Science Task 2

• 1. Differences between unicellular and multicellular cells

  Unicellular:

  • Made up of one cell
  • Simple cell organisation
  • Shorter life span
  • Cannot do much
• 1. Differences between unicellular and multicellular cells

  Multicellular:

  • Made up of more than one cell
  • Complex cell organisation
  • Longer life span
  • Can do many things
• 2. Body Systems

  
  

  Digestive system:

  • Includes mouth, stomach, small intestine, rectum, anus
  • Breaks down food and absorbs nutrients for energy and growth
• 2. Body Systems

  
  

  Circulatory system:

  • Includes heart, veins, arteries, capillaries, blood
  • Delivers oxygen and nutrients to cells and takes away waste
• 2. Body Systems

  
  

  Respiratory system:

  • Includes lungs, windpipe, diaphragm
  • Takes up oxygen from the air we breathe and expels the unwanted carbon dioxide
• 2. Body Systems

  
  

  Urinary system:

  • Includes kidneys, bladder, ureters, uretha
  • Filters blood and creates urine as a waste product
• 3. Nervous vs Endocrine

  
  

  Nervous system:

  • Messages travel along the spinal cord
  • Messages in the form of electrical impulses
  • Messages travel in one direction
  • Messages cause very quick reactions
  • E.g. receptor of sensory info, perception, brain growth
• 3. Nervous vs Endocrine

  
  

  Endocrine system:

  • Messages travel in the bloodstream
  • Messages in the form of hormones
  • Messages travel throughout the body but only act on their target cells
  • Messages cause slow reactions
  • E.g. reproduction, mood, growth, metabolism
• 4. Cell specialisation refers to cells being specialised (having a certain role) to perform a function

  Cells → tissues → organs → organ systems

  E.g. nerve cells, sperm, egg, blood cells
• 5. Neurons

  • Dendrite = fine branches that receive messages from receptors and convey nerve signals to the cell body
  • Cell body = contains the nucleus which supplies energy and nutrients
  • Axon = a long structure where the nerve impulses pass through. It is insulated by the myelin sheath and has branches at its end
• 5. Neurons

  • The electrical impulse travels in one direction
  • Dendrite → axon branches
  • Impulse jumps between synapses through using neurotransmitters produced at the axon terminals
• 5. Neurons

  • Sensory neurons = carry the impulse to the central nervous system
  • Interneurons = carry the impulse through the central nervous system
  • Motor neurons = Takes the impulse from the central nervous system to effectors (muscles or glands)
• 6. and 7. Homeostasis

  • The process of maintaining a relatively stable internal environment
  • Detecting a change and a response to return the body back to normal (negative feedback)
• 8. Types of receptors

  • Mechanoreceptors = sensitive to touch and brings awareness to muscles being stretched
  • E.g. bladder stretching when full
• 8. Types of receptors

  • Photoreceptors = sensitive to light, found in the eye (cones and rods)
  • E.g. Filtering different levels of light and colours
• 8. Types of receptors

  • Thermoreceptors = responds to changes in temperature
  • E.g. sends info about temperature change to brain
• 8. Types of receptors

  Chemoreceptors = sensitive to chemicals (such as in food)

  E.g. can tell whether food is bitter or sweet
• 9. Stimulus-response model

  Stimulus → receptor → messenger → effector