Central Nervous System - Part 1 PDF

Central Nervous System-Part 1 Unless otherwise indicated, image source forPARA all slides: 1002...

Central Nervous System-Part 1 Unless otherwise indicated, image source forPARA all slides: 1002 Human Anatomy, 8th edition Marieb, et.al. (Pearson, 2017) 1 Coverings of the CNS The brain and spinal cord are protected on the outside by the cranium and vertebral column There are also membranous inner covering called meninges which are composed of 3 layers: Dura Mater – (2 layered)the strong, white, fibrous outer layer of the meninges which also serves as the inner periosteum of the cranial bones Arachnoid Mater – a thin, mesh-like layer between the dura and pia mater Pia Mater – the thin, transparent membrane that adheres to the surface of the brain and spinal cord. It contains fine blood vessels PARA 1002 2 1  Dura PARA 1002 3 Wear a Helmet! Severe epidural hematoma from a blow to the head PARA 1002 4 2  Epidural Hematoma 90 % are from fractures of the skull over the pterion causing rupture of the middle meningeal artery PARA 1002 5 Arachnoid Arachnoid Blood vessels Subarachnoid space Arachnoid villi drains CSF into venous sinuses PARA 1002 6 3  Arachnoid PARA 1002 7 Subarachnoid Space Produced in ventricles CSF in subarachnoid space Central canal of spinal cord Path of CSF in subarachnoid space and from ventricles PARA 1002 8 4  Pia Mater Pia Mater PARA 1002 9 Ventricles of the Brain 2 lateral (1 and 2) Third Fourth Between pons and cerebellum Continuous with the central canal of spinal cord PARA 1002 10 5  CSF Cerebrospinal Fluid Produced in Choroid Plexus in ventricles Leaves through 4th ventricle Enters subarachnoid space PARA 1002 11 Hydrocephalus Results from poor drainage of CSF through cerebral aqueduct PARA 1002 12 6  The Brain Cerebrum Diencephalon Brain Stem Midbrain (mesencephalon) Pons Medulla oblongata Cerebellum PARA 1002 13 The Brain (cont…) PARA 1002 14 7  PARA 1002 15 Parts of the Brain Medulla Oblongata – Responsible for regulating heart rate, respiration, vascular control (blood pressure) – Very vulnerable to occipital lobe injuries – motor/sensory tracts to and from cortex, cerebellum and spinal cord – Reflex centers for coughing, sneezing, gagging, swallowing, vomiting, salivation, sweating, movements of tongue & head – Cranial Nerves VIII, IX, X, XI, XII PARA 1002 16 8  Parts of the Brain Pons – Contains 2 respiratory centres that establish and maintain normal breathing rhythm with the medulla – Bridges medulla with other areas of the brain – Cranial Nerves V, VI, VII Midbrain – Integration of visual and auditory reflexes – Maintenance of balance and equilibrium – Cranial Nerves III, IV PARA 1002 17 Parts of the Brain Cerebellum – Coordination of body movement, spatial acuity, muscle tone and posture – Operates on a completely “subconscious” level in response to sensory input Hypothalamus – Produces antidiuretic hormone (ADH) and oxytocin – Produces releasing factors that cause release of pituitary hormones – Regulation of body temperature and “hunger” – Integration of ANS function – Stimulates visceral responses to emotion – Regulation of circadian rhythms and “biological clock” PARA 1002 18 9  Parts of the Brain Thalamus – Integrates incoming sensory impulses (except smell) and allows the cerebrum to interpret them as one sensation (holding a hot drink) – Perceives pain but does not localize the stimulus – Suppresses“ distracting” sensations that would otherwise interfere with cerebral function (concentration) Cerebrum – The largest or “main” part of the brain divided into two hemispheres, connected by the corpus callosum – The outer part of the cerebrum, the cerebral cortex, is the major “functional” part and it is composed of grey matter (cell bodies) PARA 1002 19 The Brain PARA 1002 20 10  Cerebellum – a closer look Under occipital bone Anterior and posterior lobes Primary fissure Cerebellar hemispheres Cerebellar peduncles link the cerebellum with the midbrain, diencephalon and cerebrum PARA 1002 21 Cerebellum Precise timing for skeletal muscle activity and control of balance and equilibrium Body movements are smooth and co-ordinated Balance from fibers of the: inner ear eye proprioceptors of skeletal muscle PARA 1002 22 11  Cerebrum (Cerebral Hemispheres) “Seat of intelligence” Communication, memory, logic, awareness and emotional response Superior portion of the brain Make up over 80% of brain mass PARA 1002 23 Cortex - Surface Anatomy Gyri, Sulci, Fissures PARA 1002 24 12  Cerebral Cortex 2 hemispheres: Right and left Divided by the longitudinal fissure Further divided into lobes: – Frontal; parietal; occipital and temporal and insula Acts on opposite side of the body *No area acts alone (explain) PARA 1002 25 Cerebral Hemispheres 83% of total brain mass Forms a “mushroom cap” over the diencephalon and brainstem P F Five lobes: O Frontal T Parietal Occipital Temporal Insula I PARA 1002 26 13  “Cerebral” Assignment For homework – Please describe the cerebral cortex and outline the basic function of each of the four lobes of the cerebral hemispheres and the “Insula” …This should be just 1 or 2 pages … Please submit to the FOL Dropbox before the end of this week. See FOL for Details PARA 1002 27 Cerebral Hemispheres 83% of total brain mass Forms a “mushroom cap” over the diencephalon and brainstem Frontal Lobe Primary motor area “precentral gyrus” Consciously move skeletal muscle Premotor cortex: – Learned motor skills Directs the muscles involved in speech Language comprehension Reasoning PARA 1002 28 14  Cerebral Hemispheres Parietal Lobe Somatic sensory area Postcentral gyrus Integrate and interpret senses Can recognize pain; coldness or a light touch Temporal Lobe Memory Auditory Balance Olfactory PARA 1002 29 Cerebral Hemispheres Occipital Lobe Vision Insula Gustation Memory? PARA 1002 30 15  Layers of Cerebrum Cerebral cortex (Grey Matter) Cerebral white matter Basal ganglia (deep grey matter) PARA 1002 31 Basal Nuclei (Ganglia) Muscle tone and unconscious contractions Receive input from cortex and other areas Relay to motor and premotor areas Important in starting, stopping and monitoring movement Control intensity of movement, and antagonists Repetitive tasks and habit formation PARA 1002 32 16  Parkinson’s Disease Results from a breakdown in connection between a portion of the midbrain (substantia nigra) and the basal ganglia Loss of inhibitory input - “stuck break” effect PARA 1002 33 17