Course 2: How the Brain Works

Question 1

Multiple sclerosis

Answer 1

Large scale loss of the myelin sheath on neurons leads to a lack of insulation which interrupts electrical signals, causing a number of symptoms, such as dizziness, fatigue, loss of motor control, and sexual dysfunction.

Question 2

Glial cell

Answer 2

Glial cells provide scaffolding on which the nervous system is built, help neurons line up closely with each other to allow neuronal communication, provide insulation to neurons, transport nutrients and waste products, and mediate immune responses.

Question 3

Neuron

Answer 3

Neurons are the central building blocks of the nervous system, 100 billion strong at birth. They send information in the form of electrical signals to other cells. A cell membrane surrounds neutrons, separating intracellular fluid (like cytoplasm) from extracellular fluid.

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Question 4

Soma

Answer 4

The cell body of a neuron where the nucleus is located. It branches into dendrites and an axon.

Question 5

Dendrites

Answer 5

The branched extension of a neuron that receives signals from other neurons. Dendrites on one neuron receive signals from other neurons’ terminal buttons in the form of neurotransmitters.

Question 6

Axon

Answer 6

A branched part of a neuron that carries nerve impulses. They can range from a fraction of an inch to several feet. Glial cells can form a fatty myelin sheath around it, which insulates and increases the rate of which signals are sent. The axon ends at multiple terminal buttons.

Question 7

Terminal buttons

Answer 7

The neural signal moves from the axon to the terminal buttons, where synaptic vesicles release neurotransmitters into the synapse.

Question 8

Neurotransmitters

Answer 8

A chemical released that transfers nerve impulse from one cell to another. Different neurotransmitters bind to different receptors on dendrites (lock-and-key relationship). Receptors are proteins with different shapes and sizes.

Question 9

Synapse

Answer 9

Synapses are the small space between neurons where communication between cells occurs. Synapses can be chemical or electrical: Chemical synapses involve communication with neurotransmitters, and electrical synapses have ions freely flowing from one neuron to the other.

Question 10

Neuronal membrane

Answer 10

Membrane that separates the neuron’s intracellular fluid from extracellular fluid. There is a difference in electrical charge between the inside of the neutron and the outside for this reason; this is called the membrane potential, which provides energy for the signal. The fluids are charged because of ions, and the semi permeable nature of the membrane causes ions to build up mainly on either side of the cell.

Question 11

Resting potential

Answer 11

As ions line up on either side of the membrane and wait to rush across when the neutron goes active, this is called the resting potential.

Question 12

Sodium-potassium pump

Answer 12

Allows movement of ions in and out of the membrane. In the resting state, sodium (Na+) is at higher concentrations outside the cell, so it will tend to move into the cell. Potassium (K+), on the other hand, is more concentrated inside the cell, and will tend to move out of the cell. Additionally, the inside of the cell is slightly negative, attracting sodium ions. For every 2 K+ that goes in, 3 Na+ goes out.

To sum, intracellular has a negative net charge, and extracellular has a positive net charge.

Question 13

When a neuron receives a signal…

Answer 13

When a neuron receives a signal at the dendrites from neurotransmitters attaching to its receptors, pores open on the membrane to allow sodium ions in. Once the charge becomes positive enough (threshold of excitation), the neuron activates and the action potential begins.

Question 14

Peak action potential

Answer 14

When the action potential begins, a massive amount of Na+ ions enter the neuron, causing a massive spike in the membrane potential.

Question 15

Repolarization

Answer 15

After the peak action potential, the sodium gates close and the potassium gates open, allowing positive potassium ions to leave the neuron. At first, it hyperpolarizes, becoming more negative than the resting potential. After a while, the neuron restabalizes.

Question 16

Why is there a spike in action potential?

Answer 16

The electrical signal moves from the axon to the axon terminals like a wave. At each section, sodium ions diffuse into the next part, raising the charge past the threshold of excitation and triggering an influx of more sodium ions.

Question 17

Action potential is an ______ phenomenon.

Answer 17

Action potential is an all or none phenomenon. This means that the signal is either enough to reach the threshold of excitation or it isn’t. Once the process starts, it can’t be stopped. This property causes the signal to be recreated at every point along the axon causing your brain to perceive an injury to a distant body part like your toe as equally painful as one to your nose.

