exam 2

• Nervous system


  Receives and processes sensory information from both external and internal environments. Sensory, motor, and information processing.
• Nervous system


  • Has two major divisions:
  • Central nervous system - consists of the brain and spinal chord
  • Peripheral nervous system - consists of nerves, which lie outside the CNS. 12 cranial nerves that comes off from the brain and 31 spinal nerves that comes off from the spine.
• Neurons


  Chemical messengers that send electrical impulses and chemical signals, transmit information to different parts of the brain, to the nervous system
• Three major parts of a neuron

  • Cell body
  • Dendrites - carries information or impulses toward the cell body
  • Axons - carries information/impulses away from the cell body
• Neuroglia cells


  Do not provide electrical or transmit impulses, provide physical support and nourishment to the neurons
• Four types of neuroglia cells found in the CNS

  • Microglial
  • Oligodendrocyte
  • Astrocyte
  • Ependymal
• Two neuroglia cells found in the PNS


  • Schwann cells
  • Satellite
• Four major parts of the brain

  • Cerebrum (telencephalon)
  • Cerebellum
  • Diencephalon
  • Brain stem
• Cerebrum (telencephalon)


  • Has four lobes:
  • Frontal - solving problems, think, speak, hear, smell
  • Parietal lobe - the taste area
  • Occipital lobe - vision/visual
  • Temporal - hearing
• functions of the Cerebellum

  • Responsible for posture, balance, and coordination
• Diencephalonfunctions


  • Thalamus - relay station that carries messages to other parts of the brain. Also for alertness and consciousness.
  • Hypothalamus - regulates water balance, hunger and thirst, body temp and homeostasis, sexual appetite and emotional behavior.
• Three parts of the brain stem

  • Midbrain - eye movement
  • Pons - bridge connects various parts of the brain
  • Medulla oblongata - controls/regulates heart rate, blood pressure, breathing
• Spinal cord


  • Communication between brain and body (called the reflex center)
  • Gray matter - for memory, movement, and emotions. Does not contain myelin sheath
  • White matter - contains myelin sheath and helps us to think fast, walk straight, and keeps us from falling
  • Central canal - contains CSF, which removes toxins from the brain
• Amygdala


  Almond shaped and responsible for emotions, fear, and pleasure
• Hippocampus


  Responsible for learning and memory
• Three layers of meninges

  • Dura mater - outer layer
  • Arachnoid mater - middle
  • Pia mater - inner
• Spinal nerves


  • 8 cervical
  • 12 thoracic
  • 5 lumbar
  • 5 sacrum
  • 1 coccyx (31 total)
• Two divisions of the peripheral nervous system

  • Somatic - movement of skeletal muscles, voluntary
  • Autonomic - movement of cardiac and smooth muscle, involuntary
• Two subdivisions of the autonomic nervous system

  • Sympathetic - fight or flight, occurs in emergency situations; high heart rate, blood pressure, and breathing
  • Parasympathetic - rest and digest, normal heart rate, blood pressure, breathing
• As a person ages, they lose 10,000 nerve cells a day
• Nerve cells cannot be reproduced
• As nerve cell decreases

  Function of nervous system declines
• Decline in performance tasks and reaction time, due to slow processing of the brain
• Nerve conduction impulses slows, as myelin sheath disintegrates
• Decline in intelligence, word usage, and short term memory
• Decline in blood flow to the parts of the body (Stroke patients)
• Decreased reflex response due to atrophy, lack of inactivity or exercise
• Inability to control bladder
• Age-related changes to the nervous system

  • Loss of 10,000 nerve cells per day
  • Nerve cells cannot be reproduced
  • Decline in function of nervous system
  • Decline in performance tasks and reaction time
  • Slowing of nerve conduction impulses
  • Decline in intelligence, word usage, and short term memory
  • Decline in blood flow
  • Decreased reflex response
  • Inability to control bladder
• Conditions affecting the nervous system

  • Menopause/post menopause - lack of exercise, medication, stress
  • Alzheimer's disease - neurodegenerative disease that affects memory, caused by too much buildup of protein/plaque called amyloid, and loss of neurons in the brain
  • Stroke - blood clot that blocks the flow of blood and oxygen to the brain, symptoms include muscle weakness, face drooping, and difficulty speaking
• Sensory receptors


  Convert signals from the environment called stimuli, into nerve impulses (sensory transduction)
• Types of sensory receptors

  • Exteroceptors - detect stimuli from outside the body (taste, smell, vision, hearing, equilibrium)
  • Proprioceptors - detect muscle movements (eccentric - lengthening, concentric - shortening)
  • Chemoreceptors - detect taste or smell
  • Osmoreceptors - detect fluid balance
  • Nociceptors - detect pain
  • Mechanoreceptors - detect balance, pressure, and vibration
  • Interoceptors - detect balance, pressure, and vibration
  • Photoreceptors - detect light
  • Thermoreceptors - detect temperature (hot or cold)
• Gustation (taste)


  • Umami - delicious taste
  • Alkaloids - bitter taste (e.g. wine, beer, cola), have a pH of 8-14
  • Bases (pH 8-14), Acids (<7), Neutral (>7)
• Age-related changes to taste

  • Poor oral hygiene
  • Taste aberration
  • Dry mouth
  • Increase of viscosity (thickness)
  • Formation of fissures and furrows (cracks) on the tongue
• Olfaction (smell)


  • Anosmia - loss of smell
  • Each olfactory has dendrites
• Age-related changes to smell

  • Nasal allergies
  • Sinusitis
  • Nasal polyps
  • Loss of nerve endings
  • Loss of production of mucus in the nose
• Parts of the ear

  • Pinna - collects sound waves
  • Auditory canal - filters air
  • Tympanic membrane (eardrum)
  • Ossicles - malleus, incus, stapes
  • Auditory tube - equalizes air pressure
  • Semicircular canals - rotational equilibrium
  • Vestibule - gravitational
  • Cochlea - hearing and balance
• Age-related changes to the ear

  • Gradual loss of hearing
  • Presbycusis - loss of hearing, typically high pitched sounds are the first to be lost
  • Tinnitus - caused by too much earwax/cerumen, head injuries, whiplash, medications
  • Deafness or complete hearing loss
  • Dizziness or vertigo
• Parts of the eye

  • Sclera - white outer layer, helps maintain shape
  • Cornea - absorbs scattered light rays
  • Choroid - black, pigmented middle layer which absorbs light rays
  • Retina - inner layer, photoreceptor
  • Pupil - regulates light entrance
  • Aqueous and vitreous humor
  • Optic nerve - transmits impulses from the occipital lobe to the brain
  • Iris - admits light
  • Fovea centralis - makes acute vision
• Age-related changes to the eye

  • Vision problems - shrinkage of the eyes, pupil gets smaller by 1/3
  • Presbyopia - nearby objects become very blurry
  • Blindness - complete or partial
  • Glaucoma - damage to the optic nerve as a result of elevated blood pressure
  • Cataracts - cloudy lens or window
  • Diabetic retinopathy - damage on the retina caused by diabetes
  • Macular degeneration - eye disease that causes vision loss or blurry vision, caused by fatty deposits under the retina