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Coordination and response


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Coordination and response

  2. 2. 3.1 Response and coordination  Changes may occur around us or inside of our body  Organisms can detect the changes in the environment and respond to the changes in certain ways  The external environment- physical & chemical conditions outside an organism and how these conditions affect it(light,sound,smell,etc..)  The internal environment- physical & chemical conditions of the tissue fluid surrounding the tissues of an organism(body temperature, osmotic pressure and blood glucose level)
  3. 3. The need for an organism to be sensitive  The internal environment must be constant for an organism to be healthy or survive  An organism cannot control its external environment, can control internal env. to a certain extent
  4. 4. Being able to respond enables an organism:  To regulate its internal environment  Obtain and use resources, grow, reproduce, and maintain stable internal conditions while living in a constantly changing external environment
  5. 5. Responses of humans, animals and plants to stimuli  Stimulus – changes in the external and internal environment  Receptor – detect the stimulus  Afferent neurone – carries the nerve impulse to the integrating centre(central nervous system) in the brain  Efferent neurone – carries the nerve impulse from brain to the effector  Effector – reacts to cause a response (muscles/glands)
  6. 6. Pathways of information due to external stimuli Example: Sound of doorbell Stimulus (sound of doorbell) Receptor in the ear INTERGRATING CENTRE/CNS (brain) Effector (muscles in hand) Response (open the door)
  7. 7. Pathway of information due to internal stimuli  Internal stimuli are detected by receptors sensitive to changes within the body  The endocrine system and nervous system control and coordinate functions in the body to maintain a constant internal environment through a negative feedback system  Negative feedback operates to counteract the change in the internal environment to restore it to normal
  8. 8. Body temperature Integratin g centre (brain) Effector (skin and endocrine glands) Response (Activities to increase heat loss from body surface) Normal body temperature Stimulus (high body temperature) Receptors in the skin By negative feedback Lowers body temperature Rises due to excess heat Changes in body temperature detected by
  9. 9. Coordination  Is the process involved in the detection of stimulus and the subsequent response of the organism towards the stimulus  Involve nervous system and endocrine system
  10. 10. 3.2 Role of human nervous system  Role of nervous system: - Detect changes by receptors, process the received sensory information and initiates the response - Helps us think and act consciously - Stores information and allows us to learn from past experiences - Adapts the body to changes in the environment - Controls and coordinates the activities of all other systems in the body
  11. 11. Organisation of nervous system  NS is made up of : 1) Central nervous system [brain & spinal cord] 2) Peripheral nervous system [cranial nerve & spinal nerve]
  12. 12. Central nervous system  Control centre of the body  Consists of brain & spinal cord  Processes sensory information, making decision and initiating responses
  13. 13. Peripheral nervous system  Is responsible for the communication between the CNS and the rest of the body  Consists of all the nerves that branch out from the CNS and connects it to the rest of the body  Cranial nerves – nerves that carry impulses to and from the brain  Spinal nerves – nerves that carry impulses to and from the spinal cord
  14. 14. Structure and function of the brain  Brain weighs about 1.4kg  Consists of: 1. Cerebrum 2. Cerebellum 3. Medulla oblongata 4. Hypothalamus 5. Thalamus 6. Pituitary gland
  15. 15. 1. Cerebrum  The largest region,divided into the right and left hemisphere  Each hemisphere has folds to increase the surface area  The left H. controls the right side of the body while the right H. controls the left side  Interprets information from receptors and controls movement of skeletal muscles in VOLUNTARY ACTION  Is the site of intelligence and carries out complex mental processes such as learning, remembering and making judgements
  16. 16. 2. Cerebellum  2nd largest region  Has two hemispheres  Coordinates the contraction of the muscles and helps control BALANCE to produce precise movements
  17. 17. 3. Medulla oblongata  Relays information between the spinal cord and the brain  Controls INVOLUNTARY ACTIONS such as heartbeat, breathing and blood circulation  Control reflex centre for heart rate, blood pressure, blinking, sneezing, peristalsis, vomiting, swallowing
  18. 18. 4. Thalamus  Receives information from all sensory receptors and then transmits it to the proper region of the cerebrum for further processing
  19. 19. 5. Hypothalamus  Control centre for recognition and analysis of hunger,thirst,fatigue, anger and body temperature  Controls the coordination and the nervous system and endocrine system
  20. 20. 6. Pituitary gland  Is attached to hypothalamus  Connects the central nervous system with the endocrine system  Produce many important hormones
  21. 21. Spinal cord  Is the link between the brain and the peripheral NS  Consists of grey matter in the middle and white matter around it  Spinal nerves arise from spinal cord  Each spinal nerve has a dorsal root (contains afferent neuron) and ventral root (contains efferent neurone)  CONTROL REFLEX ACTION
  22. 22. Structure of a neurone