Biology - Brain And Behaviour Flashcards
(33 cards)
What is the comparison between modern and historical concepts of mind?
Historical= dualism - ourself is separate from the mind e.g. We can switch body with another and retain our essential self (Descartes) Current = the mind is dependent on the body and your consciousness will not survive in another neutral structure (monism)
What are the individual differences in brain structure?
- Alzheimer’s disease = a lot less grey matter in the brain
- every brain is unique even siblings
- a 43 year old alcoholic has the same brain damage as an 87 year old with Alzheimer’s
What is the relationship of psychobiology to other areas of psychological endeavour?
Physiological psychologists= hippocampal lesions e.g. HM
Psychopharmacologists= neurochemostry of Alzheimer’s disease - the role of acetylcholine in memory
Neuropsychologists= alcohol produced brain damage- Korsakoff’s syndrome
What are sensory neurons?
Carrying messages to the central nervous system
What are motor neurons?
Carrying messages to the central nervous system to the voluntary muscles
What is the order how it works when touching something?
Skin receptors, sensory neurons (incoming information), interneurons, motor neurons (outgoing information), muscle pulls away
What is a glial cell?
Cell surrounding neuron holding them in place providing nutrients neurons need and isolating toxins that would harm the neurons
What is the hindbrain?
The lowest and most primitive level of the brain
Brain stem= support vital life functions,includes medulla and pons
Medulla= plays an important role in vital body functions such as heart rate and respiration. Damage = death
Pons= liés just above the medulla and carries nerve impulses between higher and lower levels of the nervous system = also has clusters to regulate sleep damage = death
Cerebellum= concerned primarily with muscular movement coordination but also plays a role in learning and memory, easily disrupted by alc and damage can result in severe motor disturbances
What is the midbrain?
Contains clusters of sensory and motor neurons
Has motor neurons that control eye movements
Reticular formation= acts as a kind of sentry, both altering higher centres of brain that messages are coming and then either blocking those messages or allowing them forward
Has a central role in consciousness, sleep and attention
^without reticular stimulation of higher brain regions, sensory messages do not register in conscious awareness
What is the forebrain?
The brains most advanced portion from an evolutionary point
Cerebrum= consists of two large hemispheres a left side and a right side.
Cortex = thin layer covering the outer portion of the forebrain
Thalamus= has sometimes been linked to a switchboard that organises inputs from sensory organs and routes them to the appropriate areas of the brain
^visual, auditory and body senses have major relay stations there
^key role in routing sensory info to higher brain
Hypothalamus= plays a major role in many aspects of motivation and emotion, including sexual behaviour, temperature regulation, sleeping, eating, drinking and agression
Important connection with the endocrine system (body’s collection of hormone producing glands)
Involved in our experience of pleasure and displeasure
Limbic system= set of structures lying deep within the cerebral hemispheres, helps coordinate behaviours needed to satisfy motivational and emotional urges that arise in the hypothalamus
Hippocampus= involved in forming and retrieving memories
Amyglada= organises motivational and emotional response patterns, particularly thise linked to aggression and fear
Cerebral cortex= 0.63cm thick sheet of grey (unmyelinated) cells that form the outermost layer of the human brain
Motor cortex= controls 600 or more muscles involved in voluntary body movements
Sensory cortex= receives sensory input that gives rise to our sensations of heat, touch and cold and to our senses of balance and body movements
Wernickes area= in the frontal lobe, is primarily involved in speech comprehension
Broca’s area= in the frontal lobe, is mainly involved with the speech production through its connections with the motor cortex region that controls the muscles used in speech
Association cortex= involved in many important mental functions including perception language and thought
Prefrontal cortex= located just behind the forehead is the seat of so called executive functions e.g. Mental strategic planning
What is neural plasticity?
The ability of neurons to change in structure and function
What is the adrenal gland?
Twin structures perched on top of kidney that serve as hormone factories producing and serving about 50 different hormones
What are the three components to the Neuron?
Cell body, dendrites, axon
^cell body also called soma and contains the biochemical structures needed to keep the neuron alive and its nucleus carries the genetic information that determines how the cell develops and functions
Dendrites= specialised recieveing units like antennae that collect messages from the neighbouring neurons and send them onto the body
Axon= conducts electrical impulses away from the cell body to other neurons, muscles or glands
What is the mechanism of the resting and action potential, and of synaptic transmission?
