Concept 49.1 Nervous Systems Consist of Circuits of Neurons and Supporting Cells

Chapter 49  Nervous Systems Student Guided Notes Concept 49.1 Nervous systems consist of circuits of neurons and supporting cells In most animals with nervous systems, clusters of neurons perform specialized functions.  Such clustering is absent in the cnidarians, the simplest animals with nervous systems. o In cnidarians, nerve cells form a ______. In more complex animals, the axons of multiple nerve cells may be bundled to form ______.  Animals with bilaterally symmetrical bodies have more specialized nervous systems. o Such animals exhibit cephalization, ______.  In vertebrates, the ______and the ______form the central nervous system CNS; the ______and ______make up the peripheral nervous system (PNS). A variety of glia are present throughout the vertebrate brain and spinal cord. The major types of glia (connective tissue of nervous system) nourish, support and regulate neurons. o ______and ______cells function in axon myelination, a critical activity in the vertebrate nervous system. o Astrocytes induce cells that line the capillaries in the CNS to form tight junctions. o The result is the ______, which controls the extracellular environment of the CNS by restricting the entry of substances from the blood.The brain and spinal cord of the vertebrate CNS are tightly coordinated.  The brain integrates the complex behavior of vertebrates.  The spinal cord conveys information to and from the brain and generates basic patterns of locomotion.  The spinal cord acts independently as part of the simple nerve circuits that produce reflexes, ______(ex. pulling hand away from hot stove.)49-1  Cerebrospinal fluid is formed in the brain ______. o In mammals, it fills the spaces in the brain and the spinal cord. The function is to act as a shock absorber.  The brain and the spinal cord contain gray and white matter. o Gray matter consists of ______, dendrites, and unmyelinated axons. o White matter contains ______with myelin sheaths. The PNS transmits information to and from the CNS and regulates a vertebrate’s movement and internal environment.See Figure 49.8 p. 1083 Sensory (______) Division  incoming neurons Motor (______) Division  outgoing neurons o The motor system is also divided: o Somatic Nervous System  controls signals to skeletal muscles (voluntary and involuntary.) o ______nervous system  is involuntary. (memory tip: “autonomic is automatic”) The three divisions of the autonomic nervous system—______, ______, and ______—control the organs of the digestive, cardiovascular, excretory, and endocrine systems. See Figure 49.9 p. 1084 The sympathetic and parasympathetic divisions function antagonistically. The sympathetic division is responsible for ______and ______. (FIGHT OR FLIGHT) o The heart beats ______, the liver converts ______to ______, ______is inhibited, and secretion of ______from the adrenal medulla is stimulated. Uses norepinephrine as a neurotransmitter.  The parasympathetic division causes opposite responses that promote ______and a return to ______. (REST AND DIGEST) 49-2 o Lowers ______, increases ______production, and enhances ______. Uses acetylcholine as a neurotransmitter. Concept 49.2 The vertebrate brain is regionally specializedSee Figure 49.11 p. 1086-87 o The vertebrate brain has three major regions: the ______, ______, and ______. o The forebrain activities include ______, ______, ______, and ______. • Cerebrum, Diencephalons, Thalmus, Hypothalamus, Epithalmus o The midbrain coordinates ______ o The hindbrain controls ______, such as ______, and coordinates ______, such as locomotion. • Pons, Medulla oblongata, Cerebellum SUMMARY OF PARTS OF THE BRAIN AND FUNCTIONS Brainstem (aka “lower brain”) Major functions of the brainstem: homeostasis, coordination of movement, conduction of information to higher brain centers 1) Medulla oblongata (also called simply the medulla)  Controls ______(ex. respiration, swallowing digestion, heart rate, circulation) 2) Pons  Also helps control automatic functions (ex. regulate breathing centers in the medulla) 3) Midbrain  Acts as a projection center; send coded sensory information to parts of the forebrain Cerebellum  Functions in coordination, muscle action Involved in ______and remembering ______Balance and ______coordination Thalmus/Hypothalmus/Epithalmus 49-3 Epithalmus  Produces ______fluid Thalmus  Main ______center for information going to the ______Main ______center for information leaving the cerebrum Hypothalmus  Important in homeostatic regulation Control center including ______functions (sleep/wake), circadian rhythm Source of hormones (refer to CH 45) AND regulates the pituitary ______of the body Regulates ______Sexual and mating behavior Initiates ______response Cerebrum  Most highly developed structure in the mammalian brain Right and left hemispheres are connected by the ______Right side  math, logical operations, serial sequences of information Left side  pattern and face recognition, spatial relations, nonverbal thinking Each hemisphere consists of: Gray matter (cerebral cortex) - covering White matter – internal part Basal nuclei - found deep in the white matter; important in ______Cerebral cortex  (“gray matter”) largest and most complex part Includes extra layers called the neocortex in mammals Each side of the cerebrum has four lobes: Frontal  motor cortex, speech, emotions Parietal  somatosensory cortex, taste, speech, reading, touch, pain, pressure, temp Temporal  smell, hearing Occipital  visionThe brainstem and cerebrum control arousal and sleep. Arousal and sleep are controlled in part by the ______, a system of neurons that passes through the brainstem. 49-4 Circadian rhythms rely on a biological clock.  Circadian rhythms are daily cycles of ______. Circadian rhythms rely on a biological clock (typically 24 hours), ______. (This is also partially due to external signals) Responsible for hormone release and sex drive. Emotions depend on many brain structures. The generation and experience of emotions depend on many brain structures, including the ______, ______, and parts of the ______. o These structures border the brainstem in mammals and are grouped as the ______. o The limbic system forms a ring around the brainstem and is composed of the hippocampus and the olfactory cortex. o The limbic system also functions in motivation, olfaction, behavior, and memory. Emotions are due to the frontal lobe and the limbic system. Emotional memory related to fear is stored separately from the memory system that supports explicit recall of events. o The brain structure with the most important role in storage of emotional memory is the ______, an almond-shaped mass of nuclei located ______.Concept 49.3 The cerebral cortex controls voluntary movement and cognitive functions The cerebrum is essential for awareness of our surroundings, language, ______, ______, and consciousness.  