Co ordination


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Co ordination

  1. 1.  all organs and systems in a healthy human body are co-ordinated  co-ordinated means :  they co-operate with one another and work together efficiently
  2. 2.  Consider the tennis player about to hit the ball: Physical activity is one function that requires co-ordination 1 Eyes see ball. 2 3 Information goes to brain & is processed. Brain sends messages to muscles to hit the ball.
  3. 3. Co-ordination of body functions involves:
  5. 5. Brain & Spinal cord:  the main parts of the NS  are called the CNS
  6. 6. Vertebrae protect the spinal cord Spinal cord Vertebra Vertebral column
  7. 7. How is the CNS connected to the various parts of the body?
  8. 8. The Nervous System receives messages from: Sense organs CNS
  9. 9. The Nervous System sends messages to:  Muscles  Glands Effectors CNS Salivary glands
  10. 10. Flow of information What are ‘stimuli’?
  11. 11. A stimulus is:  a change in the environment that can be detected by a sense organ and brings about a response
  12. 12. Stimuli [stimulus = singular] Cold Heat Sound Chemicals in air Pain
  13. 13. Neurones and nerves Neurone = nerve cell Nerve = a bundle of nerve cells neurones
  14. 14. Neurones can be very long
  15. 15. Sensory neurones Motor neurones Intermediate or Relay neurones Three types of Neurone
  16. 16. Structure of a sensory neurone
  17. 17. Function of the myelin sheath to insulate the fibre speeds up the impulses Myelin sheath: FAT
  18. 18. Direction of impulse along a sensory neurone Axon carries impulse: Away from the cell body
  19. 19. Fig. 4 A motor neurone. [axon terminal] Direction of impulse
  20. 20. Differences in structure between a: 1. Long axon 2. No receptor 3. Cell body terminal & has dendrites 4. Many short dendrons 1. Short axon 2. Receptor 3. Cell body at the side; no dendrites 4. One long dendron receptor axon axon dendron Sensory neuroneMotor neurone C N S C N S
  21. 21. Differences in function between a: receptor Sensory neuroneMotor neurone C N S C N S Carries the impulse towards the CNS Carries the impulse away from the CNS
  22. 22. Fig. 5 Connections between a sensory, a relay and a motor neurone.  Neurones DO NOT touch each other Sensory neurone Motor neurone Relay neurone
  23. 23. A synapse is a tiny gap between neurones synapse
  24. 24. Impulses travel in direction across a synapse Sensory neurone Motor neurone Relay neurone Effector Receptor
  25. 25. How many synapses on one cell body? 1,000 to 10,000!!
  26. 26. Fig. 6 A synapse.
  27. 27. A Reflex Action is a  rapid, automatic, involuntary response to a stimulus
  28. 28. Examples of reflex actions:  Sneezing
  29. 29.  Blinking  Coughing  Removing the leg when stepping on a pin
  30. 30. Examples of reflex actions:  withdrawing your hand from a hot object
  31. 31. Why are reflex actions useful to the body?
  32. 32. Question: SEP 2010 1. What is the main function of the nervous system? (2) The NS contains a network of specialised cells called neurones that coordinate the actions of an animal and transmit signals between different parts of its body.
  33. 33. b. List the stimulus and response for each of the following reflex actions: i. swallowing; (3) Stimulus: food in mouth Response: food goes down oesophagus ii. coughing. (2) Stimulus: foreign particles in trachea Response: removal of foreign object from trachea
  34. 34. Question: MAY, 2011 [2B] A student accidentally touches a beaker of hot water. The student pulled her hand away from the hot water very quickly. This is an example of a reflex action. a) Define the term reflex action. (2)
  35. 35. Question: MAY, 2011 [2B] b) List TWO examples of reflex actions taking place in newborn babies. (4) Suckling reflex Grip reflex Stepping reflex Crying reflex
  36. 36. The reflex arc is:  the path along which a nerve impulse travels from the receptor to the effector  e.g. :  Knee jerk reflex arc  The hand withdrawal reflex arc
  37. 37. The knee jerk is a reflex action
  38. 38. The knee jerk reflex arc MuscleSpinal cord
  39. 39. Dorsal [back] TS spinal cord Ventral [front]
  40. 40. A sensory neurone always enters via the DORSAL ROOT
  41. 41. Dorsal root ganglion is a collection of cell bodies of the sensory neurones
  42. 42. Fig. 7 The hand withdrawal reflex arc.
  43. 43. Myelin = FAT = white Grey matter White matter TS spinal cord Why is the white matter white?  due to nerve fibres covered by myelin
  44. 44. Grey matter White matter  due to nuclei present in cell bodies TS spinal cord Remember nuclei look DARK. Why is the grey matter grey?
  45. 45. Question A transverse section through the spinal cord is examined under the high power of the microscope. Part of it looks like diagram A and part looks like diagram B. Which is grey matter and which is white matter? Give reasons for your decision. A B
  46. 46. Answer Diagram A represents nerve fibres cut in cross- section and therefore comes from white matter. Diagram B shows many cell bodies which constitute much of the grey matter. A B
  47. 47. Label the diagram. Draw arrows to show direction of impulse A – receptor B – sensory neurone C – motor neurone D – synapse
  48. 48. Question: SEP, 2004 6d) The following diagram demonstrates the rapid and automatic removal of a finger from a flame. i) Complete the diagram by drawing and naming the neurones that bring about this reflex action.
