Introduction to Nervous System Functions of the nervous system Sensory input: · Millions of sensory receptors to monitor changes occurring both inside and outside the body Integration: · Processing and interpreting sensory input and decide an appropriate response. Motor output: · Activation of effector organs - the muscle & glands - to cause a response. Sensory input 3 Integration Motor output Divisions of the nervous system CNS - Central Nervous System · Brain & spinal cord · Represent the integrating & control centre of the nervous system Peripheral Nervous System (PNS) · Bundles of nerve fibres that extend from the brain and spinal cord, include the cranial nerves and spinal nerves (respectively) . Communication lines between the CNS and the rest of the body
Introduction to Nervous System Levels of organisation in the nervous system Afferent (Sensory) Central nervous system (CNS) · Brain and spinal cord · Integrative and control centers Peripheral nervous system (PNS) . Sensory . Cranial nerves and spinal nerves Communication lines between the CNS and the rest of the body Sensory (afferent) division . Somatic and visceral sensory nerve fibers Conducts impulses from receptors to the CNS Motor (efferent) division . Motor nerve fibers - Conducts impulses from the CNS to effectors (muscles and glands) Somatic sensory fiber Somatic nervous system Autonomic nervous system (ANS) Skin . Somatic motor (voluntary) · Visceral motor (involuntary) Conducts impulses from the CNS to skeletal muscles Conducts impulses from the CNS to cardiac muscles, smooth muscles, and glands Visceral sensory fiber Stomach Skeletal muscle Motor fiber of somatic nervous system Sympathetic division = Mobilizes body systems during activity Parasympathetic division = Conserves energy · Promotes house- keeping functions during rest Sympathetic motor fiber of ANS Heart · Structure = Function -Sensory (afferent) division of PNS -Motor (efferent) division of PNS Parasympathetic motor fiber of ANS information carried toward the CNS from a receptor Efferent (Motor) · Motor information carried to the target organ Somatic (Body wall) · Somatic nervous system (voluntary nervous system): somatic fibres that control the activity of the skeletal muscles Visceral (internal organs) (related to homeostasis) Visceral nervous system (involuntary nervous system): visceral motor (autonomic) fibres that control the activity of the cardiac muscles, smooth muscles and glands. NP4 (Principle) Peripheral nervous system 1 Sensory (afferent) neurons conduct signals from receptors to the CNS. 3 Motor (efferent) neurons conduct signals from the CNS to effectors such as muscles and glands. Bladder Central nervous system 2 Interneurons (association neurons) are confined to the CNS. - These two terms (somatic and visceral) fit into this principle. - Somatic nerve fibres innervate body wall structures (e.g. skeletal muscle, bone, skin) whereas visceral/autonomic nerve fibres innervate visceral structures/organs (cardiac muscle, smooth muscle, glands).
Introduction to Nervous System Follow up task: Decide whether each of the following is innervated by the somatic or autonomic nervous system Structure Biceps branchii Heart muscle Liver Skin Blood vessels Femur Orbicularis oris System innervating structure Somatic Autonomic Autonomic Somatic Autonomic Somatic Somatic NEURAL PATHWAYS · Communication