A&P 1 : Chapter 12 -- Objectives

describe the general function of the basal nuclei (basal ganglia) "MUMS"

-deep in each cerebral hemisphere -- 3 nuclei -- caudate -- putamen -- globus pallidus -closely association with substantia nigra of midbrain and subthalamic nuclei functions: - Movement: regulate initiation and termination - Unwanted movements: inhibit (Parkinson's) - Muscle tone: maintain (posture, balance)

differentiate among commissures, association fibers, and projection fibers (tracts of cerebrum)

- Commissures: connect 1 hemisphere with the other; the largest bundle of commissural fibers is the corpus callosum, about 300 million fibers; communication between both sides - Association fibers: connect areas of cortex within same hemisphere; communication on one side -- arcuate (bowed) fibers -- short association fibers - Projection fibers: connect the cerebrum to other parts of the brain and spinal cord; the projection fibers form the internal capsule; highways sending info up and down spinal cord

explain lateralization (specialization) of cortical function

- each cerebral hemispheres has unique abilities not shared by the other half aka specialization - left (categorical) hemisphere: verbal memory, speech motor area, Wernicke's area, right hand motor control, language and math comprehension, sequential and analytical reasoning, categorization and symbolization - right (representational) hemisphere: memory for shapes (limited lang comprehension), left hand motor control, musical and artistic ability, recognition of faces and spatial relationships, comparison of sights, sounds, smells, tastes shape asymmetries of frontal and occipital lobes called petalias

explain how cerebrospinal fluid is formed and describe its circulatory pathway

- formed in choroid plexus (embryonic network) in each ventricle -composed of layer of ependymal cells and blood capillaries that lie within pia mater

Cranial Dural Septa

-The meningeal layer of the dura mater extends as flat partitions (septa) into the cranial cavity at four locations. -Collectively, these double layers of dura mater are called cranial dural septa. -They separate parts of the brain and provide additional stabilization and support to the entire brain. -Four: The falx cerebri (largest and extends to hood on crista gali in the longitudinal fissure), tentorium cerebelli, falx cerebelli, and diaphragma sellae. -margins on either side of dural septa 2 dural venous sinuses: superior and inferior sagittal sinus

name and locate the ventricles of the brain

1 & 2. lateral ventricles: paired, deep within each cerebral hemisphere, separated by septum pellucidum (clear membrane) 3. third ventricle: lies within diencephalon, communicates w lateral ventricles via 2 interventricular foramina 4. fourth ventricle: lies between pons and cerebellum, communicates w 3rd ventricle via cerebral aqueduct; at inferior end, merges w central canal in spinal cord -all lined w ependymal cells, filled with CSF

name the major regions of the adult brain

1. Cerebral hemispheres: cortex, white matter, basal nuclei 2. Diencephalon: thalamus, hypothalamus, epithalamus 3. Brain stem: midbrain, pons, and medulla oblongata 4. Cerebellum ("little brain"

List the major lobes, fissures, and functional areas of the cerebral cortex.

