Brain Stem
Is continuous with the spinal cord and consists of the medulla oblongata, pons, and midbrain.
Diencephalon
Superior to the brain stem, consists of the thalamus, hypothalamus, and epithalamus.
Cerebrum
The largest part of the brain. Supported on the diencephalon and brain stem.
Cranial meninges
Are continuous with the spinal meninges, have the same basic structure and bear the same names: the outer dura mater, the middle arachnoid mater, and the inner pia mater.
Falx cerebri
Seperated the two hemispheres of the cerebrum
Falx cerebelli
Seperated the two hemispheres of the cerebellum
Tentorium cerebelli
Seperates the cerebrum from the cerebellum
Blood brain barrier
Protects the brain cells from harmful substances and pathogens by preventing passage of many substances from blood into brain tissue.
Cerebrospinal fluid
A clear, colorless liquid that protects the brain and spinal cord from chemical and physical injuries.
Ventricles
The four cavities within the brain
Lateral Ventricle
Located in each hemisphere of the cerebrum.
Septum pellucidum
Anteriorly, the lateral ventricles are separated by a thin membrane.
Third ventricle
A marrow cavity along the midline superior to the hypothalamus and between the right and left halves of the thalamus.
Fourth ventricle
Lies between the brain stem and the cerebellum
Choroid plexus
One of the sites of CSF production. Networks of blood capillaries in the walls of the ventricles.
Blood-cerebrospinal fluid barrier
Permits certain substances to enter the CSF but excludes others, protecting the brain and spinal cord from potentially harmful blood-bourne substances.
Interventricular foramina
The CSF formed in the choroid plexus of each lateral ventricle flows into the third ventricle through the narrow, oval openings.
Arachnoid villi
CSF is gradually reabsorbed into the blood through.... fingerlike extensions of the arachnoid that priject into the dural venous sinuses, especially the superior sagittal sinus.
Arachnoid granulation
A cluster of arachnoid villi is called...
Medulla oblongata
Is continuous with the superior part of the spinal cord; it forms the inferior part of the brain stem. Begins at the foramen magnum and extends to the inferior border of the pons. Vital controls: cardiovascular center, respitory center. Nonvital centers:
Pyramids
Some of the white matter bulges on the anterior aspect of the medulla. Are formed by the large corticospinal tracts that pass from the cerebrum to the spinal cord.
Decussation of pyramids
90% of the axons in the left pyramid, cross to the right side and 90% of the axons in the right side cross to the left side. This explains why each side of the brain controls voluntary movements on the opposite side.
Medullary rhythmicity area
adjusts the basic rhythm of breathing.
Olive
Just lateral toe each pyramid is an oval-shaped swelling.
Inferial olivary nucleus
recieves an input from the cerebral cortex, red nucleus of the midbrain and spinal cord.
Gracile nucleus and Cuneate nucleus
Nuclei associated with the sensations of touch, pressure, vibration, and conscious proprioception are located in the posterior part of the medulla.
Medial Lemniscus
The axons ascend to the thalamus in a band of white matter called.... which extends through the medulla, pons and midbrain.
Posterior column-medial lemniscus pathway.
The tracts of the posterior columns and the axons of the medial leminiscus are collectivelly known as...
Gustatory nucleus
Of the medulla is part of the gustatory pathway from the tongue to the brain; it receives gustatory input from the taste buds of the tongue.
Cochlear nuclei
Of the medulla are part of the auditory pathway from the inner ear to the brain; they receive auditory input from the cochlea of the inner ear.
Vestibular nuclei
Of the medulla and pons are components of the equilibrium pathway from the inner ear to the brain; they receive sensory information associated with equilibrium from proprioceptors in the vestibular apparatus of the inner ear.
Pons
Lies directly superior to the medulla and anterior to the cerebellum. It is a bridge that connects different parts of the brain with one another. These connections are provided by a number of axons. Consists of nuclei, sensory tracts and motor tracts.
Pontine nuclei
Signals for voluntary movements from the motor areas of the cerebral cortex are relayed through... into the cerebellum.
