Lecture 15- The Brain

20 billion

The brain consists of roughly ___________ neurons

Prosencephalon, Mesencephalon, Rhombencephalon

what are the 3 primary brain vesicles that are formed in the forth week of development?

telencephalon and diencephalon

what is formed by the prosencephalon at 6 weeks development?

Metencephalon and Myelencephalon

what is formed by the rhombencephalon at 6 weeks development?

midbrain

what brain regions are formed from the mesencephalon?

Prosencephalon

what primary brain vesicle later forms the cerebrum, epithalamus, thalamus, and hypothalamus

Rhombencephalon

what primary brain vesicle later forms the cerebellum, pons, and medulla oblongata

medulla oblongata

relays information to the thalamus and brainstem/regulates heart rate, blood pressure, and digestion

pons

Relays information to the cerebellum and the thalamus/regulates somatic and visceral motor center

mesencephalon (midbrain)

processes visual and auditory data/maintains consciousness and alertness/involved with reflexive somatic motor responses to stimuli

thalamus

relays information to the cerebrum/processes sensory information

hypothalymus

involved in emotions, thirst, some habitual activity/connects to the pituitary gland
(hypophysis) via the infundibulum

cerebellum

coordinates somatic motor function/adjusts output of somatic motor centers resulting in smooth operation

cerebrum

conscious thought processes/intellectual functions. Memory storage/conscious regulation of skeletal muscle contractions

sulci

grooves in the cerebrum

gyri

ridges in the cerebrum

bones, meninges, cerebrospinal fluid, blood-brain barrier, blood supply

what elements are involved in protection of the skull

dura mater, arachnoid mater, pia mater

3 layers of the cranial meninges from. outermost to inermost

periosteal cranial dura

• Outermost layer of the dura mater
• This is the layer felt within the anterior fontanelle of a baby
• Fused to the periosteum lining of the cranial bones

Meningeal cranial dura

Innermost layer of the dura mater

spaces between 2 layers of the cranial dura

what creates dural sinuses?

falx cerebri

Meningeal layer that extends into the longitudinal fissure

superior sagittal sinus and inferior sagittal sinus

what main sinuses are contained in the falx cerebri?

tentorium cerebelli

Separates the cerebellar hemispheres from the cerebral hemispheres

transverse sinus

what main sinuses are contained in the tentorium cerebelli?

subdural space

space between arachnoid mater and meningeal cranial dura

arachnoid granulations

the arachnoid mater contains projections called ___________ where SF flows through to enter into venous circulation

hypothalamus, capillaries in pineal gland, capillaries in choroid plexus, capillaries in posterior lobe of pituitary gland

What are the Four major regions within brain where the blood brain barrier (BBB) is different from rest of brain?

prevents neural tissue from touching surrounding bones, supports brain, transports nutrients, transports waste

function of cerebrospinal fluid

ependymal cells in the choroid plexus

where is CSF produced?

medulla oblongata

continuous with the spinal cord to the brainstem, all info passes through during communication between brain and spinal cord

Gracile nucleus and cuneate nucleus

Pass somatic sensory information to the thalamus

Solitary nucleus

Receives visceral sensation from the spinal nerves and cranial nerves

olivary nuclei

▪ Pass information from the cerebrum, spinal cord, diencephalon, and brainstem to the cerebellum
▪ create the olives (bulges on the medulla oblongata)))

8-12

what cranial nerves are located in the medulla oblongata?

5-8

what cranial nerves are located in the pons?

controls breathing and relays cerebellar commands

functions of the pons

apneustic center

increases the rate of breathing

pneumotaxic center

decreases the rate of breathing

mesencephalon

another name for the midbrain

corpora quadrigemina

pairs of nuclei found in the midbrain are collectively called….

inferior colliculi

Auditory processing occurs in the __________

superior colliculi

The part of the midbrain where visual processing occurs is the __________

epithalamus

Contains the pineal gland/produces melatonin

hypothalymus

-Subconscious control of skeletal muscles
– Heart rate, blood pressure, respiration, and digestive functions
– Secretion of antidiuretic hormone (via the supraoptic nucleus) and oxytocin (via the paraventricular nucleus)
– Emotional and behavioral drives and thirst drives

cerebellar cortex

subconscious coordination of movements

arbor vitae

subconscious coordination of movements

superior cerebellar peduncles

connect cerebellum with mesencephalon, diencephalon, and cerebrum

middle cerebellar peduncles

communicate between cerebellum and pons

inferior cerebellar peduncles

connect cerebellum with the medulla oblongata

frontal lobe

conscious control of skeletal muscles

occipital lobe

perception of visual stimuli

parietal lobe

conscious perception of touch, pressure, vibration, pain, temperature, and taste

temporal lobe

conscious perception of auditory and olfactory stimuli/deep is the insula

precentral gyrus

– Anterior to the central sulcus
– Neurons direct voluntary movements by controlling somatic motor neurons in the brainstem and spinal cord
– Consists of primary motor cortex and pyramidal cells

postcentral gyrus

– Consists of the primary somatosensory cortex
– Posterior to the central sulcus
– Neurons receive somatic sensory information for touch, pressure, pain, taste, and are associated with visual cortex, auditory cortex, olfactory cortex, and gustatory cortex

