mind class mod 10 quiz

Darwin's theory of evolution by natural selection

of evolution by natural selection (Figure 3.3). In simple terms, the theory states that organisms that are better suited for their environment will survive and reproduce, while those that are poorly suited for their environment will die off.

It’s easy to get confused about two fields that study the interaction of genes and the environment, such as the fields of evolutionary psychology and behavioral genetics. How can we tell them apart?

• Evolutionary Psychology looks at how human behaviors developed over time to help us survive and reproduce. It asks, "Why do we behave this way?" based on our evolution.

• Behavioral Genetics focuses on how our genes and the environment shape our behaviors. It asks, "How do genes and the environment influence how we act?"

Chromosomes

are long strings of genetic material known as deoxyribonucleic acid (DNA).

deoxyribonucleic acid (DNA)

DNA is a helix-shaped molecule made up of nucleotide base pairs.

In each chromosome, sequences of DNA make up ____ that control or partially control a number of visible characteristics, known as traits, such as eye color, hair color, and so on. A single gene may have multiple possible variations, or alleles.

genes

allele

is a specific version of a gene. So, a given gene may code for the trait of hair color, and the different alleles of that gene affect which hair color an individual has.

genotype

is the genetic makeup of that individual.

Phenotype

on the other hand, refers to the individual’s inherited physical characteristics, which are a combination of genetic and environmental influences

dominant allele

either from one parent (Bb) or both parents (BB) will always result in the phenotype associated with the dominant allele.

When someone has two copies of the same allele, they are said to be ___ for that allele

homozygous

When someone has a combination of alleles for a given gene, they are said to be

heterozygous

recessive allele

a version of a gene that only shows its effect if an individual has two copies of it (one from each parent). If there is a dominant allele present (which is stronger), it will hide the effect of the recessive allele

polygenic

controlled by more than one gene. Height is one example of a polygenic trait, as are skin color and weight.

A mutation

is a sudden, permanent change in a gene. While many mutations can be harmful or lethal, once in a while, a mutation benefits an individual by giving that person an advantage over those who do not have the mutation.

Range of reaction asserts

asserts that our genes set the boundaries within which we can operate, and our environment interacts with the genes to determine where in that range we will fall.

genetic environmental correlation

Stated simply, our genes influence our environment, and our environment influences the expression of our genes. Not only do our genes and environment interact, as in range of reaction, but they also influence one another bidirectionally.

epigenetics

looks beyond the genotype itself and studies how the same genotype can be expressed in different ways. In other words, researchers study how the same genotype can lead to very different phenotypes.

identical twins

develop from a single fertilized egg that split, so the genetic material is exactly the same in each;

fraternal twins usually

usually result from two different eggs fertilized by different sperm, so the genetic material varies as with non-twin siblings).

The nervous system is

composed of two basic cell types: glial cells (also known as glia) and neurons. Glial cells are traditionally thought to play a supportive role to neurons, both physically and metabolically.

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.

Neurons

on the other hand, serve as interconnected information processors that are essential for all of the tasks of the nervous system. This section briefly describes the structure and function of neurons.

semipermeable membrane.

This membrane allows smaller molecules and molecules without an electrical charge to pass through it, while stopping larger or highly charged molecules.

The nucleus of the neuron is located in the soma, or cell body. The soma has branching extensions known as

dendrites The neuron is a small information processor, and dendrites serve as input sites where signals are received from other neurons.

These signals are transmitted electrically across the soma and down a major extension from the soma known as the

axon

which ends at multiple

terminal buttons

The terminal buttons contain _____ that house neurotransmitters, the chemical messengers of the nervous system.

contain synaptic vesicles

Axons range in length from a fraction of an inch to several feet. In some axons, glial cells form a fatty substance known as the

myelin sheath

The myelin sheath is not continuous and there are small gaps that occur down the length of the axon. These gaps in the myelin sheath are known as the

the Nodes of Ranvier. The myelin sheath is crucial for the normal operation of the neurons within the nervous system: the loss of the insulation it provides can be detrimental to normal function.

