Anatomy ~ Chapter 13

Motor Speech Area

~ (also known as the Broca area) is located in most individuals within the inferolateral portion of the left frontal lobe - This region is responsible for regulating the breathing and controlling the muscular movements necessary for vocalization

Thalamus

~ (bed) forms the superolateral walls of the third ventricle, and its paired oval masses of gray matter that lie on either side of the third ventricle. - When viewed in midsagittal section, the thalamus is located between the anterior commissure and the pineal gland. - The interthalamic adhesion (or intermediate mass) is a small, midline mass of gray matter that connects the right and left thalamic bodies - thalamus has about a dozen major thalamic nuclei that are organized into groups; axons from these nuclei project to particular regions of the cerebral cortex. Sensory nerve signals from all the conscious senses except olfaction converge on the thalamus and synapse in at least one of its nuclei

Central White Matter

~ of the cerebrum lies deep to the gray matter of the cerebral cortex - It is composed primarily of myelinated axons - Most of these axons are grouped into bundles called tracts, which are classified as: Association Tracts - connect different regions of the cerebral cortex within the same hemisphere, arcuate fibers: short tract connecting neighboring gyri, longitudinal fasciculi: longer tracts connecting gyri in different lobes Commissural Tracts - extend between the cerebral hemispheres through axonal bridges called commissures. The prominent commissural tracts that link the left and right cerebral hemispheres include the large, C-shaped corpus callosum and the smaller anterior and posterior commissure Projection Tracts - link the cerebral cortex to both the inferior brain regions and the spinal cord The packed group of axons in these tracts passing in between the cerebral nuclei and the gray matter of the thalamus is called the internal capsule

Primary Auditory Cortex & Auditory Association Area

~ primary auditory cortex is located within the temporal lobe, where it receives and processes auditory information ~ auditory association area - is located within the temporal lobe, posteroinferior to the primary auditory cortex. - Within this association area, the cortical neurons interpret the characteristics of sound and store memories of sounds heard in the past. - The next time a song is playing over and over in your head, you will know that this auditory association area is responsible

Motor Areas

~ somatic motor area, is specifically located within the precentral gyrus of the frontal lobe - Neurons in this area control voluntary skeletal muscle activity. The axons of these neurons project contralaterally (to the opposite side) within either the brainstem or the spinal cord. Thus, the left primary motor cortex controls the skeletal muscles on the right side of the body and the right primary motor cortex controls the skeletal muscles on the left side of the body. - The distribution of primary motor cortex innervation to various body parts can be diagrammed as a motor homunculus (little man) on the precentral gyrus

Premotor Cortex

~ somatic motor association area - it is located within the frontal lobe immediately anterior to the precentral gyrus. - It is primarily responsible for coordinating learned, skilled motor activities, such as moving the eyes in a coordinated fashion when reading a book or playing the guitar. - An individual who has sustained trauma to this area would still be able to understand written letters and words but would have difficulty reading because his or her eyes couldn't follow the lines on a printed page - The primary motor cortical regions are connected to adjacent association areas that coordinate discrete skeletal muscle movement

Functions of Hypothalamus

1 ~ Master control of the autonomic nervous system - is a major autonomic integration center. In essence, it is the "president" of the corporation known as the autonomic nervous system - It projects descending axons to autonomic nuclei in the brainstem that influence heart rate, blood pressure, digestive activities, and respiration. 2 ~ Master control of the endocrine system - is also "president" of another corporation—the endocrine system—overseeing most but not all of that system's functions. - The hypothalamus secretes hormones that control secretory activities in the anterior pituitary gland, and it produces both antidiuretic hormone and oxytocin, which are stored in the posterior pituitary gland 3 ~ Regulation of body temperature - body's thermostat is located within the hypothalamus - Neurons in the preoptic area detect altered blood temperatures and signal other hypothalamic nuclei, which control the mechanisms that heat or cool the body 4 ~ Control of food intake - neurons within the ventromedial nucleus monitor levels of nutrients such as glucose and amino acids in the blood and produce sensations of hunger. 5 ~ Control of water intake - specific neurons within the anterior nucleus of the hypothalamus continuously monitor the concentration of dissolved substances in the blood to regulate the sensation of thirst - When the hypothalamus detects dehydration from the blood, our sensation of thirst is stimulated. 6 ~ Regulation of sleep-wake (circadian) rhythms - suprachiasmatic nucleus directs the pineal gland of the epithalamus to secrete melatonin at certain times of the day. - Thus, both work to regulate circadian rhythms. 7 ~ Control of emotional behavior - is located at the center of the limbic system, the part of the brain that controls emotional responses, such as pleasure, aggression, fear, rage, contentment, and the sex drive

