Introduction of neuroanatomy Syed abdul basit Mphil anatomy What is neuro anatomy • Study of the nervous system • The nervous system is made up of vast neural networks; signalling within these circuits enables thinking, language, feeling, learning, memory, and all function and sensation. It is well-established that through plasticity of existing cells our nervous systems can adapt to situations not previously encountered, but it also has been shown that cells (NSCs) are plastic and involved in creating new connections in adaptation and response to injury. The Nervous System has three specific functions: • Sensory Input - Sensory receptors present in the skin and organs respond to external & internal stimuli by generating nerve impulses that to the central nervous system • Integration - The brain and spinal cord of the Central Nervous System combine and sum up all the data received from the body and send out nerve impulses. • Motor Output - The nerve impulses from the Central Nervous System go to the effectors (muscles and glands). Muscle contractions and gland secretions are responses to stimuli received by sensory receptors. The Nervous System is divided into two main divisions 1.Central Nervous System (CNS) 2.Peripheral Nervous System (PNS) Cns divided into two parts brain and spinalcord • The Brain is divided into four main parts[1]: • Brain stem, consisting of the medulla, pons, and midbrain • Cerebellum • Diencephalon, with the thalamus and hypothalamus • Cerebral hemispheres (comprised of the cerebral cortex, basal ganglia, white matter, hippocampi and amygdalae). The right and left hemisphere are connected by the corpus callosum which facilitates communication between both sides of the brain. The Hemispheres are then further divided into four lobes. NEURONS • Neurons are cells of the nervous system, located within the grey matter, and responsible for all neurological functions of the brain. • They are any of the impulse-conducting cells that constitute the brain, spinal column, and nerves in vertebrates, consisting of a nucleated cell body with one or more dendrites and a single axon. See Neurone link for more detailed information Neurological conditions • Neurological Conditions: many neurological conditions affect the CNS. They range dramatically in scope, impact, and nature of the effect. Some conditions lead to progressively impaired movement eg Parkinson disease. Huntington chorea. The demyelination in multiple sclerosis can cause acute attacks, and over time, chronic degradation of function. Others may impact cognition such as the various dementias. Epilepsy can cause uncontrolled excitation. Headaches often impair the daily function of patients. Traumatic injuries can cause plegia or paresis and may result a wide range of deficits depending on the location and extent of the lesion The cerebrum consists of two cerebral hemispheres, the right and left hemisphere are connected by the corpus callosum which facilitates communication between both sides of the brain, with each hemisphere in the main connection to the contralateral side of the body i.e. the left hemisphere of the cerebrum receives information from the right side of the body resulting in motor control of the right side of the body and vice versa. The hemispheres are then further divided into four lobes; Occipital Parietal Temporal (medial part of which are a series of structures including the Hippocampus) Frontal Cerebral cortex • The outer layer of the cerebral hemisphere is termed the cerebral cortex. This is inter-connected via pathways that run sub-cortically. It is these connections as well as the connections from the cerebral cortex to the brainstem, spinal cord and nuclei deep within the cerebral hemisphere that form the white matter of the cerebral hemisphere. The deep nuclei include structures such as the basal ganglia and the thalamus. Basal ganglia • The “basal ganglia” refers to a group of subcortical nuclei within the brain responsible primarily for motor control, as well as other roles such as motor learning, executive functions, emotional behaviours, and play an important role in reward and reinforcement, addictive behaviours and habit formation. hypothalamus • The hypothalamus is an organ central to many autonomous functions of the human body, notably the regulation of homeostasis. It has a significantly large efferent output to the ANS and has a highly significant role in the control of pituitary endocrine function. • The hypothalamus lies on either side of the 3rd ventricle, below the thalamus and between the optic chiasm and the midbrain. It receives a large input from limbic structures. See link for detailed description. Meningis • The CNS is enclosed within the skull and vertebral column. These structures are separated by a series of membranes known as the Meninges. The Pia Mater is separated from the delicate arachnoid membrane by the subarachnoid space, which is then in turn separated from the Dura mater by the Sub-dural space