Question 18

Action potential graph

Answer 18

Resting potential

Threshold of activation

Peak action potential

Repolarization

Hyperpolarization

Question 19

Reuptake

Answer 19

Once the signal is delivered, excess neurotransmitters are broken down or reabsorbed in a process known as reuptake. Reuptake involves a neurotransmitter being pumped back into the axon terminal that released it. This cleans the synapse, provides an on/off stage to synapses, and regulates neurotransmitter production (full synaptic vesicles send a signal to stop neurotransmitter production).

Question 20

Neuronal communication is an _______ event.

Answer 20

Neuronal communication is often referred to as an electrochemical event. The movement of the action potential down the length of the axon is an electrical event, and movement of the neurotransmitter across the synaptic space represents the chemical portion of the process.

Question 21

Psychotropic (psychoactive) medication

Answer 21

Psychotropic medications are drugs that restore neurotransmitter balance. These can be either agonists or antagonists. Agonists strengthen the effect of neurotransmitters at the receptor site. Antagonists impede or block neurotransmitters. These both work by binding to receptor sites.

Question 22

Acetylcholine

Answer 22

Involved with muscle action and memory. Potentially increases arousal and enhances cognition.

Question 23

Beta-endorphin

Answer 23

Involved with pain and pleasure. Potentially decreases anxiety and tension.

Question 24

Dopamine

Answer 24

Involved with mood, sleep, and learning. Potentially increases pleasure and suppresses appetite.

Question 25

Gamma-aminobutyric acid (GABA)

Answer 25

Involved with brain function and sleep. Potentially decreases anxiety and tension.

Question 26

Glutamate

Answer 26

Involved with memory and learning. Potentially increases learning and memory.

Question 27

Norepinephrine

Answer 27

Involved with heart, intestines, and alertness. Potentially increases arousal and suppresses appetite.

Question 28

Serotonin

Answer 28

Involved with mood and sleep. Potentially modulates mood and suppresses appetite.

Question 29

SSRI

Answer 29

SSRI stands for selective serotonin reuptake inhibitors. It is generally used to treat depression by strengthening the effect of serotonin, giving it more time to interact with serotonin receptors on dendrites.

Question 30

Peripheral nervous system

Answer 30

Made up of thick bundles of axons, the PNS connects the CNS with the muscles, organs, and senses in the periphery of the body (i.e., everything outside the CNS). The PNS can be seperated into the somatic nervous system and the autonomic nervous system.

Question 31

Somatic nervous system

Answer 31

The somatic nervous system deals with actions that we consider voluntary. It contains motor and sensory neurons that transport information to and from the CNS. Motor neurons carry info FROM the CNS to the muscles, and are called efferent (moving away from) fibers. Sensory neurons are afferent fibers (moving towards), carrying sensory info TO the CNS.

Question 32

Autonomic nervous system

Answer 32

The autonomic nervous system controls our internal organs and glands and is generally considered to be outside the realm of voluntary control. It can be divided into the parasympathetic system and sympathetic system.

Question 33

Parasympathetic system

Answer 33

The parasympathetic system is involved with returning the body to day-to-day functions. This can include constricting the pupil, stimulating salivation, slowing heart rate, constricting bronchi, contracting the bladder, and stimulating digestion.

Question 34

Sympathetic system

Answer 34

The sympathetic system is involved with preparing our body for stressful situations. This can include dilating the pupil, inhibiting salivation, increasing heart rate, dilating the bronchi, inhibiting the contraction of the bladder, and inhibiting digestion.

Question 35

Homeostasis

Answer 35

The parasympathetic system and sympathetic system are complementary functions, working together to maintain homeostasis. Homeostasis is the equilibrium where your body’s biological conditions are maintained at optimal levels.

Question 36

Fight or flight response

Answer 36

When faced with a stressful situation, your pupils dilate, heart rate and blood pressure increase, the bladder relaxes, liver releases glucose, and adrenaline surges into the bloodstream.

