C3 - Biological Bases of Mental Life and Behaviours Flashcards
What are Neurons?
Neurons are the basic unit of the nervous system, are cells that specialize in the transfer of information within the nervous system
What are the 3 types of neurons and their functions?
- Sensory Neurons - transmit information from sensory receptors to the brain (afferent)
- Motor Neurons - Transmit commands from the brain to the muscles and glands of the body (efferent)
- Inter-Neurons - helps to connect sensory and motor neurons
Anatomy of the Neuron
Dendrites - their purpose is to receive input from the surrounding cells
Cell body (soma) - includes a nucleus that contains genetic material or chromosomes
Nucleus - determines how the neurons will manipulate inputs from the dendrites
Axon - transmit information from the cell body to other neurons
Myelin sheath - coats the axon and acts as an insulator, increasing the speed of which the signal travels
Terminal buttons - sense signals from the neuron to adjacent cells
Describe resting potential
At rest, a neuron is polarized with a negative charge inside the cell membrane and a positive charge outside.
Neuron will is at -70mV
Describe graded potential
When a neuron is stimulated by another, its cell membrane is either depolarized (increase firing potential) or hyperpolarized (decrease firing potential)
Describe depolarization
The voltage gated sodium channel is open and the sodium rushes into the south. The influx of positive charges quickly shift the electric potential of the membrane
*Outside is more negative and the inside of the cell is more positive
Describe repolarization
The voltage gated potassium channel is open and it allows the potassium ions to flow out of the south. The movement of this positive ions will repolarize the south, allowing the south to have a negative internal charge relative to the positive extracellular charge
Describe and list the functions of neurotransmitters?
Neurotransmitters are chemicals that transmit information from one cell to another:
- Stored in vesicles of the presynaptic cell
- Released in response to the action potential from the presynaptic membrane
- Molecules diffuse across the synaptic cleft and bind to postsynaptic membrane
- Receptor binding produces a graded potential in the next cell
Describe the transmission of a Nerve Cell
Neurons communicate by converting an electrical charge to the chemical message. The action potential is the electrical charge. When the action potential reaches the terminal button, there are vesicles located there. These vesicles contain neurotransmitters. In response to the action potential, the vesicles are pushed downwards and infused with the membrane.
Once they are fused, they will pen up and release the neurotransmitters into the synaptic cleft.
These molecules will then diffuse across the gap and bind to postsynaptic receptors. Binding to those receptors produces a graded potential in the next cell
Drugs and effects on Neurotransmitters
Glutamate- excitation of neurons throughout the nervous system
GABA (gamma-aminobutyric acid) - inhibition of neurons in the brain
Dopamine - emotional arousal, pleasure and reward; voluntary movement; attention
Serotonin - sleep and emotional arousal; aggression; pain regulation; mood regulation
Acetycholine - learning and memory
Endorphins and Enkephalins - pain elevation of mood
Describe the Endocrine system
A collection of glands that release hormones into the blood stream.
System for intercellular communication but global messages through the bloodstream
What are the two subdivisions of Autonomic Nervous System (ANS)
- Sympathetic - emergency system, typically activated in face of a threat (e.g., fight or flight)
- Parasympathetic - vegetative functions (e.g., digestion)
The two systems often act in opposition (e.g., heart rate but can act out in concert (e.g., sexual reflexes)
What does the hindbrain consist of? List and describe
Medulla Oblongata - extension of spinal cord that regulates heartbeat, circulation and respiration
Cerebellum - involves in movement, learning, and sensory discrimination
Reticular Formation - a network of neurons involved in consciousness and arousal
Pons - links medulla oblongata and cerebullum with upper part of the brainstem
What does the midbrain consist of? List and describe
Tectum - involved in movement and arousal
Tegmentum - involved in movement and arousal. It plays an important role in learning to produce behaviors that minimize unpleasant (aversive) consequences and maximize pleasant (rewarding) consequences
What does the forebrain consist of? List and describe
The forebrain is involved in complex ‘higher order’ sensations and behavior
Hypothalamus - helps regulate eating, sleeping, sexual activity and emotional experiences
Thalamus - processes incoming sensory information and transmit it to higher brain areas
Basal ganglia - involved in the control of movement and also plays a part in ‘automatic’ responses and judgement
Limbic system - regulates autonomic or endocrine function in response to emotional stimuli and also is involved in reinforcing behavior
