Human Anatomy Exam 2 - Lecture 7, The Central Nervous System (CNS), *The Brain and the Spinal Cord*

What is the folia of the cerebellum?

"leaves" on the surface of the cerebellum, analogous to gyri of cerebrum - gray matter. Separated by fissures

What is the Arbor vitae of the cerebellum?

"tree of life" branching arrangement of the white matter of the cerebellum

What is the vermis of the cerebellum?

"worm-like" structure on the superior midline of cerebellum, involved in posture and balance

What do the Meninges include?

- Dura Mater "tough mother" (against skull) - Arachnoid "spidery" - Pia Mater "gentle mother" (against brain)

What is included in the Dura Mater?

- Large dural sinuses which contain blood sinuses - normally small subdural space contains CSF

What is white matter made of?

- Neuroglia - mixture of myelinated and non-myelinated fibers

What is gray matter made of?

- Neuroglia - non-myelinated neurons - cell bodies (somas)

What is the function of Cerebrospinal Fluid (CSF)?

- Provides buoyancy for brain and spinal cord - Provides a cushion for brain and spinal cord - Traffics nutrients & waste products - Different in composition than blood

Name the protective layers of the central nervous system from superficial to deep layers.

- Skin and sensory nerves - Skull and Vertebrae - Meninges

What are the 4 main parts of the brain?

- cerebrum - diencephalon - cerebellum - brain stem

What does the gray matter of the spinal cord include?

- dorsal horns - ventral horns - lateral horns

Where is the CSF?

- fills ventricles & central canal of the spinal cord - enters sub meningeal spaces via the median and lateral apertures

What is included in the Arachnoid?

- large subarachnoid space contains CSF

What does the cerebrum include?

- many clusters of cell bodies - elaborate cortex

What does the brain stem include?

- midbrain - pons - medulla

What is included int he Pia Mater?

- normally small subpial space contains CSF

What does the cerebellum play a role in?

- posture - balance - smoothing/coordinating body movements

What is the process of the cerebellum functioning?

- receives info from the cerebrum on movements being planned - compares planned movements with current body position/movements (proprioception) - Instructs cerebrum on how to resolve differences

What does the thalamus do?

- relay of all sensory information (except olfaction) - involved in learning, memory, emotions, awareness (all signals to/from the cerebral cortex (except smell) must pass through at least one nucleus of the thalamus)

What does the pineal gland do?

- releases melatonin - involved in circadian rhythm

What does the hypothalamus do?

- seat of homeostatic control of the body (thirst, hunger temperature) - produces regulatory (tropic) hormones - control of the autonomic nervous system - emotional & reproductive responses - involved in memory circuits

What does the Diencephalon include?

- thalamus - hypothalamus - epithalamus (pineal gland)

How can you tell the dorsal side from the ventral side of the spinal cord?

- the ventral median fissure is usually wider than the dorsal median sulcus - butterfly -> the head of the butterfly (larger wings) point towards the ventral side

What is the volume or CSF in adults and how long does it take to replace?

150mL in adults and replaced every 4-6 hours.

How many neurons are in every chain from the brain to an effector organ? (descending- efferent pathways)

2-3 neurons

How many neurons form every chain of sensory receptors to the brain? (ascending- afferent pathways)

2-3 neurons

How many pairs of spinal nerves does the spinal cord give rise to and where do they exit through?

32 pairs which exit through the intervertebral foramina

What is the purpose of the median eminence?

A gap in the blood- brain barrier so that the hypothalamus can monitor blood.

What is the Temporal lobe responsible for?

Auditory and Limbic

How is the spinal cord held in place?

By the filum terminale which is an extension of the pia mater.

What is the Frontal lobe responsible for?

Decision making & motor control

What is the pineal gland a part of?

Epithalamus (on the dorsal side of hypothalamus, just anterior to the brain stem)

In general, how is the gray and white matter distributed in the spinal cord?

Gray matter forming a butterfly shape on the inside (deep) and white matter surrounding it (superficial).

In general, where is the gray and white matter in the brain?

Gray matter is on the outside (superficial) part of the brain, while the white matter is on the inside (deep) part of the brain. Also the cortex in the middle tho has some gray matter

What is the Parietal lobe responsible for?

Sensory integration

What does the Central Nervous System (CNS) include?

The big bad brain and the long slim spinal cord

How many neurons does the cerebellum have compared to the rest of the brain?

The cerebellum has as many neurons as the rest of the brain

What is the corpora quadrigemina?

These are four rounded protrusions are reflex centers involved with vision and hearing.

What does the white matter of the spinal cord contain?

Tracts of mostly myelinated axons - ascending fibers - descending fibers - commissural fibers (arranged in 3 funiculi -> dorsal, ventral, and lateral funiculus)

What is the Occipital lobe responsible for?

