Neuroanatomy IRF

Three main divisions of the nervous system

1.) central nervous system

2.) peripheral nervous system

3.) autonomic nervous system

Central nervous system

Includes the brain and spinal cord

Peripheral nervous system

Includes ganglia and nerve fibers

Motor neuron

Cell body is at the end of the cell, with axon extending to innervate its target

Sensory neuron

Cell body is in the middle of the cell; dendrites extend to the periphery, and axon extends into the cell body and back to the CNS

Neural tube

a groove formed in the top layer of differentiated cells in the embryo that eventually becomes the brain and spinal cord

Big picture of neural tube formation

Sheet of epithelial cells in developing embryo start to bulge and get big, change shape, rise up, and make a tube; the tube continues to bend and grow into the brain and spinal cord

Embryonic ectoderm

Layer of cells in the developing embryo that is located dorsal to the notochord

Notochord

Develops into the vertebrae; located ventral to the embryonic ectoderm

Five steps of neural tube development

1.) Embryonic ectoderm begins to grow thicker, forming the neural plate

2.) Groove begins to form within the neural plate, pushing the cells up laterally, and creating the neural groove

3.) Neural groove develops into the neural fold as the ells continue to be pushed up dorsally

4.) Cells on the left and right side fuse together, forming the neural tube

5.) While the neural tube is forming, the cells of the neural crest pinch off to migrate through the body to form other neural structures

Embryonic ectoderm —> ________ —> ___________ —-> ______________ ——> neural tube

Embryonic ectoderm —-> neural plate —-> neural groove —-> neural fold —-> neural tube

Neural crest

A band of cells along the border where the neural tube pinches off from the ectoderm; the cells migrate to various parts of the embryo and form the pigment cells in the skin, bones of the skull, the teeth, the adrenal glands, and parts of the peripheral nervous system

Cells developing in the neural tube are in particular _________ and will have a particular ___________ in the adult stage

Locations; function

Three anatomical structures of neural tube

1.) sulcus limitans

2.) alar plate

3.) basal plate

Sulcus limitans

Groove at the center of the neural tube that divides the developing neural tube into a dorsal and ventral half

Alar plate

Dorsal half of the neural tube; cells will have a sensory function

Basal plate

Ventral half of the neural tube; cells will have a motor function

The neural tube continues to have a process of __________ growth

Differential

Three primary vesicles of neural tube

1.) Prosencephalon

2.) Mesencephalon

3.) Rhombencephalon

Neural tube is a __________ structure full of fluid that will eventually become the cerebral spinal fluid

Hollow

Prosencephalon

Rostral part of neural tube during primary stage

Mesencephalon

Middle part of neural tube during primary stage

Rhombencephalon

Caudal part of neural tube during primary stage

Five secondary vesicles of neural tube

1.) Telencephalon

2.) Diencephalon

3.) Mesencephalon

4.) Metencephalon

5.) Mylencephalon

Which secondary vesicles came from the Prosencephalon?

Telencephalon and diencephalon

Which secondary vesicles came from the mesencephalon?

Mesencephalon

Which secondary vesicles came from the Rhombencephalon?

Metencephalon and mylencephalon

The telencephalon eventually becomes the...

Anatomic brain

The diencephalon-mylencephalon eventually becomes the...

Anatomic brainstem

Clinical term for Prosencephalon (telencephalon/diencephalon)

Forebrain

Clinical term for Mesencephalon

Midbrain

Clinical term for Rhombencephalon (Metencephalon/myelencephalon)

Hindbrain

Clinical term for Metencephalon

Pons and cerebellum

Clinical term for Mylencephalon

Medulla oblongata

The hollow portion of the neural tube eventually develops into...

The ventricular system

Ventricular system

The cerebrospinal fluid-filled spaces inside the brain

Five components of ventricular system

1.) Lateral ventricles

2.) Interventricular foramen

3.) Third ventricle

4.) Mesencephalic aqueduct

5.) Fourth ventricle

Lateral ventricles

Two C-shapes ventricles found in the telencephalon

Interventricular foramen

Located between each lateral ventricle and connects them to the third ventricle

Third ventricle

the ventricle located in the center of the diencephalon

mesencephalic aqueduct

Found in the mesencephalon; connects the third and fourth ventricles

Fourth ventricle

Located deep to the cerebellum and spans both the Metencephalon and mylencephalon

Two openings of the fourth ventricle

1.) foramen of luschka

2.) foramen of magendie

Foramen of luschka

Openings located laterally on the fourth ventricle that open up to the subaranoid space

