AS L7

• General sense


  Mostly associated with the sense of touch, do not have a specialized organ for the sensation, sensory information is gathered by the skin and other tissues
• Special senses


  Have specialized sense organs that collect sensory information and convert it to nerve impulses
• Touch


  • Ability to sense pressure, vibration, temperature, pain & other tactile stimuli, receptors are found in the skin
• Mechanoreception


  • Detection of pressure and vibration
• Nociception


  • Detection of pain or harmful stimuli
• Thermoception


  • Detection of temperature changes
• Equilibrium


  • Perception of balance and spatial orientation, receptors are found in the inner ear

  
• Equilibrium (how does it work?)

  Otoliths (stones) move with head movement, bending hairs in otolithic membrane, activating hair cells to send signals to cerebellum
• Hearing


  • Ability to detect sound waves, receptors are found in the ears

  
• Hearing (how does it work?)

  Sound waves enter ear, vibrate eardrum, vibrations travel through middle ear bones, liquid in cochlea moves, hair cells send nerve impulses to auditory nerve

  
• Sight


  • Ability to sense light and see, majority of sensory receptors are in the eyes
• Sight (how does it work?)

  Light passes through cornea, pupil, lens, focused on retina, rod and cone cells convert light to nerve impulses, travel to brain

  
• Smell


  • Ability to detect and identify molecules in the air, receptors are in the nose
• Smell (how does it work?)

  Olfactory nerves in nasal cavity sense chemicals and interpret as odor
• Taste


  • Ability to perceive flavor, receptors are on the tongue
• Taste (how does it work?)

  Taste receptor cells in taste buds make contact with chemicals, generating nerve impulses to CNS
• Thermoregulation


  Ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different
• Types of organisms based on thermoregulation

  • Warm-blooded (Homeotherms)
  • Cold-blooded (Poikilotherms)
• Homeotherms


  Organisms that maintain their body temperature at a constant level
• Poikilotherms


  Organisms that cannot regulate their internal body temperature with the change in the environment
• Warm-blooded animals can generate heat through consumption of food / metabolism, cold-blooded animals need heat from the environment to survive
• Warm-blooded animals usually have an internal body temp. of 35-40°C, cold-blooded animals do not have a specific body temp. as they match the environment
• Some warm-blooded animals hibernate in cold conditions, cold-blooded animals hibernate (in cold conditions) and aestivate (in hot conditions)
• Ways warm-blooded animals generate heat

  • Muscles and liver generating heat
  • Ingesting hot food or water
  • Conduction (laying on a warm area)
  • Radiation (sun rays)
• Ways warm-blooded animals lose heat

  • Conduction and convection
  • Sweating and micturition
  • Breathing
• Some animals have adaptive properties that allow them to survive harsh environments, some other factors in thermoregulation