Neurons and neurotransmitters Flashcards
What does the cell body of a neuron do?
It contains the nucleus and is connected to the dendrites. Most important role is manufacturing new cell components
Which part of the neutron receives the electrical messages from other neurons?
Dendrites
What is the myelin sheath?
A protective covering over the axon. Speeds up synaptic transmission.
The sheath contains gaps along the axon called nodes. The neural signal jumps from node to node and this is how transmission is sped up
What is an axons role in a neutron?
Conducts the electrical impulses from the cell body to send to other neurons as a message
Explain resting potential.
The resting state involves an imbalance in charge across the cell membrane. Inside is more negative than outside
Explain graded potential
Are electrical charged caused by signals from other neurons. Can be either excitatory or inhibitory.
What is an excitatory graded potential?
Depolarisation.
Membrane potential becomes more positive. This makes it closer to the firing threshold which makes the neuron more likely to fire!!
What is an inhibitory graded potential?
Hyperpolarisation.
Membrane potential becomes more negative and moves further away from the threshold which makes the neuron less likely to fire.
Glial cells
Surround neurons and provide support and insulation between them
What is the synapse?
The synapse is the fluid filled gap between the neurons that the neurotransmitters travel through.
What does pre and post synaptic mean?
Refers to the positioning before or after the synapse
Describe the process of synaptic transmission
- Vesicles inside the axon containing neurotransmitters
- the vesicles fuse with the membrane and the neurotransmitters cross the synapse
- the neurotransmitters attach to the dendrites and produce a graded potential
What happens after the synaptic transmission?
The transmitter is then inactive and released from the receptor site. It will then either make its way back to the pre-synaptic cell (re-uptake) or be broken down by enzymes.
How does the lock and key model fit into the nervous system?
The lock and key model describes how the post-synaptic receptor sites are very specific and only specific neurotransmitters are accepted into the site
What is glutamate?
Main excitatory transmitter.
Involved in learning, memory and transfer of sensory input
What is GABA?
The main inhibitory transmitter.
Dampens neural activity - involved in learning, memory and sleep
What kind of drugs increase the activity of GABA?
Anti-anxiety.
Used to suppress overactive brain roles linked to worry.
What is acetylcholine (ACh)?
Muscle contractions
What is dopamine?
Involved in motor function and reward.
What is serotonin?
Involved in cortical arousal, mood, sleeping, eating.
What is noradrenaline?
Mobilises the brain and body for arousal
Involved in cortical arousal and autonomic nervous system activity
What is anandamide?
A fatty acid neurotransmitter
Associated with pain control, memory, learning and emotions
What are endorphins?
Involved in main control and mood elevation
What happens when someone has high levels of dopamine?
Schizophrenia
What happens when someone has low amounts of dopamine?
Parkinson’s disease
What is a psychoactive drug?
What are the 2 different types and how do they work?
Drug that interacts with the neurotransmitter system and affects mood, arousal and behaviour.
Agonists: (enhances receptor site activity)
Antagonists: (decrease receptor site activity)
What does SSRI stand for? And what do they do?
Selective serotonin uptake inhibitors
Used to treat depression as increases serotonin uptake
The nervous system can be divided into…..
The peripheral and central nervous systems
What is the central nervous system?
Involves the spinal cord and the brain
What role does the spinal cord play?
Receives sensory input and sends this info to the brain - also responds to motor output
What role does the brain play?
directs psychological activity, processes information and maintains life supports
What does the peripheral nervous system consist of?
The somatic nervous system and the autonomic nervous system
What is the somatic nervous system?
Voluntary control of muscle movements via skeletal muscles
What does the autonomic nervous system do and what does it consist of?
sends and receives information to and from the glands and organs of the body – involuntary. Things you can’t control eg. hormone release.
Consists of the sympathetic and parasympathetic nervous systems
What does the sympathetic nervous system do?
General arousal and responding to threats
Fight or flight
How do the parasympathetic and sympathetic systems work together?
Detection of a threat results in a stimulation of the peripheral organ and musculature response (increased breathing and heart rate, digestion/salivation inhibited, pupil dilation, bladder/bowel relaxation, hair standing erect)
Response: threat is appropriately responded to (flight or fight or our perception changes)
Activation of the parasympathetic branch – restores normal levels of function.
- Parasympathetic nervous system – routine maintenance of energy resources (rest and digest) and decreasing arousal
What does the parasympathetic nervous system do?
Calms the body down and maintains energy
Rest and digest
Explain the endocrine system
The endocrine system is a system of glands that control vital functions (eg. growth, metabolism, reproduction). Hormones are chemicals that are released into the blood stream by this system that influence some organs. They bind to cell receptor sites in the body which is similar to neurotransmitters.
What does the hypothalamus do?
Maintains homeostasis
Releases hormones by activating pituitary gland
What is the pituitary gland and what does it do?
is a master gland that is under the control of the hypothalamus and releases hormones which have a direct effect or will active glands further down the chain.
What is oxytocin?
the love molecule involved in birth contractions, milk production and interpersonal trust
What are the adrenal glands?
Glands located near the kidneys that release adrenaline and cortisol to trigger or maintain the flight or fight response
What does the thyroid gland do?
Releases growth and metabolism hormones
What does the pancreas do?
controls blood sugar levels and produces insulin
What do gonads do?
release sex hormones (estrogen and testosterone)
What is the absolute refractory period?
Time during which another action potential is impossible
