Chapter 12: BIO 240

Chapter 12

Terms in this set (...)

Name the major regions of the adult brain.

(Ch. 12 Obj. 1)
Cerebral hemispheres
brain stem (midbrain, pons, and medulla oblongata)

Central cavity, surrounded by a gray matter core, external to which is white matter.

The cerebrum and cerebellum have an outer gray matter layer, which is reduced to scattered gray matter nuclei in the spinal cord.
Name and locate the ventricles of the brain.

(Ch. 12 Obj. 2)
The ventricles of the brain are continuous w/ each other, and with the central canal of the spinal cord. They are lined w/ ependymal cells, and are filled w/ cerebrospinal fluid.
a.) The paired lateral ventricles lie deep w/in each cerebral hemisphere, and are seperated by the septum pellucidum.
b.) The third ventricle lies w/in the diencephalon, and communicates with the lateral ventricles via two interventricular foramina.
c.) The fourth ventricle lies in the hindbrain and communicates with the third ventricle via the cerebral aqueduct.
List the major lobes, fissures, and functional areas of the cerebral cortex.

(Ch. 12 Obj. 3)
part 1
GYRI: elevated ridges of tissue.
SULCI: shallow grooves
FISSURES: deeper grooves
LONGITUDINAL FISSURE: seperates the cebral hemispheres
TRANSVERSE CEREBRAL FISSURE: separates the cerebral hemispheres from the cerebellum bellow.
lies in the frontal plane, separates the Frontal lobe from the Parietal lobe.
PRECENTRAL GYRUS: bordering the central suclus anteriorly.
POSTCENTRAL GYRUS: bordering the central sulcus posteriorly
LATERAL SULCUS outlines the flaplike TEMPORAL LOBE and seperates it from the parietal and frontal lobes.
INSULA: is buried deep within the lateral sulcus and forms part of its floor.
Explain lateralization of hemisphere function.

(Ch. 12 Obj. 4)
One hemisphere (often the left) dominates language abilities, math, logic, and the other hemisphere (often the right) dominates visual-spatial skills, intuition, emotion, and artistic and musical skills.
Allows conscious control of skilled voluntary movement
Primary motor cortex
Region controlling learned motor skills
Premotor cortex
Motor speech area that controls muscles involved in speech production
Broca's area
Controls eye movement
Frontal eye field
Allows spatial discrimination and the ability to detect location of stimulation.
Primary somatosensory cortex
Integrates sensory information and produces and understanding of the stimulus being felt
Somatosensory association cortex
Allow reception and interpretation of visual stimuli
Primary visual cortex and visual association area
Allow detection of the properties and contextual recognition of sound.
Primary auditory cortex and auditory association area
Allows detection of odors.
olfactory cortex
Allows perception of taste stimuli.
Gustatory cortex.
Responsible for conscious awareness of balance.
vestibular cortex.
Involved with intellect, cognition, recall, and personality, and is closely linked to the limbic system.
Prefrontal cortex
Involved in comprehension and articulation include these.
Wernicke's area, Broca's area, the lateral prefrontal cortex, and the lateral and ventral parts of the temporal lobe.
Receives input from all sensory areas, integrating signals into a single thought.
Posterior association area
Involved in conscious visceral sensation.
Visceral association area
Responsible for communication between cerebral areas and cerbral cortex and lower CNS centers.
Cerebral white matter
Group of subcortical nuclei, which play a role in motor control and regulating attention and cognition.
Basal nuclei
Differentiate between commissures, association fibers, and projection fibers.

(Ch. 12 Obj. 5)
Cerebral white matter is composed mostly of myelinated fibers bundled into large tracks. They're named for the direction they run.
Commissures: connect gray areas of the two hemispheres so they can function as a whole. Largest commissure is the corpus callosum (thickened body). Run horizontally.
Association fibers: connect different parts of the same hemisphere. Run horizontally.
Projection fibers: enter the cerebral hemispheres from lower brain or cord centers, and those that leave the cortex to travel to lower areas. These tie the cortex to the rest of the nervous system and to the body's receptors and effectors. Run vertically.
Describe the general function of the basal nuclei (basal ganglia).

(Ch. 12 Obj. 6)
Receive input from entire cerebral cortex and doesn't have direct access to motor pathways. Consist of a group of subcortical nuclei, which play a role in motor control (starting, stopping, and intensity of movements) and regulating attention and cognition.
(sometimes incorrectly reffered to as Basal ganglia)
Disorders of basal nuclei result in either too much movement, as with Huntington's chorea, or too little movement, as with Parkinson's disease.
Describe the location of the diencephalon, and name its subdivisions and functions.

