Biopsychology - Advanced Information Flashcards
What is the nervous system?
Specialised network of cells.
Primary internal communication system
Two Main Functions:
- Collect,process and respond to info and environment
- Coordinate working of different organs and cells in the body
Divided into CNS and PNS
Draw and label the subdidivisions of the nervous system
What is the CNS?
Made up of brain and spinal cord
What is the brain as part of the CNS?
- Centre of all concious awareness.
- Cerebral cortex (outer layer) highly develpoed and is what distinguishes higher mental functions from animals.
- Two hemispheres
What is the spinal cord as part of the CNS?
- Extension of the brain.
- Repsonsible for relflex actions
- Passes messages to and from brain and connects nerves to PNS
What is the PNS?
Transmits messages via millions of neurones to and from CNS.
What is the PNS divided into?
Autonomic and Somatic Nervous System (ANS & SNS)
What is the ANS?
- Involuntary system governs vital functions in body e.g. breathing, heart rate, digestion etc.
- Controls smoth muscles and glands.
- Control centre for this in brain stem
- Contains only motor pathways
- Subdivided into sympathetic and parasympathetic
What is the SNS?
- Under concious control.
- Controls muscle movement and recieves info from sensory receptors
- Controls skeletal muscles and movement .
- Control centres are in motor cortex.
- Contains sensory and motor pathways.
Describe the relationship of the parasympathetic and sympathetic branches of the ANS.
- Parasympathetic in opposition to sympathetic (actions are antagonistic)
- Acts as breaks and reduces activites of body that were increased by sympathetic branch
- ‘rest and digest’ response
What is the sympathertic branch responsible for?
- Increase HR
- Increases breathing rate
- Dilates pupils
- Inhibits digestion
- Inhibits saliva production
- Contracts rectum
What is the parasympthetic branch responsible for?
- Decrease HR
- Decreases breathing rate
- Constricts pupils
- Stimulates digestion
- Stimulates saliva production
- Relaxes rectum
What are neurons?
- Basic building blocks of nervous system - nerve cells that process and transmit messages through electrical and chemical impulses
- 100 billion neurons (80%) in brain
- Provide nervous system with its primary communication
Draw and label a typical neuron
What is the nucleus?
- Control centre of cell.
- Contains all chomosomal DNA
What is a dendrite?
- Receives nerve impulse/signal from adjacent neurons
What is an axon?
- Where the electrical signal passes along.
What is the myelin sheath?
- Insulate/protects axon from external influences that might effect transmission of nerve impulse down the axon.
What are the Nodes of Ranvier?
Speed up transmission of impulse by forcing it to ‘jump’
What are the terminal buttons?
- Send signals to an adjacent cell.
What is a sensory neuron?
- Carry messages from PNS to CNS
- Long dendrites
- Short axons
Draw and label a sensory neuron
What is relay neuron?
- Connect sensory neurons to motor or other relay neurons
- Short dendrites
- Short axons
Draw and label a relay neuron.
What is a motor neuron?
- Connects CNS to effector like muscle/gland
- Short dendrites
- Long axons
Draw and label a motor neuron.
Describe electrical transmission
- At rest, neuron negatively charged inside compared to outside
- When activated by stimulus, inside becomes posivitely charged for split second causing action potential to occur.
- Creates electrical impulse that travel down axon towards end of neuron.
Describe the basic reflex
- E.g., knee-jerk
- Stimulus (hammer hitting knee) detected by sense organs in PNS, conveying message along sensory neuron.
- Message reaches CNS where it connects with relay neuron.
- Then transfers message to motor neuron.
- Then carries message to an effector (muscle) causing contraction and hence knee to move/jerk.
How do neurons communicate with other cells?
Synapses
What is a synapse?
- Conjunction of a terminal button of one neuron and the membrane of another neuron, muscle cell/gland cell. Terminal button belongs to presynaptic neuron.
What is a presynaptic neuron?
Neuron that sends the message.
Describe signal within and between neurons.
- Signals within neurons - transmitted electrically
- Signals between neurons - transmitted chemically across a synapse
What is synaptic transmission?
- Process where neighbouring neurons communicate by chemical messages across the synape that separates them.
- Neuron receives messages from many terminal buttons and its terminal buttons form synpases with many other neurons.
Describe the processes involved in synaptic transmission.
- Electrical impulse (action potential) reaches presynaptic terminal
- Signal triggers release of neurotransmitter from synaptic vesicles
- Neurotransmitter diffuses across synpase.
- Neurotransmitters combine with receptors on postsynaptic membrane of adjacent neuron
- specific molecular structure so fit perfectly into post-synaptic receptor site (e.g., lock and key)
- Stimulation of postsynaptic receptors by neurotransmitter result in excitation (depolarisation) or inhibition (hyperpolarisation) of -postsynaptic memebrane.
Draw and label a diagram for synaptic transmission
What is excitation?
- Neurotransmitter (e.g adrenaline) increases positive charge of postsynaptic neuron.
- Increases likelihood neuron will fire and pass on electrical impulse.
What is inhibition?
- Neurotransmitter (serotonin) increases negative charge of post synaptic neuron.
- Decreases likelihood neuron will fire and pass electrical impulse
Describe the excitatory and inhibitory influences.
- Summed.
- If net effect in post synaptic neuron is excitatory, neuron will be more likely to ‘fire’
- If net effect is inhibitory the neuron wil be less likely to fire.
Are neurotransmitters excitatory or inhibitory?
Most can be both except GABA which is purely inhibitory.
Can an action potential travel in more than one direction? Why?
- Only in one direction.
- As synaptic vesicles containing neurotransmitter one present on and released from presynaptic membrane.
- Also receptors for neurotransmitters only present on post synaptic membrane.
- It’s binding of neurotransmitters to receptor which enables signal to be transmitted to next neuron.
Name the four ways to study the brain.
- Functional Magnetic Resonance Imaging (fMRI)
- Electroencephalogram (EEG)
- Event-related potential (ERP)
- Post-mortem examinations
What is fMRI?
- Method used to measure brain activity while person performs task using MRI technology
- detecting radio waves from changing magnetic fields
- Enable reserachers to detect regions in brain rich in oxygen so active
How does fMRI work?
Detects changes im blood oxygenation and flow that occur due to neural activity in specific parts.
When brain more active consumes more oxygen and to meet increase demand bood flow directed to activated area (haemodynamic response)
What type of imaging does fMRI proudce and what does this show?
- 3D imaging shows which parts of brain involves in particular mental process.
- Has important implications for undertsanding localisation of function.