A&P 1 Final Exam

• Free-nerve endings 


  • Pain and temperature receptors of the dermis
  • Nociceptors, thermoreceptors, hair receptors, and Markel disc
  • Ligand-gated channels
• Encapsulated endings

  • Encapsulated to enhance sensitivity
  • Pressure and touch receptors
  • Meissner, Pacinian, and Krause end bulbs
  • Mechanical-gated channels
• Specialized receptor cell

  • Structural component for a specific stimulus
  • Photoreceptor
  • A protein instead of neuron
• Exteroceptor

  • Near stimulus and external environment
  • Eyes, taste, pain, temperature, touch, and pressure
• Interoceptor

  • Interprets stimuli from internal organs and tissues
  • Chemoreceptors and baroreceptors
• Proprioceptor

  • Nearing moving parts of the body to interpret the position of tissues as tissues move
  • Golgi tendon organs and muscle spindles
  • Has a connection with homeostasis and equilibrium
• Chemoreceptor-

  Chemical stimuli, blood composition, taste, and smell
• Osmoreceptor

  • solute concentration in body fluid
• Nociceptor


  pain stimulus from chemicals released due to tissue damage
• Photoreceptor


  rods and cones for vision
• Mechanoreceptor

  • Pressure, vibration, and body position
  • Proprioceptors and baoreceptors
• Thermoreceptor

  • temperature, cold or hot
• Taste

  Sweet, sour, bitter, and umami (may be a sense for fat), taste buds have receptor cells sensitive to chemicals

  • This is a chemoreceptor
• Salty- perception of sodium

  Sour- perception of hydrogen

  Sweet- sugar (glucose)

  Bitter- associated with alkaloids and gag reflex to avoid poisons

  Umami- amino acids (savory foods)
• Taste Buds

  Taste buds are mostly on tongue and are 50-100 epithelial cells
• Gustatory (taste) cells

  have microvilli (gustatory hairs) in the taste pore and a sensory fiber connection at the base of the cell
• Sensory signal


  1. projected through facial, glossopharyngeal, and vagus nerves to postcentral of parietal lobe

  • Facial and vagus cranial nerve plays a very minimal role when it comes to taste
• Smell (Olfaction)

  Odorant molecules (must be in gas form) dissolve in the mucus of the nasal epithelium (pseudostraified)
• Bipolar neurons with cilia (olfactory hairs)


  Only neurons that are replaced
• Primary Olfactory cortex

  is in the temporal lobe, it also projects to the reticular formation and limbic system in the hypothalamus to associate with long-term memory and emotional response
• Olfaction


  also has a tract leading to the frontal lobe
• Smell does not synapse in the thalamus before the cerebral contex
• Small can trigger memories and emotions directly
• Accessory Structure

  Lacrimal gland (tears):

  • Lacrimal duct leads to the eye and conjunctiva
  • Four straight and two oblique extrinsic eye muscles
  • Eyelids, eyebrows, and eye lashes for protection
• Lens

  • Biconvex, flexible structure to help focus light on the retina, held by suspensory ligaments which attach to ciliary muscles
• Sclera


  Whites of the eye, extrinsic muscle attachment
• Choroid


  Nourishes retina, found between retina and sclera
• Ciliary Body

  Has muscles to act on lens, constantly produces aqueous humour to nourish lens and cornea
• Iris


  Pigmented part of the eye that controls pupil size by smooth muscle
• Retina

  Has the rods and cones, attached to optic disc (blind spot) and the ora serrata (separates retina from ciliary body), is pushed against the choroid by vitreous body (jelly filling between lens and retina which lasts a lifetime), has fovea centralis (high concentration of cones)
• Pigmented epithelium


  Absorbs stray light and prevents reflection
• Rods and Cones

  • Photoreceptors
  • Bipolar cells -> Ganglion cells -> Optic nerve
• Cornea

  • most anterior, clear, lets light enter
• Optic Nerve (CN II)

  • carries sensory information to brain (occipital lobe)
• Rods and Cones

  130 million rods vs. 6.5 million cones

  • every one cone connects with one bipolar cell
  • every 30 rods connects with one bipolar cell
• Rods 


  • cylindrical stacks covered in proteins, they react to light, more rods the further from the fovea
• Cones

  Sense color (blue, green, and red) and are concentrated in the fovea
• Hyperopia

  • eyeball is short, light focuses after the retina (farsightedness)
• Myopia

  • eyeball is long, light focuses before the retina (nearsightedness)
• Diplopia


  • eyes don't focus on same spot (double vision)