Biopsychology Flashcards
What is the nervous system?
Primary internal communication system, transmitting electrical/chemical signals between different parts of the body via a specialised network of nerve cells
What are the 2 main functions of the nervous system?
Collect, process, and respond to information in the environment
Co-ordinate the working of different organs and cells in the body
What are the divisions of the nervous system?
What is the function of the central nervous system?
Controls behaviour and regulates physiological processes
Origin of all complex commands + decisions
What is the purpose of the brain?
Centre of all conscious awareness/psychological processes, including higher order thinking
Interprets + stores info, sending order to muscles/glands
What are the parts of the brain?
3mm outer layer cerebral cortex
2 hemispheres
What is the purpose of the spinal cord?
Extension of the brain via brain stem
Connects brain to PNS so info is transferred between brain and body
responsible for reflex actions
What is the similarity between the brain and spinal cord?
Both control involuntary processes
eg: brain- breathing
eg: spinal cord- reflexes
What are 2 differences between the brain and spinal cord?
Brain is responsible for conscious awareness allowing for higher order thinking BUT spinal cord allows for simple reflex responses
Brain has multiple regions responsible for dif functions BUT spinal cord has 1 main function (to connect brain to PNS)
What is the function of the peripheral nervous system?
Transmits messages via millions of neurons/nerve cells to/from CNS
What does the peripheral nervous system consist of?
All nerves that lie outside of brain and spinal cord
What does the somatic nervous system do?
Sensory neurons recieve info from sensory receptor cells in the sense organs/skin (communication with outside world), transmits messages to CNS
Motor neurons transmit motor signals from CNS to skeletal muscles to produce voluntary muscles movement (under conscious control)
BUT some movement are involuntary, eg: reflex arc
What does the autonomic nervous system do?
Involuntary processes (outside of conscious control) eg: heart rate, blood pressure
Self-regulates internal environment (homeostasis) and controls smooth muscles + glands
Transmits info from internal body organs/glands to CNS and back
What is the similarity between the somatic NS and autonomic NS?
Both respond to external stimuli
eg somatic- sensory neurons to CNS
eg autonomic- fight or flight preparation
What are 3 differences between the somatic NS and autonomic NS?
SNS voluntary (under conscious control) : ANS involuntary (outside of conscious control)
SNS controls skeletal muscles/movement : ANS controls internal body organs/glands/smooth muscles
SNS sensory + motor pathways : ANS only motor pathways
How do the 2 branches of the autonomic nervous system work?
Each branch connected to a number of bodily organs
Works with endocrine system to bring about physiological change
Works in opposition: as activity in one falls, rises in the other
What is the function of the sympathetic nervous system?
Brings about physiological arousal in fight or flight response
Messages travel from SyNS to organs in body to prepare for action in dangerous situations
What is the main neurotransmitter involved in the sympathetic nervous system branch?
Noradrenaline
What is the function of the parasympathetic nervous system?
Calms body to normal state in rest and digest
Maintains body functions under ordinary conditions to save energy
What is the main neurotransmitter involved in the parasympathetic nervous system branch?
Acetylcholine
What are neurons?
Basic building block of nervous system enabling communication via electrical (within) and chemical (between) signals
What do sensory/afferent neurons do?
Carries sensory info (nerve impulses) from sensory receptors to CNS
Then translated into sensations for a reaction
Stimulates reflexes through spinal cord to motor neuron
What do relay/inter-neurons do?
Connects sensory neurons to motor neurons/other relay neurons
Transmits info from one area of CNS to another to analyse sensation + decide how to respond -> relays info to motor neuron
Where are relay neurons found?
Brain, visual system, spinal cord
What do motor/efferent neurons do?
In/voluntary motor response by sending info from CNS to effectors (eg: muscles, glands)
For reflex response, direct response from sensory info via relay neurons
When stimulated, releases NT to bind to muscle receptors for movement, strength of contraction depends on rate of neuron firing
What do dendrites do?
Carries functional info towards cell body and receives signals from other neurons
What do myelin sheaths do? Which neurons are these found in?
Protects axon and speeds up electrical transmission
Sensory + motor
What do nodes of Ranvier do?
Speeds transmission of impulse by forcing it to jump across gaps along the axon
What is another word for the cell body? What do these contain
Soma, with nucleus
What does the axon of a neuron do?
Carries nerve impulses in form of electrical signal (action potential) away from cell body to axon terminal
What does the axon terminal do?
Contains NTs and communicates with next neurons across synapse via synaptic transmission
What are the cells called along the axon of sensory/motor neurons?
Schwan cells
What are neurotransmitters?
Chemical messengers that transmit nerve impulses across the synapse
What are the 2 effects neurotransmitters can have when they bind to receptor cells on the post-synaptic neuron?
Excitatory
Inhibitory
How do excitatory neurotransmitters work?
Increases positive charge of post-synaptic neuron
Results in excitatory post-synaptic potential (EPSP)
Post-synaptic neuron more likely to fire
How do inhibitory neurotransmitters work?
Increases negative charge of post-synaptic neuron
Results in inhibitory post-synaptic potential (IPSP)
Post-synaptic neuron less likely to fire
What is 1 example of an excitatory NT?
Noradrenaline
What is 1 example of a purely inhibitory NT?
GABA
How is the neurotransmitter dopamine involved in schizophrenia/Parkinsons?
Responsible for voluntary muscle movement, attention, learning, emotion
What do neurons communicate within?
