Study unit 2.1 Nervous System

Question 1

Neurons

Answer 1

Individual cells that receive, integrate and transmit information. They are the basic links.

Question 2

Dendrite

Answer 2

Feeler-like branch that receives the information.

Question 3

Soma (cell body)

Answer 3

Cell nucleus or the chemical machinery where information flows through.

Question 4

Axon

Answer 4

Long, thin fibre that transmits signals to other neurons, muscles or glands.

Question 5

Myelin

Answer 5

Insulating material that encases the axon and speeds up signal transmission and stabilizes axon structures and patterns of connection.

Question 6

Terminal buttons

Answer 6

Small knobs that secrete neurotransmitters.

Question 7

Synapses

Answer 7

Points where neurons interconnect and information is transmitted from one neuron to another.

Question 8

Action potential

Answer 8

Brief shift in electrical charge, traveling along axon.

Inside and outside the neuron there are fluids in which there is electrically charged atoms and ions. The + sodium and potassium and the - chloride flow back and forth across the cell membrane. When stimulated the cell membrane opens and lets + sodium come in resulting in it being less negative and it gradually becomes positive within the cell membrane.

Question 9

Resting potential

Answer 9

Stable negative charge when cell is inactive

Question 10

Glia

Answer 10

Cells found throughout the nervous system that provides various types of support for neurons. They supply nourishment to neurons, help remove waste from neurons and provide insulation around many axons. Heroes of NS. Some types can detect neural impulses and send signals to other glia cells.

Question 11

Absolute refractory

Answer 11

Minimum length of time after an action potential before another action potential can begin. “Downtime”

Question 12

Synoptic cleft

Answer 12

The microscopic gap between the terminal button, neuron and cell membrane of another cell membrane. It is where the signals cross.

Question 13

Postsynaptic potential (PSP)

Answer 13

Neurotransmitter and receptor molecule combine. A voltage change occurs at the receptor site on the postsynaptic cell membrane. Don’t follow all or none law, is graded (vary in size) and increases or decreases the probability of a neural impulse in the receiving cell in proportion to the amount of voltage change.

Question 14

Excitory message (PSP)

Answer 14

+ voltage shift that increases the likelihood of AP fire

Question 15

Inhibatory message (PSP)

Answer 15

• voltage shift that decreases the likelihood of AP fire

Question 16

Reuptake

Answer 16

Neurotransmitters are sponged up from the synaptic cleft by the presynaptic membrane. Recycled.

Question 17

Synaptic pruning

Answer 17

The elimination of old synapses, the nervous system forms more synapses than needed and gradually eliminates the less active. It is a key process in neural network formation and is crucial to communication in the nervous system.

Question 18

Acetylcholine (ACh)

Answer 18

Released by motor neurons controlling skeletal muscles. Contributes to the regulation of attention, arousal, and memory. Some receptors are stimulated by nicotine. The disorder associated is Alzheimer’s.

Question 19

Dopamine (DA) - Monoamine

Answer 19

Control of voluntary movement. Activity at synapses is activated by cocaine and amphetamines. Dopamine circuits in mediual forebrain characterised as the “reward pathway’. The disorders associated is Parkinsons, Schizophrenic and addictive.

Question 20

Norepinephrine (NE) - Monoamine

Answer 20

Modulation of mood and arousal. Activity at synapses is activated by cocaine and amphetamines. Depressive disorders are associated.

Question 21

Serotonin - Monoamine

Answer 21

The regulation of sleep and wakefulness , eating and aggression. Serotonin circuits affected by prozac and similar antidepressant drugs. The disorders associated are depressive, obsessive-compulsive and eating.

Question 22

GABA (Gamma-aminobutyric acid)

Answer 22

An inhibatory transmitter. Regulation of anxiety and sleep/arousal. Valium and similar antianxiety drugs. Anxiety disorders are associated.

Question 23

Endorphins

Answer 23

Internally produced chemicals. Resembles opiate drugs in structure and effects. Role in pain relief and response to stress. Contributes to regulation of eating behavior.

