Lutfi - PBC9102 Post Bacc Anatomy II Head & Neck - CEREBRUM PDF

BRAIN AND NERVOUS SYSTEM III DR. KIRAN C. PATEL COLLEGE OF OSTEOPATHIC MEDICINE Nicholas, Lutfi, MD, MS, DPM OBJECTIVES Objectives 1. Identify the lobes of the cerebrum: Frontal, Parietal, Occipital, and Temporal lobes 2. Describe structural components of the lobes of the cerebrum LECTURIO AND READI...

BRAIN AND NERVOUS SYSTEM III DR. KIRAN C. PATEL COLLEGE OF OSTEOPATHIC MEDICINE Nicholas, Lutfi, MD, MS, DPM OBJECTIVES Objectives 1. Identify the lobes of the cerebrum: Frontal, Parietal, Occipital, and Temporal lobes 2. Describe structural components of the lobes of the cerebrum LECTURIO AND READING ASSIGNMENTS Lecturio Videos 1. Frontal Lobe 2. Parietal Lobe 3. Occipital Lobe 4. Temporal Lobe Readings 1. Telencephalon – The Anatomy and Function of the Cerebrum Visual/Technology Resources 1. Complete Anatomy (3D4Medical) INTRODUCTION INTRODUCTION The Central Nervous System (CNS) consists of: BRAIN MIDBRAIN CNS BRAIN STEM SPINAL CORD PONS MEDULLA OBLONGATA INTRODUCTION The CNS begins its development about 2 ½ after fertilization Rapidly proliferating cells of the dorsal embryo fold over to form a neural tube The caudal end of the neural tube becomes the spinal cord The cranial end develops three enlargements which will be the future brain 1. Forebrain 2. Midbrain 3. Hindbrain FUNCTIONS OF THE BRAIN FUNCTIONS OF THE BRAIN The brain is more complicated than the most powerful computer and has billions of neurons, each of which may connect to thousands of other neurons. It is our major communications and control center. 1. 2. 3. Stimulates movement - requires coordination of sensory and motor information Maintains homeostasis – integrates internal and external environment Origin of conceptual thought – (intelligence) creativity, imagination, memory, learning calculation, prediction, abstract reasoning, altruism, free will, and personality. NEURAL TUBE DEVELOPMENT NEURAL TUBE DEVELOPMENT This involves a folding of embryonic ectoderm that leaves a central hollow core, the central canal. NEURAL TUBE DEVELOPMENT ORIGINAL ENLARGEMENT FOREBRAIN (prosencephalon) DERIVATIVES CENTRAL CANAL DEVELOPMENT TELENCEPHALON = Cerebral Hemispheres RIGHT AND LEFT VENTRICLES Thalamus DIENCEPHALON = THIRD VENTRICLE Hypothalamus MIDBRAIN (Mesencephalon) HINDBRAIN (Rhombencephalon) MESENCEPHALON = Midbrain CEREBRAL AQUEDUCT Cerebellum METENCEPHALON = Pons MYELENCEPHALON = Medulla Oblongata SPINAL CORD CENTRAL CANAL NEURAL TUBE DEVELOPMENT CLINICAL COMMENTS https://nova.lecturio.com/medical-courses/hydrocephalus-etiology-examination.lecture HYDROCEPHALUS This is a condition in which cerebrospinal fluid (CSF) builds up within the ventricles. When this occurs in a developing fetus, the brain and bones of the skull expand, and the baby’s head is enlarged. While the fetus is still in the uterus, a shunt can be used to drain the excess fluid and prevent brain damage (mental retardation). If it occurs in an adult, the increased intracranial pressure causes headaches and can lead to brain damage unless a shunt is used to drain the excess fluid. https://nova.lecturio.com/medical-courses/hydrocephalus-definition-treatment.lecture https://nova.lecturio.com/medical-courses/hydrocephalus-diagnosis-management.lecture VIEWS OF THE BRAIN VIEWS OF THE BRAIN As we begin the study of the brain, we must first orient ourselves to determine which is anterior (nostral) and which is the posterior (caudal) end of the cerebral hemisphere. Terminology Also, whether we are looking at the ventral or the dorsal brainstem. 3. Fissures are deeper than sulci 1. Gyrus = elevated portion of a brain fold 2. Fissure/sulcus (sulci) = are “cracks” that separate lobes LATERAL VIEW OF THE BRAIN https://nova.lecturio.com/medical-courses/frontal-lobe.lecture Pre-central gyrus = Part of the frontal lobe. It is the primary motor area - Fine motor control Parietal lobe = Extends from the central sulcus to the occipital lobe Frontal lobe = Lies in the anterior cranial fossa Parieto-occipital sulcus = Between the parietal and occipital lobes. Easily seem from a medial view Lateral fissure = Separated the temporal lobe from frontal lobe Occipital lobe = Most caudal lobe. Important receptor of visual information Temporal lobe = Hearing, olfaction, memory and learning Transverse fissure = Separation between cerebrum and cerebellum Pons = Superior enlargement of ventral hindbrain Cerebellum = Connected to pons, medulla oblongata and midbrain. It is essential for coordination of motor activity. It lies in the posterior cranial fossa Medulla oblongata = Inferior enlargement of