Cranial Nerves

1. CN I - Olfactory Nerve - Sensory Nerve for olfaction (smell) 2. CN II - Optic Nerve - Sensory Nerve for vison 3. CN III - Oculomotor Nerve - Motor Nerve that controls muscles that move eye, lift eyelid, change pupil diameter, change lens shape 4. CN IV - Trochlear Nerve - Motor nerve that controls superior oblique eye muscle 5. CN V - Trigeminal Nerve - Mixed nerve that receives somatic sensation from face; controls muscles involved in chewing 6. CN VI - Abducens Nerve - Motor nerve that controls lateral rectus muscle that abducts eye 7. CN VII - Facial Nerve - Mixed nerve that controls muscles of facial expression and conducts taste sensations from tounge 8. CN VIII - Vestibulocochlear Nerve - Sensory nerve involved in hearing and equilibrium 9. CN IX - Glossopharyngeal Nerve - Mixed Nerve that receives taste and touch from tounge; motor control of pharynx muscle 10. CN X - Vagus Nerve - Mixed nerve that controls muscle in pharynx and larynx; conducts sensation from many viscera; major source of parasympathetic output 11. CN XI - Accessory Nerve - Motor nerve that controls muscles of neck, pharynx 12. CN XII - Hypoglossal Nerve - Motor nerve controls tounge muscles

Tegmentum

~ (covering structure) is sandwiched between the nuclei of the substantia nigra and the periaqueductal gray matter. - The tegmentum contains the pigmented red nuclei and the reticular formation. - The reddish color of these nuclei is due to both blood vessel density and iron pigmentation in the neuronal cell bodies. - The tegmentum integrates information from the cerebrum and cerebellum and issues involuntary motor commands to the erector spinae muscles of the back to help maintain posture while standing, bending at the waist, or walking

Epithalamus & Pineal Gland

~ (epi = upon) partially forms the posterior roof of the diencephalon and covers the third ventricle. - The posterior portion of the epithalamus houses the pineal gland and the habenular nuclei. - The pineal (pineus = pineconelike) gland - or pineal body, is an endocrine gland, it secretes the hormone melatonin, which appears to help regulate day-night cycles known as the body's circadian rhythm. (Some companies are marketing the sale of melatonin in pill form as a cure for jet lag and insomnia, although this cure has yet to be proven.) - The habenular (habena = strap) nuclei - relay signals from the limbic system to the midbrain and are involved in visceral and emotional responses to odors

Hydrocephalus

~ (hydro = water, kephale = head) refers to the pathologic condition of excessive CSF, which often leads to brain distortion. - Most cases of hydrocephalus result from either an obstruction in CSF flow or impaired absorption of CSF at the arachnoid villi. - If hydrocephalus develops in a young child, the head becomes enlarged and neurologic damage may result. - If hydrocephalus develops after the cranial sutures have closed, the brain may be compressed within the fixed cranium as the ventricles expand, resulting in permanent brain damage. - Hydrocephalus may be treated surgically by implanting shunts (tubes) that drain excess CSF to other body regions (usually the drainage site is the peritoneum in the abdominal cavity). - The fluid is then absorbed into the blood.

Hypothalamus

~ (hypo = under) is the anteroinferior region of the diencephalon. - A thin, stalklike infundibulum (in-fŭn-dib′ū-lŭm; funnel) extends inferiorly from the hypothalamus to attach to the pituitary gland

Cerebellum

~ (little brain) is the second largest part of the brain - It coordinates fine control over skeletal muscle actions and stores memories of movement patterns, such as the playing of scales on a piano - composed of left and right cerebellar hemispheres - Each hemisphere consists of two lobes, the anterior lobe and the posterior lobe - which are separated by the primary fissure - A narrow band of nervous tissue known as the vermis (worm) lies along the midline between the left and right cerebellar lobes - The cerebellar hemispheres and vermis have surface folds called folia (folium = leaf) (These folds are similar to the gyri of the cerebrum.) - three regions: an outer gray matter called the cerebellar cortex, an internal region of white matter, and the deepest gray matter layer that is composed of cerebellar nuclei. - The internal region of white matter is called the arbor vitae (arbor = tree, vita = life) because its distribution pattern resembles the branches of a tree - Three thick nerve tracts, called peduncles, connect the cerebellum with the brainstem - The superior cerebellar peduncles connect the cerebellum to the midbrain

