CH 4: Genetics, evolution, Development & Plasticity Flashcards
1
Q
What is Neurolaw?
A
-It is giving more lenient sentencing based upon a person’s genetic makeup
2
Q
Does human behavior depend on genetics, environmental influences or both?
A
-Both bc its Nature & Nurture topic
3
Q
What are Genes at said by Mendel?
A
-They are discrete units of heredity
4
Q
What is the key form of Genes?
A
-They come in pairs= alleles
5
Q
What is a Gene?
A
-They are a portion of a chromosome composed of DNA
6
Q
What is the job of DNA?
A
-It serves as the model for the synthesis of RNA
7
Q
What are the key functions of RNA?
A
- It is a single strand chemical that serves as a template for protein synthesis (this template would be mRNA)
- It controls the sequences of amino acids in a protein molecule
8
Q
What are the key functions of Proteins?
A
-They determine the development of the body by forming part of the structure of the body & serves as enzymes=biological catalysts that regulate chemical reactions in the body
9
Q
What do the sequences of bases along a DNA strand determine?
A
-It determines the order of bases along a strand of RNA
10
Q
How many chromosomes do we have?
A
-23 chromosomes
11
Q
How many chromosomes do we have compared to autosomes?
A
- We have 1 sex chromosome (Y chromosome makes baby male)
- We have 22 autosomes
12
Q
When does a Dominant Gene show?
A
-It shows a strong effect in either homozygous or heterozygous conditions
13
Q
When does a Recessive Gene show?
A
-It shows its effect only in homozygous conditions
14
Q
When does an intermediate gene show?
A
-It occurs in a phenotype where this is incomplete dominance in the heterozygous conditions (skin color, hair color)
15
Q
What are Autosomal genes?
A
-They are basically all other genes except for the sex-linked ones
16
Q
What are Sex-linked genes?
A
- They are genes located on the X of the sex-chromosomes
- The X chromosome is also present in both sexes but only effects females
17
Q
What is a Mutation?
A
-It is a heritable change in DNA molecule
18
Q
What is Microduplication/ Micro detection?
A
-It is part of a chromosome that might appear once, twice or not at all
19
Q
Example of Microduplication?
A
-Schizophrenia bc of the brain relevant genes
20
Q
What is Epigenetics?
A
-It is the field concerned w/ changed in gene expression w/o the modification of the DNA sequence
21
Q
What is the explanation for differences between monozygotic (identical) twins?
A
-Epigenetics boi
22
Q
What alters the activity of Genes?
A
-Experiences
23
Q
How is a Gene turned on?
A
-When an acetyl group is added, histone protein loosens its grip on DNA= facilitates gene expression
24
Q
How is a Gene turned off?
A
-When a methyl group is added to promoter, it turns off the gene
25
How can traits w/ strong hereditary influence be modified?
-Environmental influence (ex. can effect PKU)
26
What is PKU?
-Phenylketonuria= genetic inability to metabolize the amino acid phenylalanine
27
How can PKU be effected by environmental influence?
-If you change your diet to avoid high PKU foods
28
What is the relationship between Genes & Behavior?
- Genes produce proteins that increase the probability that a behavior will develop under certain circumstances
- They can have an indirect impact affect
29
How can genes alter your Environment?
-Via producing behaviors or traits that alter how people in your environment react to you
30
What is Artificial Selection?
-Selecting plants/animals for desired traits
31
What is the fundamental issue of the relationship between genes and behavior?
-It is HOW MUCH genes and environment play into shaping human behaviors?
32
When does CNS begin to form for an embryo?
-at 2 weeks
33
How does the brain begin to form?
- The dorsal tube thickens= forms neural tube surrounding fluid-filled cavity
- The forward enlarges & turns into hindbrain, midbrain & forebrain
- The rest of the neural tube becomes the spinal chord
34
What does the Spinal Chord need in order to develop?
-Folic acid
35
What does the Fluid-Filled (cerebral spinal fluid) cavity become?