ventral hindbrain Spinal cord Central sulcus = Depression in the central portion of the lateral brain Post-central gyrus = Part of the parietal lobe and it is the primary sensory reception area Insular lobe Considering one hemisphere only, the brain has 5 lobes: 1. Frontal 2. Occipital 3. Parietal 4. Temporal 5. Insular MEDIAL VIEW OF THE BRAIN https://nova.lecturio.com/medical-courses/parietal-lobe.lecture Corpus callosum = Commissural fibers. Structural and functional connection of hemispheres Cerebral aqueduct = Passageway between the third and fourth ventricles Septum pellucidum = Thin tissue separating the lateral Ventricles Medulla oblongata = Inferior part of the brainstem for autonomic reflex control of heartbeat and respiration Interventricular foramen = Opening between lateral and third ventricles Central sulcus = Separates frontal from parietal lobe Thalamus = Oval-shaped enlargement formed of nuclei (groups of cell body neurons). The two sides meet at the massa intermedia. One of its functions is to serve as a rely for most sensory information Paracentral lobule = U-shaped continuation of pre and postcentral gyri Hypothalamus = Delineated from thalamus by hypothalamic sulcus. Involved in functions of autonomic nervous system, limbic system and endocrine system Choroid plexus = Produces CSF Optic chiasm = Where optic fibers cross Parieto-occipital sulcus Hypophysis (pituitary gland) = Secretes hormones important in maintaining homeostasis. Rests in the hypophyseal fossa of the sphenoid bone Pineal gland = Involved in wake/sleep cycles Mammillary body = nucleus related to emotional function (limbic system) Superior/inferior colliculi = Midbrain structures. Relay visual and auditory information Cerebral peduncle of midbrain = Motor processes are located here Calcarine fissure = Primary visual cortex BASE OF THE BRAIN: VENTRAL BRAINSTEM https://nova.lecturio.com/medical-courses/temporal-lobe.lecture https://nova.lecturio.com/medical-courses/occipital-lobe.lecture FUNCTIONS OF THE CEREBRUM The brain is more complicated than the most powerful computer and has billions of neurons, each of which may connect to thousands of other neurons. FUNCTIONS OF THE BRAIN It is our major communications and control center. Stimulates movement - requires coordination of sensory and motor information Maintains homeostasis – integrates internal and external environment Origin of conceptual thought – (intelligence) creativity, imagination, memory, learning calculation, prediction, abstract reasoning, altruism, free will, and personality. CONTRALATERAL BRAIN FUNCTION The left hemisphere controls most of the motor function of the right side of the body and receives most of the sensory information from the right side of the body. The right side of the brain controls the left side of the body and receives left-side sensory information. CONTRALATERAL BRAIN FUNCTION The dominant hemisphere, the left in the majority of right-handed people, is more involved in complex communication and calculation. The right hemisphere is more important in spatial orientation. Because of the complexity of the brain, it is important that areas within hemispheres communicate and that hemispheres communicate with each other: 1. Commissural fibers – nerve cell processes by which hemispheres communicate. E. g. corpus callosum 2. Association fibers – for communication within a hemisphere 3. Projection fibers – communication from cortex to other parts of the CNS. E. g. tracts BRODMANN AREAS (NUMBERS) They were assigned to many functional areas of the brain in the early 20th century It is important to note that we now have a better understanding of the brain and the ability of regions of cells to adapt to other functions when needed. These numbered areas are not rigid, but they give us a basic understanding of the location of functions in a normal brain. MOTOR AND SENSORY CORTICAL HOMUNCULI MOTOR AND SENSORY CORTICAL HOMUNCULI General motor and sensory functions have their origin in the precentral and postcentral gyri, respectively. The paracentral lobule is a continuation of these gyri. For instance, the cell bodies that receive general sensory information from the right foot will be found in the paracentral lobule of the left hemisphere. MOTOR AND SENSORY CORTICAL HOMUNCULI A homunculus (little man) is drawn when illustrations of body parts are placed on the cortex where the body part is represented. Therefore, the sensory homunculus will be represented by a coronal section of the brain cut through the postcentral gyrus. The motor homunculus will be visualized by a cut through the precentral gyrus. THANK YOU!...