1. Lobes - Frontal: voluntary motor functions, concentration, verbal communication, decision making, motivation, aggression, sense of smell, planning, personality, mood ; everything characteristic to humans - Parietal: major center for receiving and evaluating most sensory information, except for smell, hearing, and vision - Occipital: receiving and integrating visual input and storing visual memories - Temporal: receives and evaluates input for smell and hearing and plays a role in memory; abstract thought and judgement - Insula: center for social emotions; lust & disgust, pride & humiliation; guilt & atonement; reads body states like hunger and cravings 2. Fissures (deep sulci/grooves) - longitudinal -- separates hemispheres @ midline - transverse cerebral -- separate hemispheres from cerebellum 3. Functional areas - Motor areas: A. primary motor cortex -- voluntary movement of skeletal muscles; initiation of planned movement -- pyramidal neurons : allow to consciously control voluntary skeletal movements -- contralateral in brain step or spinal cord -- precentral gyrus B. premotor cortex -- learned skilled motor activity (eyes when reading) -- sequential nature of movements of muscles -- movement processed here and sent to primary to be carried out C. broca's area -- regulation of breathing patterns and muscle contractions to form speech -- damage here = aphasia -- common place for stroke D. frontal eye fieId -- controls and regulates voluntary eye movements -- some of most precise movements in body - Sensory areas: A. primary somatosensory cortex: -- parietal lobe, postcentral gyrus -- general sensory info: touch, pain, pressure, vibration, temp, body position -- sensory homunculus B. primary visual cortex: -- occipital lobe -- receives & processes visual info C. primary auditory cortex: -- temporal lobe D. vestibular (equilibrium) cortex: insula and adjacent parietal cortex E. primary olfactory cortex: temporal lobe; awareness of smells F. gustatory cortex: insula; processing taste info G. visceral sensory area: insula; conscious perception of visceral sensations (e.g full bladder) - Association areas: memory banks A. somatosensory association cortex : -- integrates sensory info and Interprets sensations to determining texture, temp, pressure, shape of objects -- allows us to identify objects without seeing them B. visual association area: processes visual info by analyzing color, movement and form ; integrated visual info into recognizable objects C. auditory association area: interprets characteristics of sound and stores memories of sounds heard D. anterior association area (prefrontal cortex): intellect, cognition, working memory E. posterior association area: recognizing patterns and faces, localizing us and our surroundings F. Wernicke's area: language comprehension; regions of parietal, occipital and temporal lobes; integrates all somatosensory, visual, auditory info being processed by the association areas within these lobes G. limbic association area: emotional impact of events and emotional memory -- ex. walking on campus at night and feeling worried sensory receptors > primary sensory > primary association area > multimodal association area

identify the brain areas involved in language

Left Cerebral Hemisphere Broca's area (speech expression) - left frontal lobe Wernicke's area (comprehension) - left cortex at junction of occipital, parietal and temporal lobes

locate the limbic system and the reticular formation, and explain the role of each functional system

Limbic System: Structure - "C Hip HAT" - Cingulate gyrus: creates border between diencephalon and cerebrum; mounds - Hippocampus: emotional memory - Hypothalamus: HQ of this system - Amygdala: emotional memories that often include danger/fear (ex, walking at night, hear footsteps > scared) - Thalamus: executive secretary Function - "MEL'S MBA" - Motivation - Emotions - Learning - Senses - Memory - Behaviors - ANS Reticular Formation: "TBS" - Thalamus - Brain Stem - Senses Functions - "CHAP'S MA" - Consciousness - Habituation - Arousal (reticular activating system - controls degree of attention and ability to direct attention) - Posture (proprioceptors) - Senses (no olfactory -- which is why smoke detectors have lights and loud noises) - Muscle tone - ANS

describe how meninges, cerebrospinal fluid, and the blood brain barrier protect the CNS

Meninges -- Dura mater (tough mother): - most durable, outermost covering (dense irregular), limits movement of brain in cranium; 2 layers - periosteal layer: more superficial, forms periosteum on internal cranial bone surfaces -- epidural space (potential space between dura mater and bones of skull; real space if fluid and blood accumulate - epidural hematoma) contains arteries and veins that nourish the meninges and bones of cranium - meningeal layer: superficial to arachnoid; fused to periosteal layer -- meni and perio layer separate to form blood filled spaces called dural venous sinuses which drain blood from the brain Arachnoid Mater (spider web): - middle meninx forms loose brain covering composed of delicate web of collagen and elastic fibers - subdural space: potential space between arachnoid and dura mater; becomes an actual space if blood or fluid accumulate (subdural hematoma) - subarachnoid space: immediately deep to arachnoid, space that contains CSF, cerebral arteries, and veins Pia Mater (gentle mother): - innermost layer (areolar CT) clings tightly to the brain Cerebrospinal Fluid: CSF - fluid within ventricles of brain and surrounding brain and spinal cord - mostly water -- gives buoyancy t brain - protects from impact damage - delivery medium for nutrients and chemical signals Blood Brain Barrier (BBB): - regulates which substance can and cannot enter brain - astrocytes - missing/reduced in : choroid plexus, hypothalamus or pineal gland

identify the three major regions of the brain stem, and note the functions of each area

