Anatomy of brain and spinal cord BMS 231: 2015/2016 DR SOBIA IKRAM DR AQEELA BANO

Objectives 1.To know the basic anatomy of brain, brain stem, spinal cord, spinal meninges and brain ventricles. 2.To know the Anatomical location of the parts of the brain.

INTRODUCTION Brain is a soft fragile organ that is protected in the bony structure called skull. Brain weighs about 3 pounds but it contains 100 billion cells. Acts as a command and control center for voluntary actions. Act as main coordinating center for automatic actions.

ANATOMY Anatomically brain is divided into three parts 1.Cerebrum 2.Cerebellum 3.Brain stem

ALSO CONTAIN 1.Grey matter 2.White matter 3.Ventricles 4.Cerebrospinal fluid ANATOMY

Largest part of the brain On the surface are present several elevations and depressions called gyri and sulci. Divided by inter hemisphere sulcus into 1.Right hemisphere 2.Left hemisphere Lt hemisphereRt hemisphere Cerebrum

Functions of cerebrum Act as integrating center for highly complex functions like Memory, learning, emotions, language and reasoning. Cerebrum

Parts of cerebrum Cerebrum is divided into four lobes by various fissures 1.Frontal lobe 2.Parietal lobe 3.Temporal lobe 4.Occipital lobe All the four lobes have different highly complex functions Cerebrum

Parts of cerebrum 1. Frontal lobe Planning, organizing and controlling Cognition and memory 2. Parietal lobe Processing of sensory input Body orientation Recognition of somatic areas 3.Occipital lobe Primary visual perception area 4. Temporal lobe Auditory receptive area Express behaviour Language Memory and information retrieval area Cerebrum

CEREBELLUM Also called little brain Present on the posterior and inferior part of the cerebrum Has two hemispheres Connected to the spinal cord through the medulla oblongata.

Functions of cerebellum 1.The cerebellum plays an important role in motor control.motor control 2. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses.cognitive functionsattention language 3. The cerebellum does not initiate movement, but it contributes to coordination, precision, and accurate timing. coordination CEREBELLUM

Brain stem It is the part of the brain that connects the cerebrum to the spinal cord. It consists of three parts : 1.Mid brain 2.Medulla oblongata 3.pons

1.Mid brain It is the smallest portion of the brain that act as a relay station for the auditory and visual informations. It also control eye movements and body movements. Brain stem

2. Pons Pons, is the part of the brainstem lying above the medulla oblongata The pons is a broad, horseshoe-shaped mass of transverse nerve fibres that connect the medulla with the cerebellum. Brain stem

FUNCTIONS OF THE PONS 1.Act as a connecting pathway for signals between cerebrum and cerebellum 2.Controls the respiration 3.Responsible for consciousness 4.Also play role in hearing Brain stem

Medulla oblongata The medulla oblongata is conical in shape. Its broad part joins the pons above and narrow part becomes continuous with the spinal cord. The junction between medulla and spinal cord is at the level of the upper border first cervical vertebra. Its length is about 3 cm and its width is about 2cm. Brain stem

Functions of medulla oblongata Medulla oblongata involves in the regulation of 1.Heart rate 2.Blood pressure 3.Breathing 4.Digestion 5.Sleep and arousal Brain stem

Ventricles and cerebrospinal fluid VENTRICLES ventricles are the set of four cavities in the brain parenchyma that intercommunicates with each other. They are lined with the blood vessels that are called choroid plexuses, it secretes fluid called cerebrospinal fluid. Four ventricles are 1.Two lateral ventricles 2.Third ventricle 3.Fourth ventricle

Ventricles and cerebrospinal fluid

Cerebrospinal fluid A watery fluid that is continuously produced and absorbed and that flows in the ventricles within the brain and around the surface of the brain and spinal cord. Abbreviated as CSF. CSF is produced by the choroid plexus, a series of infolded blood vessels that project into the cerebral ventricles, and it is absorbed into the venous system. Ventricles and cerebrospinal fluid

FUNCTIONS OF CEREBROSPINAL FLUID Absorbs physical shocks to the brain Distributes nutritive materials to and removes wastes from nervous tissue Provides a chemically stable environment Ventricles and cerebrospinal fluid

Grey and white matters are present in both brain and spinal cord. Grey matter is composed of neuron cell bodies but white matter is composed of nerve fibers. GREY AND WHITE MATTER

If the spinal cord is cut in transverse section there is a tiny central canal which contains CSF. There is a dark portion of H- shaped or butterfly shaped “gray matter”, surrounded by a larger area of “white matter”. GREY AND WHITE MATTER

The Spinal cord The spinal cord is a cylindrical grayish white structure that begins from medulla oblongata above and terminates below In adults: at the level of upper border of first lumber vertebra. In the young child it is relatively longer and ends at the upper border of third lumber vertebra

Inferiorly the spinal cord tapers off into the structure called conus medullarius. The nerve roots of the lumbar and sacral regions are called cauda equina. The Spinal cord

There are 31 pairs of spinal nerves.

Spinal Meninges Membranes that covers the spinal cords and its nerve roots are called spinal meninges. The outer layer is called dura mater. This is a tough, fibrous memebrane. The middle layer, the arachnoid, runs This is delicate and transparent. The innermost is called, pia mater. It is highly vascular and tightly attached to the spinal cord and its roots. The Spinal cord

That’s all about the brain and spinal cord. Its so easy isn't it? THANK U