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