Vision

What is the Falx? What are the different ones in the brain?

a structure shaped like a sickle - Falx cerebri (covers most of cerebrum) - Tentorium cerebelli (covers superior part of cerebellum) - Falx cerebelli (covers posterior part of cerebellum)

How many nuclei does the hypothalamus have?

about 12 main nuclei

How many nuclei does the thalamus contain?

about 14 main nuclei per side

Where is the CSF absorbed into?

absorbed back into the bloodstream via the arachnoid granulations (villi) of the dural venous sinuses along the length of brain and spinal cord

What is the function of the infundibulum (pituitary stalk)?

allows for hormones synthesized in the hypothalamus to be sent to the posterior pituitary for release into the bloodstream.

When referring to brain, what does rostral mean?

anterior

Where is the Primary somatosensory cortex found?

anterior edge of the parietal lobe, just posterior to the central sulcus

What is gray commissure?

area around central canal containing unmyelinated commissural axons (connects dorsal and ventral sides)

What do the two inferior colliculi process?

auditory information

What's another small layer of protection of the brain?

blood-brain barrier

How is cerebrospinal fluid made?

by specialized ependymal cells in the choroid plexus

What is spina bifida?

caudal end of neural tube doesn't close (and/or the vertebral laminae don't form)

What are association fibers?

connect different regions of the same hemisphere

What is the cerebellar peduncles of the cerebellum?

connections of cerebellum to the brain stem - inferior (medulla) - middle (pons) - superior (midbrain)

What and where are the cerebral peduncles?

connections to the cerebrum and the cerebellum in the midbrain

What is the purpose of the corpus callosum?

connects right and left cerebral hemispheres

What are commissural fibers?

connects the two cerebral hemispheres (corpus callosum)

What do the ventral horns include?

contain cell bodies and synapses of somatic motor (efferent) neurons

What do the lateral horns include?

contain cell bodies and synapses of visceral motor (efferent) neurons of the autonomic nervous system

What do the dorsal horns include?

contain interneurons receiving afferent info from somatic and visceral sensory neurons

What is the additional outer layer of gray matter in the cerebrum and cerebellum called?

cortex

What is the basal nuclei?

deep gray matter - "neural calculators" that initiate and terminate: motor activities, cognitive processes, and emotional behaviors

What is the corpus callosum composed of?

dense myelinated tracts

What is the spinal cord an extension of and inferior to?

extension of the medulla oblongata, inferior to the foramen magnum.

The optic nerves and retinas are _____________ of the diencephalon.

extensions

How does the neural tube form?

from invaginating ectoderm

Is the diencephalon mostly white or gray matter?

gray matter

What is the cortex of the cerebrum?

gray matter (cell bodies)

What are the raised regions of the cerebrum called?

gyri

What is a sinus in the brain?

im pretty sure its just a large vein

What is important about the functions behind the brain stem?

it contains many nuclei associated with basic life processes such as - breathing centers - cardiovascular centers origins of the autonomic nervous system - swallowing center

Does CSF have less or more proteins than blood plasma?

less

Does the corpus callosum have any pprocessing?

no, as far as we can tell

Where can the lateral horns be found?

only present in the thoracic, upper lumbar, and sacral regions or the spinal cord

What's another function of the Dura Mater other than being a protective layer?

physically stabilizes the brain

When referring to brain, what does caudal mean?

posterior

Where is the Primary motor cortex found?

posterior edge of the frontal lobe, just anterior to the central sulcus

The brain stem carries most of the motor output from the cerebral cortex to the spinal cord through the ____________- of the medulla. What is special about these?

pyramids, they cross (decussation)

What is anencephaly?

rostral end of neural tube doesn't close

What is the function of the olfactory bulbs?

sense of smell

What is the purpose of the mammillary bodies?

sense of smell and long-term memory

Spinal cord carries __________ information to the brain and _____________ information from the brain.

sensory (afferent), moto (efferent)

What is the Broca's area responsible for?

speech formation (part of frontal lobe)

What is the Wernicke's area's function?

speech understanding (parietal lobe)

What are the depressions of the cerebrum called?

sulci

What is special about the brain stem in relation to the rest of the central nervous system?

the brain stem interconnects all parts of the CNS

The ventricles and central canal are remnants of _________________.

the neural tube

Where does the spinal cord descend through?

the vertebral foramina

What are projection fibers?

vertical afferent and efferent fibers connecting the cortex to a lower area, forming ascending and descending pathways

What is the function of the optic nerves?

vision (join at optic chiasm, continue posteriorly as the optic tracts)

What do the two superior colliculi process?

visual information

How are the spinal cord segments named?

where the spinal nerves emanate from the cord

How are spinal nerves named?

where they exit the vertebral column

What are the axonal tracts of the cerebrum?

white matter (association, commissural, & projection fibers)

Does the spinal cord integrate some sensory/motor information?

yes, spinal reflexes

Is the spinal cord covered by the same 3 meningeal layers as the brain?

yuh