- It becomes the central canal of the spinal cord
| - And the 4 ventricles of the brain
36
How much does the human brain weigh at birth?
350 grams
37
How much does an adult brain weigh?
1,200-1,400 grams= 3lbs
38
What are the 5 processes for the development of neurons?
1) proliferation
2) migration
3) differentiation
4) mylination
5) synaptogenesis
39
What is the Proliferation stage of neuron formation?
-It is the production of new cells/neurons that occurs early in life
40
What 3 things happen during the Proliferation stage?
- The cells lining the ventricles divide
- Some cells become stem cells= continues to divide
- Others stay where they are or become neurons/glia that migrate to other locations
41
What is the Migration stage of Neuron Formation?
-The newly formed neurons & glia move to their eventual locations
42
What process takes place during the Migration stage?
-It occurs via cells following chemical path in the brain (immunogloblins & chemokines)
43
What happens if there's a deficiency in immunoglobins & chemokines during Migration stage?
- Impaired migration
- Decreased brain size
- Cognitive disability
44
What is the Differentiation stage of Neuron formation?
-It is the formation of axon & dendrites= gives neurons their shape
45
What processes takes place during the Differentiation stage?
-The axon grows first then the dendrites develop
46
What makes neurons different from one another?
-Size and chemical component depending on their location in the brain
47
What is the Myelination stage of Neuron Formation?
-It is the process where glia produces the fatty sheath that covers the axons of some neurons
48
Where does Myelination first occur?
-In the spinal cord, then in the hindbrain, midbrain, & forebrain
49
What is the Synaptogenesis stage of Neural development?
-It is the development & formation of synapsis between neurons
50
What processes occur during the synaptogenesis stage?
-It occurs throughout life as neurons & are constantly forming new connections while discarding the old ones
51
What are Stem cells?
-They are undifferentiated cells found in the interior of the brain= generates daughter cells= can transform into glia or neurons in olfactory bulb
52
What do new olfactory receptors do?
-They continually replace dying ones
53
What are Rosehip neurons?
- They are a new discovery
- Are unique to primates & humans that forms connections w/ pyramidal
- They are a dense bundle of neurons clustered around the nucleus
- Inhibitory neurons serve as traffic cops
54
What is the lifespan of Skin neurons?
-They are the newest= under a year old
55
What is the life span of heart cells?
-They are actually as old as the person, we don't get new heart cells
56
What is the life span of neurons in mammalian cerebral cortexes?
-Actually no new/ very few formations of neurons after birth
57
How do axons reach their appropriate target?
-They follow a gradient of chemicals ( they are attracted to some but repelled by others)
58
What is a Neurotrophin?
-It is a chemical that promotes the survival & activity of neurons
59
What is Apoptosis?
-It is a preprogrammed mech of cell death for axons that aren't exposed to neurotrophins after making connections
60
What is the Nerve Growth factor?
- aka NGF
| - It is a type of neurotrophin replaced by muscles that promote the survival & growth of axons
61
What allows the brain to have the exact number of incoming axons to the number of receiving cells?
-The system of overproducing neurons & then applying apoptosis
62
What is the purpose of Neurotrophins?
-They increase the branching on axons & dendrites throughout life
63
What is critical for normal development later in life?
-Precise chemical environment bc chemical distortions can cause impairment & developmental problems
64
What is Fetal Alchohol Syndrome?
-A condition that children are born with when their mom drinks heavily during pregnancy
65
How is Fetal Alchohol Syndrome marked?
- Hyperactivity & impulsiveness
- Difficulty maintaining attention
- Varying degrees of cognitive disability
- Motor problems & heart defects
- Facial abnormalities
66
What are the neural characteristics of kids with Fetal Alchohol syndrome?
- They have dendrites w/ short branches
- Suppressed glutamate & enhanced release of GABA
- Neurons receive less excitation & exposure to neurotrophins & undergo apoptosis
67
What are the characteristics of children who were born from cocaine-using mothers?
