C3.1 integration of body systems

• what occurs at gas exchange surfaces in the lungs of mammals?

  Concentration gradients are maintained by ventilation. Water is lost
• what conveys messages from the central nervous system to an endocrine gland

  sensory neurons
• System integration 


  when components communicate and coordinate
• system 


  is a group of interacting component parts that act together to form a unified whole.
• tissue


  group of two or more different types of cells with specialized structures and functions working and communictaing together.
• provide an example of tissue

  type 1 and type 2 pneumocytes in alvelar tissue (lungs)
• organ 


  group of two or more types of tissue working together to perform a specific function
• example of organ


  spongy mesophyll tissue and palisade mesophyll tissue in a leaf. Lung (alveolar tissue, cartilage tissue, ciliated epithelium tissue)
• organ system


  group of organs working together to perform a function of life
• integration requieres coordination, which requires co:mmunication

  hormones and neurons. Transport of materials.
• hormones 


  chemicals, which travel through the blood stream to the whole body. They effect any cells with the proper receptior (target cell). This form of transport is slower than nervous signaling and lasts until the hormone is broken down.
• Nervous signalling 


  electrical impulses (100 m/s), transmitted by neurons to a specific location, effects muscles or glands only and is faster than hormones but is very short.
• The brain receives and stores information and then processes the information --> sends signals to effector organs 


  brain may send signals to effector organs muscles or glands if a response is required. Sensory - brain - effector
• CNS (central nervous system)


  Comprised of the brain and spinal cord
• The spinal cord has 2 main tissues

  white matter = transmits signals from sensory receptors to the brain, then the brain to other organs Grey matter = Contains cell bodies and synapses processing information, decision making, unconcoius processes only. Examples include movement of food through the digestive track.
• Sensory receptors --> sensory neurons --> CNS 


  CNS --> motor neurons --> effector organs
• Types of receptors


  External = Touch, heat, light Internal = stretch receptors, chemoreceptors
• photoreceptors 


  photon of light
• thermorecptors


  varying degree of heat
• chemoreceptors


  oxygen, pH, various organic molecules (glucose)
• mechanoreceptors


  pressure, cell stretch, vibration, sound, acceleration
• nerve


  bundle of fibers surrounded by a sheath
• nerves contain both 


  sensory and motor neurons, each can only transmit signals one way
• pain reflex arc


  an involuntary and rapid response to specific stimulus
• superachiasmatic nucleus


  pacemaker of circadian rhythm of neuron firing frequencies
• melatonin


  light receptors --> CNS --> pineal gland