The Nervous System Terms Flashcards
Ascending Tracts
Nerve tracts carrying sensory information up spinal cord to brain
Axon
Single projection of a neuron that conducts impulse away form nerve cell
body
Brain
One of the largest organs in body and coordinates most body activities; is center for all thought, memory, judgement, and emotion; each part of brain is responsible for controlling different body functions, such as temperature regulation and breathing; four sections to brain are cerebrum, cerebellum, diencephalon, and brain stem
Brain Stem
This area of brain has three components: medulla oblongata, pons, and midbrain; brain stem is pathway for impulses to be conducted between brain and spinal cord; also contains centers that control respiration, heart rate, and blood pressure; in addition, twelve pairs of cranial nerves begin in brain stem
Central Canal
Canal that extends down length of spinal cord; contains cerebrospinal fluid
Central Nervous System (CNS)
Portion of nervous system consisting of brain and spinal cord; receives impulses from all over body, processes information, and then responds with action; consists of both gray and white matter
Cerebellum
Second largest portion of brain, located beneath posterior portion of cerebrum; this part of brain aids in coordinating voluntary body movements and maintaining balance and equilibrium; is attached to brain stem by pons; cerebellum refines muscular movement that is initiated in cerebrum
Cerebral Cortex
Outer layer of cerebrum; is composed of folds of gray matter called gyri, which are separated by sulci
Cerebral Hemispheres
Division of cerebrum into right and left halves
Cerebrospinal Fluid (CSF)
Watery, clear fluid found in ventricles of brain; provides protection from shock or sudden motion to brain
Cerebrum
Largest section of brain; located in upper portion and is area that possesses thoughts, judgement, memory, association skills, and ability to discriminate between items; outer layer of cerebrum is cerebral cortex, which is composed of folds of gray matter; elevated portions of cerebrum, or convolutions, are called gyri and are separated by fissures or sulci; cerebrum has both a left and right division or hemisphere, each with its own four lobes: frontal, parietal, occipital, and temporal
Cranial Nerves
Nerves that arise from brain
Dendrite
Branched process off a neuron that receives impulses and carries them to cell body
Descending Tracts
Nerve tracts carrying motor signals down spinal cord to muscles
Diencephalon
Portion of brain that contains two of most critical areas of brain, thalamus and hypothalamus
Glands
Organs of body that release secretions; exocrine glands, like sweat glands, release their secretions into ducts; endocrine glands, such as thyroid gland, release their hormones directly into bloodstream
Gray Matter
Tissue within central nervous system; consists of unsheathed or uncovered nerve cell bodies and dendrites
Gyri
Convoluted, elevated portions of cerebral cortex; they are separated by fissures or sulci; singular is gyrus
Hypothalamus
Portion of diencephalon that lies just below thalamus; controls body temperature, appetite, sleep, sexual desire, and emotions such as fear; also regulates release of hormones from pituitary gland and regulates parasympathetic and sympathetic nervous systems
Medulla Oblongata
Portion of brain stem that connects spinal cord with brain; contains respiratory, cardiac, and blood pressure control centers
Meninges
Three connective tissue membrane layers that surround brain and spinal cord; three layers are dura mater, arachnoid layer, and pia mater; dura mater and arachnoid layer are separated by subdural space; arachnoid layer and pia mater are separated by
subarachnoid space
Midbrain
Portion of brain stem
Muscles
Bundles of parallel muscle tissue fibers; as fibers contract (shorten in length), they pull whatever they are attached to closer together; may move two bones closer together or make opening narrower; muscle contraction occurs when message is transmitted from brain through nervous system to muscles
Myelin
Tissue that wraps around many of nerve fibers; composed of fatty material and functions as insulator
Myelinated
Nerve fibers covered with layer of myelin
Nerve Cell Body
Portion of nerve cell that includes nucleus
Nerves
Structures in nervous system that conduct electrical impulses from brain and spinal cord to muscles and other organs
Neuroglial Cells
Cells that perform support functions for neurons
Neuron
Name for individual nerve cell; neurons group together to form nerves and other nervous tissue
Neurotransmitter
Chemical messenger that carries electrical impulse across gap between two neurons
Peripheral Nervous System (PNS)
Portion of nervous system that contains cranial nerves and spinal nerves; these nerves are mainly responsible for voluntary muscle movement, smell, taste, sight, and hearing
Pons
This portion of brain stem forms bridge between cerebellum and cerebrum; also where nerve fibers cross from one side of brain to control functions and movement on other side of brain
Sensory Receptors
Nerve fibers located directly under skin surface; these receptors detect temperature, pain, touch, and pressure; messages for these sensations are conveyed to brain and spinal cord from nerve endings in skin
Spinal Cavity
Dorsal body cavity within spinal column that contains spinal cord
Spinal Cord
Provides pathway for impulses traveling to and from brain; column of nerve fibers that extends from medulla oblongata of brain down to level of second lumbar vertebra
Spinal Nerves
Nerves that arise from spinal cord
Sulci
Also called ‘fissures’; grooves that separate gyri of cerebral cortex; singular is sulcus
Synapse
Point at which axon of one neuron meets dendrite of next neuron
Synaptic Cleft
Gap between two neurons
Thalamus
Portion of diencephalon; composed of gray matter and acts as center for relaying impulses from eyes, ears, and skin to cerebrum; pain perception is also controlled by thalamus
Tract
Bundle of fibers located within central nervous system
Ventricles
Fluid-filled spaces within cerebrum that contain cerebrospinal fluid
Vertebral Canal
Bony canal through vertebrae that contains spinal cord
Vertebral Column
Part of axial skeleton; a column of 26 vertebrae that forms backbone and protects spinal cord; divided into five sections: cervical, thoracic, and lumbar vertebrae, sacrum, and coccyx; also called ‘spinal column.’
White Matter
Tissue in central nervous system; consists of myelinated nerve fibers