The synaptic cleft

is a very small space between two neurons and is an important site where communication between neurons occurs.

Receptors,

proteins on the cell surface where neurotransmitters attach, vary in shape, with different shapes “matching” different neurotransmitters.

The neuronal membrane keeps these two fluids separate—a critical role because the electrical signal that passes through the neuron depends on the intra- and extracellular fluids being electrically different. This difference in charge across the membrane, called the

membrane potential

Between signals, the neuron membrane’s potential is held in a state of readiness, called the

resting potential.

threshold of excitatin,

this influx of positive ions, the internal charge of the cell becomes more positive. If that charge reaches a certain level, called the neuron becomes active and the action potential begins.

action potential:

the electrical signal that typically moves from the cell body down the axon to the axon terminals. The electrical signal moves down the axon with the impulses jumping in a leapfrog fashion between the Nodes of Ranvier. The Nodes of Ranvier are natural gaps in the myelin sheath.

all-or-none

phenomenon. In simple terms, this means that an incoming signal from another neuron is either sufficient or insufficient to reach the threshold of excitation. There is no in-between, and there is no turning off an action potential once it starts.

Psychologists who take a biological perspective

and focus on the physiological causes of behavior assert that psychological disorders like depression and schizophrenia are associated with imbalances in one or more neurotransmitter systems. In this perspective, psychotropic medications can help improve the symptoms associated with these disorders.

Psychotropic medications

are drugs that treat psychiatric symptoms by restoring neurotransmitter balance.

Acetylcholine

Muscle action, memory, Increased arousal, enhanced cognition

Beta-endorphin

pain pleasure, Decreased anxiety, decreased tension

dopamine

Decreased anxiety, decreased tension, Increased pleasure, suppressed appetite

Gamma-aminobutyric acid (GABA)

Brain function, sleep

Decreased anxiety, decreased tension

Glutamate

Memory, learning

Increased learning, enhanced memory

Norepinephrine

Heart, intestines, alertness, Increased arousal, suppressed appetite

Serotonin

Mood, sleep, Modulated mood, suppressed appetite

The nervous system can be divided into two major subdivisions:

the central nervous system (CNS) and the peripheral nervous system (PNS)

somatic nervous system

is associated with activities traditionally thought of as conscious or voluntary. It is involved in the relay of sensory and motor information to and from the CNS; therefore, it consists of motor neurons and sensory neurons. Motor neurons, carrying instructions from the CNS to the muscles, are efferent fibers (efferent means “moving away from”). Sensory neurons, carrying sensory information to the CNS, are afferent fibers (afferent means “moving toward”).

autonomic nervous system

controls our internal organs and glands and is generally considered to be outside the realm of voluntary control. It can be further subdivided into the sympathetic and parasympathetic divisions

The sympathetic nervous system

is involved in preparing the body for stress-related activities;

the parasympathetic nervous system

is associated with returning the body to routine, day-to-day operations. The two systems have complementary functions, operating in tandem to maintain the body’s homeostasis.

Homeostasis

is a state of equilibrium, or balance, in which biological conditions (such as body temperature) are maintained at optimal levels.

fight or flight response

allows the body access to energy reserves and heightened sensory capacity so that it might fight off a threat or run away to safety.

The sympathetic nervous system is activated when we are faced with stressful or high-arousal situations. The activity of this system was

adaptive for our ancestors, increasing their chances of survival.

neuroplasticity

Neuroplasticity refers to how the nervous system can change and adapt. Neuroplasticity can occur in a variety of ways including personal experiences, developmental processes, or, as in Woodruff's case, in response to some sort of damage or injury that has occurred. Neuroplasticity can involve creation of new synapses, pruning of synapses that are no longer used, changes in glial cells, and even the birth of new neurons.

