Chapter 7 Nervous System
presbyopia
farsightedness caused by loss of elasticity of the lens of the eye, occurring typically in middle and old age.
Synaesthesia
A perceptual experience in which stimulation of one sense produces additional unusual experiences in another sense
occipital lobe
A region of the cerebral cortex that processes visual information
umami
A savory taste due to the presence of glutamic acid, an amino acid that occurs naturally in meats and other protein rich foods.
vitreous humor
jellylike substance found behind the lens in the posterior cavity of the eye that maintains its shape
sensory homunculus
map showing the amount of sensory cortex devoted to each body region
7. Neuron Cell Body
nucleus & metabolic center of the cell Nissl Bodies: Neurofibrils: Nucleus:
Myopia (nearsightedness)
occurs when the image is focused in front of the retina
semicircular canals
passages in the inner ear associated with maintaining equilibrium
6. Schwann Cells
produce myelin sheaths in jelly roll-like fashion around axons (PNS)
Autonomic Nervous System (ANS)
Efferent division of the peripheral nervous system that innervates cardiac and smooth muscles and glands; also called the involuntary or visceral motor system.
medulla oblongata
Part of the brainstem that controls vital life-sustaining functions such as heartbeat, breathing, blood pressure, and digestion.
Peripheral Nervous System (PNS)
Portion of the nervous system consisting of nerves and ganglia that lie outside of the brain and spinal cord.
Hypothalamus
Region of the Diencephalon forming the floor of the third ventricle of the brain
tympanic membrane
a membrane forming part of the organ of hearing, which vibrates in response to sound waves. In humans and other higher vertebrates it forms the eardrum, between the outer and middle ear.
Hippocampus
a neural center located in the limbic system; helps process explicit memories for storage
Dopamine
a neurotransmitter that regulates motor behavior, motivation, pleasure, and emotional arousal
Iris
a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening
5. Satellite Cells
act as protective cushioning cells for neuron cell bodies in the PNS
motor cortex
an area at the rear of the frontal lobes that controls voluntary movements
18. Nerves
bundles of nerve fibers in the PNS
21. Sensory (Afferent) Neurons
carries nerve impulses FROM sensory receptors TO the CNS.
Myelin
A white, fatty lipid substance
1. Astrocytes
Abundant, star-shaped cells Braces/supports neurons Form barrier between capillaries and neurons
Sensory Neuron
An initiator of nerve impulses following receptor stimulation
Reflex
Automatic reaction to stimuli
Central Nervous System
Brain and spinal cord.
Cerebellum
Brain region most involved in producing smooth, coordinated skeletal muscle activity
Dendrite
Branching neuron process that serves as a receptive, or input, region; transmits the nerve impulse toward the cell body.
Efferent
Carrying away or away from, especially a nerve fiber that carries impulses away from the central nervous system
Afferrent
Carrying to or toward a center
Neuron
Cell of the nervous system specialized to generate and transmit nerve impulses
Ganglion
Collection of nerve cell bodies outside of the CNS.
Brain Stem
Collectively the midbrain, pons, and medulla of the brain.
Somatic Nervous System
Division of the peripheral nervous system that provides the motor innervation of skeletal muscles; also called the voluntary nervous system
Nervous System
Fast-acting control system that triggers muscle contraction or gland secretion
Myelin sheath
Fatty insulating sheath that surrounds all but the smallest nerve fibers.
Synapse
Functional junction or point of close contact between two neurons or between a neuron and an effector cell
Depolarization
Loss of a state of polarity; loss or reduction of negative membrane potential
Depolarization neuron
Loss of a state of polarity; loss or reduction of negative membrane potential.
Repolarization
Movement of the membrane potential to the initial resting (polarized) state.
Pituitary Gland
Neuroendocrine gland located beneath the brain that serves a variety of functions including regulation of gonads, thyroid, adrenal cortex, lactation, and water balance.
Cerebrospinal Fluid (CSF)
Plasmalike fluid that fills the cavities of the CNS and surrounds the CNS externally; protects the brain and spinal cord.
Autonomic
Self-directed; self-regulating; independent
extrinsic eye muscles
Six muscles attach to the outer surface of the eye and produce eye movements
Diencephalon (interbrain)
That part of the forebrain between the cerebral hemispheres and the midbrain
Cranial Nerves
The 12 nerve pairs that arise from the brain.
Spinal Nerves
The 31 nerve pairs that arise from the spinal cord
Cornea
The clear tissue that covers the front of the eye
Gustation
The sense of taste, also called the gustatory sense.
White Matter
White substance of the central nervous system; myelinated nerve fibers.
white matter
Whitish nervous tissue of the CNS consisting of neurons and their myelin sheaths.
