3.2.2 Biopsychology Flashcards
Outline the key features of the nervous system
The nervous system is a specialised network of cells which act as our primary internal communication.
It is based electrical signals and has two main functions which are :
-to correct process and respond to information in the environment
-to coordinate the working of different cells in the body.
It is divided into 2 systems: the central nervous system and the peripheral nervous system.
Outline The structures and function of the central nervous system.
CNS is made up of the brain and the spinal cord.
-the brain Is the centre of all conscious awareness
-the cerebral cortex is what distinguishes our higher mental functions from animals
- the brain is divided into two hemispheres the left hemisphere which controls language and the brain stem, which allows impulses to travel between the brain and spinal cord
-the spinal cord is responsible for reflex actions passes messages to, and from the brain and connects nerve to the PNS.
Outline the structure and functions of the peripheral nervous system
The PNS is made up of all the nerves outside the PNS and Transmits messages through millions of neurons, to and from the central nervous system.
The PNS is further divided into :
~The somatic nervous system - this governs muscle movement and receives information from
Sensory receptors
~the autonomic nervous system- this governs vital functions such as heart rate, breathing rate, digestion, sexual arousal and stress responses
Outline the features The autonomic nervous system
The autonomic nervous system is further divided into :
~The sympathetic nervous system - involved in responses that prepare the body for fight or flight. The impulses travel from the sympathetic nervous system to organs in the body, which help us prepare for intensive action when we are faced with dangerous situations for example, increasing our heart rate, breathing rate and blood pressure.
~The parasympathetic nervous system- relaxes the body and returns us to our normal resting state, by slowing down our heart rate and breathing rate and reducing our blood pressure
Describe the structure and function of the neurons
Neurons transmit signal electrically and chemically. There are 3 types :
~SENSORY - carry information from the PNS/receptors(found in sense organs) to the CNS. They have long dendrites and short axons
~ RELAY - connect the sensory neurons to the motor neurons or other relay neurons. They have short dendrites and short axons. Mostly found in the brain and visual system.
~MOTOR - transmit information from the CNS to effectors such as muscle and glands. They have short dendrites and long axons. The long axons form part of the PNS
Describe the features of the structure of a neurone and their role
-Cell body/ soma - includes a nucleus which contains the genetic material of the cell
-dendrites - branchlike structures that protrude from the cell body which carry nerve impulses from neighbouring neurons to the cell body
-axon - carries the electrical impulse away from the cell body down the length of neuron
- myelin sheath - fatty layer which protects the axon
- nodes of ranvier- gaps in the axon which speed up the transmission of the impulse.
-terminal buttons - located at the end of axons which communicate with the next neuron in the chain across the synapse
What is electrical transmission?
The firing of a nuerone. 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.
Explain The process of synaptic transmission
In order for a message to be taking an onwards, the nerve impulse must cross The synaptic gap from the pre-synaptic neuron to the postsynaptic neuron.
-When an impulse reaches the end of the pre-synaptic neuron, a neurotransmitter (biochemical) is released (from synaptic vesicles) into the gap called the synaptic cleft.
-The neurotransmitter diffuses across the gap to bind to receptors on the receiving neuron (post-synaptic neuron).
- This means that the nerve impulse is now carried along the post-synaptic neuron.
-The neurotransmitters are taken back into the pre- synaptic neuron for recycling. This is known as reuptake.
What are neurotransmitters?
Neurotransmitters are chemicals diffuse across the synapse to the next neuron in the chain. Each neurotransmitter has his own specific molecule structure that fits perfectly into a post synaptic receptor site.
Each neurotransmitter has a specific function, for example, serotonin affects mood and social behaviour, which is why it has been implicated as a cause of depression.
Explain Excitation and inhibition
Neurotransmitters can either be excitatory or inhibitory.
~An excitatory neurotransmitter increases The positive charge of the postsynaptic neuron, making it more likely the postsynaptic neuron will fire an impulse.
~ An inhibitory neurotransmitters will increase the negative of the postsynaptic neuron, making it less likely that the post- synaptic neuron will fire an impulse
What is the endocrine system?
The endocrine system controls the vital function in the body through the action of hormones.
Hormones are slow acting (compared to the nervous system) but can take their messages over a much wider area and have more powerful effects.
What is the main gland and its function ?
Glands are organs in the body that produce hormones. The main endocrine gland is the pituitary gland, which is located in the brain that controls the release of hormones from all the other endocrine glands in the body.
Hormones are secreted in the bloodstream and affect any cell in the body that has a receptor for the particular hormone
Function of the endocrine system ( glands)
~ The pituitary gland -produces hormones which stimulate other glands to produce their hormones.
~adrenal glands - releases adrenaline which prepares the body for fight or flight and has several effects including raising blood pressure, heart rate and breathing rate. Also regulates metabolism, processes in the cell ( eg water balance and blood pressure)
~ the testes - secrete a hormone called testosterone which is important for the development of male sex characteristics (the production of sperm, the growth of facial hair from puberty onwards).
~ ovaries - produce the hormones oestrogen and progesterone, which are important for the development of female sex characteristics and reproduction (e.g. monthly menstruation).
~ thyroid gland - releases thyroxine which regulates your metabolism and energy.
Explain the fight or flight response
A stressor/threat is processed by the hypothalamus which activates the The sympathetic nervous system, which sends a message to the adrenal gland and Adrenaline is released into the bloodstream and creates the physiological response known as fight, or flight. This causes changes in target organs in the body e.g. increased heart rate, dilation of pupils decreased production of saliva. Once the threat has passed our body returns to the parasympathetic state which reduces the activities of the body that were increased by the actions of the sympathetic state.
Outline the differences between the sympathetic state and para sympathetic state
the sympathetic system ‘excites’ the bodily functions while the parasympathetic system ‘inhibits’ the bodily functions.
The sympathetic state increases heart rate and breathing rate, dilates the pupils, inhibits digestion and saliva production. Whereas the parasympathetic state decreases heart and breathing rate, constricts pupils and stimulates digestion and saliva production