Cerebral Peduncles (midbrain)

~ (pedunculus = little foot) are motor tracts located on the anterolateral surfaces of the midbrain - Descending axon bundles of the pyramidal system project through the cerebral peduncles and relay voluntary motor commands from the primary motor cortex of each cerebral hemisphere - Superior Cerebellar Peduncles - connect the midbrain to the cerebellum - Bands of myelinated sensory axons composing a medial lemniscus extend from the medulla oblongata, through the pons and midbrain, to the thalamus

Pia Matter (Meninges)

~ (pia = tender, mater = mother) is the innermost of the cranial meninges. It is a thin layer of delicate areolar connective tissue that tightly adheres to the brain and follows every contour of the brain surface

Substantia Nigra

~ (substantia = substance, niger = black) consists of bilaterally symmetric nuclei within the midbrain - Its name derives from its almost black appearance due to melanin pigmentation - The substantia nigra houses clusters of neurons that produce the neurotransmitter dopamine, which affects brain processes to control movement, emotional response, and ability to experience pleasure and pain

Five Lobes in Each Hemisphere

~ Each cerebral hemisphere is divided into five anatomically distinct lobes. - Four of these lobes are visible on the external surface and are named for the overlying cranial bones: the frontal, parietal, temporal, and occipital lobes. - The fifth lobe, called the insula, is not visible at the surface of the hemispheres. - The cerebral cortex of each lobe exhibits specific cortical regions and association areas.

Primary Visual Cortex & Visual Association Area

~ Primary Visual Cortex - is located within the occipital lobe, where it receives and processes incoming visual information ~ Visual Association Area - is located within the occipital lobe and it surrounds the primary visual area. - It enables us to process visual information by analyzing color, movement, and form and to use this information to identify the things we see. - For example, when we look at a face, the primary visual cortex receives bits of visual information, but the visual association area is responsible for integrating all of this information into a recognizable picture of a face

Primary Olfactory Cortex & Primary Gustatory Cortex

~ Primary olfactory (olfactus = smell) cortex - is also located within the temporal lobe and provides conscious awareness of smells ~ Primary gustatory (gustatio = taste) cortex is within the insula and is involved in processing taste information

Special Capillaries

~ The BBB is formed of specialized capillaries surrounded by astrocytes. - Capillaries are typically composed of an endothelial lining resting on a basement membrane - Capillaries forming the BBB exhibit three significant structural differences from other capillaries - (1) The endothelial cells contain tight junctions, which prevent the passage of materials between cells. Thus, most substances are forced through the endothelial cells and their movement is controlled by membrane transport processes. - (2) The capillary wall is made more substantial by a thickened basement membrane that further restricts the passage of substances from the blood into the brain. - (3) The capillaries forming the BBB are wrapped in the perivascular feet of astrocytes, which form the outermost portion of the BBB. The BBB acts as a gatekeeper to control which materials pass from the blood into the brain.

Brain and Spinal Cord Composed of Grey and White Tissue

~ The anatomic structure of gray matter within the CNS primarily derives its color from the cell bodies and dendrites of the neurons that compose it. One indication that a general brain structure is composed of gray matter is that these areas are often (though not always) designated as - Cortex, which is a superficial layer of gray matter (like the bark of a tree), or - Nucleus, or center, which are clusters of neuron cell bodies within gray matter that are either close to the surface or deep within the brain - function of each of the different regions of gray matter, in either the brain or the spinal cord, is to serve as an integrating and processing area. Specifically, the synapses within the gray matter allow for integration and processing to occur - white matter, in comparison, derives its color from the bundles of myelinated axons that compose it. - These bundles of myelinated axons within the CNS are called tracts and are located on or close to the surface (outer white matter) or deep (inner white matter)