Midbrain: "SUB n PARK" - Cerebral peduncles (little mounds) : motor tracts - Substantia Nigra: produce dopamine -- control of movement, emotional response, pleasure and pain, -- Parkinson's: "SMART" --- Shuffling gait --- Mask like face, frozen/locked in place --- Akinesis : without movement --- Rigidity : body is stiff, too much muscle tone --- Tremor : resting - Tegmentum (covering structure): -- red nuclei and parts of reticular formation -- integrates info from cerebrum and cerebellum and issues involuntary motor commands to erector muscles of back to help maintain posture - Tectum (roof): -- Corpora Quadrigemina (startle reflex): 4 nuclei that form mounds on dorsal surface --- 2 superior mounds : superior colliculi (visual/movement of head and neck) --- 2 inferior mounds : inferior colliculi (auditory) Pons: bridge - Pontine Sleep Center -- initiates rapid eye movements - Pontine Respiratory Center (secondary) -- works w resp centers in medulla to help control resp movements - conduction pathways between brain and spinal cord - pontine nuclei relay info from cerebrum to cerebellum - nuclei for cranial nerves V VI VII VIII IX Medulla Oblongata: "HD VCR" - continuous with spinal cord - Homeostasis - Decussation : crossing of fibers across brain - Vasomotor center : control of blood pressures (vasodilation and vasoconstriction) - Cardiovascular center : heart rate/force of contraction - Respiratory center - coughing, sneezing, salivation, swallowing, gagging, vomiting

Describe the cause (if known) and major signs and symptoms of cerebrovascular accidents, Alzheimer's disease, Parkinson's disease and Huntington's disease.

Parkinson's - results from deterioration of dopamine secreting neurons of substantia nigra that leads to loss in coordination of movement and a persistent resting tremor

describe the structure and function of the cerebellum "BE PC"

Structure - little brain - folia (leaf) -- folds of cerebellar cortex increase surface area - left & right cerebellar hemispheres - vermis (worm) : band of cortex along midline between cerebellar hemispheres; receives sensory input reporting torso position and balance - arbor vitae (tree of life): distribution pattern of white matter - cerebellar (superior, middle, posterior) peduncles: nerve tracts that link cerebellum w brain stem; enable cerebellum to fine tune skeletal muscle movements and interpret al body proprioceptive movements Functions - Balance - Evaluates movements: comparator function - intention vs execution - Posture - Cognition Disorders - disease -- intentional tremors (inability to stop and start skeletal muscle actions quickly)

describe the location of the diencephalon, and name its subdivisions and functions

located underneath cerebrum Thalamus: "MR. LAG" - 80% of the diencephalon - Motivation : limbic system (emotional brain) - Relay station : last stop before cerebral cortex, all sensory info except smell passes through here - Learning - Arousal / Alertness : reticular formation -- filter: ex. studying in noisey place - block It out -- executive secretary : decides what info is alerted in brain - Gateway to cerebral cortex Hypothalamus: "SWEET BATH" - 1/4 of an ounce - Sleep - Wake --- circadian rhythm/bio clock (SETH): sleep, eat, temp, hormones - Endocrine : in charge of, HQ of system, hormones - Emotional brain : HQ limbic system - Temperature : controls and regulates - Behaviors - ANS : HQ - Thirst - Hunger : appetite center Epithalamus: "PM" - Pineal Gland : secretes Melatonin - melatonin helps regulate circadian rhythm -- hypothalamus has melatonin receptors which shuts down body for the night - also houses habenular nuclei -- relays signals from limbic system to midbrain and involved in visceral and emotional responses to odors (moms cookies baking in oven)