-They have a decrease in language skills, slight decrease in IQ score, impaired hearing
68
What are the characteristics of children who were born to mothers who used nicotine?
-Increased risk for low birth weight, sudden infant death syndrome, ADHD, long term intellectual defects, impairment of the immune system
69
What can the brain do in response to experience?
-It has the limited ability to reorganize itself
70
What does the gain & loss of dendritic spines indicate?
-It indicates new connections & new info processing
71
What is the relationship between being raised in a vibrant environment w/ others & dendrites?
-If you're raised w/ others you have more dendritic branches and a thicker cortex
72
What effect does extensive practice have on the brain?
-It reorganizes the brain in a way that improves the ability for that skill/maximizes performance
73
What is Focal Hand Dystonia?
- AKA musicians cramp
| - makes fingers clumsy, tired, & produce involuntary movements
74
Why does Focal Hand Dystonia occur?
-Bc theres extensive reorganization of the sensory thalamus & cortex= responses to one finger overlap those of another
75
What is Plasticity?
- The ability to strengthen neural connections @ synapses & establish new connections
- This is also the basis to form new memories & learn new things
76
What do survivors of brain damage show in terms of recovery?
-Subtle to significant behavioral recovery depending on the severity of the damage
77
What do some of the mechs include when trying to recover from brain damage?
-Mechs similar to the branching of axons & dendrites
78
What are the possible causes for brain damage?
- Tumors
- Infections
- Exposure to toxic substances
- Degenerative diseases
- Closed- head injuries (concussions)
79
What are the 3 types of strokes?
- Ischemia
- Hemorrhage
- Aneurism
80
What is Ischemia?
- The most common type of stroke
- caused by blood clot/ obstruction of an artery
- Results in Neurons losing their oxygen & glucose supply
81
What is Hemorrhage?
- Less frequent type of stroke
- Caused by a ruptured artery
- Results in neurons being flooded w/ excess blood, calcium, oxygen, other chemicals
82
What do both Ischemia & Hemorrhage lead to?
- Edema
| - They can also impair the Na/K pump which leads to an accumulation of Na in neurons
83
What is Edema?
-The accumulation of fluid in the brain resulting in increased pressure on the brain & increasing the probability of having further strokes
84
How does Edema & the excess of Na occur?
- They trigger the release of Glutamate which opens the Na/Ca channels
- This leads to overstimulation of neurons= damaging neurons & synapses
85
What are some treatments after stroke?
- Drugs that breaks up blood clots or blocks Ca entry
- Weed
- Omega 3 fatty acids
86
How can the application of Omega 3- Fatty acids be used as treatment after brain damage (stroke)
- Omega 3's are a large component of cell membranes
| - They block apoptosis & other neural damage
87
What is Diaschisis?
-Decreased activity of surviving neurons after damage to other neurons
88
What can happen to the brain after brain damage has occurred?
-The cell bodies cannot be replaced BUT the damaged axons can grow back under certain circumstances (therapy)
89
How much can damaged axons regenerate in mature mammals?
1-2 mm
90
What can scar tissue do?
-It makes a mechanical barrier to axon growth
91
What are Collateral Sprouts?
- New branches formed by other non-damaged axons that attach to vacant receptors
- The sprouts that fill in can be useful, neutral or harmful (depending if they in the right place)
92
What do cells release when they have lost their innervation?
-Neurotrophins= induce axons to form collateral sprouts
93
What is Denervation Supersensitivity?
-The heightened sensitivity to a neurotransmitter after the destruction of an incoming axon
94
What is Disuse Supersensitivity?
-The hypersensitivity to a neurotransmitter after a result of inactivity by an incoming axon
95
What can be the treatment for Phantom Limb?
- Learned adjustments
- Prosthetics
- VR
96
What is Phantom Limb?
- continuing to fell sensation of an amputated body part
| - The cortex reorganizes itself post-amputation & the original axons degernate= other axons nearby sprout in
