3.2: Cenbral Lobes, Basal Nuclei, Diencephalon, Limbic System, Midbrain, Pons, Medulla Oblongata, & Cerebellum

Cenbral Lobes, Basal Nuclei, Diencephalon, Limbic System, Midbrain, Pons, Medulla Oblongata, & Cerebellum

The _ is the largest portion of the brain and is divided into left and right cerebral hemispheres

cerebrum

Each hemisphere contains neural tissue arranged in numerous folds called _

Gyri

The gyri are separated by shallow grooves called _ and by deeper grooves called Fissure

Sulci

The main sulcus that can be detected in MRI is the _, which divides the Precentral Gyrus of the Frontal Lobe from the Postcentral Gyrus

Central Sulcus

The _ is considered the motor strip of the brain

precentral gyrus

The _ is considered the sensory strip of the brain

postcentral gyrus

The two main fissures of the cerebrum are the_

Longitudinal Fissure and the Lateral Fissure or Sylvian Fissure

The Longitudinal Fissure is a long, deep furrow that divides the _

left and right cerebral hemisphere

Within the longitudinal fissure is the _

Falx cerebri and superior sagittal sinus

The Lateral Fissure is a deep furrow that separates the

frontal and parietal lobes from the temporal lobe

The lateral fissure contains _

several blood vessels

The cerebrum consists of

Grey Matter (Neuron Cell Bodies) and White Matter (Myelinated Axons)

The Cerebral Cortex, the outermost portion of the Cerebrum is composed of _ 3 to 5mm thick

Grey Matter

The Cortex is responsible for sensory input, and sends information to the muscles and glands for _

control of bodily movement and activity

_ is deep to the cortex, and contains fibers that transmit nerve impulses to and from the cortex

White matter

The largest and densest bundle of white matter fibers within the cerebrum is the

Corpus Collosum

The other two important bundles of white matter ribers are the

anterior and posterior commissures

The Corpus Callosum is made of white matter, and forms the

roof of the Lateral Ventricle

The four portions of the corpus callosum, from anterior/inferior to posterior, are the:

• Rostrum

• Genu

• Body

• Splenium

The cerebral cortex of each meisphere can be divded into four lobes, which correspond with the cranial bones of the same name:

• Frontal

• Pariteal

• Occipital

• Temporal

The _ is the most anterior lobe of the brain

Frontal Lobe

The frontal lobe is separated from the parietal lobe by the

central sulcus

The frontal lobe is separated from the temporal lobe by the

lateral fissure of sylvian fissure

Reasoning

frontal lobe

judgement

frontal lobe

emotional response

frontal lobe

planning and execution of complex action

frontal lobe

control of muscle movement

Frontal Lobe

The frontal lobe is also involved in the production of speech and contains the motor speech center, _

Broca’s area

Broca’s area lies unilaterally on the _

inferior surface of the frontal lobe dominant for language (typically the left frontal gyrus)

The _ is located in the middle portion of each cerebral hemisphere just posterior to the central sulcus

Parietal Lobe

The_ seprates the parietal love from the temporal lobe

horizontal portion of the lateral fissure

temperature

parietal lobe

touch & pressure

parietal lobe

vibration

parietal lobe

pain

parietal lobe

taste

parietal lobe

involved in writing and in some aspects of reading

parietal lobe

The most posterior lobe, the Occipital Lobe is separated from the parietal lobe by the

parieto-occipital fissure

The _ is involved in the conscious perception of visual stimuli

occipital lobe

The primary visual area receives input from the optic tract via the

optic radiations extending from the thalamus

The Temporal Lobe is anterior to the Occipital Lobe and is separated from the Parietal Lobe by the

Lateral Fissure

Conscious perceptions of auditory and olfactory stimuli are functions of the _, as well as dominance for language

temporal lobe

Memory processing occurs via the

amygdala and hippocampus in the parahippocampal gyrus

Deep to the temporal lobe is an area of cortical gray matter termed the _ often referred to as the fifth lobe

Insula or Island of Reil,

The _ is thought to mediate the motor and sensory functions of the viscera

Insula

The Basal Nuclei are a collection of subcortical gray matter consisting of the

caudate nucleus, lentiform nucleus, and claustrum

The largest basal nuclei are the

caudate nucleus and the lentiform nucleus

The caudate nucleus parallels the lateral ventricle and consists of a

head body and tail

The head of the caudate nucelus causes an indentation to the frontal horns of the lateral ventricles, and the tail

terminates at the amygdal

The lentiform nucleus is a biconvex lens-shaped mass of gray matter located between the

insula, caudate nucleus, and the thalamus

The lentiform nucleus can be further divided into the

globus pallidus and the putame

The _ is a thin linear layer of gray matter lying between the insula and lentiform nucleus

claustrum

The diencephalon consists of the

Thalamus, Hypothalamus, and the Epithalamus

The _ consists of a pair of large, oval gray masses that are interconnected with most regions of the brain and spinal cord via a vast number of fiber tracts

thalamus

The thalamus makes up a portion of the walls of the third ventricle by adhesions known as

massa intermedia

The _ consists of a cluster of small nuclei

hypothalamus

The hypothalamus is located below the

thalamus, just posterior to the optic chiasm, and forming the floor of the third ventricle

