Chapter 2 : The nervous system Flashcards
What are the two divisions of the Nervous system?
The Central Nervous system (CNS)
Peripheral Nervous system (PNS)
What makes up the CNS?
The brain and the spinal chord
What are the two divisions of the Peripheral nervous system?
The Somatic nervous system and the Autonomic nervous system
What is the role of the spinal chord?
The spinal chord transmits sensory information from the Peripheral nervous system to the brain. It also sends motor messages from the brain down the spinal chord to the PNS
What is the role of the brain?
The brain is a mass of neurons responsible for how we think, feel and how we react to the world around us. The brain coordinates all activities of the nervous system and communicates information through the spinal chord
How does the brain receive sensory information?
The spinal chord receives sensory information from the PNS and transmits it along ascending tracts up to the brain for further processing.
How does the brain receive Motor information?
Motor information is sent from the brain and carried along descending tracts where it can then be relayed to muscles, organs and glands so they can react.
What does the Peripheral nervous system do?
Conveys sensory information from the body’s internal and external environments to the CNS and transmit motor commands from the CNS to the rest of the body through the spinal chord
What are the two subdivisions of the PNS
The somatic nervous system (SNS)
The autonomic nervous system (ANS)
What responses are the somatic nervous system responsible for?
The SNS is responsible for voluntary responses
How does the SNS receive sensory information?
receptor cells located throughout the body such as skin, joints, eyes and tongue
What does the autonomic nervous system do?
The ANS controls involuntary activities, its responsible for the activity level of our internal organs such as heart beat, pupils dialating, stomach digestion ect.
What are the three divisions of the ANS
Sympathetic nervous system
Parasympathetic nervous system
Enteric nervous system
The parasympathetic nervous system acts as the body’s ______________
Car brakes
What is the role of the sympathetic nervous system?
The SNS activates when we perceive a threat, when activated the bodys internal resources provide extra energy to help the body respond to the threat.
What is the role of the parasympathetic nervous system?
The PNS has the opposite effect is maintains a level of homeostasis and brings the body back to a normal level of arousal after the sympathetic nervous system has been activated.
What does the Enteric nervous system do?
Gut control: the enteric nervous system receives and sends messages to the sympathetic and parasympathetic nervous system, it also controls many functions of the digestive system.
roles of the sympathetic nervous system include
Accelerating heart rate
Dialating pupils
inhibits digestion
relaxes bladder
Is constricting pupils due to the sympathetic or parasympathetic nervous system?
parasympathetic
Some roles of the parasympathetic nervous system include:
Slows heart rate
stimulates digestion
Constricts pupils
contracts bladder
What controls involuntary muscles that regulate internal organs?
The autonomic nervous system
What is a spinal reflex?
an unconscious response that occurs independently of the brain, they are essential for survival and automatic.
What happens when someone steps on a nail?
Initially, an intense sensation is detected in your foot by a sensory receptor. Instantly, the sensory receptor fires off a message via the sensory neurons to your spinal cord and activates an interneuron, which in turn transmits a message via the motor neurons, causing your leg muscles to contract and allowing you to withdraw your foot from the sharp nail.
What is a neuron?
Neurons make up the nervous system, they receive process and transmit information all around the body.
what do dendrites do?
Receive neurotransmitters from other neurons and convert into action potential to then send a message to the soma
What are ‘locks’?
The receptor site in the postsynaptic membrane that has a specific shape to fit a certain neurotransmitter.
What are ‘keys’?
The neurotransmitters which fit into specific receptor sites.
A primary excitatory neurotransmitter, involved in high speed neural transmission.
Glutamate
What happens when glutamate is released?
When glutamate is released at the synapse it binds to a glutamate receptor site located on the postsynaptic neuron. As a result it activates these receptor sites and makes it more likely for the postsynaptic neuron to fire an action potential.
What is the primary inhibitory neurotransmitter?
GABA
How does GABA work?
GABA calms and slows neural transmission, when GABA activates receptor sites, the cells that have those receptors are inhibited and therefore less likely to fire an action potential.
What is the difference between neurotransmitters and neuromodulators?
Neurotransmitters are fast acting and short lived. Neuromodulators are slow acting but long lasting and can affect a large number of neurons at the same time.
What is the main role of dopamine?
important in motivating behaviour in search of rewards, in learning how to predict when rewards are likely and in initiating movements.
What does serotonin influence?
Pain, mood and sleep
What are the two main neuromodulators?
Seretonin and Dopamine
Define learning
Learning begins at birth and continues throughout our lifetime. It enables us to function daily and adapt to changes that are constantly occurring in the world around us.
Define memory
Memory is an active information processing system that receives, organises, stores and recovers information when needed. Memory begins as you take in information from both the internal and external environment via our senses. Our nervous system converts this sensory information into impulses of electrochemical energy and transmits it to our brain where it is processed, interpreted and stored for future use.
What is synaptic plasticity?
Neural plasticity that occurs in the synapse, leading to either an increase or decrease in activity between neurons.
The growth of new synaptic connections is…
sprouting
Getting rid of existing neural connections
Pruning
Explain long term potentiation
is a long-lasting strengthening of neural connections at the
synapse as a result of repeated stimulations from a presynaptic to postsynaptic neuron during learning.
a change to the connection between neurons that results in a long- lasting reduction in the strength of a neural response due to persistent weak stimulation.
Long term depression (LTD)
Why is LTD good?
helps to weaken and prune back unused synapses (synaptic pruning) – or those that are not stimulated. By doing this the brain becomes more efficient and therefore so do the learning and memory processes.
