Vocabulary
1. Neuroscience- Interdisciplinary field studying how biological processes relate to behavioral and mental processes
2.Neuron- Cell of the nervous system responsible for receiving and transmitting electrochemical information
3. Glial Cells- Cells that provide structural, nutritional and other support for the neurons as well as communication within the nervous system also called glia or neuroglia
4. Dendrites-Branching neuron structures that receive neural impulses from other neurons and convey impulses toward the cell body
5. Cell Body- the part of the neuron that contains the cell nucleus, as well as other structures that help the neuron carry out its functions (AKA soma)
6. Axon- A long, tubelike structure that conveys impulses away from the neuron’s cell body toward other neurons or to muscles or glands
7.Myelin Sheath- layer of fatty insulation wrapped around the axon of some neurons, which increases the rate at which nerve impulses travel along the axon
8. Action Potential- Neural impulse that carries information along the axon of a neuron. The action potential is generated when positively charged ions move in and out through channels in the axon’s membrane
9. Synapse- Function between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. During an action potential, chemicals called neurotransmitters are released and flow across the synaptic gap
10. Neurotransmitters- Chemicals released by neurons that affect other neurons
11. Endorphins- Chemical substances in the nervous system that are similar in structure and action to opiates and are involved in pain control, pleasure, and memory
12. Endocrine System - Collection of glands located throughout the body that manufacture and secrete hormones into the bloodstream
13. Hormones- Chemical manufactured by endocrine glands and circulated in the bloodstream to produce bodily changes or maintain normal bodily functions
14. Central Nervous System- Brain and spinal chord
15.Peripheral Nervous System- All nerves and neurons connecting the central nervous system to the rest of the body 16.Somatic Nervous System- a subdivision of the peripheral nervous system (PNS) thatconnects to sensory receptors and controls skeletal muscles.
17.Sensory Neuron- transmit messages from sense organs to the central nervous
system.
18.Motor Neuron- transmit messages from the central nervous system to organs, muscles, and glands.
19.Interneurons- neurons within the central nervous system that internally communicate and intervene between the sensory and motor neurons.
20.Automatic Nervous System- subdivision of the peripheral nervous system (PNS) that controls involuntary functions such as heart rate and digestion. It is further subdivided into the sympathetic nervous system, which arouses, and the parasympathetic nervous system, which calms.
21. Symphathetic Nervous System - Subdivision of the autonomic nervous system responsible for arousing the body and mobilizing its energy during times of stress; “fight or flight”
22.Parasymphathetic Nervous System- Subdivision of the autonomic nervous system (ANS); responsible for calming the body and conserving energy
23.Brainstem- Area of the brain that houses parts of the hindbrain, midbrain, and forebrain, and helps regulate reflex activities critical for survival (heartbeat and respiration)
24. Hindbrain- collection of the brain structures including the medulla, pons, and cerebellum
25.Medulla - hindbrain structure responsible for automatic body functions such as breathing and heartbeat
26.Pons - hindbrain structure involved in respiration, movement, walking, sleep, and dreaming
27. Cerebellum- hindbrain structure responsible for coordinating fine muscle movement, balance, and some perception and cognition.
28.Midbrain - Collection of brain structures in the middle of the brain responsible for coordinating movement patterns, sleep, and arousal
29.Reticular Formation (RF)- Diffuse set of neurons that screens incoming info and controls arousal
30. Thalamus- forebrain structure at the top of the brainstem that relays sensory messages to the cerebral cortex.
31. Hypothalamus- small brain structure beneath the thalamus responsible for emotions and drives, and regulating the body’s internal environment.
32. Limbic System - interconnected group of forebrain structures involved with emotions, drives, and memory
33. Cerebral Cortex - thin surface layer on cerebral hemisphere that regulate4s most complex behavior (sensations, motor control)
34. Frontal Lobes-2 lobes at the front of the brain governing motor control, speech production and higher functions-thinking, personality, emotion, and memory.
