Chapter three Flashcards
Behavioral genetics
The study of the role of heredity in behaviour
Three principles of behavioral genetics
1) Behaviors come from many genes, not just one or two, the relationship between genes and behavior is complex
2) By studying twins and adoptees, or by manipulating genes in animals can help separate behavior caused by environment and behavior caused by genes
3) The environment influences how and when genes affect our behavior
Twin Studies
Research into hereditary influences involving comparing fraternal and identical twins
Adoptive studies:
adoptive people are compared to their biological and adoptive parents
Twin- adoption studies
Research into twins, both fraternal and identical, who were adopted and raised apart and those who were raised together
Gene-by-environment study
to study heritability, it allows researchers to assess how genetic differences interact with the environment to produce certain behaviours in some people but not in others
- studies parts of the genome itself and examines how different variants act with different kinds of environments to produce different kinds of behaviours
- variation example: the same gene in different people might differ in how many particular DNA sequences it has.
What is the genetic sequence antisense?
A synthetic DNA sequence used to block the expression of a gene
What is a knockout?
a small animal that has had a specific gene removed
What is a transgenic?
an animal that has had a foreign gene inserted from its genome
What is epigenetics?
the principle that genes can be turned off or on without change to the sequence of DNA
Example of epigenetics?
When we eat or drink certain things and sometimes when we exercise, molecular tags known as methyl groups can get attached to specific nucleotides in the DNA, targeting cytosines. These tags can turn off certain genes
Real life example of animal epigenetics?
rats that lick their offspring produce less stressed-out babies
changes the way their stress gene is expressed
What does the central nervous system contain
brain and spinal cord
what does the peripheral nervous system contain?
the somatic and autonomic nervous systems
What does the autonomic nervous system contain?
the sympathetic and the parasympathetic nervous system
What part of the NS is “fight or flight”?
the sympathetic nervous system
What part of the NS is “rest and digest”?
the parasympathetic nervous system
What do glial cells do
structural support of CNS and PNS
90% of the brain cells are glial cells
What is the soma?
The cell body
What is the myelin sheath?
substance that insulates the axon of some neurons, at regular intervals along the axon’s length
What is the myelin sheath made of?
oligodendrocytes and schwann cells
What are the gaps in the myelin sheath?
nodes of raviner
they functino for electrical impulses to jump along the axon much quicker
What is “white matter” in the brain
part of brain with myelinated axons
Grey matter?
cell bodies, dendrites and small unmyeinated neurons
the neuron before the synaptic cleft is called what
the presynaptic neuron
the neuron after the synaptic cleft is called what
The postsynaptic neuron
Sensroy neuron
recieve incoming sensory information
motor neurons
take infor/commands from brain to muscles
interneurosn
communicate with other neurons, relaying information
What are the two jobs of a neuron
1) transmit a message to its target neuron across synapse
2) transmit messange along itself
What is a graded potential?
chemical communication at the synapse
action potentials?
all signal to travel all the way down the neuron
what generates graded potentials?
neurotransmitters when they are released into the synaptic cleft, all started by action potentials
What generates action potentials?
graded potentials, some of the time, produce action potentials in the next neuron
what is resting potential and what does it mean
resting potential of the neuron is -70mV
this means the inside of the cell is slightly more negative than the outside of the cell
transmitter dependent channels
open when a specific neurotransmitter binds to it
voltage-dependant channels
open when there is a change in the electrical gradient along the neuron
What are synaptic vesicles
sacs neurotransmitters are packaged in in the presynaptic terminal
depolarization
when the charge difference between the inside of the neuron and the outside of the neuron lessens. \the inside of the neuron becomes less negative
hyperpolarization
when the charge difference between in the inside of the neuron and the outside of the neuron becomes greater.
the charge on the inside of the neuron becomes more negative
threshold?
-55mV all or nothing, if it reaches this action potential happens
What happens when an action potential happens
1) sodium channels open allowing Na
this temporarily raises the charge to 40mV
2)as the impulses travel down neurons. potassium, K, channels open which allow K to exit the neuron
restoring the resting potential
3)This continues until cell is super-negatively charged “refractory period” when the neuron cannot generate another action potential
4) once action potential reaches terminal, third ion gate opens
Enzymatic degradation
the process of deactivating a neurotransmitter at synapse where specific enzymes alter the neurotransmitters so nothing can bind to receptors
presynaptic reuptake
removing excess neurotransmitters from the synapse, packaging them in special proteins and returning them to the presynaptic neuron for future use
action or graded potential potential for a long distance message
graded potential
