central nervous system (CNS)
including the brain and spinal cord
peripheral nervous system (PNS)
including the peripheral nerves connecting target cells/organs to the CNS
enteric nervous system
the nerve network of the digestive tract
somatic
carries sensory information from skin, skeletal muscles
visceral
carries sensory information from smooth muscle, glands and organs – aka autonomic
afferent (input) divisions: sensory
somatic
visceral
shares information about an organ into the system
efferent (output) divisions: motor
somatic nervous system
autonomic nervous system
somatic nervous system
motor neurons that supply skeletal muscles
autonomic nervous system
motor neurons that innervate smooth muscle, cardiac muscle, and glands (involuntary)
autonomic divisions
sympathetic
parasympathetic
sympathetic nervous system
fight or flight response
parasympathetic nervous system
resting/digesting
astrocytes
physical support neurons in proper spatial (3d space) relationships
induce formation of blood-brain barrier
take up excess K+ to help maintain proper brain ECF ion concentration and normal neural excitability
oligodendrocytes
form myelin sheaths in CNS
- get attacked in MS
microglia
play a role in defense of brain as phagocytic scavengers
ependymal cells
contribute to formation of cerebrospinal fluid
meninges
_ covers CNS
dura mater
tough outer coat
arachnoid matter
blood vessels
subarachnoid space
filled with cerebral spinal fluid (blood)
pia mater
on brain surface
blood-brain barrier
_ limits access of blood-borne material into brain tissue
cerebrospinal fluid (CSF)
cushioning fluid that surrounds brain and spinal chord (CNS)
- is produced inside ventricles in the brain and flows out into the subarachnoid space
ventricles and CSF
• Serves as a shock-absorber to prevent brain from hitting skull.
• Exchange of materials between neural cells and interstitial fluid surrounding brain.
• Constant production and flow out of CNS and into venous system; carries wastes out of CNS.
blood and oxygen supply
• Brain depends on a constant blood supply.
• Unlike most tissues the brain cannot produce ATP without O2.
• Brain normally uses only glucose but does not store any.
Under resting conditions the brain uses 20% of the O2 and 50% of the glucose consumed in the body
more basic the function
the lower the part of the brain the _
cerebrum
• makes up about 80% of total brain weight.
• Largest unit in the brain
Longitudinal fissure
deep groove that separates cerebrum into right and left cerebral hemispheres
each hemisphere divided into lobes
gyrus
thick fold
sulcus
shallow grove
cerebral cortex
Outer surface of each hemisphere composed of gray matter and is the complex integrating area of the brain
caps core of white matter
organized into 6 well defined layers
gray matter
primarily neuronal cell bodies, dendrites, and glial cells
integration of neural input and ignition of neural output
white matter
contains all axons, surrounded in myelin
consists of bundles of nerve fibers that interconnect brain areas
occipital lobe
houses the visual cortex
temporal lobe
houses the auditory cortex
parietal lobe
responsible for reception and perception of somatosensory input - somatic
frontal lobe
responsible for voluntary motor movement
somatosensory cortex
Site for processing and perception of both somesthetic (sensation from surface) and proprioceptive (awareness of position) input
• Located in each parietal lobe as the post-central gyrus.
somesthetic sensations
from the surface of the body (touch, pressure, heat, cold, and pain)
proprioception
awareness of body position
opposite
• The somatosensory cortex receives input from the _ side of the body.
• Regions of the somatosensory cortex receives input from a specific areas of the body.
sensory homunculus
the distribution map
the size of each body part in the homunculus is proportional to the level of sensory perception associated each body part
primary motor cortex
• Located in the frontal lobe as the pre-central gyrus.
• Controls voluntary movement produced by skeletal muscles
• Sends information to theventral portions of the spinal cord to activate motor neurons
motor cortex
_ on each side of the brain primarily controls muscles on the opposite side of the body
larger
Body parts needing fine control of movement occupy _ area of motor homunculus