35. Parietal Lobes - 2 lobes at the top of the brain where bodily sensations are interpreted
36.Temporal Lobes - 2 lobes on each side of the brain above the ears involved in hearing, language comp., memory, and some emotional control
37. Occipital Lobes - 2 lobes at the back of the brain responsible for vision and visual perception 38. Association Areas - So-called quiet areas in the cerebral cortex involved in interpreting, integrating, and action of into processed by other parts of the brain
39. Lateralization- specialization of the left and right hemispheres of the brain for particular operations
40. Spinal Cord- responsible for transmitting information between the brain and the rest of the body; handles simple reflexes
41. Corpus Callosum- Bundle of nerve fibers connecting the brains’ left and right hemispheres
42. Chromosome - threadlike molecule of DNA that carries genetic information
43. Gene - a segment of DNA that occupies a specific place on a particular chromosome and carries the code for hereditary transmission
44.Natural Selection - the driving mechanism behind evolution, which allows individuals with genetically influenced traits that are adaptive in a particular environment to stay alive and produce offspring
45. Neurogenesis - The division and differentiation of nonnueronal cells to produce neurons
46. Stem Cell - immature cells that give birth to new specialized cells; holds all the information needed to make any part of the human body and can also copy itself
47. Localization of function - specialization of various parts of the brain for particular functions
48. Split brain - surgical separation of the brain’s 2 hemispheres; used medically to treat epilepsy
49. Evolutionary psychology - branch of psychology that studies the ways in which natural selection and adaptation can explain behavior and mental processes
50. Amygdala - area of the brain’s limbic system involved in emotional responses
51. Heritability - a measure of the degree to which a characteristic is related to genetic inherited factors
52. Behavioral genetics - study of the relative effects of heredity and environment on behavior and mental processes
53. Neuroplasticity - the brain’s lifelong ability to reorganize and change its structure and function
54. Nodes of Ranvier - points at which is myelin is very thin or absent on an axon
55. Terminal buttons - at the tip of each branch of an axon; release chemicals called neurotransmiters
56. Refactory period - brief stage that a neuron enters after it fires where it cannot fire again
57. All-or-none law - an action potential either fires completely or not at all
58. Excitatory vs. inhibitory signals - after a neurotransmitter molecule travels across the synapse and attaches to the membrane of the receiving neuron, it delievers either an excitatory or an inhibitory message. The receiving neuron only produces an action potential when the amount of excitatory messages received outweighs the number of inhibitory messages received.
59. Wernicke's area - a section of the left temporal lobe of the brain that is involved in language comprehension. Damage to this area results in failure to understand what is read/heard. Speech is often unintelligible.
60. Broca's area - a section of the left frontal lobe in the brain that is responsible for speech production. Damage to this area results in difficulty speaking.
61. Phineas Gage - a railroad supervisor who was injured on the job and had a metal rod blow through the frontal lobes of his brain. He survived physically, but his personality changed significantly. This incident revealed that the frontal lobes are involved in motivation, emotion, and other cognitive activities.
62. Efferent neurons - neurons that carry impulses OUTWARDS away from the CNS
63. Afferent neurons - neurons that carry impulses INWARDS towards the CNS
64. Sodium potassium pump - an active transport mechanism that moves potassium ions into and sodium ions out of a cell
Interesting Facts: 1. The endrocrine system does more than releasing hormones to regulate our body’s normal functioning, it also plays an important role in responding to emergencies. The hypothalamus sends a message to the neural system and to the endocrine system. Once it reaches the endocrine system, the hormonal message is sent to the adrenal glands which releases “cortisol.” This hormone increases energy and blood sugar levels or also known as “adrenaline.” This adrenaline or “stress hormone” helps one’s body to react and regulate during a high stress situation or crisis.(Huffman, Karen. Psychology in Action. Vols. Eight Edition. Hoboken: John Wiley & Sons, Inc., 2007. Print.))

