Unit 1 Exam Review PDF

Unit 1 Exam Review  Brain Brain and spinal cord develop from the ectodermal neural tube. Gyri = folds / convolutions (singular = gyrus) Fissures = deep grooves Inner mass = cerebral white matter Association tracts – conduct impulses between gyri in the same hemisphere...

Unit 1 Exam Review  Brain Brain and spinal cord develop from the ectodermal neural tube. Gyri = folds / convolutions (singular = gyrus) Fissures = deep grooves Inner mass = cerebral white matter Association tracts – conduct impulses between gyri in the same hemisphere Commissural tracts – conduct impulses between gyri in one hemisphere to another Projection tracts – conduct impulses to lower parts of the CNS the white matter remains connected by a bundle of transverse white fibers = corpus callosum (connects the two hemispheres) Gray matter contains unmyelinated neurons while white matter contains myelinated neurons  Brain Organization Major Parts of the Brain Structures/Functions Brain Stem the continuation of the spinal cord and consists of the medulla oblongata, pons and midbrain Cerebellum the second largest part of the brain; coordinates subconscious movements; contributes of muscle tone, posture, and balance Diencephalon gives rise to the thalamus & hypothalamus & epithalamus Cerebrum the newest (evolutionarily) and largest part of the brain as a whole It is in the cerebral cortex that perception, thought, imagination, judgment, and decision making occur. Brain Organization – also know the functions of each part Lobes of the Cerebrum Precentral gyrus Anterior to the central sulcus in the anterior lobe Primary motor area of the cerebral cortex Postcentral Posterior to the central gyrus sulcus in the parietal lobe Primary somatosensory area of the cerebral cortex Parieto-occipital Separates the parietal sulcus lobe from the posterior- most occipital lobe Lateral cerebral Separates the frontal sulcus (fissure) lobe from two laterally placed temporal lobes The Cerebral Cortex – functional areas Brodmann’s areas = numbered regions of cortex that have been “mapped” to specific cognitive functions Sensory areas = receive and interpret incoming sensory impulses Parietal lobe –areas for touch, proprioception, pain, temperature, visual, auditory, taste, smell, etc. Occipital lobe – areas for vision Temporal lobe – areas for hearing, smell, etc. Motor areas – control executions of voluntary movements Mostly located in the frontal lobe Association areas = interpret the meaning of the incoming sensory info Memory, emotions, reasoning, judgement, personality, intelligence Located between sensory and motor areas The Cerebrum Brodmann’s areas: Numbered Regions of Cortical tissue (cerebral cortex)  Primary somatosensory area Parietal lobe contains sensory areas for touch, proprioception, pain, temp., visual, auditory, taste, smell, etc. (post-central gyrus) Occipital contains sensory areas for vision lobe Temporal contains sensory areas for hearing, smell, etc. auditory lobe cortex Primary motor area controls voluntary contractions of specific muscles or groups of muscles. Motor cortex also has a homunculus map, with more cortical area devoted to muscles involved in skilled, complex, or delicate movement. Association Areas Somatosensory Permits you to determine the exact shape and texture of an object by feeling it, to determine the orientation of one object in respect to another as they are felt, and to sense the relationship of one body part to another; memory and recall of past sensations Visual Relates present and past visual experiences and is essential for recognizing and evaluating what is seen – primary visual is responsible for vision Facial Recognition Stores information about faces and it allows you to recognize people by their faces (right side) Auditory Allows you to recognize a particular sound as speech, music or noise Orbitofrontal Cortex Allows you to identify odors and to discriminate among different orders (right side) Wernicke’s Area Interprets the meaning of speech by recognizing spoken words (left); contributes to verbal communication by adding emotional content Common Integrative Integrates sensory interpretations allowing the formation of thoughts Area based on a variety of sensory inputs Prefrontal Cortex Concerned with the makeup of a person's personality, intellect, complex learning abilities, recall information, initiative, judgement, foresight, reasoning, conscience, intuition, mood, planning for the future and development of abstract thought. Premotor Area Cause specific groups of muscles to contract in a specific sequence and serves as a memory bank for such movements The Diencephalon Located near the midline of the brain, above the midbrain Thalamus + Hypothalamus + epithalamus (pineal gland) Diencephalon surrounds the 3rd ventricle Diencephalon acts as a relay station (thymus) Also helps regulate body rhythms, emotions; secretes hormones Epithala Thalamus mus Hypothala mus Thalamus Pair of oval masses of gray matter, on either side of roof of 