cerebral cortex

is very uneven, characterized by a distinctive pattern of folds or bumps, known as gyri

sulci

grooved in the brain

. These gyri and sulci form important landmarks that allow us to separate the brain into functional centers. The most prominent sulcus, known as the

longitudinal fissure

hemispheres

the left hemisphere and the right hemisphere seprates the rain to two halves

There is evidence of specialization of function—referred to as

lateralization—in each hemisphere, mainly regarding differences in language functions. The left hemisphere controls the right half of the body, and the right hemisphere controls the left half of the body.

left hemisphere

hemisphere has been shown to be superior for forming associations in memory, selective attention, and positive emotions.

right hemisphere

on the other hand, has been shown to be superior in pitch perception, arousal, and negative emotions

hemispheres are connected by a thick band of neural fibers known as the

corpus callosum, consisting of about 200 million axons. The corpus callosum allows the two hemispheres to communicate with each other and allows for information being processed on one side of the brain to be shared with the other side.

forebrain

which is the largest part of the brain. The forebrain contains the cerebral cortex and a number of other structures that lie beneath the cortex (called subcortical structures): thalamus, hypothalamus, pituitary gland, and the limbic system (a collection of structures). The cerebral cortex, which is the outer surface of the brain, is associated with higher level processes such as consciousness, thought, emotion, reasoning, language, and memory.

parietal lobe

is located immediately behind the frontal lobe, and is involved in processing information from the body’s senses.

somatosensory cortex

is essential for processing sensory information from across the body, such as touch, temperature, and pain. The somatosensory cortex is an area of the brain which processes touch and sensation.

temporal lobe

is located on the side of the head (temporal means “near the temples”), and is associated with hearing, memory, emotion, and some aspects of language.

The auditory cortex,

the main area responsible for processing auditory information, is located within the temporal lobe.

Wernicke’s area,

important for speech comprehension, is also located here. Whereas individuals with damage to Broca’s area have difficulty producing language, those with damage to Wernicke’s area can produce sensible language, but they are unable to understand it

occipital lobe

is located at the very back of the brain, and contains the primary visual cortex, which is responsible for interpreting incoming visual information.

The thalamus

is a sensory relay for the brain. All of our senses, with the exception of smell, are routed through the thalamus before being directed to other areas of the brain for processing

limbic system

is involved in processing both emotion and memory. Interestingly, the sense of smell projects directly to the limbic system; therefore, not surprisingly, smell can evoke emotional responses in ways that other sensory modalities cannot.

The hippocampus

is an essential structure for learning and memory.

The amygdala

is involved in our experience of emotion and in tying emotional meaning to our memories.

hypothalamus

regulates a number of homeostatic processes, including the regulation of 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.

midbrain

is comprised of structures located deep within the brain, between the forebrain and the hindbrain.

reticular formation

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

substantia nigra

(Latin for “black substance”) and the ventral tegmental area (VTA) are also located in the midbrain. Both regions contain cell bodies that produce the neurotransmitter dopamine, and both are critical for movement. Degeneration of the substantia nigra and VTA is involved in Parkinson’s disease

hindbrain

is located at the back of the head and looks like an extension of the spinal cord. It contains the medulla, pons, and cerebellum (

The medulla

controls the automatic processes of the autonomic nervous system, such as breathing, blood pressure, and heart rate. The word pons literally means “bridge,” and as the name suggests, the pons serves to connect the hindbrain to the rest of the brain.

cerebellum

(Latin for “little brain”) receives messages from muscles, tendons, joints, and structures in our ear to control balance, coordination, movement, and motor skills. The cerebellum is also thought to be an important area for processing some types of memories. In particular, procedural memory, or memory involved in learning and remembering how to perform tasks, is thought to be associated with the cerebellum.

