there are meninges   (membranes) covering            cord and brain
​   a. dura mater
   b. arachnoid mater
   c. pia mater​      

sagittal and inferior views:
​Corpus callosum 
​Fornix
Thalamus 
Hypothalamus 
Pineal gland 
Pituitary gland 
Infundibulum 
Optic chiasm
Olfactory bulbs
Optic nerve
Mammillary body 

Dorsal nerve roots carry
    sensory info
via  afferent nerves
 to the CNS from the PNS. 

    gray matter forms three pairs of horns:
    1. dorsal/posterior horns have neurons that receive sensory                   information from the body which is relayed via                               ascending pathways to the brain.
    2. ventral/anterior horns have motor neurons that leave
               the spinal cord to control skeletal muscle.
    3. intermediate columns and lateral horns contain neurons                     that control visceral organs.​

external features of the Cerebrum:
​​Cerebral cortex (= crinkled surface of grey matter)
Longitudinal fissures
Cerebral hemispheres
Cerebral lobes: frontal, parietal, temporal, occipital
Gyrus (gyri) & sulcus (sulci)
         (= ridges & grooves on cerebral cortex)

 exiting and entering cord through the bone of the vertebrae from the PNS are dorsal and ventral nerves called nerve roots

 the spinal cord is  divided into grey matter and white matter

Information in the purple boxes will be on the practical

             spinal cord:
    from outside to inside...
vertebrae bone
dura mater
arachnoid matter
​   sub-arachnoid space
pia mater
white matter
grey matter                   

​ CNS: Central Nervous System
PNS: Peripheral Nervous System

     spinal nerves may combine their nerve fibers
​                      to form a nerve plexus      

​1. Cervical Plexus: (nerves C1-C5) 
    ​(ears, neck, back of head, shoulders and diaphragm) 

​2. Brachial Plexus: (nerves C5-T1) 
      (controls muscles of the shoulder, elbow, wrist and hand) 

3. Lumbar Plexus: (nerves L1-L4) 
     (controls muscles of the lower limbs)
    
4. Sacral Plexus (nerves L4-S4) 
    ( controls lower legs and feet)

​   ( Thoracic Nerves T2-T12
     Spinal nerves arising from the thoracic vertebrae
     do not form a plexus for nerves T2-T12...
     each nerve runs along one rib to innervate the rib,
     skin and muscle in that thoracic area)

    what are functions of the PNS?

    Each column contains axons with specific functions.

Nervous System lab

    gray matter forms three pairs of horns:
    1. dorsal/posterior horns 
    2. ventral/anterior horns 
    3. intermediate columns and lateral horns 

functions: initiate/coordinate movement, vision, hearing, touch, judgment and
reasoning along with problem solving, emotions, and learning.

fourth ventricle

CNS: Spinal Cord & Brain 

​The cerebellum's functions include:
coordinating voluntary muscle movements/maintaining posture, balance, and equilibrium.

​The cerebrum has a right and left hemisphere joined by the corpus callosum.

 Dorsal root ganglia are found on the dorsal root of nerves entering the spinal cord.

 peripheral nerves  

   white matter is subdivided
    into dorsal, lateral and ventral columns.

  spinal nerve plexi

​​​Cerebellum with:
Arbor vitae
Cortex

​​
​    Ventral nerve roots carry info 
viaefferent nerves
 from the CNS to the PNS
​to initiate a response in a muscle or gland.

      Descending tracts carry motor instructions from the brain.

    Ascending tracts of column fibers carry sensory information
up to the brain.

CNS: the brain   

     spinal nerves may combine
their nerve fibers to form
​           a nerve plexus      
 ​1. Cervical Plexus
 ​2. Brachial Plexus
 3. Lumbar Plexus
 4.  Sacral Plexus

   a ganglion is a cluster
    nerve cell bodies (soma) located outside the CNS. 
Dorsal root ganglia transmit sensory info from receptors (PNS) ​to the spinal cord (CNS). 

    grey matter contains many cell bodies but few myelinated axons,
while white matter 
​contains few cell bodies but myelinated axons...
    the color difference is due to the white myelin

a nerve plexus is a network of nerves formed by the merging of nerve fibers from different spinal nerves. They distribute nerve signals to specific parts
of the body.

​functions: movement of eyes/mouth, sensory relay of heat/pain, respiration, consciousness, cardiac function, involuntary muscle movements, sneezing, coughing, vomiting/swallowing.

The medulla is the control center for the heart/lungs.

brain ventricles are interconnected cavities within the brain that produce and circulate cerebrospinal fluid. CSF circulates through the ventricles, the subarachnoid space and the central canal of the spinal cord.

major regions of the Brain:
Cerebrum
​Cerebellum
Brainstem

interneurons are found in the spinal cord and relays signals between (afferent) sensory neurons, and (efferent) motor neurons. Reflexes depend on these signals 

    PNS = Peripheral Nervous System

The brainstem includes the pons, midbrain, and the medulla.

reminder:

spinal nerves have a ventral and dorsal root. 
the ventral root carries instructions away from the spinal cord and the dorsal root carries sensory information to the spinal cord

​Ventricles

you are not required to learn the names of individual tracts.