Cerebral Hemispheres

~ The paired cerebral hemispheres are separated by a narrow, deep cleft called the longitudinal fissure, which extends along the midsagittal plane. - The cerebral hemispheres are separate from one another, except at a few locations where bundles of axons called tracts form white matter regions that allow for communication between them. - The largest of these white matter tracts, the corpus callosum (corpus = body, callosum = hard) connects the hemispheres - The corpus callosum provides the main method of communication between these hemispheres. - Although selected regions of the cerebral cortex do participate in specific functions, in many cases it is difficult to assign a precise function to a specific region of the cerebral cortex. Considerable overlap and indistinct boundaries permit a single region of the cerebral cortex to exhibit several different functions. Additionally, some aspects of cortical function, such as memory or consciousness, cannot easily be assigned to any single region. - As a general rule, both cerebral hemispheres receive their sensory information from, and project motor commands to, the opposite side of the body. The right cerebral hemisphere controls the left side of the body, and vice versa. - The two cerebral hemispheres appear as anatomic mirror images, but they display some functional differences, termed cerebral lateralization. For example, the regions of the brain that are responsible for controlling speech and understanding verbalization are frequently located in the left cerebral hemisphere.

Functions of Blood Born Barriers

~ This barrier strictly regulates which substances can and cannot be filtered from the blood to enter the interstitial fluid of the brain. - As a result, the BBB helps prevent exposure of neurons in the brain to drugs, waste products in the blood, and variations in levels of normal substances (e.g., ions, hormones) that could adversely affect brain function

Four Ventricles Within the Brain

~ Two lateral ventricles are in the cerebrum, separated by a thin medial partition called the septum pellucidum (pellucid = transparent). - Within the diencephalon is a smaller, thinner ventricle called the third ventricle. - Each lateral ventricle is connected with the third ventricle through an opening called the interventricular foramen (formerly called the foramen of Munro). - A narrow canal called the cerebral aqueduct(also called the mesencephalic aqueduct and formerly called the aqueduct of Sylvius) passes through the midbrain and connects the third ventricle with the tetrahedron-shaped fourth ventricle. - The fourth ventricle is located between the pons, medulla oblongata, and cerebellum. - It opens to the subarachnoid space via paired lateral apertures and a single median aperture. - The fourth ventricle narrows at its inferior end before it merges with the slender central canal of the spinal cord.

Functional Brain Regions

~ acts as a multi-association area between lobes for integrating information from individual association areas. - One functional brain region is the prefrontal cortex, located in the most anterior (rostral) portions of the frontal lobes. - The prefrontal cortex is associated with many higher intellectual functions such as complex thought, judgment, expression of personality, planning future behaviors, and decision making. - By retrieving and coordinating information from multiple areas of the brain, the prefrontal cortex also will evaluate potential consequences of one's actions, and in so doing will modulate one's behavior based on societal norms. - Interestingly, the prefrontal cortex continues to develop into our teens and 20s, as the axons continue to myelinate in this region and unnecessary synapses are removed. - As a result, neuroscientists hypothesize, the reason many teenagers may have difficulty in planning and are impulsive, emotional, and risk takers is because the prefrontal cortex has not fully matured - Another functional brain region is the Wernicke area, which is typically located only within the left hemisphere. - The Wernicke area is involved in recognizing, understanding, and comprehending spoken or written language. As you may expect, the Wernicke area and the motor speech area must work together for fluent communication to occur

Arachnoid Mater

~ also called the arachnoid membrane, lies external to the pia mater. - The term arachnoid means "resembling a spider web," and this meninx is so named because it is partially composed of a delicate web of collagen and elastic fibers, termed the arachnoid trabeculae. - Immediately deep to the arachnoid mater is the subarachnoid space, which contains cerebrospinal fluid. - The arachnoid trabeculae extend through this space from the arachnoid to the underlying pia mater. - Both the arachnoid trabeculae and cerebrospinal fluid support cerebral arteries and veins within the subarachnoid space

Cranial Nerve Nuclei of Medulla

~ associated with the vestibulocochlear (CN VIII), glossopharyngeal (CN IX), vagus (CN X), accessory (CN XI), and hypoglossal (CN XII) cranial nerves. - The medulla oblongata also contains the nucleus cuneatus (wedge) and the nucleus gracilis (slender), which relay somatic sensory information to the thalamus. - The medial lemniscus exits from these nuclei and projects through the brainstem to the ventral posterior nucleus of the thalamus

