Superior and Inferior Colliculus -Human Physiology and Anatomy - Lecture Slides, Slides of Physiology

Download Superior and Inferior Colliculus -Human Physiology and Anatomy - Lecture Slides and more Slides Physiology in PDF only on Docsity! Superior and Inferior Colliculus • Tectum (4 nuclei - corpora quadrigemina) – superior colliculus (tracks moving objects, blinking, pupillary and head turning reflexes) – inferior colliculus (reflex turning of head to sound) 1 Docsity.com Reticular Formation ‘Copyright The MeGran-Hill Companies, ins, Permission required for repraduetion ar display. Radiations to ‘cerebral cortex Visual input Ascending general sensory fibers Descending motor: fibers to spinal cord 2 Docsity.com Diencephalon: Hypothalamus • Walls and floor of 3rd ventricle • Functions – hormone secretion – autonomic NS control – thermoregulation – food and water intake (hunger and satiety) – sleep and circadian rhythms – memory (mammillary bodies) – emotional behavior 5 Docsity.com Diencephalon: Hypothalamus • Mammillary bodies contain 3 to 4 nuclei that relay signals from limbic system to thalamus 6 Docsity.com Diencephalon: Epithalamus 7 Epithalamus consists of pineal gland (endocrine) and the habenula (connects limbic system to midbrain) Docsity.com Tracts of Cerebral White Matter Copyright © The MeGraw-Hill Companies, Inc. Permission required lor reproduction ar display. Association tracts Temporal lobe Occipital lobe Longitudinal fissure ‘Corpus callosum " ‘Commissural tracts Lateral ventricle Basal nuclei lye Thalamus i - Third ventricle Cerebral peduncle Mameniliary body Projection tracts pons Pyramid Decussation in pyramids ‘Medulla oblongata 10 Docsity.com {b) Frontal section Tracts of Cerebral White Matter • Most of cerebrum is white matter • Types of tracts – projection tracts • from brain to spinal cord, forms internal capsule – commissural tracts • cross to opposite hemisphere – corpus callosum – anterior and posterior commissures – association tracts • connect lobes and gyri within a hemisphere 11 Docsity.com Cerebral Cortex • Surface layer of gray matter -- 3 mm thick • Neocortex (six-layered tissue) – newest part (paleocortex and archicortex) – layers vary in thickness in different regions • 2 types of cells – stellate cells • dendrites project in all directions – pyramidal cells • axon passes out of the area 12 Docsity.com EEG and Brain Waves • Electroencephalogram – records voltage changes from postsynaptic potentials in cerebral cortex • Brain waves – 4 types distinguished by amplitude and frequency 15 Docsity.com Brain Waves • alpha – occur when awake; resting with eyes closed • beta – eyes open; performing mental tasks • theta – sleep or emotional stress • delta – deep sleep 16 Docsity.com Sleep • Temporary state of unconsciousness – sleep paralysis = inhibition of muscular activity – suprachiasmatic nucleus acts as biological clock to set our circadian rhythm • Controlled by hypothalamus, reticular formation, thalamus, and cerebral cortex • Restorative effect – brain glycogen levels increase – memories strengthened • synoptic connections reinforced or eliminated 17 Docsity.com Cognition • Mental processes – such as awareness, perception, thinking, knowledge and memory – association areas = 75% of brain • integration of sensory and motor information occurs 20 Docsity.com Brain lesions • parietal lobe – contralateral neglect syndrome • temporal lobe – agnosia - inability to recognize objects – prosopagnosia - inability to recognize faces • frontal lobe – problems with personality (inability to plan and execute appropriate behavior) 21 Docsity.com Lobotomy of Phineas Gage • Ventromedial region of both frontal lobes • Personality change – irreverent, profane • Prefrontal cortex functions – planning, moral judgement, and emotional control 22 Docsity.com Somesthetic Sensation • Receptors – for touch, pressure, stretch, temperature, and pain • Gracile and cuneate fasciculi and spinothalamic tracts – ascending signals decussate, go to thalamus, to cortex • Somatosensory area in postcentral gyrus 25 Docsity.com Sensory Homunculus • Area of cortex dedicated to sensations of body parts is proportional to the sensitivity of that body part (# of receptors) • Somatotopy 26 Docsity.com Functional Regions of Cerebral Cortex ‘Copyright © The McGraw-Hill Companies, Inc, Permission required for reproduction or display. Primary somesthetic