Question 37

Spinal cord

Answer 37

The spinal cord is connected to the brain, extending from the brain stem to just below your ribs. At the brain stem, basic processes of life are controlled like breathing and digestion. The spinal cord is separated into 30 segments corresponding with the vertebrae. Nerves branch out from the spine at each vertebra. Sensory nerves bring messages in; motor nerves send messages out to the muscles and organs. The spinal cord is protected by bony vertebrae and cushioned in cerebrospinal fluid. When injured in an upper section, all the sections below are cut off from the brain, causing paralysis.

Question 38

Central nervous system

Answer 38

The CNS is made up of the brain and spinal cord.

Question 39

Spinal reflex

Answer 39

Some sensory messages are immediately acted on by the spinal cord, without any input from the brain. Withdrawal from heat and knee jerk are two examples. When a sensory message meets certain parameters, the spinal cord initiates an automatic reflex. The signal passes from the sensory nerve to a synapse within the spinal cord.

Question 40

Cerebral cortex

Answer 40

The cerebral cortex is the surface of the brain, filled with gyri and sulci. These divide the brain into different sections. It is associated with higher level processes such as consciousness, thought, emotion, reasoning, language, and memory.

Question 41

Folds/bumps on the cerebral cortex

Answer 41

Gyri (singular: gyrus)

Question 42

Grooves on the cerebral cortex

Answer 42

Sulci (singular: sulcus)

Question 43

Longitudinal fissure

Answer 43

The most prominent sulci in your brain, it divides it into two hemispheres.

Question 44

Hemispheres

Answer 44

The two hemispheres are different in terms of function, and this is called lateralization. The right hemisphere controls the left side of your body, and vice-versa.

Question 45

Corpus callosum

Answer 45

The thick bands of neural fibers that connect your two hemispheres together. They consist of around 200 million axons.

Question 46

Treatment of severe epilepsy

Answer 46

In some cases of severe epilepsy, doctors elect to sever the corpus callosum as a means of controlling the spread of seizures. While this is an effective treatment option, it results in individuals who have split brains. For instance, a split-brain patient is unable to name a picture that is shown in the patient’s left visual field because the information is only available in the largely nonverbal right hemisphere. However, they are able to recreate the picture with their left hand, which is also controlled by the right hemisphere. When the more verbal left hemisphere sees the picture that the hand drew, the patient is able to name it (assuming the left hemisphere can interpret what was drawn by the left hand).

Question 47

Forebrain

Answer 47

The forebrain is the largest part of the brain, containing the cerebral cortex, both hemispheres, thalamus, hypothalamus, pituitary gland, and the limbic system (collection of structures).

Question 48

Frontal lobe

Answer 48

The frontal lobe is involved in reasoning, motor control, emotion, and language. It contains the motor cortex which plans/coordinates movement, prefrontal cortex which is responsible for cognitive functioning like reasoning and personality, and Broca’s area which is for language production.

Question 49

Phineas Gage

Answer 49

On September 13, 1848, Gage (age 25) was working as a railroad foreman in Vermont. He and his crew were using an iron rod to tamp explosives down into a blasting hole to remove rock along the railway’s path. Unfortunately, the iron rod created a spark and caused the rod to explode out of the blasting hole, into Gage’s face, and through his skull. Although lying in a pool of his own blood with brain matter emerging from his head, Gage was conscious and able to get up, walk, and speak. But in the months following his accident, people noticed that his personality had changed. Such changes in personality would be consistent with loss of impulse control - a frontal lobe function.

Question 50

Parietal lobe

Answer 50

The parietal lobe is involved with processing information from the body’s senses. It contains the somatosensory cortex, which processes sensory info like touch and temperature. It is organized topographically, meaning certain parts of your body correlate to certain parts of the somatosensory cortex.

Question 51

Temporal lobe

Answer 51

The temporal lobe is located on either side of the head (temporal means near the temples). It is associated with hearing, memory, emotion, and some aspects of language. It contains the auditory cortex, responsible for processing auditory info, and Wernicke’s area, required for speech comprehension. Damage to Wernicke’s area allows the patient to produce speech unlike Broca’s area, but they are unable to understand it.

