Neuroscience: Synapses and Action Potentials

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Questions and Answers

Which part of the brain is primarily responsible for regulating heart rate and breathing?

Hippocampus

Substantia nigra

Medulla oblongata (correct)

Cerebellum

What is the role of the amygdala in the brain?

Regulates hunger and thirst

Controls voluntary movements

Forms new memories

Connects sensations and emotions (correct)

Which neurotransmitter is linked to movement and reward?

Dopamine (correct)

Glutamate

GABA

Serotonin

Which division of the brain is responsible for coordinating cognitive processes and fine movements?

Hindbrain Signup and view all the answers

What is the primary function of the hypothalamus?

Regulate hunger, thirst, and sex drive Signup and view all the answers

Which neurotransmitter primarily regulates mood, sleep, and learning?

Norepinephrine Signup and view all the answers

Which structure is responsible for transferring information between the cerebral hemispheres?

Corpus callosum Signup and view all the answers

What condition is associated with a deficiency of acetylcholine?

Alzheimer's disease Signup and view all the answers

What type of signal is carried by the axon?

Action potential Signup and view all the answers

What role do sensory neurons play in the somatic nervous system?

Provide information to the brain about the environment Signup and view all the answers

Which component of the autonomic nervous system prepares the body for vigorous activity?

Sympathetic nervous system Signup and view all the answers

What is the function of neurotransmitters in neural communication?

Assist in the transfer of signals between neurons Signup and view all the answers

What type of signal does a postsynaptic potential represent?

An electrochemical signal Signup and view all the answers

What is the consequence of an excitatory postsynaptic potential on a neuron?

It depolarizes the neuronal membrane Signup and view all the answers

Which part of the neuron primarily detects signals from other neurons?

Dendrite Signup and view all the answers

How do receptors function in relation to neurotransmitters?

They recognize and bind with certain neurotransmitters Signup and view all the answers

What type of signal is typically traversed in the synapse?

Chemical signal Signup and view all the answers

What is the main function of the peripheral nervous system?

Transmitting information between the CNS and the body Signup and view all the answers

What is the primary function of the parasympathetic nervous system?

Facilitate digestion and relaxation Signup and view all the answers

What role does the spinal cord play in reflex actions?

Controls involuntary behaviors without brain input Signup and view all the answers

Which structure in the brain is primarily responsible for processing visual information?

Visual cortex Signup and view all the answers

What is the main function of the cerebellum?

Coordinates finely tuned motor movements Signup and view all the answers

Which part of the forebrain regulates sex drive, hunger, and thirst?

Hypothalamus Signup and view all the answers

The corpus callosum serves what primary function?

Facilitates communication between the cerebral hemispheres Signup and view all the answers

Which neuron type conveys messages from the senses to the brain?

Afferent neurons Signup and view all the answers

Which brain structure is primarily involved in emotional regulation and memory?

Limbic system Signup and view all the answers

What is the key characteristic of the motor cortex?

Facilitates voluntary movements of the body Signup and view all the answers

What does lateral dominance refer to in terms of brain function?

The tendency for one hemisphere to excel at certain functions Signup and view all the answers

What role do hormones play in the body?

They regulate functions ranging from stress to physical growth. Signup and view all the answers

What is the primary neurotransmitter responsible for slowing or inhibiting brain activity?

GABA (gamma-aminobutyric acid) Signup and view all the answers

What is the role of the autonomic nervous system?

It carries messages between the central nervous system and internal organs. Signup and view all the answers

Which part of the brain is involved in controlling stress responses, such as the fight or flight reaction?

Hypothalamus Signup and view all the answers

What type of chemical communication occurs between neurons?

Neurotransmitter diffusion Signup and view all the answers

What is the main role of glial cells in the nervous system?

They hold neurons together and assist in communication. Signup and view all the answers

How does myelin affect the speed of action potentials?

It increases the speed. Signup and view all the answers

What happens during depolarization of a neuron?

The inside of the cell may become less negative or even positive. Signup and view all the answers

What are synapses?

The tiny gaps between neurons for communication. Signup and view all the answers

What would primarily prevent a neuron from firing an action potential?

A highly polarised state. Signup and view all the answers

What role do dendrites play in a neuron?

They receive signals from other neurons. Signup and view all the answers

What is an action potential?

An abrupt wave of electrochemical changes in a neuron. Signup and view all the answers

What is the function of the nodes of Ranvier?

They enable the action potential to be propagated and regenerated. Signup and view all the answers

What is the primary function of the thalamus in the brain?

Interprets and relays sensory information Signup and view all the answers

Which neurotransmitter is primarily associated with regulating movement and reward?

