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Control system

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This document discusses the human sensory and nervous systems. It explains that humans have various sense organs like skin, eyes, ears, taste buds and nose that collect information about the environment. This information is detected by sensory receptors and transmitted via sensory neurons and nerves to either trigger instant reflex responses or alert the conscious brain. It also describes the endocrine system and how hormones released by glands produce longer-lasting responses than the nervous system to control various bodily functions and maintain homeostasis.

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Control system
In order to live and interact with our world, we need to have ways of getting information
Sensing danger
Avoiding Damage
We need to be able to collect information, proce ss it and respond to it.
Getting Around
We have sense organs  Skin  Eyes  Ears  Taste buds  Nose
These collect a multitude of information so we can understand and interact with our world
Some senses cause an instant response
Senses are picked up by receptors  Chemoreceptors sense chemicals (smell, taste)  Nociceptors sense pain  Mechanoreceptors sense pressure , light touch & stretch  Thermoreceptors sense temperature changes  Photoreceptors sense light and shadow and colours
Sensory Nerves Sensory receptors start electrical impulses along sensory nerve fibres to be processed. The cell body decides how to respond, sending impulses  to other neurons to cause an effect (Right) – reflex action  to alert the conscious brain to the stimulus.
Sensory Neuron Structure Receive input from a receptor OR from another neuron at the dendrites Pass the message to the cell body and then down the axon to pass the message on to other neurons.
Peripheral Nerves Dendrites receive information Cell body manages information Axon conducts signal ultra fast because of myelin sheath Terminal buds interact with another nerve cell dendrites or effector organ eg muscle
Sensory Motor Reflex Signal sent to interneuron receptor • Passes message to motor nerve • Simultaneous message sent to brain interneuron • Signal to muscle • Muscle contraction Motor nerve
Nervous System The Rapid Response System for stimuli that require immediate action that is short lasting and has no permanent change on the body
Endocrine System Sometimes the body needs a longer lasting response that the nervous system cannot coordinate This is where chemical messages, called hormones play a role in controlling body systems The endocrine system controls the release of hormones
Hypothalamus – receives information about internal body and sends messages to glands to in response Pineal Gland – manages day/night cycle Pituitary Gland – master control Thyroid/Parathyroid Gland – controls metabolism Thymus Gland Adrenal Gland – fight and flight response Pancreas – controls digestive enzymes and insulin Ovary/Testes – controls sexual cycles
Hormones Insulin in the Pancreas  Released in response to sugar levels in the blood  Acts to store the excess sugar in cells for later use when needed  Glucagon is the opposite acting hormone and releases sugars when blood sugars are low
Adrenal Glands  Near the kidneys, the adrenal glands act when a body is under stress  Release of adrenaline  Increased heart rate  Increases blood flow to the muscles  Increase blood pressure  Increase metabolic rate
Hormones Are often in the blood at varying concentrations.
Hormones Act slowly  Seconds - adrenal  Minutes- pancreas  Hours, days, months, years – sex hormones Long lasting response that may be reversible or not
Summary of Control Systems  Via 2 systems (fast and slow)  Keeps the body at optimum function  HOMEOSTASIS – the state of the body is kept within normal parameters, eg blood sugar, blood pH, temperature of the body

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Control system

  • 2. In order to live and interact with our world, we need to have ways of getting information
  • 5. We need to be able to collect information, proce ss it and respond to it.
  • 7. We have sense organs  Skin  Eyes  Ears  Taste buds  Nose
  • 8. These collect a multitude of information so we can understand and interact with our world
  • 9. Some senses cause an instant response
  • 10. Senses are picked up by receptors  Chemoreceptors sense chemicals (smell, taste)  Nociceptors sense pain  Mechanoreceptors sense pressure , light touch & stretch  Thermoreceptors sense temperature changes  Photoreceptors sense light and shadow and colours
  • 11. Sensory Nerves Sensory receptors start electrical impulses along sensory nerve fibres to be processed. The cell body decides how to respond, sending impulses  to other neurons to cause an effect (Right) – reflex action  to alert the conscious brain to the stimulus.
  • 12. Sensory Neuron Structure Receive input from a receptor OR from another neuron at the dendrites Pass the message to the cell body and then down the axon to pass the message on to other neurons.
  • 13. Peripheral Nerves Dendrites receive information Cell body manages information Axon conducts signal ultra fast because of myelin sheath Terminal buds interact with another nerve cell dendrites or effector organ eg muscle
  • 14. Sensory Motor Reflex Signal sent to interneuron receptor • Passes message to motor nerve • Simultaneous message sent to brain interneuron • Signal to muscle • Muscle contraction Motor nerve
  • 15. Nervous System The Rapid Response System for stimuli that require immediate action that is short lasting and has no permanent change on the body
  • 16. Endocrine System Sometimes the body needs a longer lasting response that the nervous system cannot coordinate This is where chemical messages, called hormones play a role in controlling body systems The endocrine system controls the release of hormones
  • 17. Hypothalamus – receives information about internal body and sends messages to glands to in response Pineal Gland – manages day/night cycle Pituitary Gland – master control Thyroid/Parathyroid Gland – controls metabolism Thymus Gland Adrenal Gland – fight and flight response Pancreas – controls digestive enzymes and insulin Ovary/Testes – controls sexual cycles
  • 18. Hormones Insulin in the Pancreas  Released in response to sugar levels in the blood  Acts to store the excess sugar in cells for later use when needed  Glucagon is the opposite acting hormone and releases sugars when blood sugars are low
  • 19. Adrenal Glands  Near the kidneys, the adrenal glands act when a body is under stress  Release of adrenaline  Increased heart rate  Increases blood flow to the muscles  Increase blood pressure  Increase metabolic rate
  • 20. Hormones Are often in the blood at varying concentrations.
  • 21. Hormones Act slowly  Seconds - adrenal  Minutes- pancreas  Hours, days, months, years – sex hormones Long lasting response that may be reversible or not
  • 22. Summary of Control Systems  Via 2 systems (fast and slow)  Keeps the body at optimum function  HOMEOSTASIS – the state of the body is kept within normal parameters, eg blood sugar, blood pH, temperature of the body