2. __http://www.youtube.com/watch?v=f-88OtK_iUk__ This youtube video is a helpful tutorial on the transmission of information between two different neurons. It tells how the information passes along the axon of a neuron and then transfers to another neuron through the terminal buttons, and along to the dendrites of another neuron.

3. What is the biological difference between identical and fraternal twins? Identical twins occur when a fertilized egg divides into two separate (but identical) cells that go on to produce two individuals with 100% identical genetic material. Fraternal twins are created when two separate eggs are fertilized by different sperm and go on to develop into two separate individuals sharing around 50% of the same genes. Psychologists often study twins to gain insight about genetic inheritance in humans because of their uniquely high proportion of shared genes. (Huffman, Karen. Psychology in Action. Vols. Eight Edition. Hoboken: John Wiley & Sons, Inc., 2007. Print.)

4. A fact that I found interesting from Chapter 2 was that the word “glial” comes from the Greek word for “glue.” This makes a lot of sense and is very interesting because the glial cells hold the neurons together and surround them, making sure neural messages aren’t scrambled.(Huffman, Karen. Psychology in Action. Vols. Eight Edition. Hoboken: John Wiley & Sons, Inc., 2007. Print.)

5. Split-brain is a lay term to describe the result when the corpus callosum connecting the two hemispheres of the brain is severed to some damage. A patient with split-brain will be unable to vocally name what they have seen. This is because the speech-control center is in the left side of the brain in most people, and the image from the left visual field is sent only to the right side of the brain. (Huffman, Karen. Psychology in Action. Vols. Eight Edition. Hoboken: John Wiley & Sons, Inc., 2007. Print.)

People of Interest:
Terri Schiavo- Her situation showed the importance of the cerebral cortex in being a functioning human being. After suffering an accident involving malnutrition due to her bulimia, she became engulfed in a vegetative state, only surviving off a feeding tube. Scans of her brain show low amounts of brain tissue, resulting from her cerebral cortex failure to function. There was a debate over whether to keep her alive due to ethical reasons, although many advocates of euthanasia say that a person is “dead” once their cerebral cortex lacks the ability to function.
Paul Broca- Best known for his research on Broca’s area- a region of the frontal lobe that has been named after him. Broca’s area is known to play a crucial role in speech development. Broca was the first to discover that patients with damage to this area had great difficulty speaking but could comprehend written or spoken language.
Phineas Gage- He was a 25-year-old railroad supervisor. In the year 1848, a metal mod blew through the front of his face and brain. He was stunned and his extremities shook convulsively, but amazingly the blow was not fatal. He was able to talk and walk around before receiving any medical treatment. Although he survived physically, he did not fare so well psychologically. A serious personality transformation had occurred. According to his friends, “Gage was no longer Gage”. Why did Gage survive this extreme incident and why did his personality change? The rod went through the front part of the brain, which is unnecessary for physical survival. However, this damage to the frontal lobes of his brain resulted in serious personality changes because the frontal lobes are intimately involved in motivation, emotion, and several other cognitive activities.
Carl Wernicke- a German neurologist. He noted that patients with damage in the left temporal lobe of the brain could not understand what they read or heard. But they could speak quickly and easily. However, their speech was often unintelligible. The left temporal area of the brain is now referred to as Wernicke’s area.
Charles Darwin- Charles Darwin, who was born in 1859, started the idea of evolutionary psychology, which suggests that many behavioral commonalities, like fighting and eating, emerged and remain in human populations because they helped our ancestors and ourselves survive. Charles Darwin started this evolutionary perspective and contributed many writings to the subject. He further suggested that natural forces select traits that are adaptive to the organism’s survival and this process of “natural selection” occurs when one particular genetic trait gives a person a reproductive advantage over others.
Roger Sperry- Roger Sperry, born in 1913, was a neuropsychologist, neurobiologist, and a Nobel laureate who won the Nobel Prize in Medicine with David Hunter Hubel on 1981 for split-brain research. He did a lot of experiments on the brain, leading to evidence that suggested that areas of the brain were largely undifferentiated and interchangeable. He showed that after early development, circuits of the brain are largely hardwired. His most famous experiment involved him severing the corpus callosum and discovering that each hemisphere had its own conscious system contributing to the research and understanding of the lateralization of the brain. Chapter 2: Neuroscience and Biological Foundations -The brain and the rest of the nervous system are the power behind our psychological life as well as our physical being -Neuroscience: the scientific study of the biology of behavior and mental processes What is a neuron? -Neuron: a cell of the nervous system that communicates electrochemical info throughout the brain and the rest of the body; tiny information processing system, receives and sends signals to other neurons -Neurons are held in place by glial cells: cells that provide structural, nutritional, and other support for neurons; play a direct role in nervous system communication Basic Parts of a Neuron -3 basic features: -Dendrites: branching structures hat receive electrochemical info from other neurons and transmit it to the cell body -Cell body (soma): accepts the incoming messages -Axon: long, tubelike structure that carries the info away from the cell body