Foramen of magendie

Opening located medially on the fourth ventricle that open to the subarachnoid space

Neural tube also develops into the ________ _________ of spinal cord through which CSF will flow into after fourth ventricle

Central canal

Layers of the developing neural tube (superficial to deep):

1.) Marginal

2.) Mantle

3.) Germinal

Marginal layer of neural tube

Becomes white matter of spinal cord

Mantle layer of neural tube

Becomes gray matter of spinal cord

Germinal layer of neural tube

Becomes ependymal layer of spinal cord (lines central canal of spinal cord)

Funiculus

Large bundle of white matter in the spinal cord

Fasciculus

Small bundle of white matter in the spinal cord

Three funuculi of the spinal cord

1.) Dorsal

2.) Lateral

3.) Ventral

Horns of spinal cord

Gray matter of spinal cord

Three horns of spinal cord

1.) Dorsal

2.) Ventral

3.) lateral

Dorsal horn has ________ function

Sensory

Ventral horn has __________ function

Motor

Lateral horn has ___________ function

Lumbar cord

The gray matter of the spinal cord contains...

Spinal cord neurons

Two types of spinal cord neurons

1.) Sensory neurons

2.) Motor neurons

Spinal cord neurons of the dorsal horn

1.) GSA

2.) GVA

3.) SSA

4.) SVA

GSA

general somatic afferent

GVA

general visceral afferent

SSA

special somatic afferent

SVA

special visceral afferent

Spinal neurons of ventral horn

1.) GSE

2.) SVE

GSE

general somatic efferent

SVE

special visceral efferent

Spinal neurons of lateral horn

GVE

Three structures of ventral Mylencephalon

1.) Pyramids

2.) Trapezoid body

3.) Olive

Pyramids

Part of pyramidal motor system

Trapezoid body

Part of auditory system; rostral limit of the mylencephalon

Olive

Cytosynapse in extrapyramnidal motor system

Three structures of dorsal Mylencephalon

1.) Fasciculus gracious

2.) Fasciculus cuneatus

3.) Tract of cranial nerve V

fasciculus gracilis

Two bundles that run along the dorsal midline of spinal cord; bundle that comes from pelvic limb of body and carries impulses called consciou propropception

fasciculus cuneatus

Lateral to Fasciculus gracilus; bundle that takes information from thoracic limb and carries conscious propropception

Tract of cranial nerve V

Comes from the head/face and carries pain and temperature information

What cranial nerves does the mylencephalon have?

Nerves VI-XII

Obex

junction between fourth ventricle and central canal located in the mylencephalon

What ventricles are located in the Mylencephalon?

Fourth ventricle (Caudal half)

Two structures of ventral Metencephalon

1.) Transverse fibers of pons

2.) Longitudinal fibers of pons

Transverse fibers of pons

Associated with pyramidal motor system; take pyramidal motor into cerebellum through cerebellar peduncles

Longitudinal fibers of pons

Pyramidal motor fibers going through brainstem and into spinal cord; deep to the transverse fibers of pons

Two structures of dorsal Metencephalon

1.) Cerebellum

2.) Cerebellar peduncles

Cerebellum

A large structure of the hindbrain that controls fine motor skills; coordination

Cerebellar peduncles

connect the cerebellum to the brainstem

three cerebellar peduncles

1.) middle

2.) caudal

3.) rostral

What cranial nerve is in the metencephalon?

Cranial nerve V

What ventricles are in the metencephalon?

Rostral half of the fourth ventricle

Sulcus limitans

Groove where wall of fourth ventricle joins the floor; anything dorsal to it is sensory neruons and anything ventral is motor

Dorsal median sulcus

Line that continues up from the caudal end of spinal cord to the midline groove in floor of ventricle; forms the midline and divides the Fasciculus gracilus in two

Two structures of ventral Mesencephalon

1.) Crus cerebri

2.) Interpenduncular fossa

Crus cerebri

Bundles of fibers coming down through the brain stem; portion of pyramidal motor pathway

interpenduncular fossa

Space between right and left crus cerebri

One structure of dorsal Mesencephalon

Corpora quadrigemina

corpora quadrigemina

located in the midbrain; contains reflex centers for vision and auditory reflexes

Two sections of corpora quadrigemma

1.) rostral colliculus

2.) caudal colliculus

Rostral colliculus

Visual reflexes

Caudal colliculus

Auditory reflexes

What cranial nerves are in the Mesencephalon?

Cranial nerves III and IV