Chapter 39 The Nervous System

Question 1

Action Potential

Answer 1

occurs when the membrane potential of a specific cell location rapidly rises and falls: this depolarisation then causes adjacent locations to similarly depolarise.

Question 2

Amygdala

Answer 2

a roughly almond-shaped mass of gray matter inside each cerebral hemisphere, involved with the experiencing of emotions.

Question 3

Autonomic Nervous System

Answer 3

the part of the nervous system responsible for control of the bodily functions not consciously directed, such as breathing, the heartbeat, and digestive processes.

Question 4

Axon

Answer 4

the long threadlike part of a nerve cell along which impulses are conducted from the cell body to other cells.

Question 5

Basal Ganglion

Answer 5

The basal ganglia (or basal nuclei) are a group of subcortical nuclei. Situated at the base of the forebrain and top of the midbrain.

Question 6

Blood-Brain Barrier

Answer 6

a highly selective semipermeable border that separates the circulating blood from the brain and extracellular fluid in the central nervous system

Question 7

Brain

Answer 7

an organ of soft nervous tissue contained in the skull of vertebrates, functioning as the coordinating center of sensation and intellectual and nervous activity.

Question 8

Cell Body

Answer 8

(Soma) The spherical part of the neuron that contains the nucleus.

Question 9

Central Nervous System

Answer 9

the complex of nerve tissues that controls the activities of the body. In vertebrates it comprises the brain and spinal cord.

Question 10

Cerebellum

Answer 10

the part of the brain at the back of the skull in vertebrates. Its function is to coordinate and regulate muscular activity.

Question 11

Cerebral Cortex

Answer 11

the outer layer of the cerebrum, composed of folded gray matter and playing an important role in consciousness.

Question 12

Cerebral Hemisphere

Answer 12

each of the two parts of the cerebrum (left and right) in the brain of a vertebrate.

Question 13

Cerebrum

Answer 13

the principal and most anterior part of the brain in vertebrates, located in the front area of the skull and consisting of two hemispheres, left and right, separated by a fissure. It is responsible for the integration of complex sensory and neural functions and the initiation and coordination of voluntary activity in the body.

Question 14

Corpus Callosum

Answer 14

a broad band of nerve fibers joining the two hemispheres of the brain.

Question 15

Dendrite

Answer 15

a short branched extension of a nerve cell, along which impulses received from other cells at synapses are transmitted to the cell body.

Question 16

Dorsal Root Ganglion

Answer 16

a cluster of neurons (a ganglion) in a dorsal root of a spinal nerve.

Question 17

Effector

Answer 17

an organ or cell that acts in response to a stimulus.

Question 18

Excitatory Postsynaptic Potential

Answer 18

a postsynaptic potential that makes the postsynaptic neuron more likely to fire an action potential

Question 19

Forebrain

Answer 19

the anterior part of the brain, including the cerebral hemispheres, the thalamus, and the hypothalamus.

Question 20

Ganglion

Answer 20

a structure containing a number of nerve cell bodies, typically linked by synapses, and often forming a swelling on a nerve fiber.

Question 21

Glia

Answer 21

the connective tissue of the nervous system, consisting of several different types of cell associated with neurons.

Question 22

Gray Matter

Answer 22

the darker tissue of the brain and spinal cord, consisting mainly of nerve cell bodies and branching dendrites.

Question 23

Hindbrain

Answer 23

the lower part of the brainstem, comprising the cerebellum, pons, and medulla oblongata.

Question 24

Hippocampus

Answer 24

the elongated ridges on the floor of each lateral ventricle of the brain, thought to be the center of emotion, memory, and the autonomic nervous system.

Question 25

Hypothalamus

Answer 25

a region of the forebrain below the thalamus which coordinates both the autonomic nervous system and the activity of the pituitary, controlling body temperature, thirst, hunger, and other homeostatic systems, and involved in sleep and emotional activity.

Question 26

Inhibitory Postsynaptic Potential

Answer 26

a kind of synaptic potential that makes a postsynaptic neuron less likely to generate an action potential.