A computerized tomography (CT) scan

involves taking a number of x-rays of a particular section of a person’s body or brain

Positron emission tomography (PET)

scans create pictures of the living, active brain (Figure 3.27). An individual receiving a PET scan drinks or is injected with a mildly radioactive substance, called a tracer. Once in the bloodstream, the amount of tracer in any given region of the brain can be monitored. As a brain area becomes more active, more blood flows to that area.

magnetic resonance imaging (MRI)

a person is placed inside a machine that generates a strong magnetic field. The magnetic field causes the hydrogen atoms in the body’s cells to move. When the magnetic field is turned off, the hydrogen atoms emit electromagnetic signals as they return to their original positions. Tissues of different densities give off different signals, which a computer interprets and displays on a monitor.

Functional magnetic resonance imaging (fMRI) operates

on the same principles, but it shows changes in brain activity over time by tracking blood flow and oxygen levels. The fMRI provides more detailed images of the brain’s structure, as well as better accuracy in time, than is possible in PET scans

Electroencephalography (EEG)

serves this purpose by providing a measure of a brain’s electrical activity. An array of electrodes is placed around a person’s head. The signals received by the electrodes result in a printout of the electrical activity of their brain, or brainwaves, showing both the frequency (number of waves per second) and amplitude (height) of the recorded brainwaves, with an accuracy within milliseconds. Such information is especially helpful to researchers studying sleep patterns among individuals with sleep disorders.

endocrine system

consists of a series of glands that produce chemical substances known as hormones

hormones

are chemical messengers that must bind to a receptor in order to send their signal. However, unlike neurotransmitters, which are released in close proximity to cells with their receptors, hormones are secreted into the bloodstream and travel throughout the body, affecting any cells that contain receptors for them. Thus, whereas neurotransmitters’ effects are localized, the effects of hormones are widespread. Also, hormones are slower to take effect, and tend to be longer lasting

pituitary gland

descends from the hypothalamus at the base of the brain, and acts in close association with it. The pituitary is often referred to as the “master gland” because its messenger hormones control all the other glands in the endocrine system, although it mostly carries out instructions from the hypothalamus. In addition to messenger hormones, the pituitary also secretes growth hormone, endorphins for pain relief, and a number of key hormones that regulate fluid levels in the body.

the thyroid gland

releases hormones that regulate growth, metabolism, and appetite. In hyperthyroidism, the thyroid secretes too much of the hormone thyroxine, causing agitation, bulging eyes, and weight loss. One cause of hyperthyroidism is Graves' disease, an autoimmune disease in which one’s own body attacks itself. In hypothyroidism, reduced hormone levels cause sufferers to experience tiredness, and they often complain of feeling cold. Fortunately, thyroid disorders are often treatable with medications that help reestablish a balance in the hormones secreted by the thyroid.

adrenal glands

sit atop our kidneys and secrete hormones involved in the stress response, such as epinephrine (adrenaline) and norepinephrine (noradrenaline).

The pancreas

is an internal organ that secretes hormones that regulate blood sugar levels: insulin and glucagon. These pancreatic hormones are essential for maintaining stable levels of blood sugar throughout the day by lowering blood glucose levels (insulin) or raising them (glucagon).

People who suffer from diabetes do not produce enough of what?

enough insulin: therefore, they must take medications that stimulate or replace insulin production, and they must closely control the number of sugars and carbohydrates they consume.

gonads

secrete sexual hormones, which are important in reproduction, and mediate both sexual motivation and behavior. The female gonads are the ovaries; the male gonads are the testes. Ovaries secrete estrogens and progesterone, and the testes secrete androgens, such as testosterone.

Pituitary

Growth hormone, releasing and inhibiting hormones (such as thyroid stimulating hormone), Regulate growth, regulate hormone release

thyroid

Thyroxine, triiodothyronine, Regulate metabolism and appetite

Pineal

melatonin, regulate some biological rhythms such as sleep cycles

Adrenal

Epinephrine, norepinephrine, Stress response, increase metabolic activities

Pancreas,

Insulin, glucagon, regulate blood sugar levels

Ovaries

Estrogen, progesterone, Mediate sexual motivation and behavior, reproduction

Testes

Androgens, such as testosterone, Mediate sexual motivation and behavior, reproduction