Anatomy for Sports Science SS202 Nervous System PDF

Anatomy for Sports Science SS202 Nervous System Siobhán O’Connor MSc PhD Certified Athletic Therapist (CAT) ∙ ∙ ∙ • • ∙ Highly specialized cells Transmit information rapidly Most complex system in body – regulate 1oos of activities simultaneously. It is the source of intelligence, consciousness...

Anatomy for Sports Science SS202 Nervous System Siobhán O’Connor MSc PhD Certified Athletic Therapist (CAT) ∙ ∙ ∙ • • ∙ Highly specialized cells Transmit information rapidly Most complex system in body – regulate 1oos of activities simultaneously. It is the source of intelligence, consciousness, creativity & allows us to communicate & experience emotions. It controls all voluntary actions & non- voluntary up to some extent like breathing Two major parts: 1. Central Nervous System (CNS) 2. Peripheral Nervous System (PNS). ∙ The activity of nervous system is performed by nerve cells called “Neurons”. Function of Nervous System Sensory input/function ∙ ∙ ∙ Gathering information To monitor changes occurring inside and outside the body like increasing blood acidity or external stimuli etc. Then sensory information is carried to brain & spinal cord through cranial & spinal nerves. Integration ∙ To process and interpret sensory input and decide if action is needed. Motor output/function ∙ ∙ A response to stimuli Activates muscles or glands Central nervous system • Consists of brain and spinal cord. Peripheral nervous system • Consists of nerves that arise from brain and spinal cord (CNS) & spread in different parts of body. CNS = brain + spinal cord PNS = nerves All these components are made of neurons ∙ ∙ ∙ ∙ Neurons ∙ This is the basic conducting cell of the nervous system Cells specialized to transmit electrochemical messages transmit information from one part of the body to the other in the form of electrical impulses the human nervous system consists of billions of neurons plus supporting cells called neuroglial cells neurons communicates with other neurons in nervous system and also communicates with other cells of body such as heart cells, muscle cells etc This communication occurs through junctions called synapses Neuron Anatomy ∙ 3 components: Cell body (soma), Dendrites & Axon Cell body ∙ Expanded part, contains nucleus, ribosomes, mitochondria and apparatus necessary for metabolic activity Dendrites ∙ Fibrous & highly branched projections extending outwards from the cell body, responsible for receiving and transmitting information Axon ∙ Each cell contain 1 axon that is a thin, long, cylindrical fibre that conduct nerve impulses away from the cell body. Structural Classification of Neurons Pseudounipolar ∙ Short single process that branches like a T e.g. Sensory neurons. Bipolar neurons ∙ Have 2 processes e.g. Retina of the eye. Multipolar ∙ Have several dendrites and 1 axon e.g. Motor neuron. Functional Classification of Neurons 1. Sensory neurons ∙ ∙ Carry nerve impulses from a receptor to the CNS Have long dendrites and short axons 2. Motor neurons ∙ ∙ Carry nerve impulses from the CNS to an effector (ex. muscle or gland) Have short dendrites and long axons 3. Interneurons ∙ ∙ ∙ Found completely within the CNS Provide a link within the CNS between sensory neurons & motor neurons Have short dendrites and long or short axons Sample of nerves of Lumbosacral plexus ∙ ∙ ∙ ∙ Sciatic – M,S e.g. hamstrings etc ∙ Common Fibular (peroneal) – M,S e.g. peroneal longus, brevis Femoral – M,S e.g. Quads, Sartorius etc Obturator – M,S e.g. adductors etc Tibial – M,S e.g. gastrocnemius, soleus, popliteus etc Cutaneous supply of peripheral nerves in lower limb The Brachial Plexus Ulnar Nerve – Motor & Sensory, “the funny bone” Radial Nerve – Motor & Sensory ∙ Motor: Triceps brachii, extensor muscles of forearm Median Nerve – Motor & Sensory ∙ Motor: Flexor & pronator muscles Cranial nerves ∙ ∙ ∙ 12 pairs of nerves that mostly serve the head and neck Numbered in order, front to back Most are mixed nerves, but three are sensory only ∙ • I Olfactory nerve – sensory for smell ∙ • II Optic nerve – sensory for vision ∙ • III Oculomotor nerve – motor fibers to eye muscles ∙ • IV Trochlear – motor fiber to eye muscles ∙ • V Trigeminal nerve – sensory for the face; motor fibers to chewing muscles ∙ • VI Abducens nerve – motor fibers to eye muscles ∙ VII Facial nerve – sensory for taste; motor fibers to the face ∙ • VIII Vestibulocochlear nerve – sensory for balance and hearing ∙ • IX Glossopharyngeal nerve – sensory for taste; motor fibers to the pharynx ∙ • X Vagus nerves – sensory and motor fibers for pharynx, larynx, and viscera ∙ • XI Accessory nerve – motor fibers to neck and upper back ∙ • XII Hypoglossal nerve – motor fibers to tongue