chapter 4

Question 1

what r the 2 types genes

Answer 1

sex linked and all other

Question 2

two ways genes can change

Answer 2

mutation: heritable change in a dna molecule

micro deletion / duplication - part of a chromosome that might appear once may appear twice or not at all

Question 3

explain the 2 widely studied mechanisms of epigenetic

Answer 3

histone remodelling -histone changes she and influences the shape of adjacent DNA ..can influence or decrease gene expression\

DNA methylation: methyl group attaches and tends to reduce adjacent DNA expression

Question 4

overtime what happens to intelligence correlations between adopted siblings

Answer 4

decreases

Question 5

genes account for about ____ percent of characteristics

Answer 5

50

Question 6

what is PKU ? how can it be influenced

Answer 6

genetic inability to metabolize the amino acid phenylalanine …changes in diet can fix

Question 7

how do genes produce behavior

Answer 7

produce proteins that increase the probability that a behavior will develop under certain circumstances

Question 8

explain maturation of the brain

Answer 8

begins to form when an embryo is 2 weeks

1. dorsal surface thickens, forming a neural tube surrounding a fluid filled cavity
2. the forward end enlarges and differentiates into the hind brain, midbrain and forebrain
3. the rest of the neural tube becomes the spinal cord

Question 9

what are the 5 stages of development of neurons

Answer 9

proliferation, migrarton, diffraction, myelination, synaptogeniss

Question 10

3 parts of proliferation

Answer 10

production of new cells/neruons
early in development the cells lining the ventricles divide
some cells become stem cells that continue to divide

Question 11

what is important about migration

Answer 11

chemicals known as immunoglobulins and chemokine guide neuron migration

Question 12

what chemicals guide migration

Answer 12

immunoglobulins and chemokine

Question 13

what is differation

Answer 13

forming of the axon and dendrites that gives the neuron its distinctive shape …axon grows first

Question 14

what order does myelination occur

Answer 14

spinal cord, hind brain, mid brain, forebrain

Question 15

what is synaptogenisis..whats important about time

Answer 15

the formation of the synapses between neurons ..occurs throughout life as neurons are constanty forming new connections and discarding ……slows significantly later in lifetime

Question 16

what does newer research on new neurons later in life say

Answer 16

stem cells: undifferentiated cells found in the interior of the brain that generate “daughter cells “ that can transform into glia or neurones

stem cells differentiate into new neurons in the adult hippocampus of mammals and faccilitate learning

Question 17

what did sherry’s research with newts show about axons

Answer 17

that they follow a chemical trail to reach their approximate target …by taking out eyes and rotating and then allowed them to recover

Question 18

describe duane syndrome

Answer 18

the nerves controlling the eye muscles send some of their axons to the wrong destinations
-try to turn eye message goes to muscle to contact

Question 19

describe competition among axons

Answer 19

when axons initially reach their target they form synapses with several cells

-post synaptic cells strengthen connection with some cells and eliminate connection with others

it depends on the pattern of incoming axons

Question 20

what are neurotropins

Answer 20

chemicals that promote the survival and activity of neurons….axons that are not exposed to neurotropins undergo apoptosis …matches axons to number of receiving cells…impotant for healthy brain

Question 21

what’s an example of a neurotropic

Answer 21

never growth factor: released by muscles that promotes the survival and growth of axons

Question 22

what does alcohol exposure cause physiologically

Answer 22

short dendrites with fewer branches, suppression of glutamate and enchantment of gaba…less excitation and exposure to neurotropins than usual and undergo apoptosis

Question 23

what allows for more surface area for connections

Answer 23

dendrites continuously grow new spines

Question 24

the gain and loss of spines indicates

Answer 24

new connections which relates to learning

Question 25

what is an example of effects of special experiences

Answer 25

blind people improve attention to touch and sounds…occipital lobe can adapt to also process tactile and verbal information…touch activates occipital cortical area

Question 26

what is another special experience in relation to music

Answer 26

temporal lobe right hemisphere of musicians is 30 percent larger than non musicians….thicker grey matter precentral gyrus

results suggest that practicing a skill reorganizes brain to maximize performance of that skill

Question 27

what is the condition where reorganization of brain goes to far in musicians..what happens

Answer 27

focal hand dystonia ..fingers become clumsy fatigue and make involuntary movements ,,,,result of extensive reorganization of the sensory thalamus and cortex so touch responses to one finger over lap another

Question 28

some recovery of brain damage relies on what

Answer 28

growth of new branches of axons and dendrites

Question 29

5 examples of brain damage

Answer 29

tumors: abnormal proliferation cells
infections: tissue surrounding, fluid surrounding meininges

exposure to toxic substances or radiation …carbon dioxide

degenerative disease…parkkinsons

closed head injuries

Question 30

what is a stroke or cerebrovascular accident

Answer 30

temporary loss blood flow ro the brain

-common cause brain damage in the elderly

Question 31

what are the two types of strokes

Answer 31

ischia: most common..result of a blood clot or an obstruction of an artery ..also tia :transient ischemic attack.mini stroke
hemorrhage: less frequent, ruptured artery ..neurons flood excess blood and chemical…neurons loose oxygen,,,,usually permanent

Question 32

what do strokes cause?

Answer 32

edema: accumulation of fluid in the brain resulting in increased pressure and likelihood of further strokes
-disruption sodium potassium pimp
-release glutamate
sodium other things enter cell
blocks metabolism in mitochondria
kills the neuron

Question 33

how do we save neurons from death

Answer 33

blocking glutamate synapses and calcium entry thus blocking cell death

Question 34

3 stroke treatments?

Answer 34

tissues plasminogen activator…breaks up loot clots can reduce effects of ischmic strokes

blocking glutamate synapses and calcium entry

therapeutic hypothermia …cooling protects brain after ischmeia by reducing overstimulation apoptosis and inflammation….used a lot in cardiac arrest and is most successful

Question 35

what is diaschsis

Answer 35

decreased activity of surviving neurons after damage to other neurons. occurs cause activity in one area stimulates areas in others

Question 36

describe axonal regrowth in brain recovery

Answer 36

axons cannot regenerate but collateral sprouting can occur from an intact axon

Question 37

descrive denervation supersensitivity

Answer 37

tightened sensitive to a neurotransmitter after the destruction of an incoming axon,,,can cause chronic pain

Question 38

what is it called when there’s an illusion of an extra limb

Answer 38

supernumerary

Question 39

explain phantom limb

Answer 39

the continuation of sensation amputates body part. the cortex reorganizes itself by become responsive to other parts of the body..original axons degenerate leaving vacant synapses into which the axons….brain confuses it for that area of the body

Question 40

explain deafferented limb and what often people do

Answer 40

limbs that have lost their afferent sensory input. they can be used but harder so usually use something else