Question 27

Integration

Answer 27

the coordination of processes in the nervous system, including diverse sensory information and motor impulses.

Question 28

Interneuron

Answer 28

a neuron which transmits impulses between other neurons, especially as part of a reflex arc.

Question 29

Limbic System

Answer 29

a complex system of nerves and networks in the brain, involving several areas near the edge of the cortex concerned with instinct and mood. It controls the basic emotions (fear, pleasure, anger) and drives (hunger, sex, dominance, care of offspring).

Question 30

Long Term Memory

Answer 30

where informative knowledge is held indefinitely.

Question 31

Medulla

Answer 31

the inner region of an organ or tissue, especially when it is distinguishable from the outer region or cortex (as in a kidney, an adrenal gland, or hair).

Question 32

Midbrain

Answer 32

a small central part of the brainstem, developing from the middle of the primitive or embryonic brain.

Question 33

Motor Neuron

Answer 33

a nerve cell forming part of a pathway along which impulses pass from the brain or spinal cord to a muscle or gland.

Question 34

Myelin

Answer 34

a mixture of proteins and phospholipids forming a whitish insulating sheath around many nerve fibers, increasing the speed at which impulses are conducted.

Question 35

Nerve

Answer 35

a whitish fiber or bundle of fibers that transmits impulses of sensation to the brain or spinal cord, and impulses from these to the muscles and organs.

Question 36

Nerve Net

Answer 36

a diffuse network of neurons which conducts impulses in all directions from a point of stimulus.

Question 37

Neuron

Answer 37

a specialized cell transmitting nerve impulses; a nerve cell.

Question 38

Neurotransmitter

Answer 38

a chemical substance that is released at the end of a nerve fiber by the arrival of a nerve impulse and, by diffusing across the synapse or junction, causes the transfer of the impulse to another nerve fiber, a muscle fiber, or some other structure.

Question 39

Parasympathetic Division

Answer 39

conserves energy as it slows the heart rate, increases intestinal and gland activity, and relaxes sphincter muscles in the gastrointestinal tract. “Rest & Digest”

Question 40

Peripheral Nervous System

Answer 40

the nervous system outside the brain and spinal cord.

Question 41

Pons

Answer 41

the part of the brainstem that links the medulla oblongata and the thalamus.

Question 42

Postsynaptic Neuron

Answer 42

a neuron (nerve cell) that receives the neurotransmitter after it has crossed the synapse and may experience an action potential if the neurotransmitter is strong enough.

Question 43

Postsynaptic Potential

Answer 43

changes in the membrane potential of the postsynaptic terminal of a chemical synapse. Postsynaptic potentials are graded potentials, and should not be confused with action potentials although their function is to initiate or inhibit action potentials.

Question 44

Presynaptic Neuron

Answer 44

a neuron (nerve cell) that fires the neurotransmitter as a result of an action potential entering its axon terminal

Question 45

Reflex

Answer 45

an action that is performed as a response to a stimulus and without conscious thought.

Question 46

Resting Potential

Answer 46

The relatively static membrane potential of quiescent cells

Question 47

Reticular Formation

Answer 47

a set of interconnected nuclei that are located throughout the brainstem

Question 48

Sensory Neuron

Answer 48

nerve cells within the nervous system responsible for converting external stimuli from the organism’s environment into internal electrical impulses.

Question 49

Short-Term Memory

Answer 49

the capacity for holding, but not manipulating, a small amount of information in mind in an active, readily available state for a short period of time

Question 50

Sodium Potassium Pump

Answer 50

found in many cell (plasma) membranes. Powered by ATP, the pump moves sodium and potassium ions in opposite directions, each against its concentration gradient. In a single cycle of the pump, three sodium ions are extruded from and two potassium ions are imported into the cell.

Question 51

Somatic Nervous System

Answer 51

part of the peripheral nervous system associated with the voluntary control of body movements via skeletal muscles