- Resting potential= due to distribution of positively and negatively charged chemical ions inside and outside of the neuron/When the axon membrane is stable, an excess of positively charged ions is on the outside, resulting in negative voltage difference.
- Action potential= occurs when stimulated. A flow of ions in and out through cell membrane reverses the electrical charge of resting potential. This is the nerve impulse/Ion movement leads to an excess of positively charged particles inside the membrane, which produces a positive voltage swing.
- Original ionic balance is restored and neuron is again at rest/There is also a pump that uses energy to move three sodium ions out of the neuron for every two potassium ions it puts in.
• At rest, again there are relatively more sodium ions outside the neuron and more potassium ions inside that neuron
What is a synapse?
A tiny gap between the axon terminal and the next neuron
What are neuron transmitters?
Chemical substances that carry messages across the synaptic space to other neurons, muscles or glands
What is the sequence of events for the action potential?
- The neuron membrane is disturbed
- The sodium channel opens and sodium floods in
- When the voltage reaches -55 the neuron fires sending a wave of electrical impulse along the neuron.
4 Sodium channels close and Potassium opens reversing the depolarisation - Potassium channels close…resting potential again
How do neurons communicate by synaptic transmissions?
Synthesis, release, binding and deactivation
o Synthesis
▪ Transmitter molecules are formed inside the neuron
▪ They are stored in the synaptic vesicles
• Synaptic vesicles = chambers within axon terminal
▪ Vesicles move to the surface of the axon terminal when there is Action Potential
o Release
▪ There, they are released into fluid-filled space between axon of presynaptic neuron and membrane of postsynaptic neuron
o Binding
▪ Molecules bind on receptor sites of postsynaptic membrane
• Receptor Side = large protein molecules embedded in the receiving neuron’s cell membrane
▪ Receptors and neurotransmitters are like lock and key
▪ Neurotransmitter can be either excitatory (creates depolarisation in receiving neuron) or inhibitory (causes potassium ions to flow out of neuron, makes it more negative)
• To function properly, fine-tune balance between excitation & inhibition must be met
o Deactivation
▪ Can either be deactivated or shut off
▪ Some are deactivated by other chemicals in synaptic space that break them down into different components or
▪ Re-uptake = the transmitter molecules are taken back into the presynaptic axon terminal
• Some antidepressants inhibit re-uptake of excitatory transmitter serotonin
How do drugs effect the brain?
• Psychoactive drugs = chemicals that produce alterations in consciousness, emotion & behaviour
• They effect either by increasing or decreasing the synthesis, storage, release, binding or deactivation of neurotransmitters
• Agonist = drug that increases the activity of a neurotransmitter
o Can either mimic action of neurotransmitter by binding with receptor site, enhance neuron’s ability to synthesise, store or release neurotransmitter, inhibit re-uptake
• Antagonist = drug that inhibits or decreases the action of a neurotransmitter
o Prevent neurotransmitter from binding with postsynaptic neuron by fitting in or blocking receptor side, reduce ability to synthesise, store or release neurons
• Many Examples
o Alcohol
▪ Both Agonist & antagonist effects
▪ Agonistà stimulates activity of inhibitory transmitter GABA
▪ Antagonistà decreases activity of glutamate
▪ Double-barrelled effect = neural slowdown that inhibits normal brain function, clear thinking, emotional control à can appear with a couple of drugs (e.g. tranquilisers)
o Caffeine
▪ Increases activity of neurons & other cells. It’s an antagonist for adenosine, an inhibitory transmitter
o Nicotine
▪ Agonist for the excitatory transmitter acetylcholine (can bind to its receptors), so stimulates dopamine activity
o Amphetamines (e.g. Cocaine)
▪ Boost arousal & mood by increasing excitatory dopamine & norepinephrine and inhibit their re-uptake
o Rohypnol & GHB
▪ Date-rate drugs
▪ Lowers inhibition & facilitating non-consensual sexual conquest
▪ May lead to respiratory depression, loss of consciousness, even coma or death
What are genes?
They are building blocks of life
They code for proteins that make us work and make us
What is gene expression?
Whether or not a gene is turned on or off
What is homozygous?
2 identical genes on the two chromosomes
What is hetrozygous?
An unmatched pair of genes on the two chromosomes
What is a dominant and a recessive gene?
Dominant= shows a strong effect in either the homozygous or heterozygous condition – tasting PCT is dominant Recessive= shows its effect only in the homozygous condition – not tasting PCT is recessive