  49. 49. ii) Use arrows to show the pathway of the nerve impulse along the neurones. (4)
  50. 50. e) Some individuals suffer from a motor neurone disease in which the neurones gradually degenerate. How is this likely to interfere with the efficiency of reflex actions? (2) Reflex actions take longer to occur – they become less efficient.
  51. 51. Label the two neurones. What is the function of each?
  52. 52. Question: SEP 2010 Draw a labelled diagram showing the reflex arc that takes place in a knee jerk reflex. On the diagram indicate clearly the direction of flow of impulses. (You are not expected to draw the muscles involved or the spinal cord). (6)
  53. 53. Question: MAY, 2011 [2A] A student accidentally touches a beaker of hot boiling water. The student pulled away her hand within a few milliseconds. This is an example of a reflex action. a) Write a brief description about the events leading to the student pulling away her hand. (5) b) Draw a diagram showing the reflex arc responsible for producing this reflex action. In your diagram include arrows to show the direction of nerve impulses travelling along the neurones. (6)
  54. 54. The skull protects the brain
  55. 55. The cerebrum is highly folded Many neurones can be packed into a small space.
  56. 56. Two Cerebral hemispheres = cerebrum
  57. 57. The cerebrum  controls our:  sensations  movements  is responsible for:  memory  thought  intelligence Cerebrum
  58. 58. The cerebrum contains 2. Sensory areas:  for sensation 1. Motor areas:  for movement 3. Association areas :  for thinking
  59. 59. Parts of the brain: Cerebrum / cerebral hemisphere Cerebellum Medulla oblongata Pituitary gland Hypothalamus
  60. 60. Functions of:  releases hormones  homeostasis
  61. 61. Functions of the cerebellum:  controls balance and muscular co-ordination
  62. 62. Functions of the medulla oblongata:  controls various automatic processes such as:  the rate of breathing  heartbeat
  63. 63. Functions of the cerebrospinal fluid: 1. acts as a shock absorber 2. to allow oxygen and nutrients to diffuse through it to nourish neurones 3. to allow removal of wastes
  64. 64. Meninges  are layers of tissue that surround the CNS
  65. 65. Meningitis  is an infection of the meninges
  66. 66. Question: SEP 2010 1. List the function of each of the following parts within the central nervous system: i. cerebrum; (2) ii. cerebellum; (2) iii. medulla oblongata. (2) 2. In humans the cerebrum is very large and highly folded. Explain why. (2)
  68. 68. Glands in the body are: secrete an enzyme into a duct  secrete hormones  have no duct (ductless)  have a rich blood supply Exocrine gland Endocrine gland
  69. 69. What is a hormone?  a chemical which is produced by one part of the body, travels in the bloodstream and has an effect on the target organ
  70. 70. Fig. 14 Position of the main endocrine glands in the human body.
  71. 71. The main human endocrine glands and their secretions. Gland Hormone Function Thyroid Thyroxine Controls the metabolic rate
  72. 72. Gland Hormone Function Adrenals Adrenaline Prepares the body for action Kidneys Adrenal glands
  73. 73. Adrenaline, the emergency hormone
  74. 74. Adrenaline prepares the body for action Muscles need ENERGY to contract!!
  75. 75. Which process releases energy? glucose + oxygen carbon dioxide + water + energy glucose oxygen muscle energy How can MORE glucose + oxygen reach the muscle?
  76. 76. Effects of adrenaline Heart beat increases Breathing rate increases
  77. 77. Effects of adrenaline  Arteries to muscles widen What is the effect of this?
  78. 78. 5 litres of blood in an adult If more blood flows to muscles less must flow to other organs. Which?
  79. 79. Gut & Skin get less blood  As arteries narrow A person becomes pale when afraid. Why?
  80. 80. Glycogen Glucose in the blood increases Glycogen is converted to glucose Effects of adrenaline
  81. 81. Effects of adrenaline include: 1. Heart beat increases 2. Breathing rate increases 3. Arteries to gut and skin narrow 4. Arteries to muscles widen 5. The pupils of the eyes widen 6. Glycogen is converted to glucose
  82. 82. Gland Hormone Function Pancreas Insulin Decreases the blood sugar level Glucagon Increases the blood sugar level
  83. 83. Control of blood sugar
  84. 84. Question: MAY, 2011 Give a biological explanation for the following situation: A diabetic person received an insulin shot after intake of a meal rich in carbohydrates. (2) A diabetic person does not produce insulin. The insulin injected helps the person to reduce the sugar level in the blood back to normal.
  85. 85. Gland Hormone Function Ovaries Female sex hormones e.g. oestrogen Control sexual development Testes Male sex hormones e.g. testosterone Control sexual development
  86. 86. Gland Hormone Function Pituitary Growth hormone Speeds up growth FSH Causes follicle to develop into a Graafian follicle LH Causes ovulation ADH Causes kidneys to reabsorb water
  87. 87. Differences between nervous and endocrine co-ordination. Nervous Chemical Information passes as electrical impulses along nerve fibres Information passes as a chemical substance through the bloodstream Rapid transmission Slow transmission Response is immediate Response is usually slow e.g. growth Response is short-lived Response is long-lasting Response is very exact Response is usually widespread
  88. 88. Negative feedback control:  produces an effect which is the opposite of what has been happening before  e.g. if body temperature rises, sweat is produced to cool it down  is important to keep conditions constant in the body
  89. 89. Control of blood sugar as an example of: NORM Excess Deficiency Corrective mechanism Corrective mechanism NORM Negative feedback Negative feedback
  90. 90. THE END