6. Nervous System.pdf

Tishk International University Faculty of Nursing Physiology of Nervous System Lecture - 6 1st Grade – Spring Semester 2021-2022 1 Objectives: 1. Study general organization of nervous system. 2. Explain the functions and parts of n...

Tishk International University Faculty of Nursing Physiology of Nervous System Lecture - 6 1st Grade – Spring Semester 2021-2022 1 Objectives: 1. Study general organization of nervous system. 2. Explain the functions and parts of nervous system. 2 All body activities, voluntary and involuntary, are controlled by the nervous system. 3 Neurons (nerve cells) are the basic elements Structure of the and Function nervous system. Dendrites Cell body Axon Myelin Sheath Neurilemma Terminal end fibers 4  Cell Body Cell Body The main processing center of the cell Dendrites Thin branching extensions of the cell body that conduct nerve impulses toward the cell body. Axon A single branch (in most neurons) which conducts nerve impulses away from the cell body. Myelin sheath and neurilemma are coverings. 5  Impulse Transmission Impulse Transmission Terminal end fibers are located at the ends of the axon and they transmit impulses leaving the neuron across a synapse to the next neuron. synapse Neuron  Neuron B A neurotransmitter excitability All neurons have two basic properties conductivity 6  Three Types Three Types of Neurons of Neurons Efferent (motor) Conveys information from the CNS to muscles and glands Afferent (sensory) Carry information from Other Cells (Neuroglia) sensory receptors to the CNS Support, protect, Interneurons connect and remove Carry and process sensory debris from the information nervous system 7  Central Nervous System Central Nervous System Consists of the brain and spinal cord The control center of the body responsible for controlling, receiving, and interpreting all stimuli Sends nerve impulses to instruct muscles and glands to take or respond to certain actions Both voluntary and involuntary movements are controlled 8  Brain Brain Convolutions (gyri) Meninges Fissures Weighs about 3 Skull pounds in adults 75% water Corpus Cerebrum callosum Diencephalon Contains over 100 billion Midbrain neurons Brainstem Pons Controls bodily Cerebellum functions and Medulla Oblongata interactions with the outside Spinal cord world Divisions of the Brain Brainstem Cerebellum Diencephalon Cerebrum 9  Brainstem Brainstem Made up of the midbrain; pons and the medulla oblongata Midbrain Involved with visual reflexes Pons Located between the midbrain and the medulla oblongata Controls certain respiratory functions Medulla Oblongata Contains centers that regulate heart and lung functioning, swallowing, coughing, vomiting and sneezing 10  Cerebellum Cerebellum Area that coordinates musculoskeletal movement to maintain posture, balance, and muscle tone balance 11  Cerebrum Located above the Cerebrum Frontal cerebellum Parietal Contains two hemispheres with an outer portion called the cerebral cortex The two hemispheres are connected by a bridge of nerve fibers that relay information between the two hemispheres called the corpus callosum The left and right lobes are Temporal each divided into four parietal lobe lobes or parts: frontal lobe Occipital temporal lobe 12 occipital lobe Diencephalon The deep portion of the brain Diencephalon containing: -thalamus -hypothalamus -epithalamus -ventral thalamus Functions Serves as relay center for sensations Integrates with the ANS in the control of: Heart rate Blood pressure Temperature control Behavioral responses Digestive functions Water and electrolyte balance Glandular activities13  Meninges Meninges are three layers of membranes that cover the brain and spinal cord. Layers of the meninges Skull dura mater Pia mater Outer tough fibrous Subarachnoid membrane space arachnoid mater Arachnoid space Middle weblike membrane Dura containing CSF mater pia mater Innermost layer containing several blood vessels 14  Peripheral Nervous System Peripheral Nervous System Consists of 12 pairs of cranial nerves and 31 pairs of spinal nerves Cranial Nerves Function I olfactory Sense of smell II optic Sense of vision III oculomotor Eye movements IV trochlear Aids muscles that move the eyes V trigeminal Eyes, tear glands,scalp, forehead,teeth, gums, lips, and mouth muscles 15 Cranial Nerve Function VI abducens Muscle conditioning VII facial Taste, facial expressions, tear and salivary glands VIII vestibulocochlear Hearing and equilibrium IX glossopharyngeal Pharynx, tonsils tongue and carotid arteries; stimulates salivary glands X vagus Speech, swallowing, heart muscle, smooth muscle and certain glands XI accessory Muscles of the soft palate, pharynx, larynx and neck XII hypoglossal Tongue movement 16  Somatic Nervous System Somatic Responsible Nervousand for receiving System processing sensory input from the skin, muscles, tendons, joints, eyes, tongue, nose and ears as well as excite the voluntary contraction of skeletal muscles. 17  Autonomic Nervous System Carries impulses from the central nervous system to glands, various smooth muscles, cardiac muscle and various membranes. Stimulates organs, glands, and senses. 18 Sympathetic Division of ANS Sympathetic Division of ANS Operates when the body is under stress to activate responses HELP!!! necessary to react to dangerous situations. 19 Parasympathetic Division of ANS Operates to keep the body in homeostasis or balance under normal conditions. 20 Thank You 21