Midbrain or Mesencephalon
Extends from the pons to the diencephalon. The aqueduct of this passes through the midbrain , connecting the third ventricle with the fourth ventricle. Contains both nuclei and tracts.
Cerebral peduncles
The anterior part of the midbrain contains paired bundles of axons known as the... consists of axons of the corticospinal, corticopontine and corticobulbar tracts, which conduct nerve impulses from motor areas in the cerebral cortex to the spinal cord, po
Tectum
The posterior part of the midbrain, contains four rounded elevations.
Superior colliculi
The 2 superior elevations, nuclei known as... serve as reflex centers for certain visual activities.
Inferior colliculli
The two inferior elevations, are part of the auditory pathway, relaying impulses from the receptors for hearing in the inner ear to the brain.
Substantia nigra
Large area with dark pigments, help control subconscious muscle activities, Loss of these neurons are associated with Parkinson's disease.
Red nuclei
Look reddish due to their rich blood supply and iron containing pigment in their neural cell bodies.
Reticular formation
The broad region where the white matter and gray matter exhibit a net like arrangement.
Reticular activating system
Part of the reticular formation, consists of sensory axons that project into the cerebral cortex. Help maintain consciousness and it active during awakening from sleep.
Cerebellum
Second only to the cerebrum in size, occupies the inferior and posterior aspects of the cranial cavity. Has a highly folded surface that greatly increases the surface of its outer gray matter cortex, allowing for greater number of neurons.
Transverse fissure and Tentorium cerebelli
supports the posterior part of the cerebrum, separate the cerebellum and cerebrum.
Vermis
The central constricted area of the "butterfly
Cerebral hemisphere
The lateral "wings" or lobes.
Anterior and Posterior lobe
Govern subconscious aspects of skeletal muscle movements.
Flocculonodular lobe
On the inferior surface contributes to equilibrium and balance.
Cerebellar cortex
The superficial layer of the cerebellum, consists of gray matter in a series of slender, parallel folds called folia.
Arbor vitae
Deep to the gray matter, that resemble the branches of a tree.
Cerebellar nuclei
Even deeper, within the white matter are the...., regions of gray matter that give rise to axons carrying impulses from the cerebellum to other brain centers.
Cerebellar peduncles
attach the cerebellum to the brain stem.
Superior cerebellar peduncles
Contain axons that extend that extend from the cerebellum to the red nuclei of the midbrain and to several nuclei of the thalamus
Middle cerebellar peduncles
Are the largest peduncles; their axons carry commands for voluntary movements from the pontine nuclei into the cerebellum.
Inferior cerebellar peduncles
Consist of (1) axons of the spinocerebellar tracts that carry sensory information into the cerebellum from the proprioceptors in the trunk and limbs; (2) axons from the vestibular apparatus of the inner ear and from the vestibular nuclei of the medulla an
Thalamus
makes up 80% of the diencephalon, consists of paired oval masses of gray matter organized into nuclei with interspersed tracts of white matter.
Intermediate mass
A bridge of gray matter... joins the right and left halves of the thalamus in about 70% of the human brain.
Internal medullary lamina
A vertical Y-shaped sheet of white matter, divides the gray matter of the right and left sides of the thalamus.
Internal capsule
Axons that connect the thalamus and cerebral cortex pass through the... a thick band of white matter lateral to the thalamus.
Anterior nucleus
Receives input from the hypothalamus and sends output to the limbic system. It functions in emotions and memory.
Medial Nuclei
Receives input from the limbic system and basal ganglia and send output to the cerebral cortex. They function in emotions, learning, memory, and cognition.
Lateral group
Receive input from the limbic system, superior colliculi, and cerebral cortex and send output to the cerebral cortex.
Lateral dorsal nucleus
Functions in the expression of emotions
Lateral posterior nucleus and Pulvinar nucleus
Help integrate sensory information
Ventral anterior nucleus
Receives input from the basal ganglia and sends output to motor areas of the cerebral cortex; it plays a role in movement control.
Ventral lateral nucleus
Recieves input from the cerebellum and basal ganglia and sends output to motor areas of the cerebral cortex; it also plays a role in movement control.