Cognitive functions reside in the cortex, ______.  Each side of the cerebral cortex has a ______, ______, ______, and ______lobe, each named ______.Information is processed in the cerebral cortex.49-5  Some of the sensory input to the cerebral cortex comes from groups of receptors clustered in dedicated sensory organs, such as the ______and ______. o Somatosensory cortex receptors provide information about ______, ______, ______, ______, and the position of muscles and limbs. o Motor cortex commands particular behavior (ex. moving a limb.) Most sensory information coming into the cortex is directed via the ______to ______. o The thalamus directs different types of input to distinct locations: Visual information is sent to the occipital lobe, whereas auditory input is directed to the temporal lobe. Frontal lobes influence what are often called “executive functions.” (ex. planning, decision making)Language and speech are localized in the cerebrum. Damage to particular regions of the cortex by ______, ______, or ______produce distinctive changes in behavior.  Discoveries by Pierre Broca and Karl Wernicke determined the following regarding language and speech: o A small region of the ______, Broca’s area, controls muscles in the face. o A posterior portion of the left ______lobe, Wernicke’s area controls the ability to ______but not ______.Cortical function is lateralized.  The left hemisphere is more adept at ______and ______, while the right hemisphere is dominant in the recognition of ______, spatial relations, and ______.  The two hemispheres trade information through the fibers of the ______. Concept 49.4 Changes in synaptic connections underlie memory and learningThe nervous system is plastic. 49-6  The nervous system has a great capacity to be remodeled ______, o This is called neural plasticity. Autism, a developmental disorder that first appears early in childhood, involves ______. o Children affected with autism display ______and ______, as well ______.Memory and learning rely on neural plasticity. The formation of memories is due to neural plasticity.  We constantly check what is happening against what just happened a few moments ago, holding information in short-term memory and releasing it if ______. o To retain knowledge of a name or phone number requires activation of mechanisms of ______. o If we need to recall the name or number, ______. When memories are made long-term, the links in the ______are replaced by more permanent connections within the ______. o Some of this consolidation of memory is thought to occur during ______. o Repetition is also a factor – “practice makes perfect”, more accurately stated as “practice makes permanent” (so practice it correctly!!) The hippocampus is essential for ______but not ______. o Individuals who suffer damage to the hippocampus cannot ______but can ______.  Transfer of information from short-term to long-term memory is enhanced by ______. 49-7  Motor skills (“skill memory” such as riding a bike, playing the piano) are usually ______. Once learned bad habits are hard to break (ex. playing a piece with the wrong fingering technique)*** Both the nervous system and the endocrine system use chemical signaling and chemical messengers (from axons) and the response depends on the receptors mode of action ***THE FOLLOWING IS JUST FOR REFERENCE IN YOUR NOTES BUT WILL NOT BE ON THE TEST AND IS NOT INCLUDED IN THE POWERPOINT: Concept 49.5 Many nervous system disorders can be explained in molecular terms  Major research efforts are under way to identify genes that cause or contribute to disorders of the nervous system.  Family studies may help scientists distinguish between genetic and environmental variables. Schizophrenia is a severe mental disturbance characterized by psychotic episodes.  About 1% of the world’s population suffers from schizophrenia, a severe mental disturbance characterized by psychotic episodes in which patients have a distorted perception of reality.  People with schizophrenia typically experience hallucinations and delusions. Depression is a disorder characterized by depressed mood plus abnormalities in sleep, appetite, and energy level.  Individuals affected by major depressive disorder have periods in which once enjoyable activities provide no pleasure and provoke no interest. o Major depression affects about one in every seven adults at some point, and twice as many women as men.  Bipolar disorder involves swings of mood from high to low and affects about 1% of the world’s population. Drug addiction is linked to the brain’s reward system.  Drug addiction is a disorder characterized by compulsive consumption of a drug and loss of control in limiting intake.  Addictive drugs include stimulants, such as cocaine and amphetamine, and sedatives, such as heroin.  All of these drugs, as well as alcohol and nicotine, are addictive for the same reason: Each increases activity of the brain’s reward system, neural circuitry that normally functions in pleasure, motivation, and learning. Alzheimer’s disease is dementia characterized by confusion and memory loss.  The incidence of Alzheimer’s disease is age related, rising from about 10% at age 65 to about 35% at age 85.  The disease is progressive, with patients gradually becoming less able to function and eventually needing to be dressed, bathed, and fed by others. o Patients also lose their ability to recognize people, including their immediate family, and may treat them with suspicion and hostility.  Postmortem examination of the remaining brain tissue reveals two characteristic features—amyloid plaques and neurofibrillary tangles. Parkinson’s disease is a motor disorder including muscle tremors, poor balance, a flexed posture, and a shuffling gait.  Like Alzheimer’s disease, Parkinson’s disease is a progressive brain illness and is more common with advancing age. o The incidence of Parkinson’s disease is about 1% at age 65 and about 5% at age 85. 49-8

Concept 49.1 Nervous Systems Consist of Circuits of Neurons and Supporting Cells

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