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Remember that info travels through the neuron in REVERSE alphabetical order: Dendrite, Cell body, Axon

-Myelin sheath: white, fatty coating around the axon; helps insulate and speed neural impulses
 *Loss of insulation around the axon can lead to disruption between the flow of info between the brain and muscles, poor muscle coordination - ex. multiple sclerosis
-Tips of branches near the end of each axon are called terminal buttons which release neurotransmitters: chemicals that move the message to the dendrites or cell body of the next neuron -- the message continues
Communication Within the Neuron - The Action Potential (ELECTRICAL)
-Messages received by the dendrites and cell body are passed along the axon in the form of a neural impulse called an action potential: generated when positively charged ions move in and out through the channels in the axon’s membrane
-Once the action potential has started, it continues -- all or none law
-Neuron fires, enters a refactory period (cannot fire), repolarizes, and is then restored with negative ions inside and positive ions outside and is ready to fire again
-Nodes: points at which the myelin on the axon is very thin or nonexistent
-The speed of a neural impulse increases on a myelinated axon because the action potential jumps from node to node rather than traveling point by point along the whole axon
Communication Between Neurons - Neurotransmitter Action at the Synapse (CHEMICAL)
-When the action potential reaches the end of the axon, it reaches the terminal buttons; the transfer of info from one neuron to the next occurs at the junction between them known as the synapse
-Neurotransmitters are released, travel across the synapse, and attach to the membrane of the receiving neuron -- delivers either a excitatory or inhibitory message; most neurons receive both messages, so it only produces an action potential when the number of excitatory messages outnumber the amount of inhibitory messages
*This presence of competing messages is critical or our survival - our nervous system manages to balance between overexcitation (seizure) and underexcitation (death)
Between neurons in Chemical (b/c because) Within neurons in Electrical (w/e whatever)
Neurotransmitters
-There are hundreds of substances in the body that function as neurotransmitters
-Most important ones to psychologists:


Neurotransmitter
Function
Problems associated w/ an excess of defecit
Acetylcholine (excitatory)
Motor movement
Lack of is assosciated w/ Alzheimer’s
Dopamine (excitatory)
Motor movement and alertness
Lack of is associated w/ Parkinson’s; overabundance is associated w/ schizophrenia
Endorphins (inhibitory)
Pain control
Involved in addictions (painkillers often mimic the shape of an endorphin)
Serotonin
Mood control
Lack of is associated with depression

*Low doses of dopamine are associated with Parkinson’s - small Dopey is parking a car*
*High doses of dopamine are associated with schizophrenia - tall Dopey is skiing”*
*Endorphins make you happy - a running door with fins looking
happy*
*Serotonin associated with depression -
Sir Rotten, he’s always in a rotten mood*

Neurotransmitters, Poisons, and Mind-altering Drugs
-Most poisons and drugs act at the synapse by replacing, decreasing, or enhancing the amount of neurotransmitter present
-Agonists: mimic or enhance the action of the neurotransmitter
-
Antagonists: oppose or block the neurotransmitter

Hormones
-The endocrine system is a second type of communication system in our bodies that
uses
hormones to carry it’s messages
-Small brain structures: the
hypothalamus releases hormones that signal the pituitary, which in turn stimulates the release of other hormones

-Hormones are vital; they play important roles in maintaining our body’s normal functioning
-The endocrine system also is in control of our body’s response to emergencies

-In times of crisis, the hypothalamus sends messages to the pituitary, which sends hormonal messages to the adrenal glands which release cortisol (stress hormone), epinephrine (adrenaline), and norepinephrine

Nervous System Organization
-The organization of the nervous system is divided and subdivided into several branches: two separate, but interrelated parts- the central nervous system and the peripheral nervous system.
Central Nervous System: The Spinal Cord and Brain
-Primarily responsible for processing and organizing information.
Spinal Cord
-A great highway of information into and out of the brain.
-Sends information to and from the brain and peripheral nervous system, and controls reflexes.