Question 52

Occipital lobe

Answer 52

The occipital lobe is located at the rear of the brain, and contains the primary visual cortex. The visual cortex is responsible for interpreting incoming visual information. It is organized retinotopically, which means there is a correlation between the position of an object in a person’s visual field and the position of that object’s representation on the cortex.

Question 53

Thalamus

Answer 53

The thalamus is located beneath the cerebral cortex. All sensory information, excluding smell, first goes through the thalamus before being redirected to other parts of the brain.

Question 54

Limbic system

Answer 54

The limbic system is located beneath the cerebral cortex, and processes emotion and memory. The sense of smell goes directly to the limbic system, which is why we often associate scents with emotional responses. It contains the hippocampus, amygdala, and hypothalamus.

Question 55

Hippocampus

Answer 55

The hippocampus is a part of the limbic system. It is responsible for learning and memory.

Question 56

Amygdala

Answer 56

The amygdala is a part of the limbic system. It assists our experience of emotion and in tying emotional meaning to our memories.

Question 57

Hypothalamus

Answer 57

The hypothalamus is a part of the limbic system. It regulates different homeostatic processes, such as body temperature, appetite, and blood pressure. The hypothalamus also serves as an interface between the nervous system and the endocrine system and in the regulation of sexual motivation and behavior.

Question 58

Henry Molaison

Answer 58

In 1953, Henry Gustav Molaison (H. M.) was a 27-year-old man who experienced severe seizures. In an attempt to control his seizures, H. M. underwent brain surgery to remove his hippocampus and amygdala. Afterwards, while his seizures improved, he was unable to form new memories or experiences.

Question 59

Reticular formation

Answer 59

The reticular formation is centered in the midbrain, extending up into the forebrain and down into the hindbrain. It is important in regulating the sleep/wake cycle, arousal, alertness, and motor activity.

Question 60

Substantia nigra

Answer 60

Latin for black substance, it is located in the midbrain. It contains cell bodies essential for producing dopamine and sends signals that help control movement.

Question 61

Ventral tegmental area

Answer 61

The VTA is located in the midbrain. It contains cell bodies essential for producing dopamine. In addition with the substantia nigra, it is involved with mood, reward, and addiction.

Question 62

Midbrain

Answer 62

The midbrain containts the substantia nigra, VTA, and reticular formation.

Question 63

Hindbrain

Answer 63

The hindbrain is located at the back of the head and contains the medulla, pons, and cerebellum.

Question 64

Medulla

Answer 64

The medulla controls the automatic processes of the autonomic nervous system, such as breathing, blood pressure, and heart rate.

Question 65

Pons

Answer 65

The word “pons” means bridge, and it connects the brain and spinal cord. It also regulates brain activity during sleep.

Question 66

The brain stem is made up of three structures:

Answer 66

Medulla, pons, and midbrain

Question 67

Cerebellum

Answer 67

Latin for “little brain,” the cerebellum receives information from the ear in order to control balance, coordination, movement, and motor skills. It is also thought to be important for procedural memory, which is the act of learning and performing new tasks.

Question 68

Terri Schiavo

Answer 68

On February 25, 1990, a Florida woman named Terri Schiavo went into cardiac arrest, apparently triggered by a bulimic episode. While she was eventually revived, her condition progressed into a vegetative state. There was a large lawsuit over whether to keep her alive, arguing that her consciousness was still there in her occasional groans and twitches of the eye. In reality, her brain stem was still intact, and the medulla and pons maintained her breathing, causing the movements.

Question 69

Computerized tomography scan

Answer 69

A CT scan takes a number of x-rays of the body part or brain. As the waves pass through tissues of different densities, an image is formed. A CT scan is often used to determine whether someone has a tumor, or significant brain atrophy.

Question 70

Positron emission tomography scan

Answer 70

An individual receiving a PET scan drinks or is injected with a mildly radioactive substance, called a tracer. As the brain becomes more active, more blood flows into the area. The amount of tracer and its movement allows an image to be created that shows active and inactive areas of the brain. CT/PET scans allow better imaging of the activity of neurotransmitter receptors and open new avenues in schizophrenia research. In this hybrid CT/PET technology, CT contributes clear images of brain structures, while PET shows the brain’s activity.

