ANATOMY LECTURE ON NERVOUS SYSTEM MISS BADA OMOTOLA

INTRODUCTION It is a system involved with awareness. It consist of neurons and other associated cells and tissues.

FUNCTIONS Awareness Sensation Memory Intelligence Emotion Thought Coordination of muscle movement Regulation of visceral activities

ORGANIZATIONAL CHART OF THE DIFFERENT PARTS OF THE NERVOUS SYSTEM

CENTRAL NERVOUS SYSTEM It consist of structures in the centre of the system. These include Brain Spinal Cord

BRAIN A great mass of nerve tissue that lie in the skull. It consist of the following parts, viz; Cerebrum. Brainstem. Cerebellum.

THE CEREBRUM It is the largest part of the brain It consist of two hemispheres connected by the corpus callosum. It is ovoid in shape, with grey coloured convoluted surface made of alternating furrows(sulci) and ridges(gyri) called Cerebral Cortex. It is organized into six distinct layers.

PARTS OF THE CEREBRAL CORTEX Consist of parts called LOBES. LOBES are named after the skull bone that covers them. 1.OCCIPITAL LOBE 2. PARIETAL LOBE 3. TEMPORAL LOBE 4. FRONTAL LOBE

LOBES AND CONTENTS OCCIPITAL LOBE- Located at the posterior end of cortex Contains the primary visual cortex responsible for vision

LOBES AND CONTENT CONT’D PARIETAL LOBE Located between occipital lobe and central sulcus. Contains primary somatosensory cortex-Receives touch sensation, muscle stretch information and joint position information.

LOBES AND CONTENT CONT’D TEMPORAL LOBE Located in the lateral portion of each hemisphere, near the temples. Contains the auditory cortex ,essential for understanding spoken language, complex visual processes, emotional and motivational behaviour.

LOBES AND CONTENT CONT’D FRONTAL LOBE It extends from the central sulcus to the anterior limit of the brain. Contains primary motor cortex, responsible for fine movement.

ASSIGNMENT Briefly discuss the functions of the Cerebrum and the functional regions of the cortex.

BASAL GANGLIA A collection of masses of gray matter situated within each cerebral hemisphere, They are – Corpus Straitum – Divided by a band of nerve fibers INTERNAL CAPSULE into CAUDATE & LENTIFORM NUCLEUS. Amygdaloid nucleus – Considered to be a part of the LIMBIC SYSTEM. Claustrum

CLINICAL CORRELATE PARKINSON DISEASE- A progressive disease of unknown cause. Associated with neuronal degeneration of the substantia nigra . The degeneration of the neurons of the substantia nigra that sends axons to the corpus straitum results in a reduction in the release of neurotransmitter dopamine within the corpus straitum.

THALAMUS The thalamus is a large ovoid mass of gray matter. It serves as a cell station to all the main sensory systems (except the olfactory pathway).

HYPOTHALAMUS Microscopically The hypothalamus is composed of small nerve cells that are arranged in groups. The hypothalamus controls and integrates the functions of the autonomic nervous system and the endocrine systems and plays a vital role in maintaining body homeostasis. It is involved in such activities as regulation of body temperature, body fluids, drives to eat and drink, sexual behavior, and emotion.

BRAIN STEM Connects brain to spinal cord. Made up of Midbrain Pons Medulla Oblongata It consist of tracts and nuclei

MIDBRAIN Situated between the thalamus and the pons. Contains some important structures: Copora quadrigemina, which are 4 nuclei on the superior surface SUPERIOR COLLICULI- Responsible for Visual Reflexes INFERIOR COLLICULI- Responsible for auditory reflexes RED NUCLEUS- Communicate with cerebellum and maintains posture

PONS A rounded bulge between midbrain and medulla oblongata. Facilitates communication to and from cerebrum and midbrain(Ventral portion) Cerebrum to cerebellum(dorsal portion).

MEDULLA OBLONGATA It is the enlarged continuation of the spinal cord From the level of the foramen magnum to the pons All ascending and descending nerve fibres pass through it. Consist control centre for the following Respiratory centre Vasoconstriction and vasodilation Heart rate

CEREBELLUM It is located inferior to the occipital lobe and posterior to the pons and medulla oblongata. It is made up of two hemispheres These hemispheres are separated by the falx cerebelli. A structure known as the vermis connects the hemispheres. It is the chief coordinator of motor activity

SPINAL CORD A slender column of nervous tissue,continous with brain and passes through the vertebral column. Consist of 31 segments with one pair of spinal nerves each. Has two enlargements CERVICAL ENLARGEMENT -In the neck region. Nerve supply to the upper limb.

SPINAL CORD CONT’D LUMBAR ENLARGEMENT- In the lower back, nerves to the lower limb. PARTS OF THE SC Conus Medullaris-Inferior to lumbar enlargement, a tapered structure. Filum terminale-Thin cord of connective tissue descending to coccyx. Cauda Equina- Consist of filum terminale and spinal nerves below conus medullaris.

SPINAL CORD CONT’D Anterior and posterior median fissure- Divides SC into left and right halves. Gray matter- Butterfly shaped White matter- It surrounds the gray matter,3 regions(Anterior, lateral and posterior columns). Anterior ,Posterior and lateral horns – Parts of the gray matter. Gray Commisure-connects wings and surrounds central canal

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