Chapter 11 Mini Quiz - PDF

11.1 The nervous system receives, integrates, and responds to information 1\. The nervous system has three basic functions: sensory input, integration, and motor output. 2\. The central nervous system (C N S) consists of the brain and spinal cord and is the integrating and control center of the ne...

11.1 The nervous system receives, integrates, and responds to information 1\. The nervous system has three basic functions: sensory input, integration, and motor output. 2\. The central nervous system (C N S) consists of the brain and spinal cord and is the integrating and control center of the nervous system. 3\. The peripheral nervous system (P N S) is outside the central nervous system. a\. The sensory, or afferent, division of the peripheral nervous system carries impulses toward the central nervous system from sensory receptors located throughout the body. i\. Somatic sensory fibers carry impulses from receptors in the skin, skeletal muscles, and joints. Carry sensory information from the body to the brain. ii\. Visceral sensory (organs) fibers carry impulses from organs within the ventral body cavity. Nerve fibers that send sensory information from internal organs to the central nervous system. b\. The motor (physical action), or efferent, division of the peripheral nervous system carries impulses from the central nervous system to effector organs, which are muscles and glands. Carrying impulses from the CNS to muscles and glands. i\. The somatic nervous system consists of somatic motor nerve fibers that conduct impulses from the C N S to skeletal muscles and allow conscious (voluntary) control of motor activities. ii\. The autonomic nervous system (A N S) is an involuntary nervous system consisting of visceral motor nerve fibers that regulate the activity of smooth muscle, cardiac muscle, and glands. Controls involuntary functions, such as heart rate, breathing, digestion, and blood pressure. iii\. The A N S has two functional subdivisions, the sympathetic division (releases hormones to increase heart rate and prepares the body for emergencies), and the parasympathetic division (releases acetylcholine to decrease heart rate and helps relax the body and digest food) iv\. The walls of the gastrointestinal tract contain neurons of the enteric nervous system. (A network that controls digestion and other functions) c\. Nervous tissue is made of two types of cells, supporting cells called neuroglia, or glial cells, and electrically excitable neurons. 11.2 Neuroglia support and maintain neurons 1\. Neuroglia, or glial cells, are closely associated with neurons, providing a protective and supportive network. A. Neuroglia of the C N S 1\. Astrocytes repair damage, regulate neuronal communication, maintain blood-brain barrier and capillaries (small blood vessels that transports oxygen, nutrients, and blood cells throughout the body) 2\. Microglial cells monitor health and perform defense functions for neurons and protect the brain. 3\. Ependymal cells line the central cavities of the brain and spinal cord and help circulate cerebrospinal fluid, which protects the brain from injury and removing waste products 4\. Oligodendrocytes wrap around neuron fibers, forming myelin sheaths (fatty layers that wrap around nerve cells in the brain and spinal cord, increasing the speed of electrical impulses) in the central nervous system (CNS) B. Neuroglia in the PNS 1\. Satellite cells are found surrounding neuron cell bodies within ganglia and are thought to perform functions similar to astrocytes of the C N S. (regulate neural environment and support/protect neurons) 2\. Schwann cells, or neurolemmocytes, surround nerve fibers, forming the myelin sheath. (peripheral nervous system) 11.3 Neurons are the structural units of the nervous system 1\. Neurons (nerve cells) are specialized cells that conduct messages in the form of electrical impulses throughout the body. 2\. Neurons have extreme longevity, are mostly amitotic, and have an exceptionally high metabolic rate (amount of energy and organism uses) requiring oxygen and glucose. A. Neuron Cell Body 1\. The neuron cell body, also called the soma (Cell body), is the major biosynthetic and metabolic center containing mitochondria, organelles of protein and membrane synthesis, cytoskeletal elements, and pigment inclusions. a\. Most neuron cell bodies are located in the C N S. b\. Clusters of cell bodies in the C N S are nuclei, while those that lie along P N S nerves are ganglia. B. Neuron Processes 1\. Neurons have arm-like processes that extend from the cell body. a\. Dendrites are cell processes that are the receptive regions of the cell and provide surface area for receiving signals from other neurons. Receive and process information from other neurons b\. Each neuron has a single axon, the conducting region of the cell, that arises from the initial segment of the axon at the axon hillock and generates and transmits nerve impulses away from the cell body to the axon terminals. (Synaptic buttons) i\. Bundles of axons in the C N S are called tracts, and are nerves in the P N S. ii\. Axon terminals, the secretory region of the cell, release neurotransmitters that either excite or inhibit other neurons or effector cells. c\. Axonal transport is responsible for moving substances along the length of the axon and may exhibit anterograde movement away from the cell body or retrograde movement toward the cell body d\. Axons may have a myelin sheath: a whitish, fatty, segmented covering that protects, insulates, and increases conduction velocity of axons. i\. Myelin sheaths in the P N S are formed by Schwann cells that wrap themselves around the axon, forming discrete areas separated by myelin sheath gaps, called nodes of Ranvier. ii\. Myelin sheaths in the C N S are formed by oligodendrocytes that have processes that wrap around many axons.