The pituitary gland is an endocrine gland connected to the hypothalamus by the

infundibulum

The pineal gland is an endocrine gland that sits on the roof of the midbrain, just posterior to the

third ventricle and below the splenium of the corpus callosum

The _ is a complex group of interconnected brain structures and fiber tracts

limbic system

The limbic system includes the

hippocampus, amygdala, olfactory tracts, fornix, cingulate gyrus, and mamillary bodies

The parahippocampal gyrus, containing the _ is the enrolled medial border of the temporal lobe

hippocampus and amygdala

The amygdala is an almond-shaped mass of gray matter located deep within the parahippocampal gyrus, lateral to the

hypothalamus and adjacent to the hippocampus

The olfactory tracts run underneath the

frontal lobes and connect to the amygdala

The _ is an arch-shaped structure that lies below the splenium of the corpus callosum and makes up the inferior margin of the septum pellucidum

fornix

The cingulate gyrus is a prominent gyrus located on the medial border of

each cerebral hemisphere just superior to the corpus callosum

The mamillary bodies are two small rounded bodies in the floor of the posterior hypothalamus, that

receive direct input from the hippocampus via the fornix,

The mamillary bodies give rise to the fibers that terminate in the

periaqueductal gray matter of the midbrain and anterior thalamus

The brainstem as a whole acts as a conduit between the

cerebral cortex, cerebellum, and spinal cord

Located within the central portion of the brainstem and common to all three segments of it, is the

tegmentum

The tegmentum is responsible for

complex motor actions, aspects of respiratory and cardiovascular activity, and regulation of consciousness

The central core of the tegmentum contains the

reticular formation, containing many nuclei

Ten of the twelve cranial nerves originate from the

nuclei of the brainsteam

The midbrain or mesencephalon is located

superior to the pons and inferior to the Third Ventricle and Thalami

The midbrain or mesencephalon is, composed primarily of massive bundles of nerve fiber tracts and can be divided into two major segments:

cerebral peduncles and the tectum or colliculi

The midbrain surrounds the

cerebral aqueduct

Posterior to the cerebral aqueduct is the_ which makes up the roof or dorsal surface of the midbrain

tectum, or quadrigeminal plate

The tectum consists of four rounded protuberances termed the colliculi:

superior colliculi (visual reflexes) and inferior colliculi (auditory reflexes)

Anterior to the cerebral aqueduct are the two large _, composed predominately of axons that extend from the cerebral cortex to the spinal cord

cerebral peduncles

The cerebral peduncles are made more noticeable by the presence of darkly pigmented _, a broad layer of cells that contain melanin

substantia nigra

Within the tegmentum of the midbrain, at the level of the superior colliculi, is the

red nucleus, composed of motor nerve fiber

The_ is the large oval-shaped expansion of the brainstem, centrally located between the midbrain and the medulla oblongata

pons

The pons, whose name means bridge,

relays signals between the spinal cord and the cerebral and cerebellar cortice

The _ extends from the pons to the foramen magnum, where it continues as the spinal corrd

medulla oblongata

Located in the center of both the anterior and posterior surfaces of the Medulla Oblongata, are the _, which divide the Medulla Oblongata into two symmetrical halves

anterior median fissure and posterior median sulcus

Located on either side of the anterior median fissure are two bundles of nerve fibers called the

pyramid

At the lower end of the pyramids, some of the nerve tracts cross over (decussate) to the opposite side, which in part accounts for the fact that

each of the brain controls the opposite half of the body

On each lateral sufrace are rounded oval prominences called the

olive

True or false: The cerebellum lays in the posterior cranial fossa, and is composed of two cerebellar hemisphere

True

a midline structure named the _ connects the two hemispheres

vermis

On the inferior aspect of each hemisphere are two rounded prominences, termed the _

cerebellar tonsils

_ conncet the cerebellum to the brainstem

three pairs of nerve fiver tracts, the cerebellar peduncles,

the superior cerebellar peduncles connect the _

cerebellum to the midbrain, the middle to the pons, and the inferior to the medulla oblongata

Deep within the center of each cerebellar hemisphere is a collection of nuclei called the

dentate nucleus