The Brain And Behaviour Flashcards
Approximately how much does the brain weigh
1400g
What are the basic building blocks of the nervous system
Neurons
What are the three main parts of neurons
Soma
Dendrites
Axon
Where is the soma in a neuron
The cell body
What are dendrites
Specialised receiving units that collect messages from neighbouring neurons and send them on to the cell body
What do axons do
Conduct electrical impulses away from the cell body to other neurons, muscles or glands
What do neurons do
Generate electricity that creates nerve impulses
Release chemicals to communicate with neurons, muscles and glands
What are the three stages neurons go through
Resting potential
Action potential
Resting potential again
What occurs during resting potential
Neuron is separated from surrounding fluid by a cell membrane; substances pass through ion channels
What causes polarisation
Inner ions are more negatively charged that outer ions, resulting in a net negative charge for the resting neuron
What is action potential
An electrical shift that occurs when a neuron is stimulated
What causes depolarisation
Positive sodium ions entering the neuron
When does polarisation occur
During resting potential
When does depolarisation occur
During action potential
What is the absolute refractory period
The recovery period that occurs after the action potential passes along each point on the axon
What is the all or none law
Action potentials occur either at uniform and maximum potential, or not at all
Define graded potentials
Changes in the negative resting potential that do not reach the action potential threshold
What is the myelin sheath
A layer of fatty insulation that surrounds the axon
What colour is myelin
White
What does the myelin do
Allows electrical conduction to take place at a higher speed than unmyelinated axons
When does the myelin completely form in many neurons
Some time after birth
What can damage to the myelin sheath cause
Multiple sclerosis
How do neurons communicate with other cells
Through synapses
What are synapses
The conjunction of an axon terminal of one neuron and the membrane of another cell
What is the synaptic space
A tiny gap between the axon terminal and the next neuron
What are pre synaptic neurons
Neurons that send messages
What are post synaptic neurons
Neurons that receive messages
What are neurotransmitters
Chemical substances that carry messages across the synaptic space to other neurons, muscles or glands
What are the 5 steps neurotransmitters go through
Synthesis Storage Release Binding Deactivation
What occurs during the synthesis stage of neurotransmitters
The transmitters are formed
What occurs during the storage stage of neurotransmitters
Transmitter molecules are stored in synaptic vesicles in axon terminals
What happens during the release stage of neurotransmitters
Action potential causes transmitter molecules to move from synaptic vesicles across the gap
What happens in the binding stage of neurotransmitters
Transmitter molecules bind themselves to receptor sites embedded in the receiving neurons cell membrane
What are the two ways deactivation of neurotransmitters occur
Broken down by other chemicals
By reputake
What occurs in reputake
Transmitters are taken back into the presynaptic axon terminal
What is the first stage neurotransmitters go through
Synthesis
What is the second stage neurotransmitters go through
Storage
What is the third stage neurotransmitters go through
Release
What is the forth stage neurotransmitters go through
Binding
What is the fifth stage neurotransmitters go through
Deactivation
What are the two types of chemical reactions that can occur when a neurotransmitter binds to a receptor
Excitatory
Inhibitory
What does an excitatory reaction cause
It causes the action potential to fire
What does an inhibitory reaction cause
Prevents the neuron from firing
What does ACh stand for
Acetylcholine
What us acetylcholine
A neurotransmitters involved in muscle activity and memory
What is underproduction of acetylcholine a cause of
Alzheimer’s
What drugs block acetylcholine
Botulism
Botox
What can cause overproduction of acetylcholine
Black widow spider bites
What are neuro modulators
Chemicals which modulate sensitivity of 1000s of neurons to their specific transmitters
What is the best known category of neuro modulators
Endorphins
What do endorphins do
They travel through the brain inhibiting pain transmission while enhancing pleasurable feelings
What are the three main types of neurons in the nervous system
Sensory neurons
Motor neurons
Inter-neurons
What do sensory neurons do
Carry input messages from the sense organs to the spinal cord and brain
What do motor neurons do
Transmit output impulses from the brain and spinal cord to the body’s muscles and organs
What do inter-neurons do
Perform connective or associative functions within the central nervous system
What are all three types of neurons in the nervous system required for
A simple withdraw reflex
What does the peripheral nervous system contain overall
All the neural structures outside the brain and nervous system
What are two systems in the peripheral nervous system
Somatic nervous system
Autonomic nervous system
What is the somatic nervous system
A system of sensory and motor neurons that allows us to sense and respond to our environments
What is the autonomic nervous system
A system that senses the body’s internal functions and controls many glands and muscles
What are the two subdivisions of the autonomic nervous system
Sympathetic
Parasympathetic
What is the sympathetic nervous system needed for
Activation or arousal function
What is one thing controls by the autonomic nervous system
Fight or flight reflex
What does the parasympathetic nervous system do
Slows down the body, maintains a state of internal equilibrium
What is homeostasis
A delicately balanced or steady internal state
What does the central nervous system consist of
The brain and spinal cord
What is the spinal cord
A densely packed bundle of nerve fibres that run along the spine and which transmit messages from sensory and motor neurons
What do neuropsychological tests do
Measure verbal and nonverbal behaviour of brain damage sufferers
