Ch. 13 The central nervous system/CNS

cerebrum, cerebellum, diencephalon, and brain stem

what are the basic parts of the brain

cerebrum

the largest part of the brain; has prominent fold and grooves on the outer surface

cerebellum

the second largest part of the brain; inferior to the posterior part of the cerebrum

main parts include thalamus, hypothalamus, and epithalamus

what are the main parts of the diencephalon?

main parts include midbrain, pons, and medulla oblongata which is continuous with the spinal cord

what are the main parts of the brain stem?

neural tube, forebrain, midbrain, and hindbrain

embryonic development includes….

prosencephalon/forebrain, mesencephalon/midbrain, rhombencephalon/hindbrain develop from anterior part;

the neural tube includes….

the spinal cord develops from the posterior part of the neural tube

where does the spinal cord develop?

the forebrain

where do the cerebrum and diencephalon develop from?

cerebral peduncle and corpora quadrigemina

what is part of the midbrain and develop from it?

cerebellum, pons, and medulla oblongata

what is part of the hindbrain and develop from it?

the cerebrum, cerebral cortex, the lobes, cerebral white matter tracts, association tract, commissural, corpus callosum, projection tracts, basal nuclei/ganglia, lateral ventricles, diencephalon, thalamus, hypothalamus, and epithalamus

the prosencephalon/forebrain includes

the cerebrum is divided into left and right cerebral hemispheres separated at longitudinal fissure

how is the cerebrum divided?

cerebral cortex

the outer part made up of gray matter; the groove is called the sulcus or sulci (plural);

the fold is called the gyrus or gyri for (plural)

5 lobes

how many lobes in each hemisphere?

frontal lobe

deep to frontal bone; precentral gyrus for motor function

parietal lobe

deep to parietal bone; posterior to frontal lobe and central sulcus; postcental gyrus for general sensory function

occipital lobe

deep to occipital bone; posterior to parietal lobe and parieto-occipital sulcus; functions in vision

temporal lobe

deep to temporal lobe; inferior to frontal and parietal lobes and lateral sulcus; functions in hearing and small

insula lobe

deep to where frontal, parietal, and temporal lobes come together; functions is taste

cerebral white matter tracts

groups of neurons/fibers functionally related

3 types

how many types of cerebral white matter tracts?

association tract, commissural, projection tracts

what are 3 types of cerebral white matter tracts?

association tract

it connects different parts of cerebrum in the same hemisphere

commissural

connects different parts of the cerebrum in opposite (left and right) hemishperes

corpus callosum

a large bundle of more than 200 million myelinated nerve fibers that connect the two brain hemispheres, permitting communication between the right and left sides of the brain

projection tracts

sensory from thalamus to cerebral cortex;

motor from cerebral cortex to spinal cord

2 types

how many types of projection tracts?

basal nuclei/ganglia?

areas of gray matter within cerebral white matter including caudate, putamen, and globus pallidus

lateral ventricles

2 large CSF(cerebralspinal fluid) filled cavities within cerebral white matter; separated at septum pellucidum

3 main parts; thalamus, hypothalamus, epithalamus

the diencephalon has how many main parts and what are they?

thalamus

2 halves each made up of several nuclei separated by CSF filled by the third ventricle except at interthalamic adhesion/intermediate mass where they connect;

CSF flows into third ventricle through interventricular foramina

hypothalamus

inferior to the anterior part of the thalamus

hypothalamus

made up of several nuclei some of which are related to pituitary glands extending from hypothalamus via infundibulum

epithalamus

posterior part of diecephalonl; pineal gland is the main part

mesencephalon/midbrain

the superior part of the brain stem

cerebral aqueduct, corpora quadrigemina, superior colliculi, inferior colliculi, and cerebral peduncle

what does the mesencephalon/midbrain include?

cerebral aqueduct

allows for CSF to flow from the third ventricle to the fourth ventricle through the midbrain

it includes 4 colliculi; 2 on each side, posterior to cerebral aqueduct

what does the corpora quadrigemina include

2 superior colliculi and 2 inferior colliculi

what are the 4 colliculi in the corpora quadrigemina?

they’re for visual reflexes

what are the 2 superior colliculi for?

they’re for auditory reflexes

what are the 2 inferior colliculi for?

cerebral peduncle

superior to the ponds, anterior to cerebral aqueduct; cranial nerves branch off

cerebellum, cerebellar, lobes, cerebellar cortex, arbor vitae, pons, and medulla oblongata

what does the rhombencephalon/hindbrain include?

