Topic 10-14

• What is phototropism?


  a response to the stimulus of light
• What reaction is auxin involved in?


  Phototropism
• How does phototropism work?


  1.Auxin moves to the side of the shoot furthest away from light

  2.that side grows quicker due to more auxin

  3.the plant leans towards the sun
• What is auxin?


  A plant hormone that controls the growth of plants by promoting cell division
• Roots are negatively geotrophic

  shoots are positively geotrophic
• What does negatively Geotrophic mean?


  Plant grows away from stimulus
• What does positively geotrophic mean?


  plant grows towards stimulus
• What is Geotropism?


  when plant roots grow more on the side with less auxin, making the roots grow down towards the force of gravity. once it begins to grow down the auxin becomes evenly spread
• What is human body temperature?


  37 Degrees Celsius
• What are the bodies main waste products?

  carbon dioxide and Urea
• True or false, carbon dioxide and Urea cause major problems for the body if allowed to build up?


  true
• where is carbon dioxide produced in the body?


  It’s produced by cells during respiration
• Dissolved CO2 is acidic, what can It do if allowed to build up?


  cause your enzymes to denature
• CO2 does not enter red blood cells
• Where is Urea produced?


  in the liver, by the breakdown of amino acids
• How does Urea get into your blood?


  it passes from your liver cells into your blood
• What is hypothermia?


  when you’re too cold
• what is hyperthermia?


  when you’re too hot
• what is homeostasis?


  maintaining a constant internal environment
• what things need to be kept stable inside your body?

  temperature, blood sugar and water levels
• what is the part of the brain that controuls temperature?

  hypothalamus
• what is vasodilation?


  when blood vessels near the surface widen
• what is the purpose of vasodilation?


  to reduce heat lost by radiation, more blood gets nearer to the surface
• What is vasoconstriction?


  when blood vessels contract
• what is the purpose of vasoconstriction?


  to reduce the amount of blood getting near the surface, to reduce heat loss by radiation
• how does our hair help to keep us warm?

  the hair erector muscles contract and make the hair stand more upright, this traps warm still air close to the surface of the skin. less heat is lost by radiation
• how does hair help to keep us cool?

  the hair erector muscles relax and make the hairs lie flat, less air is trapped near the skins surface. more heat is lost by radiation
• true or false, blood vessels do move during vasodilation and vasoconstriction?


  false, they do not move!!!!
• how does the hypothalamus help to regulate body temperature?


  sending signals through the sympathetic nervous system to the sweat glands
• adrenaline stimulates muscle contraction releasing heat energy
• when sick sweating helps ,by making your body hotter, making your body uninhabitable for certain pathogens
• what are receptors?


  cells that can detect changes in the internal or external environment
• what are coordination centers?


  areas that receive and process the information from the receptors. they send out signals and coordinate the response of the body.
• what are effectors?


  muscle or glands that bring about responses to the stimulus that has been received. response restores body to its optimum
• what is negative feedback?


  Restoring the optimum level of a stimulus
• negative feedback loop:

  
• What is a neurone?


  a nerve cell
• what is a motor neurone?


  a neurone connected to muscle gland
• What is a sensory neurone?


  a neurone connected to a receptor
• what is a stimulus?


  a change in environment