What does the Somatic Nervous System control?
Muscle Movement and receiving sensory information from receptors
What does the CNS consist of?
The brain and the spinal cord
Define Adrenaline:
A hormone produced by the adrenal glands, part of the immediate stress response.
Increases Heart Rate
Contracts Blood Vessels
Dilates Air Passages
What happens to a neuron when it 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 down the nerve cell
What is the Fight or Flight system?
The way an animal responds when a threat is perceived, the body becomes ready to either fight a threat, or flee from it.
What is an Excitatory Neurotransmitter?
A Neurotransmitter that increases the likelihood a neuron will fire and pass on the electrical impulse
What is a dendrite?
Long branch like structures that protrude from the cell body, connect to other neurons (connects to their axons)
What are axons?
A long channel on a neuron, which carries electrical impulses, and has synapses at the end. Can be up to a metre long.
List biological changes to the body in the Sympathetic State
Heart rate and breathing rate increases Dilates Pupils Inhibits Digestion Inhibits production of saliva Contracts Rectum
What charge does a neuron have in it’s resting state?
A negative charge
What are nodes of ranvier?
Gaps in the Myelin Sheath that speed up transmission of electrical impulses
What is the Autonomic Nervous System?
part of the Peripheral System, governs functions like breathing, heart rate, digestion, sexual arousal and stress response
What does the pituitary gland control?
The release of other hormones in the body, eg those involved in the menstrual cycle.
What is a gland?
An organ in the body that synthesises (makes) substances such as hormones
What is an Inhibitory Neurotransmitter
A neurotransmitter which decreases the likelihood a neuron will fire and pass on an electrical impulse
List biological changes in the parasympathetic state
Heart rate and breathing rate decreases Constricts Pupils Stimulates Digestion Stimulates production of saliva Relaxes Rectum
What are neurons separated by?
Synapses
What are neurotransmitters?
Chemicals that relay signals across the synapse from one neuron to another.
Which type of neuron is connected to an effector? (Eg a muscle)
A motor Neuron
What are the three types of Neuron?
Sensory
Relay
Motor
Why might someone who is permanently stressed, eg has a stressful job, get ill more often?
A prolonged stressor stimulates the production of cortisol, which inhibits the immune system, meaning getting ill is easier.
What effects does cortisol have?
Releases stored glucose from the liver (for energy)
Controls swelling after injury
Suppresses immune system
What is the myelin sheath?
A fatty layer which coats the axon, insulating the axon, which protects the axon, and increases the speed of the electrical impulses.
What does the hormone thyroxine do?
Increases heart rate, produced in the thyroid gland
What are the two main Nervous Systems?
The Central Nervous System (CNS) and the Peripheral Nervous System
What is a hormone?
A chemical which circulates in the blood stream, and affects certain cells (those with receptors for that hormone)
What does the peripheral nervous system consist of
All the other nerves in your body, that make up the ANS and the SNS
Why are there gaps in the Myelin Sheath?
If the Myelin Sheath was constant, it wouldn’t speed up transmission, it would slow it down. The gaps increase the efficiency of the electrical impulses
What is the endocrine system?
The system in which hormones are secreted and received, for example adrenaline
What is an SSRI?
Selective Serotonin Reuptake Inhibitor
The drug slows the reuptake of serotonin once it reaches the synapse, ensuring it stays active in the brain for longer
Outline the bodily response to an immediate stressor
The hypothalamus activates the adrenal medulla
The adrenal medulla secretes adrenaline
This arouses the sympathetic nervous system
Once the threat is over the parasympathetic system is aroused
What type of neuron connects the peripheral nervous system and the Central Nervous system?
A Relay Neuron
Outline the Bodily Response to a Prolonged Stressor
The Hypothalamus stimulates the Pituitary Gland
The Pituitary Gland Secretes ACTH
ACTH stimulates the adrenal glands to produce Cortisol
Cortisol helps the body maintain high blood sugar through the stress
A* QUESTION
how does an excitatory neurone increase the likelihood of an action potential?
It allows sodium ion channels to open, which allows the positively charged sodium ions into the axon, triggering an action potential
A* QUESTION
how does an Inhibitory neurotransmitter prevent an action potential from occurring?
It either stimulates the closing of sodium ion channels, preventing positively charged sodium ions from entering the neurone, or it opens chloride ion channels, allowing negatively charged ions into the cell
Name three neurotransmitters
Serotonin
Dopamine
Glutamate
Could also have:
Acetylcholine
Noradrenaline