Brain
-Directs mental processes and maintains basic life functions.

Peripheral Nervous System: Connecting the Central Nervous System to the Rest of the Body
-Carries information to and from the central nervous system. Subdivided into the somatic nervous system and the autonomic nervous system.
Somatic Nervous System
-Controls voluntary muscles and conveys sensory information to the Central Nervous System and sends motor messages to muscles.
Autonomic Nervous System

-Controls involuntary basic life functions, such as heartbeat and response to stress. Further divided into two branches, the sympathetic and parasympathetic nervous systems. These two subsystems tend to work in opposition to each other but balance each other out.
Sympathetic Nervous System
-Arouses body to expend energy and respond to threat - the “fight-or-flight” response.
Parasympathetic Nervous System
-Calms body to conserve energy and restore the status quo - the relaxation response.

The Brain
-The brain can be divided into three major sections: the hindbrain, midbrain, and forebrain.
Lower-Level Brain Structures: The Hindbrain, Midbrain, and Parts of the Forebrain
-Certain brain structures are specialized to preform certain tasks, a process known as localization of function.
Hindbrain
-Three structures generally associated with the hindbrain are the medulla, pons, and cerebellum.
Medulla
-The section of the hindbrain located near the base of the brain.
-Connects the spinal cord to higher regions in the brain.
-Responsible for breathing, heartbeat, and other vital life functions.

Pons
-Located above the medulla.
-Involved with respiration, movement, waking, sleep, and dreaming.

Cerebellum
-Located at the base of the brain behind the medulla and pons.
-Responsible for coordinating fine muscle movement, balance, and some perception and cognition.

-Parts of the cerebellum are also important for basic memory and sensory, perceptual, cognitive, and language tasks.
Midbrain
-Helps coordinate movement patterns, sleep, and arousal.
-Contains a small structure involved with the neurotransmitter dopamine, which deteriorates in Parkinson’s disease.

Forebrain
-A combination of upper-level structures.
-Largest and most prominent part of the human brain.

-Includes several structures including the thalamus, hypothalamus, limbic system, and cerebral cortex.

The Thalamus:
- The major sensory relay center for the brain. It integrates information from many senses
- The Thalamus receives input from almost all the sensory systems and then relays sensory messages to the appropriate area of the cerebral cortex
-It is a forebrain structure at the top of the brainstem
-Injury to the thalamus results in deafness, blindness, possibly Schizophrenia or loss of any sense except smell. Also, any damage may cause the cortex to misinterpret information

The Hypothalamus:
- Responsible for regulating the body’s internal temperature as well as for emotions and drives such as hunger, thirst, sex and aggression. Sometimes called the “Master Control Center”
- Small brain structure beneath the thalamus ( size of a bean)

- Hypothalamus controls the pituitary and releases hormones into it’s blood supply. The Pituitary gland is an endocrine gland that releases hormones to activate other endocrine glands
- Directly controls behaviors or Indirectly controls the ANS and endocrine system
The Limbic System:
- Responsible for emotions, drives and memory
-Interconnected group of structures located along the border of the cerebral cortex and lower level brain structures
- Consists of the formix, hippocampus, amygdala, hypothalamus

-Amygdala produces and regulates aggression and fear
- Research (with rats) suggests that brain stimulation can activate neurotransmitters rather than discrete “pleasure centers”
- Injury can permanently impair social and emotional behavior

The Cerebral Cortex( The center of “higher” processing):
-Responsible for our most complex behaviors and our higher mental processes such as sensations and motor control
- Thin surface (1/8 inch) that is very wrinkled looking on the cerebral hemispheres; convolultions are the “wrinkles” which contain billions of neurons
- Both the cerebral cortex and the two hemispheres have a “Diving line” (or fissure) which seperates the right and left hemispheres
-Injury to the cerebral cortex would cause us to be completely unaware of ourselves