4. Oligodendrocytes
Wrap around nerve fibers in the CNS Produce myelin sheaths
cochlea
a coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses
Reticular Activating System (RAS)
a dense network of neurons found in the core of the brain stem; it arouses the cortex and screens incoming information
Alzheimer's disease
a progressive and irreversible brain disorder characterized by gradual deterioration of memory, reasoning, language, and, finally, physical functioning
cognition
all the mental activities associated with thinking, knowing, remembering, and communicating
sensory cortex
area at the front of the parietal lobes that registers and processes body touch and movement sensations
frontal lobe
associated with reasoning, planning, parts of speech, movement, emotions, and problem solving
11. Axon Terminals
branch-like are at the end axon and connect to the sarcolemma of muscle; contain vesicles with neurotransmitters; separated from the next neuron by a gap: Synapse and Synaptic Cleft
Photoreceptors
rods and cones in the retina
Neuroscience
the scientific study of the nervous system, especially the brain
vestibular sense
the sense of body movement and position, including the sense of balance (semicircular canals, cerebellum)
Olfaction
the sense of smell, which is the response to chemicals that contact the membranes inside the nose
ossicles (malleus, incus, stapes)
three small bones that amplify sound waves
Receptor
1) A cell or nerve ending of a sensory neuron specialized to respond to particular types of stimuli. 2) Molecule that binds specifically with other molecules, e.g., neurotransmitters, hormones, antigens.
Pons
1) Any bridgelike structure of part; 2) the part of the brain stem connecting the medulla with the midbrain, providing linkage between upper and lower levels of the central nervous system.
neuroglial cells
1. Astrocytes: Abundant, star-shaped cells; Brace neurons; Form barrier between capillaries and neurons; Control the chemical environment of the brain. 2. Microglia: Spider-like phagocytes; Dispose of debris. 3. Ependymal cells: Line cavities of the brain and spinal cord; Cilia assist with circulation of cerebrospinal fluid. 4. Oligodendrocytes: Wrap around nerve fibers in the central nervous system; Produce myelin sheaths. 5. Satellite cells: Protect neuron cell bodies. 6. Schwann cells: Form myelin sheath in the peripheral nervous system.
0. What are the three functions of the nervous system?
1. Sensory input —gathering information a. To monitor changes (stimuli) occurring inside and outside the body 2. Integration a. To process and interpret sensory input and decide if action is needed 3. Motor output a. A response to integrated stimuli b. The response activates muscles or glands
Pons
A brain structure that relays information from the cerebellum to the rest of the brain
hyperopia
A condition in which visual images come to a focus behind the retina of the eye and vision is better for distant than for near objects -- called also farsightedness.
Parasympathetic division
A division of the autonomic nervous system; also referred to as the carniosacral division.
Parasympathetic Division
A division of the autonomic nervous system; also referred to as the craniosacral division
Sympathetic Division
A division of the autonomic nervous system; opposes parasympathetic functions; called the fight-or-flight division.
Cerebellum
A large structure of the hindbrain that controls balance, coordination, and motor skills.
Thalamus
A mass of gray matter in the diencephalon of the brain.
Hypothalamus
A neural structure lying below the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.
Norepinephrine
A neurotransmitter involved in arousal, as well as in learning and mood regulation
Serotonin
A neurotransmitter that affects hunger,sleep, arousal, and mood.
temporal lobe
A region of the cerebral cortex responsible for hearing and language.
parietal lobe
A region of the cerebral cortex whose functions include processing information about touch.
Nerve Impulse
A self-propagating wave of depolarization; also called an action potential.
Axon
Neuron process that carries impulses away from the nerve cell body; efferent process; the conducting portion of a nerve cell.
2. Microglia
Spider-like phagocytes monitor neuron health Dispose of debris
cerebral cortex
The intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body's ultimate control and information-processing center.
lacrimal ducts
channels that carry tears to the eye
16. Nuclei
clusters of cell bodies within the white matter of the CNS
15. Ganglia
collections of cell bodies OUTSIDE the CNS
19. White Matter
collections of myelinated fibers (tracts)
24. Motor (Efferent) Neurons
conduct impulses away FROM the cns TO viscera, muscles, or glands
25. Interneurons (association neurons)
connect sensory and motor neurons in the CNS and
20. Gray Matter
contain unmyelinated fibers and cell bodies
8. Processes
fibers that extend from the cell body and are outside the neuron cell body Dendrites—conduct impulses toward the cell body; Neurons may have hundreds of dendrites Axons—conduct impulses away from the cell body; Neurons have only one axon arising from the cell body at the axon hillock
aqueous humor
fluid in the eye, found between the cornea and the lens
12. Synaptic Cleft
gap between adjacent neurons filled with interstitial fluid
14. Nodes of Ranvier
gaps in myelin sheath along the axon
cone cells
operate best in bright light; enable high-acuity, color vision
cerebrospinal fluid (CSF)
plasma-like clear fluid circulating in and around the brain and spinal cord (protects brain & spine)
ciliary body
ring of tissue behind the peripheral iris that is composed of ciliary muscle and ciliary processes
pupil
the adjustable opening in the center of the eye through which light enters
Thalamus
the brain's sensory switchboard, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla
Retina
the light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information
optice nerve
the nerve that carries neural impulses from the eye to the brain
Brainstem
the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; the brainstem is responsible for automatic survival functions
Pinna
the visible (outer) part of the ear
Meninges
three protective membranes that surround the brain and spinal cord
Amygdala
two lima bean-sized neural clusters in the limbic system; linked to emotion.
grey matter
unmyelinated neuron cell bodies and short, unmyelinated axons
Sclera
white of the eye
13. Myelin Sheath
whitish, fatty material covering axons protects and insulates the fibers and increases the transmission rate of nerve impulses
rod cells
work best in dim light and enable you to see black, white, and shades of gray