What is EEG used for
Recording electrical activity of neurons
How is EEG used
Electrodes are attached to the scalp and record the activity of groups of thousands of neurons
What is an issue with EEG
Not very specific
How is EEG seen
In the form of line tracings or readouts
What are examples of brain imaging
MRI
CT
PET
FMRI
What brain scans measure the structure of the brain
MRI
CT
What brain scans measure brain activity
PET FMRI
How do CT scans work
They use x-Ray technology to study brain structure
How do MRI scans work
It creates images based on how atoms in living tissue respond to a magnetic pulse from the device
What do PET scans do
Measure brain activity, including metabolism, blood flow and neurotransmitter activity
What do FMRI scans do
Produce pictures of blood flow in the brain taken less than a second apart
What are three issues with brain imaging
It’s easy to locate brain areas but interconnectivity is also important
Not precise enough yet
Knowing where doesn’t tell us what, how or why
What are the three major subdivisions of the brain
Hindbrain
Midbrain
Forebrain
Whoa is the hindbrain
The lowest and most primitive level of the brain
What does the hindbrain contain
Brain stem
Cerebellum
What does the brain stem control
Basic but vital life support functions
What are in the brain stem
Medulla
Pons
What does the medulla do
Plays a key role in heart rate and respiration, enabling them to to occur automatically
What do the pons do
Help to control vital functions, especially respiration
Help to regulate sleep
Carries nerve impulses between higher and lower levels of the nervous system
What is the cerebellum responsible for
Control and coordination of muscular movement and learning and memory
Precise timing and coordinator of movements
What can damage to the cerebellum cause
Severe motor disturbances
What does the midbrain contain
Clusters of sensory and motor neurons
The reticular formation
What does the reticular formation do
Alerts higher centres of the brain that messages are coming and then either blocks or allows these messages
Plays a role in consciousness, sleep and attention
What does the forebrain contain
Cerebrum
Thalamus
Hypothalamus
What is the most advanced part of the brain from an evolutionary standpoint
The forebrain
What is the outer part of the forebrain covered by
A layer of tissue called the cerebral cortex
What does the thalamus do
Organises inputs from sensory organs and routes them to the appropriate areas of the brain
What does the hypothalamus do
Controls hormonal secretions that regulate sexual behaviour, metabolism and reactions to stress
Involves in experiences of pleasure/pain
What does the lambic system contain
Hippocampus
Amygdala
What does the limbic system do
Helps coordinate behaviours needed to satisfy motivational and emotional urges that arise in the hypothalamus
What does the hippocampus do
Involved in forming, consolidating and retrieving memories
What does the Amygdala do
Involved in emotional behaviours
What is the cerebral cortex
A sheet of grey unmyelinated cells that outermost layer of the human brain
What does the motor cortex do
Controls the 600 or more muscles involved in voluntary body movements
What does the sensory cortex do
Receives input from our sensory receptors
What does the somatic sensory cortex do
Receives sensory input that gives rise to our sensations of heat, touch and cold and to our sense of balance and body movement
What two brain areas are involved in speech
Wernicke’s area
Broca’s area
What is the Wernicke’s used for
Speech comprehension
Where is the Wernicke’s area located
The temporal lobe
What is the Broca’s area of the brain used for
The production of speech through its connection with the motor cortex region
Where is the Broca’s area located
The frontal lobe
What does the association cortex do
Is involved in many important mental functions, including perception, language and thought
What can damage to the association cortex cause
Disruptions or loss of speech, understanding, thinking and problem solving
What is agnosia
The inability to identify familiar objects
What percentage pf the human brain is the frontal lobe
29
What is the least understood part of the brain
The frontal lobe
What can damage to the frontal lobe cause
An inability to plan and carry out a sequence of actions
What is the frontal lobe involved in
Emotional experiences
What is the corpus callosum
A large band if myelinated nerve fibres
What is hemispheric lateralisation
The relatively greater localisation of a function in one hemisphere or the other
What is the left hemisphere needed for
Mathematical and logical abilities
Most aspects of verbal abilities and speech
What is aphasia
The partial or total loss of the ability to communicate
What causes aphasia
Damage to Broca’s or Wernicke’s areas in the left hemisphere
What is the right hemisphere used for
Perceiving and understanding spatial relations, recognising faces, perceiving emotion, mental imagery and certain aspects of musical and artistic abilities
What is neural plasticity
The ability of neurons, brain areas and networks to change in structure and function
What impacts neural plasticity
Stimulating environment
Cultural factors
Your job/career
What two ways can neurons modify themselves
Structurally
Biochemically
How do neurons structurally modify themselves
Sprouting enlarged networks of dendrites; extending axons from surviving neurons
How do neurons biochemically modify themselves
Increasing neurotransmitter volume
What is neurogenesis
The production of new neurons in the nervous system
What are neural stem cells
Immature ‘uncommitted’ cells that can mature into any type of neuron or glial cell needed by the brain
What is the endocrine system
Numerous hormone secreting glands distributed throughout the body
What are hormones
Chemical messengers at are secreted from the glands into the bloodstream
What are the adrenal glands
Twin structures that serve as hormone factories, producing and secreting about 50 different hormones
What are antigens
Foreign substances that trigger a biochemical response from the immune system
What are antibodies
Biochemical weapons needed to destroy the antigens
