nervous system

• nervous system

  • master controlling and communicating system of the body
  • it creates electrical impulse (nerve impulse) which are rapid and specific cause almost immediate response
  • regulates the different activities of the body
• central nervous system

  • contains the brain and spinal cord
  • interprets incoming sensory information
  • issue instructions based on the past experience and current conditions
• peripheral nervous system

  • part of the nervous system that lies outside the central nervous system (CNS)
  • outside the brain and spinal cord
  • consist mainly of the nerves that extend from the brain and spinal cord that serve as communication lines.
• cranial nerves - carries impulses to and from the brain
• spinal nerves - carries impulses to and from the spinal cord
• sensory or afferent division

  • conveys impulses from sensory receptors located in various parts of the body
• motor or efferent division

  • motor response
  • carries impulses from CNS to effector organs, the muscles, and glands
• somatic nervous system

  • allows us to consciously, voluntarily, control our skeletal muscles
• autonomic nervous system

  • regulates events that are autonomic or involuntarily such as the activity of smooth and cardiac muscles and glands
  • involuntary nervous system
• sympathetic division

  • fight or flight system
  • happens when we are excited or find ourselves in emergency or threatening situations increases heart rate, blood pressure, blood glucose levels, dilates the bronchioles of the lungs
  • excercise, embarassment, emergency
• parasympathetic division

  • resting and digesting
  • active when the body is at rest and not threaten in any way
  • promoting normal digestion, elimination of feces and urinating
  • digestion, defecation, diuresis
• neuroglia - nerve glue
• astrocytes

  • abundant star-shaped cells
  • account for nearly half of the neural tissue
• microglia

  • spider-like phagocytes
  • monitor the health of the neurons
• oligodendrocytes

  • glia that wrap their flat extensions tightly around the nerve fibers, producing fatty insulating coverings called “myelin sheaths”
• cell body

  • “cytoplasm” organelles of neurons
  • metabolic center
• dendrites

  • neuron processes that conveys incoming messages toward the cell body
• axons

  • generates nerve impulse away from the cell body
• axon terminal

  • tiny vesicles or membranous sacs that contains neurotransmitter
• resting potential

  • when a neuron is not conducting an impulse there is a difference between the electrical charge inside and outside (fluid) of the neuron voltage
  • more positive ions Na+ and K+ outside compared to the inside inside of the neuron is negative at -70 mV
  • 55 mV or 65 mV to generate nerve impulse
• action potential

  • conduction of signal within the neuron
• reflex

  • rapid response to the stimuli
  • very rapid and short duration
  • do not rely on the brain for decision-making
  • never go to the brain, only in spinal cord
• human brain

  • 3 pounds
  • 60% of fat and is one of the fattest organs in the human body
  • capable of surviving for 5-6 minutes only if doesn’t get oxygen, otherwise it will be brain dead
• gray matter

  • cell bodies and unmyelinated bodies
• white matter

  • myelinated axon that run together in bundles in tract
• meninges (sing. Meninx)

  • protective membrane that wrapped the brain and spinal cord
• dura mater

  • white, fibrous connective tissue that lies next to the skull and vertebrae
• arachnoid

  • web like connective tissue with thin strands that attach it to the pia mater
• pia mater

  • deepest meninx
• meningitis

  • inflammation of the meninges
• encephalitis

  • inflammation of the brain
• longitudinal fissure

  • middle of the brain
  • left and right hemisphere
• parietal Lobe

  • pain, temperature, and light touch
• occipital lobe

  • posterior part - visual area
• temporal Lobe

  • lateral sulcus - auditory area
  • deep inside the temporal lobe - olfactory area
• frontal lobe

  • primary motor area
  • Broca’s area - base of the precentral gyrus - ability to speak
  • anterior part of the frontal lobe - higher intellectual reasoning;
• thalamus

  • relay station for sensory impulses passing upward to
  • sensory cortex (if sensation is pleasant or
  • unpleasant)
• hypothalamus

  • “under the thalamus”
  • regulates body temperature, water balance, and
  • metabolism
  • center for many drives and emotions
• epithalamus

  • roof of the third ventricle
• brain stem

  • thumb in diameter
  • breathing and blood pressure