Ventral posterior nucleus
Relays impulses for somatic sensations such as touch, pressure, vibration, itch, tickle, temperature, pain, and proprioception from the face and body to the cerebral cortex.
Lateral geniculate nucleus
Relays visual impulses for sight from the retina to the promary visual area of the cerebral cortex
Medial geniculate nucleus
Relays auditory impulses for hearing from the ear to the primary auditory area of the cerebral cortex.
Intralaminar nuclei
Lie within the internal medullary lamina and make connections with the reticular formation, cerebellum, basal ganglia, and wide areas of the cerebral cortex. Function in arousal and integration of sensory and motor information.
Midline nucleus
Forms a thin band adjacent to the third ventricle and has a presumed function in memory and olfaction
Reticular nucleus
surrounds the lateral aspect of the thalamus, next to the internal capsule. This nucleus monitors, filters and integrates activities of other thalamic nuclei.
Hypothalamus
A small part of the diencephalon located inferior to the thalamus. Composed of a dozen or so nuclei.
Mammillary region
Adjacent to the mid brain, is the most posterior part of the hypothalamus. It includes the mammillary bodies and posterior hypothalamic nuclei. The bodies are two, small, rounded projections that serve as relay stations for reflexes related to the sense o
Tuberal region
The widest part of the hypothalamus, includes dorsomedial nucleus, ventromedial nucleus and arcuate nucleus, plus the stalklike infundibulum.
infundibulum
Connects the pituitary gland to the hypothalamus.
Median eminence
is a slightly raised region that encircles the infundibulum.
Supraotopic region
Lies superior to the optic chiasm (point of crossing of optic nerves) and contains the paraventricular nucleus, supraoptic nucleus, anterior hypothalamus nucleus, and suprachiasmatic nuclues. Axons form the paraventricular and supraoptic nuclei form the h
Preoptic region
Anterior to the supraoptic region is usually considered part of the hypothalamus because it participates with the hypothalamus in regulating certain autonomic activities. Contains medial and lateral preoptic nuclei.
Satiety center
Causes sensation of fullness and cessation of eating.
Circadian rhythms
Patterns of biological activity (such as the sleep-wake cycle). The cycle is about 24 hours.
Epithalamus
A small region superior and posterior to the thalamus. It consists of the pineal gland and habenular nuclei.
Pineal gland
About the size of a small pea and protrudes from the posterior midline of the third ventricle. Considered part of the endocrine system because it secretes the hormone melatonin.
Melatonin
Contributes to the setting of the body's biological clock, which is controlled bu the suprachiasmatic nucleus of the hypothalamus.
Habenular nuclei
Involved in olfaction, especially emotional responses to odors such as loved one's cologne or mom's cookies.
Circumventricular organs
Lie in the walls of the third ventricle, can monitor chemical changes in the blood because they lack the blood-brain barrier. Include part of the hypothalamus, the pineal gland, the pituitary gland, and a few other nearby structures. These regions coordin
Cerebrum
The seat of intelligence" Provides us with the ability to read, write and speak; to make calculations and compose music; and to remember the past, plan for the future, and imagine things that have never existed before. consist of an outer cerebral cortex
Gyri
The folds of the brain.
Sulci
The shallower grooves between the folds.
Fissures
The deepest grooves between folds.
Longitudinal fissure
The most prominent fissure in the brain, separates the cerebrum into right and left halves.
Cerebral hemispheres
The right and left halves of the brain.
Corpus Callosum
A broad band of white matter containing axons that extend between hemispheres.
Central sulcus
Separates the frontal lobe from the parietal lobe.
Precentral gyrus
Located immediately anterior to the central sulcus, contains the primary motor area of the central sulcus.
Postcentral sulcus
Located immediately posterior to the central sulcus, contains the primary somasensory area of the cerebral cortex.
Lateral cerebral sulcus
Seperates the frontal lobe from the temporal lobe
Parieto-occipital sulcus
Seperates the parietal lobe from the occipital lobe.
Insula
Cannot be seen at the surface of the brain because it lies within the lateral cerebral sulcus, deep to the parietal, frontal, and temporal bone.
