response)

  
• 2.91 describe the structure and function of the eye as a receptor (cornea)


  Transparent convex lens that refracts light

  
• 2.91 describe the structure and function of the eye as a receptor (IRIS)


  Pigmented membrane that controls the diameter and size of Pupil to alter the quantity of light reaching the Retina

  
• 2.91 describe the structure and function of the eye as a receptor (LENS)


  Transparent disc that changes shape to focus light onto the Retina

  
• 2.91 describe the structure and function of the eye as a receptor (RETINA)


  Light-sensitive nerve tissue containing Rods (night vision) and Cones (colour vision) to convert light into electrical impulses to be interpreted by the brain for visual recognition
• 2.91 describe the structure and function of the eye as a receptor (OPTIC NERVE)


  Nerve located in the back of the eye that contains Sensory Neurons to send electrical impulses to be interpreted by the brain for visual recognition
• 2.91 describe the structure and function of the eye as a receptor (PUPIL)


  Opening in the centre of Iris that allows light to enter the Eye
• 2.91 describe the structure and function of the eye as a receptor (ciliary muscles)


  Circular muscle surrounding the lens that that contracts and relaxes to adjust the thickness of lens
• 2.92 understand the function of the eye in focusing on distant objects


  Ciliary muscles relax, meaning the suspensory ligaments tighten, causing the lens to become thinner (less curved), meaning it refracts light by a smaller amounts
• 2.92 understand the function of the eye in focusing on near objects


  ciliary muscle contracts, suspensory ligaments slacken

  
  

  lens becomes fat/ more curved

  
  

  increases the amount by which it refracts ligh
• 2.93 describe the role of the skin in temperature regulation, with reference to vasodilation (hot temp)


  blood vessels close to the surface of the skin widen

  
  

  allows more blood flow to surface

  
  

  so it can transfer more energy into surroundings and coll you down
• 2.93 describe the role of the skin in temperature regulation, with reference to sweating (hot temp)


  lots of sweat is produced, evaporates to transfer energy from your skin to the environment cooling you down
• 2.93 describe the role of the skin in temperature regulation, with reference to vasoconstriction

  blood vessels near the surface of the skin constrict, less blood flows to surface, less energy is transferred to surroundings
• 2.93 describe the role of the skin in temperature regulation, with reference to sweating (cool temp)


  little sweat is produced, shivering increases respiration rate wich transfers more energy to warm body, hairs stand on end to trap air
• smaller organisms cool down quicker


  bigger SA:V ratios, gain/lose heat faster because more area for heat to travel across
• hormones


  slower message, act for long time, act in general area
• nerves


  very fast message, act for short time, act in precise area
• 2.94 understand the sources of the following hormones: adrenaline

  Adrenal Gland
• 2.94 understand the roles of the following hormones: adrenaline


  Prepares body for 'fight or flight' response
• 2.94 understand the effects of the following hormones: adrenaline

  Increases heart and breathing rate