-PVS is persistent vegetative state which is when the cortex functions improperly for more than a month without improvement
- The hemipsheres are divided into 8 areas or lobes. Two frontal lobes, two parietal lobes, two temporal lobes and two occipital lobes
  • Remember Cerebral means “intellectual or academic” to help remember that the cerebral cortex is responsible for the most complex behaviors and mental processes
The Frontal Lobes:
- Largest of the cortical lobes
-located at the top of the two brain hemispheres, behind our forehead ( Ex. Remember Frontal lobes by remembering it is in the “Front” behind our forehead)
-Receive messages from the other 6 lobes of the cortex
- Govern motor control, speech productions, higher functions and memory

1. Motor Control- motor cortex sends messages to various glands and muscles in your body
2. Speech Production- left frontal lobe and contains the Broca’s area which plays a crucial role in speech production ( Ex. Someone would be “broke” if they couldn’t speak to attain a job)
3. Higher Functions- Thinking, personality, emotion and memory are all higher functions that distinguish us from all other living things. If damaged it affects motivation, drives, creativity, self-awareness, initiative, reasoning and emotional behavior
Phineas Gage’s Story: A 25-year-old named Phineas Gage had a metal rod blown through the front of his face and it was not fatal. However, the rod had damaged his frontal lobes and had extremely transformed his personality. So much, that he became very impatient and lazy and never held another stable job in his life.
The Parietal Lobes:
- Two lobes at the top of the brain
- Interpret bodily sensations including pain, touch, temperature, and location of parts

-Somatosensory cortex receives information about touch in different parts of the body than the motor cortex does for the frontal lobes
The Temporal Lobes:
- Two Lobes on each side of the brain above the ears
- Involved in hearing, language comprehension, memory, and some emotional control

- Auditory cortex processes incoming sensory information and sound and then sends it to the partietal lobes
-
Wernicke’s Area is involved in language comprehension and when damaged a person can not understand what they read or hear

The Occipital Lobes:
- Two lobes at the back of the brain
- responsible for vision and visual perception as well as shape, color and motion perception
-Injury can result in blindness

The Association Areas:
- Interpret, integrate, and act on information processed by other parts of the brain
- Known as “quiet areas” because they simply associate various areas and functions of the brain

- EX. Association areas of the frontal lobe help in decision making and planning



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Two Brains in One? A House Divided

-Each hemisphere has separate areas of specialization. This is referred to as lateralization -Injury to one side of the brain produced paralysis or loss of sensation on the opposite side of the body -Phineas Gage’s study documented that accidents, strokes, and tumors in the left hemisphere generally led to problems with language, reading, writing and arithmetic -Led the “silent” right hemisphere to be viewed as the “subordinate” half, lacking special functions or abilities Split-Brain Research -Portrayal of left hemisphere being dominate and right hemisphere being subordinate changed with split-brain research -Showed there is a primary connection between the left and right halves, which is a thick band of nerve fibers under the cortex called the corpus callosum -By cutting this connection, we are able to see what each hemisphere is capable of -The left hemisphere receives and sends messages from and to the right side of the body, and vice versa

Ex.) Even though cutting the corpus callosum is a last resort in surgery, some doctors must do so in cases of severe epilepsy. By doing this, it saves lives and also gives scientists a chance to study both sides of the brain. Hemispheric Specialization -The left hemisphere specializes in in language functions (speaking, reading, writing, and understanding language) and also in analytic functions, like mathematics -The right hemisphere specializes in nonverbal abilities like art, musical abilities, and perceptual and spatiomanipulative skills -Team of researches led by Fredric Schiffer discovered that different aspects of the personality appear in the different hemispheres

Ex.) It is said that right-brained thinkers are better at art and more creative, while left-brained thinkers are said to be better at math and science.


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The Myth of the “Neglacted Right Brain”
-The two hemispheres work together in a coordinated, integrated way with each making substantial contributions
Our Genetic Inheritance
-In order to answer questions about the affect our ancestors have on us and the traits that are passed down, scientists look at behavioral genetics, which is the study of the relative effects of heredity and environment on behavior and mental processes
-They also find answers in
evolutionary psychology, which studies the ways in which natural selection and adaption are connected to behavior and mental processes

-At the moment of conception, your mother contributes a set of 23 chromosomes and your father contributes another set of 23 chromosomes
-Each chromosome is a complex chemical molecule called DNA
-DNA is contained in the mother’s egg cell and the father’s sperm cell