Question 24

Peripheral nervous system

Answer 24

Made up of all those nerves that lie outside the brain + spinal cord

Question 25

Nerves

Answer 25

Bundles of neuron fibres (axons) that are routed together in the peripheral NS

Question 26

Somatic NS

Answer 26

Made up of nerves that connect to voluntary skeletal muscles and to sensory receptors

Question 27

Afferent nerve fibres

Answer 27

Axons that carry information inward to the central nervous system from the periphery

Question 28

Efferent nerve fibres

Answer 28

Axons that carry information outward from the central nervous system to the periphery

Question 29

Autonomic nervous system

Answer 29

Made up of nerves that connect to the heart, blood vessels, smooth muscles, and glands. It controls automatic, involuntary, visceral functions that we don’t normally think about. It also mediates much of the physiological arousal that occurs when we experience emotions, such as “fight or flight”

Question 30

Sympathetic division

Answer 30

Mobilizes body’s resources in case of emergencies, such as in “fight or flight”, by slowing down the digestive process, draining blood from the periphery and sending signals to the adrenal glands, triggering the release of hormones for exertion

Question 31

Parasympathetic division

Answer 31

Conserves resources to save and store energy, by slowing the heart rate, reduce blood pressure and promoting digestion

Question 32

Central nervous system

Answer 32

Consists of the brain and spinal cord

Question 33

Spinal cord

Answer 33

Houses bundles of axons that carry commands to peripheral nerves and that relay sensations from the periphery to the brain

Question 34

Forebrain

Answer 34

Is the largest and most complex. Encompassing variety of structures including the thalumus, hypothalumus, limbic system and cerebrum

Question 35

Thalamus

Answer 35

Is the relay station. It is where all sensory information (not smell) must pass through to get to the cerebral cortex and also plays a role in integrating information from various senses.

Question 36

Somas

Answer 36

Clusters of cell bodies found in the thalamus, that relay sensory information to a particular part of the cortex.

Question 37

Hypothalamus

Answer 37

Is the biological needs regulator. It regulates the basic biological needs related to survival. The 4 F’s.

Question 38

Limbic system

Answer 38

Is a loosely connected network of structures along the border between the cerebral cortex and the deeper subcortical. It also contains emotion-tinged “pleasure centres” found mostly where the medial forebrain bundle passes through the hypothalumus/ neural circuits releasing dopamine.

Question 39

Hippocampus

Answer 39

Play a role in memory processes and the consolidation of memories, which involves the conversion of information into a durable memory code.

Question 40

Amygdala

Answer 40

Central role in the learning of fear responses and processing of other basic emotional responses

Question 41

Cerebrum

Answer 41

It is the complex thought. Includes the brain areas that are responsible for our most complex mental activities.

Question 42

Cerebral cortex

Answer 42

Convulated outer layer of of the cerebrum

Question 43

Corpus callosum

Answer 43

A major structure that connects the two cerebral hemispheres

Question 44

Occipital lobe

Answer 44

It is at the back. Includes the area where most visual signals are sent and visual processing is begun. (Primary visual cortex)

Question 45

Parietal lobe

Answer 45

Is forward. Includes the area that registers the sense of touch and is involved with integrating visual input and monotoring the body’s position in space (Primary somatosensory cortex)

Question 46

Temporal lobe

Answer 46

Below. Contains an area devoted to auditory processing. (Primary auditory cortex)

Question 47

Frontal lobe

Answer 47

Largest. Contains principal areas that control the movement of the muscles. (Primary motor cortex)

Question 48

Mirror neuron circuits

Answer 48

Play fundamental role in the acquisition of new motor skills, the imitation of others; and to understanding of other’s intentions and the ability to feel empathy.

Question 49

Prefrontal cortex

Answer 49

Executive control system. One third of the cerebral cortex. Contribution to certain types of decision-making and key aspects of self-control.

Question 50

Midbrain

Answer 50

Segment of brainstem that lies between the hindbrain and forebrain. Contains an area that is concerned with integrating sensory processes such as vision and hearing. Also contains an important system of dompamine-releasing neurons that projects into various higher brain centres.

Question 51

Hindbrain

Answer 51

Includes the cerebellum, medulla, and pons.

Question 52

Medulla

Answer 52

Attaches to the spinal cord. Controls unconscious functions such as breathing, muscle tone maintenance, regulating circulation

Question 53

Pons

Answer 53

Includes a bridge of fibres that connects the brainstem with the cerebellum. Also contains clusters of cell bodies involved in sleep and arousal.

Question 54

Cerebellum

Answer 54

“Little brain”. Relatively large and deeply folded structure adjacent to the back surface of the brainstem. Involved in the coordination of movements and is critical to the sense of equilibrium (physical balance). Areas within play a role in sensing the position of our limbs. Plays a key role in the execution of the commands for muscular movements coming from higher brain centres.

Question 55

Reticular formation

Answer 55

Is situated at the central core of the brainstem and contributes to the modulation of muscle reflexes, breathing and pain perception. Best known for role in the regulation of sleep and wakefulness.