Unit 3 AOS 1 Flashcards
(17 cards)
What is spinal reflex
The spinal reflex is an example of an involuntary, unconscious response to a stimulus that is initiated by the spinal cord without input from the brain. Steps are:
Sensory stimulus detected by sensory receptors, Sensory neurons carry info via sensory afferent pathway, interneurons in spinal cord intiate an involuntary motor movement, relayed to motor neurons and carried vis motor efferent pathways to muscles, muscles perform reflex response without input from the brain.
Central nervous system
Is in the center of the body and is most important of the nervous system as it processes and coordinates responses to sensory stimuli received of the body.
Peripheral nervous system
The peripheral nervous system is comprised of all the nerves outside of the central nervous system that carry messages between the central nervous system and muscles, organs and glands throughout the body. Enables communication between the body and the cns in two ways:
Carries sensory(afferent) info to the CNS
Carries motor(efferent) info from the CNS to the body
Autonomic Nervous System
The autonomic nervous system (ANS) is a subdivision of the peripheral nervous system that controls the body’s internal environment in an autonomous or self-regulated manner. Meaning it peforms most of the functions without our concious awareness. Responsible for digestion breathing and blood pressure.
Sympathetic and Parasympathetic NS
Sub-divisions of autonomic ns
The sympathetic nervous system, which dominates when we are under threat, raising our heart beat, blood pressure, awareness, bodily functions to prepare or deal with the situation.
The parasympathetic nervous system, which dominates during normal day-to-day activities when we are relatively calm It also returns the body to a calm state after a threatening or stressful situation.
Neurons
Neurons are individual nerve cells, specialised to receive, process and transmit information within the nervous system.
Neurotransmitters
Neurotransmitters are chemicals produced by neurons that carry messages to other neurons or cells within the nervous system across a synapse, which is the point of communication between two neurons or between a neuron and a target cell such as a muscle or gland.
Excitatory and Inhibitory effects
Neurotransmitters usually have either an excitatory or inhibitory effect on the post synaptic neuron.
Excitatory: increases the likelihood that the postsynaptic neuron will fire. Glutamate is the main excitatory neurotransmitter in the nervous system, which is involved with learning and memory.
Inhibitory: decrease the likelihood that the
post-synaptic neuron will fire. The main inhibitory neurotransmitter in the nervous system is gamma-aminobutyric acid (GABA). It can be associated with anxiety, specific phobias and Parkinson’s disease.
Neuromodulators
Neuromodulators are a subclass of neurotransmitters that alter the strength of neural transmission, by increasing or decreasing the responsiveness of neurons to neurotransmitter signals. Neuromodulators can alter the overall effectiveness of neural transmission in entire regions of the brain.
released in slower manner targeting brain regions. Last longer than NT.
Dopamine
Dopamine is released when you do any activity that you enjoy giving you feelings of pleasure and wellbeing. Is a modulating neurotransmitter, or neuromodulator, because it reinforces the neural activity in regions of the brain associated with these functions. Dopamine is also associated with unhealthy and addictive behaviours, this is because whenever we see a reward worth chasing, our brain produces higher levels of
dopamine, motivating us to complete the task, no matter how unhealthy or difficult the task might be.
The Reward Pathway
The reward pathway is a group of structures in the brain that are activated by rewarding or reinforcing stimuli, such as anticipating a cold glass of water if you are thirsty. The pathway controls our responses to natural rewards, such as food, sex and social interactions, and is therefore an important determinant of motivation.
Serotonin
Serotonin is an inhibitory neurotransmitter that also acts as a neuromodulator, influencing a variety of brain activities. It modulates virtually all human behavioural processes, including
mood, reward, aggression, and appetite among others. Originates in the brain stem andextends to almost all areas of the cerebrum.
Serotonin levels
Balanced serotonin levels lead to calm, focused, happy and stable moods. When levels are low this has a devastation effect on the brains ability to regulate mood, regulate sleep cycle(reduced sleep pressure), and increases impulsive behaviours. It makes it more difficult to control and regulate emotional responses to anger, increasing aggressive and violent behaviours.
Long term potentiation and Long term depression.
LTP is the relatively permanent strengthening of synaptic connections as a result of repeated activation of a neural pathway. LTD is the relatively permanent weakening of synaptic connections as a result of repeated low level activation.
Sprouting
Sprouting involves the growth of axon or dendrite fibres at the synapse. Dendritic spines are dendrite fibres that grow as a result of
sprouting on the post-synaptic neuron.Filigree appendages are fibres that grow from the axon terminal of the presynaptic neuron as a result of sprouting. Synaptogenesis is the formation of new synapses that result from the process of sprouting
synaptic plasticity
Synaptic plasticity involves specific changes that occur within the synapse, between neurons
Rerouting and pruning
Rerouting involves new connections being formed between neurons to establish alternative neural pathways. Pruning involves the removal of excess neurons and synaptic connections to increase the efficiency of neuronal transmissions.