3rd ventricle Contains nuclei which serve as “relay stations” for all sensory impulses, except the sense of smell Each pair of nuclei help to relay a different type of information: Involved in hearing Involved in vision Involved in taste & somatic (touch, pressure, vibration, temp., pain) Involved in voluntary motor actions Involved in arousal (from sleep) Involved in emotions & memory Thalamus also registers conscious recognition of pain, temperature, light touch & pressure Hypothalamus Located below the thalamus Hypothalamus regulates MANY body functions (homeostasis) Controls & integrates ANS Serves as a “connection” between the Nervous & Endocrine Systems Detects changes in body and releases regulating factors (hormones) These hormones stimulate or inhibit specific cells in the Anterior Pituitary to release other hormones Involved in: emotions such as rage & aggression, pain. & pleasure body temperature regulation feelings of hunger & satiety (hunger is satisfied) thirst mechanism diurnal rhythms (sleep / waking states)  Pineal gland – located at midline of epithalamus in 3rd ventricle (looks like a tiny pine cone) Secretes melatonin, which is involved in diurnal cycles Melatonin is secreted mostlyepithalamus at night – causes thalamus sleepiness The Pons Superior to the medulla Pons “bridges”/connects spinal cord with brain, & brain regions to each other (Peduncle = a stem-like “connecting part”) Relays nerve impulses related to voluntary skeletal movements from the cerebral cortex to the cerebellum – Pontine Nuclei Pontine respiratory group - contains the pneumotaxic & apneustic areas The Medulla Oblongata Posterior side = 2 pairs of prominent nuclei Nuclei contain the cell bodies of sensory (ascending) tracts Nucleus gracilis Nucleus cuteatus Crossing over occurs here also Scattered inside = nuclei (gray matter) which are reflex centers Cardiovascular center = regulation of heart rate; vasoconstriction Medullary rhythmicity area = regulation of respiratory rate Non-vital reflexes = swallowing, coughing, vomiting, sneezing, hiccupping Medulla also contains an oval nucleus called the olive (fine motor control, equilibrium & posture) The Midbrain Autonomic functions Separated into the tectum & tegmentum (roof and floor) Tectum - Regulates auditory & visual reflexes Contains 4 rounded elevations = corpora quadrigemina Superior colliculi – reflex center for eye, head, neck movements in response to visual stimuli Inferior colliculi – reflex center for head, trunk, movements in response to auditory stimuli Tegmentum – contains nuclei that receive and send information through cranial nerves The Cerebellum Second largest part of the brain – “little brain” Anatomy – covered in gyri and sulci Physiology – responsible for comparing information from the cerebrum with sensory feedback from the periphery through the spinal cord Controls subconscious skeletal muscle movements (muscle tone, posture, & balance) Receives sensory impulses from proprioceptors & visual receptors and makes adjustment in muscle contractions Involved in equilibrium (balance) Circulation and the CNS Has a privileged blood supply – contents of the blood cannot simply pass through the CNS Blood Brain Barrier – specialized structure Brain is only ̴2% of total body weight , it uses ̴20% of total oxygen (VERY metabolically active). Carbohydrates storage in the brain is very limited Blood flows to the brain via common carotid arteries that branch into the internal carotid arteries and the vertebral arteries (merge into the basilar artery) Circle of Willis – composed of the R and L carotid arteries and branches of the basilar artery creating a confluence of arteries that can maintain perfusion of the brain even if narrowing or blockage limits flow through one part because it is circular and blood can flow in either direction around the circle.  Protective Coverings Cranial dura mater – two layers – an external periosteal layer and an internal meningeal layer Extensions of the dura mater form hard, non compliant membranes that Falx cerebrithe intracranial divide Strong sickle-shaped foldin vault that various separates the two cerebral hemispheres. ways: Falx cerebelli A small triangular process that separates the two cerebellar hemispheres. Tentorium Separates the cerebrum from the cerebelli cerebellum  Choroid plexus – capillary networks in the ventricles Capillaries are covered with ependymal cells, joined by tight junctions CSF is formed by filtration of blood plasma thru these cells Blood Brain Barrier (BBB) allows certain substances into CFS; excludes harmful substances (astrocytes may be involved)  CSF circulates thru: Ventricles via interventricular foramina [Lateral ventricles → 3 rd → cerebral aqueduct → 4th → subarachnoid] CSF leaves the 4th ventricle via 1 median & 2 lateral apertures The median aperture leads CSF into central canal of the spinal cord CSF gets reabsorbed back into arachnoid villi (cluster = arachnoid granulation) which extend into blood sinuses (superior sagittal sinus) CSF