cortex Primary motor cortex Somesthetic association area Primary gustatory cortex Motor association area Wernicke area Broca area Visual association area Primary visual cortex Prefrontal cortex Olfactory j i association : caters area area of Auditory association area 27 Docsity.com Motor Control • Intention to contract a muscle begins in motor association (premotor) area of frontal lobes • Precentral gyrus (primary motor area) relays signals to spinal cord – pyramidal cells called upper motor neurons – supply muscles of contralateral side • Motor homunculus - proportional to number of muscle motor units in a region 30 Docsity.com (b) Motor Homunculus ‘Copyright © The MeGraw-Hill Companies, Inc. Permission required for reproduction ar disp. 31 Docsity.com Basal Nuclei and Cerebellum • Basal nuclei in feedback circuit with cerebral cortex – highly practised movements – starting and stopping movements – walking – dyskinesias and unwanted movements • Cerebellum – learned motor skills, muscle tone, posture, and smooth muscle contractions – compares intention to actual movement and sends signal to adjust 32 Docsity.com Language Centers ‘Copyright® The McGraw-Hill Compania, Inc, Permission required for reproduction or display. Anterior Posterior Precentral gyrus Postcentral gyrus Speech center of primary motor cortex Angular Primary auditory gyrus cortex (in lateral sulcus) Primary visual cortex Broca area : Wernicke area 35 Docsity.com Aphasia • Language deficit from lesions in same hemisphere as Wernicke and Broca areas • Lesion to Broca = nonfluent aphasia – slow speech, difficulty in choosing words • Lesion to Wernicke = fluent aphasia – speech normal and excessive, but makes little sense • Anomic aphasia – speech and understanding are normal but text and pictures make no sense 36 Docsity.com Lateralization of Cerebral Functions ‘Copyright © The McGraw-Hill Companies, Ine. Permission required for reproduction or display. Lantenishew (Bl Olfaction, left nasal cavity Olfaction, right nasal cavity Anterior Memory for shapes (Limited language Speech comprehension, mute) Left hand motor control Right hand motor control Feeling shapes with Feeling shapes left hand with right hand Hearing nonvocal sounds Hearing vocal sounds (left ear advantage) (right ear advantage) Musical ability Rational, symbolic thought Intuitive, nonverbal thought Superior recognition of faces and spatial relationships Vision, left field Superior language comprehension Vision, right field Posterior 37 Docsity.com Cranial Nerves Copyright® The McGraw-Hill Companies, nc, Permizsion required for rapraduction or display. Frontal lobe ieee i . — Longitudin: Cranial nerves: fissure Olfactory bulb (from olfactory nerve, |) Olfactory tract Optic nerve (II) Temporal lobe Oculomotor nerve (Ill) Trochlear nerve (IV). Infundibulum Midbrain oe Trigeminal nerve (V) = Optic chiasm Pons y _——— Abducens nerve (VI) Facial nerve (VI!) ‘VWestibulocochlear nerve (Vill), Glossopharyngeal nerve (IX) , Vagus nerve (X) 2 : city Hypoglossal nerve (XII) ——- . ee i oblongata Accessory nerve (Xl): ‘Gerebellum Cerebellum Spinal cord 40 Docsity.com Olfactory Nerve • Sense of smell • Damage causes impaired sense of smell 41 Docsity.com Optic Nerve • Provides vision • Damage causes blindness in visual field 42 Docsity.com Trigeminal Nerve • Sensory to face (touch, pain and temperature) and muscles of mastication • Damage produces loss of sensation and impaired chewing 45 Docsity.com Abducens Nerve • Provides eye movement (lateral rectus m.) • Damage results in inability to rotate eye laterally and at rest eye rotates medially 46 Docsity.com Facial Nerve • Motor - facial expressions; salivary glands and tear, nasal and palatine glands • Sensory - taste on anterior 2/3’s of tongue • Damage produces sagging facial muscles and disturbed sense of taste (no sweet and salty) 47 Docsity.com Glossopharyngeal Nerve • Swallowing, salivation, gagging, control of BP and respiration • Sensations from posterior 1/3 of tongue • Damage results in loss of bitter and sour taste and impaired swallowing 50 Docsity.com Vagus Nerve • Swallowing, speech, regulation of viscera • Damage causes hoarseness or loss of voice, impaired swallowing and fatal if both are cut 51 Docsity.com Accessory Nerve • Swallowing, head, neck and shoulder movement – damage causes impaired head, neck, shoulder movement; head turns towards injured side 52 Docsity.com