Biopsychology Flashcards
What are the two major physiological systems that regulate behaviour in response to the environment?
The nervous system and the endocrine system
The nervous system - what is the nervous system?
What are its two main functions?
It is divided into what two subsystems?
- A specialised network of cells and our primary communication system. It is based on electrical and chemical signals
- To collect, process and respond to information in the environment and to co-ordinate the working of different organs and cells in the body
- The central nervous system (CNS) and the peripheral nervous system (PNS)
The nervous system - describe the structure and function of the central nervous system (3)
- Made up of the brain and the spinal cord
- The brain is the centre of conscious awareness. (add info about cerebral cortex) The brain is divided into 2 hemispheres
- The spinal cord is an extension of the brain and is responsible for reflex actions. It passes messages to and from the brain and connects nerves to the PNS
The nervous system - describe the structure and function of the peripheral nervous system (PNS) (5)
- It is the nervous system for the limbs and torso
- It relays messages from the environment to the CNS, via sensory neurones, and from the CNS to effectors, via motor neurones
- The PNS is further subdivided into the autonomic nervous system (ANS) and the somatic nervous system (SNS)
- ANS - governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress responses
- SNS - governs muscle movement and receives information from sensory receptors
The endocrine system - describe the endocrine system (3)
- System of glands and hormones
- It works alongside the nervous system to control vital functions in the body through the action of hormones
- It works more slowly than the nervous system (seconds instead of milliseconds)
The endocrine system - describe glands and give an example of one
- They are organs in the body that produce hormones
- The pituitary gland - located in the brain, it is called the ‘master gland’ because it controls when other glands secrete hormones
The endocrine system - describe the fight or flight response (4)
- The endocrine system and the autonomic nervous system work together
- If we perceive a stressor then the adrenal gland secretes the hormone, adrenaline, into the bloodstream and the sympathetic nervous system is activated
- This causes the physiological changes necessary for the fight or flight response. This means the body is prepared to fight the challenge or run away from it
- Once the threat has passed the parasympathetic nervous system brings the body back to its normal, resting state. This process is called rest and digest
The endocrine system - describe what the sympathetic and the parasympathetic nervous systems do
- Sympathetic - increases heart rate and blood pressure, increases breathing rate, dilates pupils, inhibits digestion, inhibits saliva production, contracts rectum
- Parasympathetic - decreases heart rate, decreases breathing rate, constricts pupils, stimulates digestion, stimulates saliva production, relaxes rectum
The structure and function of neurons - what are neurons? (2)
- The basic building blocks of the nervous system, they process and transmit messages through electrical and chemical signals
- There are hundreds of billions of neurons in the body
The structure and function of neurons - describe sensory neurons (3)
- Carry messages from the PNS to the CNS
- Long dendrites and short axons
- Located in the PNS in clusters called ganglias
The structure and functions of neurons - describe relay neurons (3)
- Connect sensory neurons to motor or other relay neurons
- Short dendrites and short axons
- Of all neurons, 97% are relay neurons and most are in the brain and visual system
The structure and function of neurons - describe motor neurons (3)
- Connect the CNS to effectors such as muscles and glands
- Short dendrites and long axons
- Cell bodies may be in the CNS but long axons form part of the PNS
The structure and function of neurons - describe the structure of a neuron (4)
- Cell body (or soma) - includes a nucleus which contains the genetic material of the cell
- Dendrites - branch-like structures, carry the impulse from other neurons to the cell body
- Axon - carries the electrical impulse away from the cell body down the length of the neuron. It is covered in a fatty layer of myelin sheath that protects the axon. Gaps in the axon called nodes of Ranvier speed up the transmission of the impulse
- Terminal buttons - at the end of the axon and they communicate with the next neuron in the chain across a gap called the synapse
The structure and function of neurons - describe electrical transmission
Resting state
Activated
This creates
- When a neuron is in a resting state the inside of the cell is negatively charged compared to the outside
- When a neuron is activated, the inside of the cell becomes positively charged for a split second causing an action potential to occur
- This creates an electrical impulse that travels down the axon towards the end of the neuron
Synaptic transmission - describe synaptic transmission (5)
Neurons
Impulses
When
Neurotransmitters
When
- Neurons are separated from each other by a gap called a synapse
- Impulses must be transferred chemically across the synapse
- When the impulse reaches the end of the neuron it triggers the release of a neurotransmitter from the synaptic vessels
- Neurotransmitters are able to cross the synapse and bind to the receptor sites
- When on the other side (the dendrite of the next neuron) the neurotransmitter is converted back into an electrical impulse
Synaptic transmission - what are neurotransmitters and give an example of one
- Chemicals that diffuse across the synapse to the next neuron in the chain
- Serotonin - affects mood and social behaviour, it has been implicated as a cause of depression
Synaptic transmission - what is excitation, inhibition and summation?
Neurotransmitters generally have either an excitatory or inhibitory effect on the neighbouring neuron
* Excitation - increasing the positive charge of a neuron which increases the likelihood of the next neuron firing (adrenaline)
* Inhibition - increases the negative charge of a neuron which decreases the likelihood of the next neuron firing (serotonin)
* Summation - a neuron can receive both positive and negative potentials, these are then summed to see what effect will be had
Localisation of function - describe the holistic theory and localisation theory (2)
- Early theories assumed that all parts of the brain were involved in processing thought and action
- Broca and Wernicke argued for localisation of function which is the idea that different parts of the brain perform different tasks and are involved with different parts of the body. If a certain part of the brain is damaged then functioning associated with that area will also be affected
Localisation of function - describe hemispheres (2)
- The brain is divided into 2 hemispheres and lateralised
- The left side of the body is controlled by the right hemisphere, the right side of the body by the left hemisphere
Localisation of function - describe the cerebral cortex (4)
- The outer layer of the brain
- 3mm thick
- Grey and highly folded (so it can all fit inside the skull)
- It is what separates us from lower animals as it is highly developed