Question 71

Magnetic resonance imaging

Answer 71

In an MRI, a person is placed inside a machine that generates a strong magnetic field. The field gives hydrogen atoms energy, spinning them out of equilibrium. When the field is turned off, the atoms return to their original positions, emitting electromagnetic signals in the process. Tissues of different densities give off different signals, which a computer interprets and displays on a monitor.

Question 72

Functional magnetic resonance imaging

Answer 72

In an fMRI, it shows brain activity over time by tracking blood flow and oxygen levels. It does so by measuring the difference in magnetic levels between oxygenated and deoxygenated blood.

Question 73

Electroencephalography

Answer 73

An EEG measures a brain’s electrical activity. Electrodes are placed around a person’s head, measuring the amplitude and frequency of the brainwaves. This is especially useful for helping individuals with sleep disorders.

Question 74

Endocrine system

Answer 74

The endocrine system contains glands that secrete hormones. The major glands are the pituitary, thyroid, parathyroid glands, adrenal glands, pancreas, uterus, and gonads.

Question 75

Hormones

Answer 75

Hormones are similar to neurotransmitters in the sense that they bind to specific receptors. They are secreted into the bloodstream by different glands. Therefore, the effect of hormones are widespread, but are slower and longer lasting. The release of hormones is controlled by the hypothalamus and pituitary gland working in tandem.

Question 76

Pituitary gland

Answer 76

The pituitary gland descends from the hypothalamus. It is often referred to as the “master gland,” as the messenger hormones it releases controls all the other glands in the endocrine system. It also secretes growth hormone, endorphins for pain relief, and hormones that manage fluid levels in the body.

Question 77

Thyroid gland

Answer 77

Located in the neck, the thyroid gland secretes hormones responsible for regulating growth, metabolism, and appetite.

Question 78

Parathyroid gland

Answer 78

Located on the posterior side of the thyroid, these four glands control the body’s calcium levels.

Question 79

Grave’s disease

Answer 79

Known as hypothyroidism, the thyroid secretes too little of the hormone thyroxine, causing agitation, bulging eyes, and weight loss. Symptoms often include tiredness and feeling cold.

Question 80

Adrenal glands

Answer 80

The adrenal glands are located above the kidneys and are used during our flight and fight response. They secrete epinephrine (adrenaline) and norepinephrine (noradrenaline).

Question 81

Pancreas

Answer 81

The pancreas secretes hormones that regulate blood sugar levels. Insulin lowers blood sugar, while glucagon raises it.

Question 82

Gonads

Answer 82

The gonads secrete sexual hormones that mediate both sexual motivation and behavior. In females, they are the ovaries, and in males they are the testis. The ovaries produce estrogen and progesterone, while the testes produce the androgens testosterone and androstenedione.

Question 83

Neuroscience

Answer 83

Study of the nervous system

Question 84

Biopsychology

Answer 84

Study of the biology of behaviour

Question 85

Interneuron

Answer 85

A type of neuron that transmits signals within the nervous system

Question 86

EPSP

Answer 86

Excitatory postsynaptic potential, depolarizes the cell (eg. -70 mV to -67 mV). EPSPs cause action potential.

Question 87

IPSP

Answer 87

Inhibatory postsynaptic potential, hyperpolarizes the cell (eg. -70 mV to -72 mV). IPSPs inhibit action potential.

Question 88

PSPs

Answer 88

Postsynaptic potentials, they are seperated into EPSPs and IPSPs. They occur when a neurotransmitter binds to a postsynaptic receptor. PSPs are graded in size, decremental, and quite fast compared to action potentials. PSPs experience temporal and spatial summation, meaning they can overlap to increase in size or cancel out.

Question 89

Sickle-cell anemia

Answer 89

Genetic condition where red blood cells take on crescent shapes. They can clog blood vessels and block blood flow, leading to high fever, swelling, pain, and tissue damage. Carriers with one copy of the gene are immune to malaria.

Question 90

Theory of evolution by natural selection

Answer 90

Organisms that are better suited towards their environment will reproduce, while those that are poorly suited will die off.