Cerebral White Matter
Consists of primarily of myelinated axons in three types of tracts.
Association tracts
Contain axons that conduct nerve impulses between the gyri in the same hemisphere.
Commissural tracts
Contain axons that conduct nerve impulses from the gyri in one cerebral hemisphere to corresponding gyri in the other cerebral hemisphere. 3 important ones: corpus callosum, anterior commissure and posterior commissure.
Projection tracts
Contain axons that conduct nerve impulses from the cerebrum to lower parts of the CNS or from lower parts of the CNS to the cerebrum.
Internal Capsule
An example of a projection tract... A thick band of white matter that contains both ascending and descending axons.
Basal Ganglia
Deep within each cerebral hemisphere are three nuclei and are termed....
Globus pallidus
One of the two side by side basal ganglia that is closer to the thalamus.
Putamen
One of the two side by side basal ganglia that us closer ti the cerebral cortex.
Lentiform nucleus
Together the glubus pallidus and putamen are reffered to as...
Caudate nucleus
The third basal ganglia... which has a large "head" connected to a smaller "tail" by a long comma-shaped body.
Corpus striatum
Together, the lentiform and caudate nuclei are known as... It refers to the striated appearance of the internal capsule as it passes along the basal ganglia.
Limbic system
Encirceling the upper part of the brain stem and the corpus callosum is a ring of structures on the inner border of the cerebrum and floor of the diencephalon.
Limbic lobe
A rim of cerebral cortex on the medial surface of each hemisphere.
Cingulate gyrus
Lies above the corpus callosum
Parahippocampal gyrus
Which is in the temporal lobe
Hippocampus
a portion of the parahippocampal gyrus that extends into the floor of the lateral ventricle
Dentate gyrus
Lies between the hippocampus and parahippocampal gyrus.
Amygdala
Composed of several groups of neurons located close to the tail of the caudate nucleus.
Septal nuclei
Are located within the septal area formed by the regions under the corpus callosum and the paraterminal gyrus.
Mammillary bodies of the hypothalamus
Are two round masses close to the midline near the cerebral peduncles.
Anterior nucleus and medial nucleus
Two nuclei of the thalamus, participate in limbic circuits
Olfactory bulb
Flattened bodies of the olfactory pathway that rest on the cibriform plate.
Sensory areas
Recieves sensory information and are involved in perception
Perception
The conscious awareness of a sensation.
Motor areas
control the execution of voluntary movements
Association areas
deal with more complex integrative functions such as memory, emotions, reasoning, will, judgement, personality traits and intelligence.
Primary somatosensoory area
Areas 1, 2, and 3. Located directly posterior to the central sulcus of each parietal lobe. It extends from the lateral cerebral sulcus, along the lateral surface of the parietal lobe to the longitudinal fissure, and then along the medial surface of the pa
Primary visual area
Located at the posterior tip of the occipital lobe mainly on the medial surface, receives visual information and is involved in visual perception.
Primary auditory area
Located in the superior part of the temporal lobe near the lateral cerebral sulcus, receives information for sound and is involved in auditory perception.
Primary gustatory area
Located at the base of the postcentral gyrus superior to the lateral cerebral sulcus in the parietal cortex, receives impulses for taste and is involved in gustatory perception and taste discrimination
Primary olfactory area
Located in the temporal lobe on the medial aspect, receives impulses for smell and is involved in olfactory perception.
Brain waves
Brain neurons are generating millions of nerve impulses (action potentials. These electrical signals are called...
Electroencephalogram
Recording of the electrical activity within the brain.
Alpha waves
These rythmic waves occur at frequency of about 8-13 cycles per second. These waves disappear completely during sleep.
Beta waves
The frequency of these waves is between 14 and 30 HZ. appear when nervous system is active- that is, during periods of sensory input and mental activity
Theta waves
These waves have frequencies of 4-7 HZ. normally occur in children and adults experiencing emotional stress. Also occur in many disorders of the brain.
Delta Waves
Frequency of these waves is 1-5 HZ. occur during sleep in adults, but they are normal in awake infants. When produced by an awake adult, they indicate brain damage.