Neural networks, where each neuron separated by a synapse
Describe the process of synaptic transmission in 5 steps
- Action potential triggers presynaptic neuron to release NTs from synaptic vesicles
- NTs diffuse across synaptic cleft, carrying signal
- NTs bind to post-synaptic receptor sites on dendrite
- Summation of EPSP and IPSP determines whether action potential produces + passed on / how frequently neuron fires (net effect)
- NTs reabsorbed into presynaptic vesicles or broken down chemically by enzymes in synapse
Why can neural messages only be sent in 1 direction?
Synaptic vesicles with NTs only released from pre-synaptic membrane (high concentration)
Receptors for NTs only on post-synaptic membrane
Diffusion of NTs only from high → low concentration, so has to be pre → post
How can drugs affect synaptic transmission? (4 ways)
- Influencing amount of NT produced
- Minimising effect of natural NTs
- Influencing rate of transmission
- Blocking effect of NTs
What is the endocrine system?
Network of glands to secrete chemical messengers (hormones)
What does the endocrine system work alongside?
The nervous system regulates physiological processes at a slower rate
What are the 2 main functions of the endocrine system?
provide a chemical system of communication by secreting required amount of specific hormones from glands into bloodstream, which binds to specific receptors
Regulates activity of cells and organs in body and controls physiological processes
How is the endocrine system regulated?
Feedback, so that stable concentrations of hormones circulate in blood
What happens if there is an imbalance of hormone levels?
Dysfunction
What are glands?
Organs that secrete different hormones to regulate activity of cells and organs in body
What are hormones?
Chemical in bloodstream to target specific cells/organs, with receptors for physiological reactions
What does the hypothalamus do?
Receives info from many sources, helps regulate these functions
Links NS to ES, regulates the endocrine system via pituitary gland
What hormone does the pineal gland secrete? What is its effect?
Melatonin
Helps regulate sleep/wake cycle (important biological rhythm)
What are 3 differences between hormonal communication and neural communication?
Hormonal: hormones travel through blood to target cells BUT neural: direct electrical impulse
Hormonal: effects last longer as broken down slower BUT neural: quick
Hormonal: responses widespread/generalised BUT neural: localised
What hormone does the testes gland secrete? What is its effect?
Testosterone
Development of male physical features eg: male genitalia, facial hair, deep voice
What is the effect of the adrenal gland?
Controls sympathetic nervous system, causes physiological change associated with arousal
What are the 2 glands that make up the adrenal gland? What hormones do they secrete? What is their effect?
Adrenal medulla -> adrenaline + noradrenaline
Fight or flight response
Adrenal cortex -> cortisol
Long-term stress response, stimulates release of glucose whilst suppressing immune system
What is the fight or flight response?
Innate sequence of activity triggered when responding to threats
Acute (immediate) response, optimisies body functioning through ANS and ES working together to sustain arousal
What is the pathway where the fight or flight response occurs?
Sympathomedullary pathway (SAM)
Describe in 5 steps the fight or flight response for acute stress via the sympathomedullary pathway (SAM)
- Threat: stressor perceived and amygdala sends distress signal to hypothalamus (command centre)
- Acute: hypothalamus triggers activity in sympathetic branch, sends immediate + fast signal to adrenal medulla
- Medulla: releases adrenaline + noradrenaline, allows release of energy for immediate action
- Adrenaline: triggers physiological arousal for F/F response
- PaNS: once threat passed, body returns to resting state by reducing activity
What are the general effects of adrenaline?
Prepare the body for F/F via physiological changes
1. ↑ blood supply + oxygen to skeletal muscles (physical action)
2. ↑ oxygen to brain (rapid response planning)
What are 3 examples of the direct effects of adrenaline?
↑ heart rate (speeds blood flow for oxygen + spreads adrenaline)
Constriction of blood vessels (speeds blood flow)
Pupil dilation (improves vision)
Evaluation: what are negative consequences of F/F response?
- modern-day stresses dif to ancestors
- less physical activity so response doesn’t help with our stresses
- physiological damage to us if repeatedly activated eg: ↑ blood pressure -> vessel damage -> heart disease
No longer an adaptive mechanism, leads to illness
Evaluation: why doesn’t the F/F response explain the full story?
Initial ‘freeze’ in response to threat
- adrenaline promotes alertness/hyper-vigilent state/attention on sensory inputs
Freeze has adaptive advantage as can find new info to make best response
Evaluate: what are the gender differences in the stress response?
Tend and befriend for females
- evolved as primary caregivers so can’t leave children
- T&B protects themselves + kids through nurturing behaviours and creating alliances
- caregiver hormone oxytocin reduces F/F response
Biological basis to sex differences in stress response
What is the brain studied in terms of?
Structure (anatomy)
Function (physiology)
What are the 3 parts of the brain?
Cerebellum
Brainstem
Cerebrum (whole) / cortex (outer surface)
What does the cerebellum do?
Coordinates muscle movement
Maintains posture + balance
What does the brainstem do?
Relay centre connected brain to spinal chord
Performs many automatic functions
How thick is the cortex?
3mm
What is the cerebrum?
Largest part of human brain associated with higher brain functioning
How is the cerebrum divided?
2 hemispheres, connected by the corpus callosum (bundle of nerves)
What is the importance of the corpus callosum?
Acts as a communication pathway so hemispheres can exchange info
Important because some functions only lie in 1 hemisphere
What is the word for one side of the brain dealing with the otehr side of the body?
Contralateral
Are eyes contralateral?
Yes, but each eye has a right/left visual field, controlled by the opposite side of the brain
What is another word for localisation of function?
Cortical specialisation
How was the brain viewed historically?
Holistic theory: all parts involved in processing thought/action