Pons

~ bridge) is a bulging region on the anterior part of the brainstem - Sensory and motor tracts are located within the pons and extend through it to connect to the brain and spinal cord. - middle cerebellar peduncles are transverse axons that connect the pons to the cerebellum. - pons houses autonomic nuclei in the pontine respiratory center (previously called the pneumotaxic center). - This vital center, along with the medullary respiratory center within the medulla oblongata, regulates the skeletal muscles of breathing. - The primary function of the pontine respiratory center is to regulate a smooth transition between breathing in and breathing out - superior olivary nuclei are located in the inferior portion of the pons. - Each nucleus receives auditory input and is involved in the pathway for sound localization. - The pons also houses sensory and motor cranial nerve nuclei for the trigeminal (CN V), abducens (CN VI), and facial (CN VII) cranial nerves. Some of the nuclei for the vestibulocochlear cranial nerve (CN VIII) also are located there.

autonomic centers in the medulla oblongata and their functions

~ cardiovascular center - composed of both the cardiac center - which regulates both the heart's rate and its force of contraction to alter cardiac output - vasomotor center which controls the contraction and relaxation of smooth muscle within the walls of the smallest arteries (the arterioles) to alter these vessels' diameter. - Both cardiac output and blood vessel diameter influence blood pressure. - The medullary respiratory center - which regulates the respiratory rate. It is composed of a ventral respiratory group and a dorsal respiratory group. These groups are influenced by the pontine respiratory center - primary function of the medullary respiratory center is to rhythmically initiate nerve signals that cause contraction of breathing muscles - Other nuclei in the medulla, which are involved in coughing, sneezing, salivation, swallowing, gagging, and vomiting reflexes

Four Major Regions of the Brain

~ cerebrum, diencephalon, brainstem, cerebellum - The cerebrum is divided into two halves, called the left and right cerebral hemispheres. - Each hemisphere may be further subdivided into five functional areas called lobes - These folds of brain tissue are called gyri (gyros = circle). The shallow depressions between those folds are called sulci (furrow, ditch), and the deeper grooves are named fissures

Cerebral Aqueduct

~ connecting the third and fourth ventricles it is surrounded by a region called the periaqueductal gray matter. - The nuclei of the oculomotor nerve (CN III) and the trochlear nerve (CN IV) are housed in the midbrain

Brain Stem

~ connects the cerebrum, diencephalon, and cerebellum to the spinal cord. - Three regions form the brainstem - from superior to inferior, these include the midbrain, the pons, and the medulla oblongata - bidirectional passageway for all tracts extending between the major regions of the brain and the spinal cord - It also contains many autonomic centers and reflex centers required for regulating body functions necessary for survival (e.g., breathing, blood pressure) and it houses nuclei of many of the cranial nerves - reticular formation - extends through all three regions of the brainstem

12 Pairs of Cranial Nerves

~ designated with both a number and a name - They are numbered with Roman numerals according to their positions originating on the brain, beginning with the most anteriorly placed nerve - Note that the number is sometimes preceded by the prefix CN

Cerebellum Function

~ does not initiate skeletal muscle movement. - coordinates and fine-tunes skeletal muscle movements that were initiated by the cerebrum - it ensures that skeletal muscle contraction follows the correct pattern, leading to smooth, coordinated movements. - The cerebellum stores memories of previously learned movement patterns - This function is performed indirectly, by regulating activity along both the voluntary and involuntary motor pathways at the cerebral cortex, cerebral nuclei, and motor centers in the brainstem. - The cerebrum initiates a movement and sends a "rough draft" of the movement to the cerebellum, which then coordinates and adjusts it. - For example, the controlled, precise movements a classical guitarist makes when playing a concerto result from fine-tuning by the cerebellum. Without the cerebellum, the guitarist's movements would be choppy and sloppy, without precise coordination between the two hands - Skeletal muscle activity is adjusted to maintain equilibrium and posture. It also receives proprioceptive (sensory) information from the muscles and joints and uses this information to regulate the body's position - the proprioceptive information from the body's muscles and joints is sent to the cerebellum and then to the cerebrum - receives convergent input from both the various sensory pathways and the motor pathways in the brain - unconsciously perceives the position of the body, receives the plan for movement, and then follows the activity to see if it was carried out correctly - detects a disparity between the intended and actual movement, it may generate error-correcting nerve signals. These nerve signals are transmitted to both the premotor and primary motor cortices via the brainstem and the thalamus. - Descending pathways then transmit these error-correcting signals to the motor neurons. - Thus, the cerebellum influences and controls movement by indirectly affecting the excitability of motor neurons.