Question 91

Genotype

Answer 91

Genetic makeup of an individual - 23 pairs of chromosomes supplied by the parents

Question 92

Phenotype

Answer 92

Physical/expressed characteristics of an individual; determined by genotype

Question 93

Allele

Answer 93

An allele is a specific version of a gene. Genes consist of sequences of DNA, which together create a chromosome.

Question 94

Phenylketonuria

Answer 94

Genetic disorder where individuals lack an enzyme that breaks down harmful amino acids. It can cause a decrease in cognitive function, seizures, and an increased risk for psychiatric disorders.

Question 95

Polygenic trait

Answer 95

A trait that is controlled by more than one gene

Eg. Height, skin colour, weight

Question 96

Punnett square

Answer 96

Four square diagram used to predict the results of a breeding experiment

Question 97

Range of reaction

Answer 97

Our genes set the boundaries in which we operate, but our environment determines where we fall within it

Question 98

Epigenetics

Answer 98

Study of how genes interact with the environment, such as how the same genotype can lead to different phenotypes

Question 99

Heterozygous

Answer 99

Consisting of two different alleles

Question 100

Homozygous

Answer 100

Consisting of two identical alleles

Question 101

Recessive allele

Answer 101

Allele that will only be expressed if the individual is homozygous for that allele

Question 102

Dominant allele

Answer 102

Allele that will be expressed if the individual possesses it

Question 103

Heredity

Answer 103

All the traits and tendencies that are inherited from one’s ancestors

Question 104

Heritability estimate

Answer 104

A value from 0 to 1 expressed as a percentage to estimate how much of the diversity for a trait within a population is due to genetic inheritance.

Question 105

Transduction

Answer 105

The conversion of sensory stimuli into other forms, such as action potentials

Question 106

The five senses are…

Answer 106

Vision, olfaction (smell), gustation (taste), audition (hearing), and somatosensation (touch)

Question 107

Absolute threshold

Answer 107

The smallest amount of stimuli that still results in being detected at least half the time

Question 108

Subliminal messages

Answer 108

Stimuli that is under the level required to excite sensory receptors; we receive the information but are unaware of it

Question 109

Noticeable difference threshold

Answer 109

Represented as jnd, it is how much of a difference in stimuli in order for a difference to be detected at least half the time

Question 110

Weber’s law

Answer 110

The difference threshold is a constant ratio of the original stimulus

Question 111

Perception

Answer 111

How sensory information is organized, interpreted, and experienced. It is influenced by factors like beliefs, values, prejudices, culture, and life experiences.

Question 112

Bottom-up processing vs Top-down processing

Answer 112

Bottom-up processing: Perception is built from sensory input

Top-down processing: How our brain interprets sensory information is influenced by experience and thoughts

Question 113

Sensory adaptation

Answer 113

Decrease in responsiveness to a stimuli over time

Question 114

Chabris and Simons experiment

Answer 114

In this experiment, participants watched a video of people dressed in black and white pass around basketballs. They were asked to count how many times the team in white passed the ball. During the video, a person dressed as a gorilla walks through the scene, visible for nine seconds. Almost half of the participants did not notice the gorilla, showcasing the importance of attention.

Question 115

Inattentional blindness

Answer 115

Failure to notice something that is completely visible due to a lack of attention

Question 116

Signal detection theory

Answer 116

The ability to discern a specific stimulus among a distracting background; can be used to explain why we sometimes hear things that are not there (psychological motivation)

Question 117

Müller-Lyer illusion

Answer 117

This illusion involves multiple, identical lines that appear to be of different lengths due to the arrows drawn at the end of them.

Question 118

Fovea

Answer 118

Light entering a normal person’s eyes will focus the image on an indentation on the retina - the fovea. The majority of cone cells are concentrated here.

Question 119

Cones

Answer 119

Photoreceptor cells that work well in bright light conditions. They are sensitive to detail and provide large spatial resolution. Cones are concentrated mainly on the fovea.

Question 120

Rods

Answer 120

Photoreceptor cells that work well in low light conditions. Located throughout the retina, they help us see in dimly lit environments and recognize movement in our peripheral vision.