gets reabsorbed at about same rate as choroid plexuses produce it CSF is clear and colorless Contains water, glucose, proteins, urea, ions, few WBCs Total CSF volume – 80-150 mL About 480 mL produced / reabsorbed per day (important for constant volume & pressure) CSF is both protective & nourishes the CNS (nutrients and waste removal) Functions in circulation, homeostasis, and protection Causes of Neurological Deficits Cerebrovascular accident (CVA) – stroke - Caused when blood circulation to the brain is blocked and brain tissue dies – TPA to treat Ischemic stroke, transient ischemic attack (TIA) (usually resolves in quickly), hemorrhagic stroke (greatest risk factor is hypertension) Wernicke’s Area – sensory and association -comprehension of speech – damage to area can still speak but cannot understand Broca’s Area - Damage to area - cannot speak but can still comprehend Neurodegenerative diseases – Alzheimer's disease, Parkinson’s disease, Huntington’s disease, amyotrophic lateral sclerosis (ALS), Creutzfeld-Jacob disease, multiple sclerosis (MS), and other disorders that result in nervous tissue degeneration. Developmental disorders – autism spectrum disorder (ASD), Attention Deficit Hyperactivity Disorder – memory, language, sensorimotor deficits Cranial Nerves The Twelve Cranial Nerves On Old Olympus’s Towering Tops, A Friendly Viking Grew Vines And Hops Purpose of the Exam Assessment of sensory neuron and motor responses Determines whether central nervous system is impaired and where Rapid- As little as 5 minutes to complete Six subsets Consists of: physical examination, review of patient history Used as screening and investigative tool for proper treatments Trauma, TIA/stroke, neurodegenerative, etc. Six Subsets of the Neurological Exam Mental Status Cerebrum Cranial nerves Nerves, Brain stem Sensory Spinal cord Motor Spinal cord Coordination Cerebellum Gait Cerebellum Multiple Sclerosis Neurological Examination  Cranial Nerves 12 cranial nerves serve head and neck Movements Cranial nerve X- Autonomic functions in thoracic/superior abdominal cavities Special senses, general senses Allows directed tests of forebrain and brain stem structures Cranial Nerves and Tests CN 1: Olfactory- CN 7: Facial- Taste Coffee/mint smells - differentiation anosmia CN 8: Vestibulocochlear- CN 2: Optic- Snellen Rinne, Romberg test chart CN 9: Glossopharyngeal- CN 3: Oculomotor- Taste differentiation, gag reflex Gaze control CN 10: Vagus- Repeating CN 4: Trochlear- Gaze consonant sounds (“lah- control kah-pah”) CN 5: Trigeminal- CN 11: Spinal accessory- Sensory discrimination shoulder shrug CN 6: Abducens- Gaze CN 12: Hypoglossal- control tongue protrusion Sensory Exam How are we Somatic senses checking? Skin, muscles, tendons Light touch- cotton- Conscious perception of body interactions with envt. tipped applicator Pinprick- pain Visceral senses Temperature- “hot” vs. Organs such as heart and stomach “cold” Homeostatic regulation Vibration- oscillating through autonomic nervous system tuning fork Sensing body Sensory exam focuses on the movements or location somatic (perceived) senses of a stimulus Romberg test - correct positioning! Motor Exam Skeletomuscular Voluntary Movements: What is being tested? system- includes Tone- passive range of upper and lower motion/resting tension motor neurons Muscle bulk- structural Activation required issues/scarring for voluntary Strength: check movements agonist/antagonist pairs, lateral Motor exam tests (L vs R) differences in strength Muscles contracting against the functions of resistance these neurons and Pronator drift- Eyes closed, arms extended forward with palms the muscles they facing upward (supination) control Drift Possible supination maintenance failure Mental Status Memory, orientation and language What is checked? How? Level of Orientation & Memory Awareness of time alertness, Amnesia awareness Anterograde, retrograde Degree of Types of Memory interaction Episodic, procedural, Orientation short-term Language & Speech Following Understand language commands Fluency & Coherency Coordination prosody – patterns in poetry Volume/rate Difference from dysarthria- slow/slurred baseline speech Aphasia Expressive, receptive, conduction Coordination – cranial nerve test Tests for proper cerebellar function – considered a separate Appendicular set of tests with Tremor check arms walking out and hold Subtests target: Check reflex Appendicular musculature (controlling contraction control limbs) Finger-to-nose test Axial musculature alternation of (posture and gait) muscle movements/groups Rapid, alternating movements Speech consonants (“lah-kah-pah”)  Gait Observe Different Aspects of Gait Base of Gait- Station subtest Can be separate part of Balance on one foot- neurological exam or Station subtest subset of coordination Ataxia Arm swing, time spent A normal gait requires on each leg, heel multiple levels of the walking, toe walking- nervous system to be Walking subtest intact Vision Strength Balance/Coordination Joint Position