(Ch. 12 Obj. 7)
Is a set of gray matter areas forming the central core of the forebrain and sorrounded by the cerebral hemispheres, that collectively enclose the 3rd ventricle, and consists of thalamus, hypothalamus, and epithalamus.
Thalamus: plays a role in meditating sensation, motor activities, cortical arousal, learning, and memory.
Hypothalamus: control center of the body, regulating ANS activity such as emotional response, body temp, food intake, sleep-wake cycles, and endocrine function.
Epithalamous: includes the pineal gland, which secretes melatonin, and regulates sleep-wake cycle.
Identify the three major regions of the brain stem, and note the function of each area.

(Ch. 12 Obj. 8)
Brain stem consists of the midbrain, pons, and medulla oblongata, produces rigidly programmed, automatic behaivors necessary for survival.
Midbrain: is comprised of the cebral peduncles, corpora quadrigemina, and substantia nigra.
The pons contains fiber tracts that complete conducting pathways between the brain and spinal cord.
The medulla oblongata is the location of several visceral motor muclei controlling vital funtions such as cardiac and respiratory rate.
Describe the structure and function of the cerebellum.

(Ch. 12 Obj. 9)
The cerebellum processes inputs from several structures and coordinates skeletal muscle contraction to produce smooth movement.
There are two cerebellar hemispheres consisting of three lobes each. Anterior and posterior lobes coordinate body movements and the flocculonodular lobes adjust posture to maintain balance.
Three paired fiber tracts, the cerebellar peduncles, communicate between the cerebellum and the brain stem.
Cerebellar processing follows a functional scheme in which the frontal cortex communicates the intent to initiate voluntary movement to the cerebellum, the cerebellum collects input concerning balance and tension in muscles and ligaments, and the best way to coordinate muscle activity is relayed back to the cerebral cortex.
Locate the limbic system and the reticular formation, and explain the role of each functional system.

(Ch. 12 Obj. 10)
Functional brain systems consist of neurons that are distributed throughout the brain but work together
The limbic system: is involved with emotions, and is extensively connected throughout the brain, allowing it to integrate and respond to a wide variety of environmental stimuli. It's located on medial aspect of each cerebral hemisphere and diencephalon. Encircles upper part of brainstem and includes parts of rhinencephalon (septal nuclei, cingulate gyrus, parahippocampal gyrus, dentate gyrus, and C-shapped hippocampus).
Amygdala: fear.
Cingulate gyrus: expressing emotions through gestures.
The reticular formation: extends through the brain stem, keeping the cortex alert via the reticular activating system, and dampening familiar, repetitive, or weak sensory inputs.
Define EEG and distinguish between alpha, beta, theta, and delta brain waves.

(Ch. 12 Obj. 11)
Brain Wave Patterns and the EEG
Normal brain function results from continuous electrical activity of neurons, and can be recorded with an electroencephalogram, or EEG.
Patterns of electrical activity are called brain waves, and fall into four types: alpha, beta, theta, and delta waves.
Compare and contrast the events and importance of slow and REM sleep, and indicate how their patterns change through life.

(Ch. 12 Obj. 13)
Sleep is a state of partial unconsciousness from which a person can be aroused, and has two major types that alternate through the sleep cycle.
Non-rapid eye movement (NREM): sleep has four stages.
Rapid eye movement (REM): sleep is when most dreaming occurs.
Sleep patterns change throughout life, and are regulated by the hypothalamus.
NREM sleep is considered restorative, and REM sleep allows the brain to analyze events or eliminate meaningless information.
Describe how meninges, cerebrospinal fluid, and the blood-brain barrier protect the CNS.

(Ch. 12 Obj. 16)
Meninges are three connective tissue membranes that cover and protect the CNS, protect blood vessels and enclose venous sinuses, contain cerebrospinal fluid, and partition the brain
The dura mater: is the most durable, outermost covering that extends inward in certain areas to limit movement of the brain within the cranium.
The arachnoid mater: is the middle meninx that forms a loose brain covering.
The pia mater: is the innermost layer that clings tightly to the brain.
Describe the formation of cerebral spinal fluid, and the blood-brain barrier protect the CNS.

(Ch. 12 Obj. 17)
Cerebrospinal fluid (CSF): is the fluid found within the ventricles of the brain and surrounding the brain and spinal cord.
CSF gives buoyancy to the brain, protects the brain and spinal cord from impact damage, and is a delivery medium for nutrients and chemical signals.
Formed by ependymal cells in the choroid plexus (approx. 50-70%), and the remainder is formed around blood vessels and along ventricular walls.
The blood-brain barrier: is a mechanism that helps maintain a protective environment for the brain. Bloodborne substances in brain's capillaries seperated from ECF by continuous endothelium of capillary wall, thick basal lamina, feet of the astrocytes, and tight junctions of capillary endothelial cells.