-The DNA molecule is made up of genes, the basic units of heredity
-A single pair of these genes will determine some of your traits
Dominant and Recessive Traits
-A dominant gene reveals its trait whenever the gene is present
-A
recessive gene is expressed only if the other gene in the pair is also recessive
-Characteristics are
polygenic, meaning they are controlled by multiple genes

Ex.)Tongue curling is a trait that depends on only one dominant gene. If a person can curl his or her tongue, at least one parent is also able to do so. If a person is not able to curl his or her tongue, then both the parents have recessive genes for curling and are “noncurlers.”
-Many polygenic traits, like height and intelligence, are also multifactorial, meaning that in addition to being influenced by several genes, they are also influenced by environmental and social factors
Certain recessive gene disorders, like cystic fibrosis, can be passed on to children if they receive the same recessive gene from each biological parent

Methods for Studying Inheritance in Humans
-The option of studying inheritance similarity in humans by selective breeding is not acceptable due to obvious ethical reasons
-There are four special methods used to study inheritance in humans, which are twin studies, family studies, adoption studies, and genetic abnormalities

a) Twin Studies: twin studies are especially useful because of the high rate of shared genes. Monozygotic (identical) twins share 100% of genes and dizygotic (fraternal) twins share 50% of genes. The fact that twins share so many genes make for an easy “natural” study.
-When doing a natural study involving twins, if a trait is shared by both identical twins, scientists can assume that heredity is more common in identical twins than fraternal twins.

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b) Family Studies: scientists study families to see if heredity is current among family members. There is increased similarity between biological relatives than blood relatives.

-For example a brother and sister would have more trait similarities than cousins would.
c) Adoption Studies: adoption studies are unlike any other inheritance study, and show the most unique results than any other study. Adoption studies are also classified as natural studies and are especially important to studies of the environment on heredity.
-For children who more closely resemble their adopted family, then heredity becomes more predominant between that family and the child. However, if the child resembles their biological family, then the environment is more powerful in influencing the child.
d) Genetic Abnormalities: when studying heredity in humans, genetic abnormalities such as mental disorders or inherited diseases becomes an important factor.
-For example an inherited disease called Down Syndrome is the result of an extra developed chromosome.
-These studies on inheritance in humans allow for scientists to measure the highest probability characteristics have to be related to genetic factors. This is also known as heritability.
-There are often many misconceptions revolving genetics and heritability. These misconceptions may arise from misleading public information, or incorrect scientific findings. Some misconceptions include:

1) Genetic traits are not fixed or inflexible. Many people may believe that just because one side of their family has had trouble with heart disease means they are more likely to have trouble with heart disease themselves. This is FALSE. Although they may have a higher chance than someone else, there are many other factors like the environment that can change a person’s vulnerability to heart disease.
2) Heritability estimates do not apply to individuals. Public reports on genetic inheritance on something like intelligence are not based on an indivdual, but a group.
3) Genes and the environment are inseparable. The biopsychosocial model is the basis for biological, psychological, and social forces all meshing together, working together,
and influencing people at the same time.
-Evolutionary Psychology suggests that all traits and actions a person possesses are the bi-product of the traits of our ancestors that have developed in order for us to survive.
-Darwin suggests that
natural selection happens when an individual genetic trait is developed in order to give “reproductive advantage” to a particular species.
-Along with natural selection comes
genetic mutation which implies that since every human has inherited certain traits, we most likely possess a trait that has mutated in order to help us survive.

-For example humans developed a genetic mutation that allowed us to walk on two legs, in order for humans to be able to walk faster and run away for predators.
-Sex Differences occurred in order for our ancestors to be able to reproduce. There was obviously a drastic sex change between male and female, or else we wouldn’t be here today.
-It is important to remember that most differences between men and women are
correlational and that the cause of the difference between men and women has yet to be determined.
-
Neurogenesis and Stem Cells are very important when it comes to the study of the brain and the amount of cells and neurons we, as humans, possess throughout our lifetime. Neurogenesis has helped scientists discover how many neurons a person is born with and how many they produce throughout their lifetime. Whereas stem cells are special cells that create more cells. Stem cells also hold important information regarding the make-up of a human body.