Language

~ include reading, writing, speaking, and understanding words - Wernicke area interpreting what we read or hear, whereas the motor speech area receives nerve signals originating from the Wernicke area and then helps regulate the motor activities needed for us to speak - central to our ability to recognize written and spoken language - Motor Speech (Broca) - area initiates speech motor program - Primary motor cortex signals motor neurons to produce speech - categorical hemisphere - (including Wernicke Area) analyzes literal meaning of speech

Cerebrospinal Fluid (CSF)

~ is a clear, colorless liquid that circulates within the ventricles and subarachnoid space. CSF bathes the exposed surfaces of the central nervous system and completely surrounds it. CSF performs several important functions: - Buoyancy - The brain floats within the CSF, thereby reducing its apparent weight by more than 95%; this prevents the brain from being crushed under its own weight. Without CSF to support it, portions of the brain would sink through the foramen magnum. - Protection - CSF provides a liquid cushion to protect delicate neural structures from sudden movements. When you try to walk quickly in a swimming pool, your movements are slowed as the water acts as a "movement buffer." CSF likewise helps slow movements of the brain if the skull or body moves suddenly and forcefully. - Environmental stability - CSF transports nutrients and chemical messengers to the brain and removes waste products from the brain. Additionally, CSF protects nervous tissue from chemical fluctuations that would disrupt neuron function. The waste products and excess CSF are eventually transported into the venous circulation.

Primary Somatosensory Cortex

~ is housed within the postcentral gyrus of the parietal lobes. - Neurons within this cortex receive general somatic sensory information from receptors of the skin regarding touch, pressure, pain, and temperature, as well as sensory input from proprioceptors from the joints and muscles regarding the conscious interpretation of body position. - We typically are conscious of the sensations received by this cortex.

Somatosensory Association Area

~ is located within the parietal lobe and lies immediately posterior to the primary somatosensory cortex. It integrates sensory information and interprets sensations to determine the texture, temperature, pressure, and shape of objects. - The somatosensory association area allows us to identify known objects without seeing them. For example, even when our eyes are closed, we can tell the difference between the coarse feel of a handful of dirt; the smooth and round shape of a marble; and the thin, flat, rounded surface of a coin because those interpretations of the textures and shapes have already been stored in the somatosensory association area

Diencephalon

~ is sandwiched between the inferior regions of the cerebral hemispheres and for this reason is often referred to as the "in-between brain." - The diencephalon components include the epithalamus, the thalamus, and the hypothalamus - associated with 3rd ventricle also

Cerebrum

~ is the location of conscious thought processes and the origin of all complex intellectual functions. It is readily identified as the two large hemispheres on the superior aspect of the brain. - The functional activities in your cerebrum enable you to read and comprehend the words in this textbook, turn its pages, form and remember ideas, and talk about what you've learned with your peers. - It is the center of your intelligence, reasoning, thought, memory, and judgment, as well as your voluntary control of skeletal muscle movement and conscious perception of your senses (e.g., vision, hearing, touch, smell, and taste)

Tectum

~ is the most posterior region of the midbrain. It contains two pairs of sensory nuclei, the superior and inferior colliculi, which are collectively called the tectal plate (quadrigeminal plate, or corpora quadrigemina). - These nuclei are relay stations in the processing pathway of visual and auditory sensory input.

Dura Matter

~ is the strongest of the meninges, as its Latin name indicates. - This outer, dense irregular connective tissue covering is composed of two layers. - The meningeal layer is immediately superficial to the arachnoid. - The periosteal layer, the more superficial layer, forms the periosteum on the internal surface of the cranial bones. - The meningeal layer is usually fused to the periosteal layer, except in specific areas where these two layers are separate and form large, blood-filled spaces called dural venous sinuses.