Somatosensory association area

allows for the understanding of size, form, and texture

premotor cortex

uses memories of learned movement to coordinate motor activities

visual association area

visually recognizes and interprets objects

auditory association area

recognizes sound

wernicke’s area

analytical area/plays a role in personality

speech center or brocas area

speech production / regulates breathing pattern for speech

receptive speech area

Adjusts the speech based on feedback from auditory stimuli

Prefrontal lobotomy

removal of a lobe of prefrontal cortex

prefrontal cortex

Performs complicated learning and reasoning functions

left hemisphere

hemisphere that is the speech center, writing, language, mathematics

right hemisphere

hemisphere that is analysis by touch, spatial visualization

association fibers

Tracts that interconnect areas of neural cortex within a hemisphere

commissural fibers

Tracts that connect the two hemispheres

projection fibers

tracts that link the cerebrum with other regions of the brain and spinal cord

basal nuclei

masses of gray matter embedded in the white matter inferior to the lateral ventricles

Caudate Nucleus and Putamen

Control the cycles of arm and leg movements when walking

Globus Pallidus

Adjusts muscle tone to prepare for walking

the limbic system

located between the cerebrum and the diencephalon just superior to the corpus callosum

12

how many pairs of. cranial nerves are there?

anterior

cranial nerves are numbered beginning at the ________ aspect of the brain

Sensory (smell)

Function of olfactory nerve I

Sensory (vision)

Function of optic nerve II

Controls extra-ocular eye muscles

Function of oculomotor nerves III

controls the superior oblique eye muscle/motor

Function of trochlear nerves IV

sensory and motor function

function of trigeminal nerves V

motor- control superior oblique eye muscles

Function of trochlear nerves VI

controls eye movements/motor function

function of the abducens nerves VI

• myelencephalon

Which secondary brain vesicle gives rise to the medulla oblongata at birth?
• telencephalon
• metencephalon
• diencephalon
• myelencephalon

• choroid plexus, third ventricle, cerebral aqueduct, fourth ventricle

Which of the following is the correct sequence of the flow of CSF associated with the brain?
• choroid plexus, third ventricle, lateral ventricle, fourth ventricle
• choroid plexus, cerebral aqueduct, third ventricle, fourth ventricle
• choroid plexus, lateral ventricle, median aperture, third ventricle,
cerebral aqueduct, fourth ventricle
• choroid plexus, third ventricle, cerebral aqueduct, fourth ventricle

• Even when circulating glucose levels are low, endothelial cells
continue to transport glucose from the blood to the interstitial fluid of
the brain.

Which of the following statements regarding endothelial transport across the blood brain barrier is TRUE?
• Endothelial cells passively absorb glycine from the interstitial fluid of
the brain and secrete it into the blood.
• It is neither selective nor directional.
• Even when circulating glucose levels are low, endothelial cells
continue to transport glucose from the blood to the interstitial fluid of
the brain.
• The permeability characteristics of the endothelial lining of the brain
capillaries are in some way dependent on chemicals secreted by
ependymal cells.

• cerebrum, thalamus, midbrain, pons, medulla oblongata

Going from superior to inferior, which of the following is the correct sequence of brain structures?
• cerebrum, midbrain, thalamus, pons, medulla oblongata
• cerebrum, thalamus, midbrain, pons, medulla oblongata
• cerebrum, thalamus, pons, midbrain, medulla oblongata
• medulla oblongata, pons, midbrain, thalamus, cerebrum

• trochlear, oculomotor, abducens

Which of the following cranial nerves control the extra-ocular eye muscles?
• oculomotor, trochlear, optic
• oculomotor, facial, abducens
• trochlear, oculomotor, abducens
• optic, abducens, oculomotor

controls muscles of the face and sensations from the face (taste)

function of the facial nerves VII

balance and hearing

function of the vestibulocochlear nerves VIII

tongue pain sensation and motor function

function of the glossopharyngeal nerves IX

receives sensory information from organs, sends motor information to organs

function of the vagus nerves X

controls the sternocleidomastoid, trapezius, palate, pharynx, and larynx muscles

function of the accessory nerves XI

controls tongue movement

function of the hypoglossal nerves XII

establishes emotional states, links conscious and unconscious functions, facilitates memory storage and retrieval

what are the functions of the limbic system?

the fornix

Tract of white matter connecting the hippocampus with the hypothalamus

mammillary bodies

control reflex movements associated with eating

limbic lobe and hippocapmus

what makes up the limbic system?

Falx cerebelli

Extends from the tentorium cerebelli to separate the cerebellar hemispheres

Diaphragma sellae

Lines the sella turcica of the sphenoid bone
• It anchors the dura mater to the sphenoid bone
• It encases the pituitary gland