Week 4, Tuesday

Topic 3 CNS Anatomy of Quiz 2 pdf (continued)

Landmarks of the superior surface:

• Longitudinal fissure:

  • Separates left and right cerebral hemispheres

Landmarks of the Medial surface:

• Corpus Collosum:

  • Major area for commissural fibers

• Parietoocipital sulcus:

  • Separates parietal and occipital lobes

• Cingulate Sulcus:

  • Separates limbic and frontal lobes

• Central sulcus:

  • Separates frontal and parietal lobes

• Subparietal sulcus:

  • Separates limbic and parietal lobes

Lobe boundaries are visible on the lateral surface:

• Frontal lobe:

  • frontal pole

  • lateral tissue

  • central sulus

• Parietal lobe:

  • Lateral tissue

  • central sulcus

  • Preoccipital notch

• Occipital lobe:

  • Preoccipital notch

  • Occipital pole

• Temporal lobe:

  • Temporal pole

  • Lateral fissure

  • Preoccipital notch

Lobe boundaries are visible on the medial surface:

• frontal lobe:

  • Frontal pole

  • Cingulate sulcus

  • Central sulcus

• Parietal lobe:

  • Cingulate sulcus

  • Central sulcus

  • Subparietal sulcus

  • Parietooccipital sulcus

• Occipital lobe:

  • Parietooccipital sulcus

  • Occipital pole

• Temporal lobe:

  • Insula

  • Limbic lobe

• Limbic Lobe:

  • Cingulate sulcus

  • Subparietal sulcus

  • Corpus callosum

What is the Insula?

• lobe found by spreading the operculum, widening the lateral fissure

Gray and White Matter:

• Gray matter= CNS area consisting primarily of cell bodies and dendrites

• White Matter= CNS area consisting primarily of axons

What are Nuclei and Tracts?

• the Gray matter of the CNS is subdivided into nuclei

  • Each nucleus consists of a collection of cell bodies of neurons with related functions

• The White matter of the CNS can also be subdivided

  • Axons of similar functions, following similar routes are often bundled together

  • A variety of names exist for this:

    • Tract

    • Lemniscus

    • Fasciculus

    • Etc.

Regions of Gray and White Matter

• Gray matter includes:

  • Cerebral cortex:

    • Lines the hemisphere

  • Subcortical gray matter:

    • Smaller collections of gray Matter deep in the hemisphere

• 2 notable areas of white matter are:

  • corona radiata:

    • White matter connected to the cerebral cortex

  • Internal capsule:

    • White Matter connected to the corona radiata and the brainstem

    • This is the route that axons take to get into and out of the cerebrum

Major Subcortical regions of Gray Matter:

• Basal nuclei:

  • Series of Subcortical nuclei

  • Regulates movement

  • Many parts including caudate nucleolus, putamen, globus pallidus

• Amygdala:

  • Subcortical nucleus

  • In temporal lobe

  • Part of the limbic system

Parts of the Basal nuclei:

• Transverse section

  • Head of the caudate nucleus and putamen are separated by internal capsule

• Caudate nucleus

  • Comma shaped

  • 3 parts:

    • Head

      • In frontal lobe

    • Body

      • In parietal lobe

    • Tail

      • In temporal lobe

  • May appear twice in some Ross sections

• Lenticular nucleus

  • Collective name for putamen and globus pallidus

  • Putamen is lateral to globus pallidus

• 2 additional parts:

  • Subthalamic nucleus:

    • In diencephalon

  • Substantia nigra:

    • in anterior midbrain

Hippocampus:

• Subcortical gray matter in temporal lobe

• Part of the limbic system

Major subdivisions of White Matter:

• Corona radiata:

  • White matter connecting the cortex to the internal capsule

• Internal capsule:

  • White mater connecting corona radiata to the brainstem

• Corpus callosum:

  • Largest set of commissural fibers interconnecting L/R cerebral hemispheres

  • Divided into 4 parts:

    • Body

      • The main part of the corpus

    • Genu

      • A curve anterior to the body

    • Rostrum

      • The anterior most portion

      • On the opposite side of the genu from the body

    • Splenium

      • The part posterior to the body

• Anterior commissure:

  • Second largest set of commissural fibers interconnecting L/R cerebral hemispheres

• Same terms viewed in a transverse plane

Ventricles:

• large spaces, filled with cerebrospinal fluid, line by ependymal cells

• L/R lateral ventricles

  • Found within the L/R cerebral hemispheres

• Third ventricle

  • Found within the diencephalon

• Fourth ventricle

  • Sits between pons and cerebellum

Interconnections between ventricles:

• interventricular foramen

  • Connects the L/R lateral ventricles to each other and the 3rd ventricle

• Cerebral aqueduct

  • Connects the 3rd and 4th ventricles

• Obex

  • Connects the 4th ventricle to the enteral canal of the spinal cord

3rd ventricle is not directly visible in a Sagittal cross section, it is the space between the L/R thalami

Cerebral aqueduct travels through midbrain to the open into the 4th ventricle, located in-between the pons and cerebellum

Note the anatomical relationship between the lateral ventricle, caudate nucleus and amygdala