Topic 3 - Biological Foundations Flashcards
What are neurons?
The building blocks of the brain.
What are the four types of neurons?
- Sensory neurons
- Interneurons
- Motor neurons
- Glial cells
What do sensory neurons do?
Help recode and transmit outside information to the spinal cord and brain.
What do interneurons do?
Communicate with other neurons.
What do motor neurons do?
Transmit messages from the central nervous system to the muscles.
What is the ratio of glial cells to neurons and what do they do?
10:1, these cells are important for waste disposal, axon protection, learning, and memory.
What is the basic journey through the neuron?
- Dendrite
- Nucleus
- Axon
- Axon terminal
- Synapse
What do dendrites do?
Absorb chemical stimulation from other neurons.
What does the nucleus do?
If there’s enough dendritic activity, it fires action potentials.
What does the axon do?
Conducts the electrical signal to axon terminals.
What does the axon terminal do?
Turn the electrical signal into a chemical squirt.
What is the synapse?
The jump the chemical has to make to be taken up by the next dendrite.
How do we observe action potentials?
Attaching microelectrodes to neurons.
Approximately how long does it take action potentials to fire?
5ms.
What are the steps for firing an action potential?
- Resting charge of -70mV
- Depolarization to positive charge
- Repolarization to negative charge
- Refractory period resulting in overcompensated negative charge
- Return to resting state in 5ms
What is the resting potential of the neuron?
The electrical charge inside the neuron when the neuron is at rest and receiving no stimulation.
When does an action potential become more likely?
When the negative resting potential becomes positive or when it becomes more negative because of hyperpolariztion.
What is another way in which information between neurons can be transmitted?
Through changes in chemical energy.
What are neurotransmitters?
Keys that unlock the gate for certain ions to jump through.
What do excitatory neurotransmitters do?
Allow positively charged ions into the postsynaptic cell, increasing the chance of an action potential.
What do inhibitory neurotransmitters do?
Allow negatively charged ions into the postsynaptic cell, decreasing the chance of an action potential.
What two ways do neurotransmitters reset?
- Terminal reuptake
- Chemical breakdown
What are some important neurotransmitters?
- Acetylcholine
- Norepinephrine
- Serotonin
- Dopamine
- GABA
What are some synthetic neurotransmitters?
- Botoz
- Prozac
How are differences in the sensory environment coded?
Changes in the rate of axon firing.
What is key about the autonomic nervous system?
It’s involuntary.
What does the parasympathetic nervous system do?
Maintains bodily function and inhibits the sympathetic.
When does the sympathetic nervous system activate?
When under pressure.
What does the somatic nervous system do?
Voluntary, controls sensory and motor nerves.
What are the three axes of the brain?
- Ventral (bottom) dorsal (top)
- Anterior (front) posterior (back)
- Medial (central) lateral (closer to ears)
What is the cerebral cortex?
The part of the brain that controls conscious function and psychology is most interested in.
What does the corpus callosum do?
Maintains connections between the brain’s hemispheres.
What does the thalamus do?
Relays key sensory signals (except smell) to the cortex.
What does the hypothalamus do?
Controls the endocrine (hormonal) system.
What is the hippocampus?
The hub related to learning, memory, and space.
What does the cerebellum do?
Regulates balance and body control.
What does the brain stem do?
Regulates breathing and heart rate.
What does the frontal lobe relate to?
Personality and executive functioning.
What is the homonculus?
Essentially, a map of the body on the brain, located on the parietal lobes.
What do temporal lobes do?
Help process auditory information.
What is Wernicke’s area
A part of the brain that deals with word repetition (not comprehension).
What does the occipital lobe do?
Processes visual information.
What does using the homonculus help treat?
Phantom limb.
What happened to Phineas Gage and what did he help us understand?
A railroad rod penetrated through his left eye, lowering his benevolence and agreeableness. He helped us understand the functions each part of the brain performs.
How can we observe the brain and brain damage?
- Before and after studies
- Lesion studies
- Dissociation deficits
What do lesion studies focus on?
The removed part of the brain.
What do single-dissociation deficits focus on?
The dissociation between behaviours in a single participant with a lesion.
What do double-dissociation deficits focus on?
The dissociation between behaviours between two people with mirror image lesions.
What does TMS do and what is an advantage and disadvantage?
Disrupts brain’s magnetic fields:
- Pro: safe way of simulating lesions
- Con: effects are not long lasting for epileptic samples
What does ERP do and what is an advantage and disadvantage?
Records electrical fields:
- Pro: very precise
- Con: spatially diffuse
What does PET do and what is an advantage and disadvantage?
Records distribution of glucose:
- Pro: allows for insights into the functionality of brain regions
- Con: poor spatial resolution, involves radioactive substances
What does MRI do and what is an advantage and disadvantage?
Records distribution of oxygenated blood:
- Pro: helps reveal brain networks
- Con: BOLD signal slow, not sure what it means
What does the endocrine system do?
Interacts with the autonomic nervous system for body regulation and secretion of hormones into the bloodstream.
What is the pituitary gland?
The main secretor of testosterone and estrogen.
When does the adrenal gland kick in?
When in trouble, it kicks in with norepinephrine and epinephrine, mobilizing the body by increasing glucose and heart rate.
What does the immune system do?
Figures out good and bad substances and generates antibodies to destroy biological enemies.
What is a consequence of an external threat to an under-active immune system?
Infection.
What is a consequence of an internal threat to an under-active immune system?
Cancer.
What is a consequence of an external threat to an over-active immune system?
Allergy.
What is a consequence of an internal threat to an over-active immune system?
Auto-immune reaction.
What is an allergy?
An over-reaction of the immune system to an external threat that results in the excretion of too much histamine.
What is an autoimmune reaction?
An incorrect attack by the immune system on our own body.
How many cells does each body have?
100 trillion.
What cells don’t contain a nucleus?
Red blood cells.
How many chromosomes does each nucleus contain?
46, arranged in 23 pairs.
Where does each chromosome come from?
One from each parent.
What are genes?
Segments of DNA that hold instructions to make proteins, the building blocks of life.
What are phenotypes?
Expressed characteristics inherited from your parents.
What are genotypes?
Non-expressed characteristics from your parents.
When is a trait recessive?
When both parents contain the gene and it’s passed onto you. They can be expressed even if both parents don’t express it.
What is the probability of sharing a gene with your biological parent?
50%.
What is the probability of sharing a gene with your biological grandparent?
25%.
When will dominant genes be expressed?
Only when you have one copy.
How do we study nature versus nurture in twins?
Find identical and fraternal twins separated at birth and raised in different environments.
What are the components of the five-factor model?
- Openness
- Conscientiousness
- Extraversion
- Agreeableness
- Neuroticism
What is the heritability coefficient?
The extent to which genetics account for within-variation in a group of individuals.
What increased through time due to adaptation?
Brain size.
What decreased through time due to adaptation?
Jaw and teeth sizes.
What is the key principle of evolution?
Characteristics that facilitate reproduction are more likely to be transmitted and vice-versa.
What is evolutionary noise?
Currently neutral characteristics that may be transmitted in the future.
What is a new adaptation phasing in?
Reading.
What is an old adaptation phasing out?
A predisposition for sweet food.