cerebellum

the largest part of the hindbrain

cerebellar hemispheres

left and right hemispheres connected medially at the vermis

3 lobes; 2 main ones are anterior and posterior separated at primary fissure

how many lobes in each hemishpere?

cerebellar cortex?

gray matter with small folds/folia and deep fissures

arbor vitae

the deep white matter of the cerebellum that connects with other parts of the CNS

pons

part of the brain stem between midbrain and medulla oblongata;

it is the bridge between the brain stem and cerebellar hemispheres; anterior to fourth ventricle; several cranial nerves branch off

medulla oblongata

the inferior part of the brain stem between the pons and the spinal cord;

the expanded anterior parts are pyramids; several cranial nerves branch off

brain protection

the skin of scalp; bones of the skull

3 connective tissue membranes

what are cranial meninges ?

dura mater

the outer, thick layer that divides into 2: periosteal and meningeal

arachnoid mater

the middle layer and it’s a thin web-like membrane

pia mater

the thin layer attached to the brain

cerebral spinal fluid

the 2 spaces in the hindbrain are filled with….

subdural space

the small space between dura mater and arachnoid mater

subarachnoid space

the larger space between arachnoid mater and pia mater;

trabeculae go through cerebral spinal fluid/CSF formation, circulation through and around the brain and spinal cord, and absorption

choroid plexus

in parts of the walls of all 4 ventricles

it includes blood capillaries and ependymal cells

what does the choroid plexus include?

the choroid plexus

where is most CSF formed from?

spinal cord

extends from the medulla oblongata at the foramen magnum though vertebral cavity to upper lumbar vertebrae

oval shape averaging about 0.5 inch diameter

what is the general structure of the spinal cord?

it is in the lower neck region

where is cervical enlargement located?

cervical enlargement

nerves for innervating upper limbs are where?

it is in the lower back region

where is lumbar enlargement located ?

lumbar enlargement

nerves for innervating lower limbs are where?

conus medullaris

most inferior cone shaped part in the lower back region

spinal cord protection

skin and muscles of back, vertebrae

3 membranes

spinal meninges consists of

dura mater

only 1 layer, meningeal, around the spinal cord

arachnoid mater

middle layer of meninges; same as around the brain

dura mater, arachnoid mater, pia mater

what are the 3 membranes of the spinal meninges?

pia mater

the inner layer of meninges; same as around the brain; extension from tip of conus medullaris; filum terminate attaches to coccyx

3

how many spaces are found around the spinal cord?

epidural only around dura mater of spinal cord; mainly contains fat and blood vessels

what are the three spaces that are found around the spinal cord?

subdural

same as around brain

subarachnoid

in addition to trabeculae, 2 denticulate ligaments go through CSF on lateral sides

2 main areas; white matter and gray matter

the internal structure is made up of….

white matter

largely consists of myelinated axons for rapid nerve impulse conduction

3 pairs

funiculi/columns have how many pairs of anatomical areas?

dorsal median sulcus

dorsal/funiculi are separated at

gray matter

lateral funiculi are separated by….

ventral median fissure

ventral funiculi are separated at

spinal cord tracts?

they are functionally related groups of neurons

2 general types

how many general types of spinal cord tracts?

ascending/sensory tracts and descending/motor tracts

what are the 2 general types of spinal cord tracts?

ascending sensory tracts

they conduct nerve impulses up to brain for general sensory functions

6 pairs

how many pairs of ascending sensory tracts ?

fasiculus gracilis and cuneatus;

doral and ventral spinocerebellar tracts;

lateral and ventral spinothalamic tracts

what are the 6 pairs of ascending sensory tracts ?

dorsal columns mainly for touch

fasiculus gracilis and cuneatus goes through….

lateral funiculi for proprioception

dorsal and ventral spinocerebellar tracts go through…

lateral and ventral funiculi for pain and temperature

lateral and ventral spinothalamic tracts go through…

descending/motor tracts

conduct nerve impulses down from the brain through the spinal cord

7 pairs

how many pairs of descending/motor tracts?

lateral and ventral corticospinal/pyramidal tracts;

rubrospinal tracts;

medial and lateral reticulospinal tracts;

vestibulospinal tracts;

and tectospinal tracts

what are the 7 pairs of descending/motor tracts

lateral and ventral corticospinal/pyramidal tracts

they go through lateral and ventral funiculi for voluntary skeletal muscle movements

rubrospinal tracts

they go through lateral funiculi for involuntary postural skeletal muscle actions

medial and lateral reticulospinal tracts

they go through ventral and lateral funiculi; same function as rubrospinal tracts