Insula

~ island) is a small lobe deep to the lateral sulcus. It can be observed by laterally reflecting (pulling aside) the temporal lobe. - The insula's lack of accessibility has prevented aggressive studies of its function, but the cerebral cortex of the insula is apparently involved in memory and the interpretation of taste

Frontal Lobe

~ lies deep to the frontal bone and forms the anterior part of the cerebral hemisphere - The frontal lobe ends posteriorly at a deep groove called the central sulcus that marks its boundary with the parietal lobe. - The inferior border of the frontal lobe is marked by the lateral sulcus, a deep groove that separates the frontal and parietal lobes from the temporal lobe. - An important anatomic feature of the frontal lobe is the precentral gyrus, which is the mass of nervous tissue immediately anterior to the central sulcus. - The frontal lobe is primarily concerned with voluntary motor functions (including motor functions involved with speech), concentration, verbal communication, decision making, planning, and personality

Pariental Lobe

~ lies deep to the parietal bone and forms the superoposterior part of each cerebral hemisphere. - It terminates anteriorly at the central sulcus, posteriorly at a relatively indistinct parieto-occipital sulcus, and laterally at the lateral sulcus. - An important anatomic feature of this lobe is the postcentral gyrus, which is the mass of nervous tissue immediately posterior to the central sulcus. - The cerebral cortex of the parietal lobe is involved with general sensory functions, such as evaluating the shape and texture of objects being touched and sensory input regarding body position from proprioceptors within our joints and muscles

Occipital Lobe

~ lies internal to the occipital bone and forms the posterior region of each hemisphere. - The cerebral cortex of the occipital lobe is responsible for processing incoming visual information and storing visual memories

Temporal Lobe

~ lies internal to the temporal bone and inferior to the lateral sulcus. - The cerebral cortex of this lobe is involved with hearing and smell

Ventricles

~ little cavity) are cavities or expansions within the brain that are derived from the neural canal (the lumen of the embryonic neural tube). - All of the ventricles are lined with ependymal cells and contain cerebrospinal fluid. - The ventricles are connected with one another as well as with the central canal of the spinal cord

The Sensory Homunculus in Primary Somatosensory Cortex

~ may be traced on the postcentral gyrus surface, similar to a motor homunculus - The surface area of somatosensory cortex devoted to a body region indicates the amount of sensory information collected within that region. - Thus, the lips, fingers, and genital region occupy larger portions of the homunculus, whereas the trunk of the body has proportionately fewer receptors, so its associated homunculus region is smaller. (However, the sensory homunculus shown is not precise, and there is extensive overlap between nearby body regions in the primary somatosensory cortex.)

Medulla Oblongata

~ medulla = marrow or middle, oblongus = rather long) is often simply called the medulla - It is the most inferior part of the brainstem and is continuous with the spinal cord inferiorly. - The most inferior portion of the medulla has a flattened, rounded shape and narrow central canal - As this tubelike opening extends (superiorly and anteriorly) toward the pons, the central canal enlarges and becomes the inferior portion of the fourth ventricle. - All communication between the brain and spinal cord involves tracts that ascend or descend through the medulla oblongata - The anterior surface exhibits two longitudinal ridges called the pyramids (pir′ă-mid), which house the motor projection tracts called the corticospinal (pyramidal) tracts that extend through the medulla oblongata

Cranial Meninges

~ membrane) are three connective tissue layers that separate and support the soft tissue of the brain from the bones of the cranium, enclose and protect some of the blood vessels that supply the brain, and contain and help circulate cerebrospinal fluid. - From deep (closest to the brain) to superficial (farthest from the brain), the cranial meninges are the pia mater, arachnoid mater dura mater

Components of Midbrain

~ mesencephalon, is the superior portion of the brainstem

Superior & Inferior Colliculi

~ superior colliculi (sing., colliculus = mound) are the superior nuclei - They are called visual reflex centers because they help visually track moving objects and control reflexes such as turning the eyes and head in response to a visual stimulus. - For example, the superior colliculi are at work when you think you see a large animal running at you and turn suddenly toward the image. - The paired inferior colliculi - auditory reflex centers, meaning that they control reflexive turning of the head and eyes in the direction of a sound, such as a sudden, loud bang

CFS Formation

~ the production of CSF by the brain occurs at a rate of about 500 milliliters (mL) (or 1/2 liter) per day, with the volume of CSF in the subarachnoid space at any given time ranging between 100 mL and 160 mL. - Cerebrospinal fluid is initially formed by the choroid plexus (chorioeides = membrane, plexus = a braid), a region of specialized tissue in each ventricle. - The choroid plexus is composed of a layer of glial cells called ependymal (ependyma = an upper garment) cells and the blood capillaries that lie within the pia mater