Three main control systems SENSORY SYSTEM How body receives/sends sensory signals NERVOUS SYSTEM Fine, rapid movements Muscle control Neurons Synapses ENDOCRINE SYSTEM Slow movements, wide temporal range Metabolic processes Hormones Most Bssues under control of both nervous and endocrine systems Chapter 14: Nervous system General organizabonal scheme Central Nervous Peripheral Nervous Vertebrate Nervous Body Control Groups of cells specialized for repeated producbon of electrical signals between cells Nervous Conducts impulses Integrates signals from mulbple neurons Generates new impulses based on sensory sbmuli Signal (sbmulus) Signal Movement Sensory receptor cells Other neurons Organs (carry out funcbons) 1. Signal arrives at neuron 2. Transduced to adjacent neurons OR to sensory receptor cells 3. Signal sent to organs to carry out funcbon Structural division of nervous system 1. Central Nervous : large structures Brain, spinal cord 2. Peripheral Nervous : all other neurons outside of CNS Central Nervous Lots of neurons and support cells interact to perform funcbons 1. Sensory neurons: Relay messages FROM receptor cells TO the CNS (brain or spinal cord) 1
Central Nervous Lots of neurons and support cells interact to perform funcbons 2. Motor neurons: Relay messages from the CNS to effectors (muscles and organs) Central Nervous Lots of neurons and support cells interact to perform funcbons 3. Interneurons: Relay informabon WITHIN the CNS InformaBon travels in neural circuits 1. SBmulus excites sensory neurons Sends info TO CNS 2. Info moves within CNS (processed) 3. Info leaves via motor neurons Axons innervate effectors 4. Effector cells receive info Carry out funcbon Peripheral Nervous All sensory or motor neurons outside of CNS Composed of nerves Axons of neurons bundled together Peripheral Nervous Different neurons make up different pathways 1. Sensory pathway à sensory neurons 2. Motor pathway à motor neurons a. SomaBc Nervous (voluntary) b. Autonomic Nervous (involuntary) Peripheral Nervous 1. SomaBc Nervous Observable behaviors and movements Skeletal muscles 2. Autonomic Nervous Controls involuntary behaviors Cardiac muscles, glands 2
Chapter 14: Nervous system General organizabonal scheme Central Nervous Peripheral Nervous Vertebrate Nervous Body Control Vertebrate Central Nervous : CNS: Brain and spinal cord Centralized and cephalized CentralizaBon and cephalizabon CentralizaBon: neurons collected into a central region of the body CephalizaBon: concentrabon of neurons at one end of the body (BRAIN) More interneurons (BeZer control) More complex spabal arrangement (CephalizaBon) Larger brains (control over more funcbons) Vertebrate Central Nervous : 2 types of Bssues: 1. Grey mazer: neuronal cell bodies, processes, and synapses 2. White mazer: myelinated axons The Brain The Brain Brain is the processing center for sensory input Input arrives at different regions Processing occurs in different regions Three regions, 5 subdivisions FuncBon varies by region Many funcbons use several regions 3
Inside the brain 1. Brain funcbon is localized 2. Brains have maps 3. Size mazers 4. EvoluBon favors expansion of forebrains 5. Neural circuits are plasbc 1. Brain funcbon is localized Neurons in different regions perform different funcbons Phrenology: study of brain bumps Traits and behaviors FuncBonal magnebc resonance imaging (fmri) and Positron emission tomography (PET) scans Confirm localizabon of funcbons 1. Brain funcbon is localized Neurons in different regions perform different funcbons 2. Brains have maps Somatotopic map: parts of body are mapped onto the corresponding parts of the brain à sbmulus in specific secbon of brain elicits response in that part of the body Roughly correspond to locabon on body Bigger is bezer! 3. Size mazers 4. EvoluBon favors expansion of forebrains Bigger forebrain is EVEN bezer! More interneurons (BeZer control) More interneurons (BeZer control) Larger forebrain (cerebral cortex) More complex spabal arrangement (CephalizaBon) Larger brains (control over more funcbons) More complex spabal arrangement (CephalizaBon) Larger brains (control over more funcbons) Many vertebrate lineages evolved larger forebrains 4
5. Neural circuits are plasbc Change in strength and effecbveness over Bme Storage of long- term memory: long- term memories generally aren t lost in concussed pabents New neurons may develop within lifebme Recent findings have sbmulated research in the stem cell field! Peripheral Nervous PNS: collecbon of nerves that relay informabon to/from CNS Axons of neurons bundled together Vertebrate Peripheral Nervous : Afferent neurons (sensory neurons) carry nerve impulses to CNS Efferent neurons (motor neurons): carry impulses away from CNS to effectors Vertebrate Peripheral Nervous : Nerves are not integrated within the PNS All informabon funneled through CNS for processing Cranial nerves connect PNS to brain Spinal nerves connect PNS to spinal cord Vertebrate Peripheral Nervous : Peripheral Nervous : 1. SomaBc Nervous 2. Autonomic Nervous Vertebrate Peripheral Nervous : 1. SomaBc Nervous Observable behaviors: LocomoBon, muscles, speech, breathing Motor signals DO NOT synapse (communicate) with other neurons Motor neurons extend from CNS directly to effector (organ, muscle) 5
2/7/14 Vertebrate Peripheral Nervous : Vertebrate Peripheral Nervous : 2. Autonomic Nervous 2. Autonomic Nervous Smooth muscles, glands, acid- secrebng cells in stomach Motor neurons synapse with other neurons at peripheral ganglia CNS 1. ParasympatheBc 2. SympatheBc Preganglionic neurons Postganglionic Ganglia Effector neurons - Neurons release Ach - Neurons from CNS (sbmulates AP) - Neurons to effectors Vertebrate Peripheral Nervous : SympatheIc : fight or flight Movements, stressful acbvibes Ganglia connect spinal cord to effectors Ganglia located near spinal cord Short preganglionic neurons (from CNS), long postganglionic neurons (to effectors) Most neurons release epinephrine (stress hormone) Vertebrate Peripheral Nervous : ParasympatheIc : business as usual Internal metabolic processes Ganglia connect brain stem to effectors Ganglia located near effector Long preganglionic neurons (from CNS), short postganglionic neurons (to effectors) All release acetylcholine(neurotransmi Zer) Vertebrate Peripheral Nervous : May funcbon together Regulate different specific funcbons within system Oppose the effects of the other (keeping system balanced) 6