Dopamine Signup and view all the answers

Which structure is responsible for coordinating fine movements and cognitive processes?

Cerebellum Signup and view all the answers

What role do hormones play in the endocrine system?

Provide feedback to the brain and pituitary gland Signup and view all the answers

What disorder is associated with a deficiency in serotonin?

Depression Signup and view all the answers

Which part of the brain is key in forming new memories?

Hippocampus Signup and view all the answers

What is the function of endorphins in the body?

Moderate pain by binding to opiate receptors Signup and view all the answers

Which component of the midbrain helps initiate smooth movements?

Substantia nigra Signup and view all the answers

What is the primary role of the locus coeruleus in the brain?

Facilitating attention and arousal Signup and view all the answers

Which part of the cerebral cortex is primarily responsible for processing auditory information?

Auditory cortex Signup and view all the answers

What role does the thalamus serve in the forebrain?

Processing and relaying sensory information Signup and view all the answers

Which structure in the brain is critical for the formation of new memories?

Hippocampus Signup and view all the answers

In what way do afferent neurons function in the spinal cord?

They transport sensory information to the spinal cord Signup and view all the answers

What is the main function of the cerebellum in the hindbrain?

Controlling and coordinating finely tuned movements Signup and view all the answers

Which structures collectively regulate emotion and memory?

Limbic system Signup and view all the answers

What is the primary role of the motor cortex?

Controlling voluntary movements Signup and view all the answers

Which structure connects the right and left cerebral hemispheres?

Corpus callosum Signup and view all the answers

What characteristic defines lateral dominance in brain function?

One hemisphere excels at specific cognitive functions compared to the other Signup and view all the answers

What occurs when a neurotransmitter binds to its receptor?

It opens channels in the membrane of the postsynaptic cell. Signup and view all the answers

Which type of postsynaptic potential makes a neuron more likely to fire an action potential?

Excitatory postsynaptic potential Signup and view all the answers

What is the main role of sensory neurons in the somatic nervous system?

To detect environmental changes and send information to the brain. Signup and view all the answers

What effect does an inhibitory postsynaptic potential have on a neuron's membrane potential?

It hyperpolarizes the membrane. Signup and view all the answers

What is the primary function of the synapse?

To facilitate communication between neurons. Signup and view all the answers

Which characteristic best describes the role of axons in the nervous system?

They carry signals away from the cell body. Signup and view all the answers

What is the function of receptors in the context of neurotransmitter action?

They recognize and respond to specific neurotransmitters. Signup and view all the answers

Which system is responsible for preparing the body for vigorous activity?

Autonomic nervous system Signup and view all the answers

What is the primary effect of the actions of neurotransmitters on postsynaptic cells?

They alter the membrane potential of the postsynaptic cells. Signup and view all the answers

The function of the autonomic nervous system primarily involves communication between the CNS and which organs?

Heart, lungs, and other organs. Signup and view all the answers

Study Notes

Refractory Period

Brief rest period between action potentials, preventing the signal from traveling back toward the cell body.

Synapses & Communication

Neurotransmitters carry signals from one neuron to another.
Neural receptors are specialized cells that detect energy and transduce it into nerve cell activity.
When a neurotransmitter binds to a receptor, channels in the postsynaptic cell membrane open, allowing ions to flow.
This ion flow creates a change in the postsynaptic cell's membrane potential, transforming the chemical signal into an electrochemical signal.

Postsynaptic Potential

Excitatory postsynaptic potential (EPSP) depolarizes the neuronal membrane, making the cell more likely to fire an action potential.
Inhibitory postsynaptic potential (IPSP) hyperpolarizes the neuronal membrane, making the cell less likely to fire an action potential.

Neuron Parts & Functions

Axon carries action potentials away from the cell body, releasing neurotransmitters.
Dendrite detects and carries signals to the cell body, generating postsynaptic potentials.
Neurotransmitter is a chemical released by one cell that binds to receptors on another cell, influencing the firing of its action potential.
Receptor is a protein on the cell membrane that recognizes specific neurotransmitters, initiating a postsynaptic potential in the dendrite.
Synapse is the area where signals transfer between neurons, usually between the axon of one cell and the dendrite of another.

Neural Networks

Groups of neurons working together to perform complex functions.

Peripheral Nervous System

Somatic nervous system:
- Transmits sensory information from the senses to the CNS.
- Carries signals from the CNS to the muscles.
- Uses sensory neurons to provide information about the environment.
- Uses motor neurons to influence muscles and organs in response to the environment.
Autonomic nervous system:
- Carries messages between the CNS and internal organs (heart, lungs, etc.).
- Sympathetic nervous system: readies the body for vigorous activity (fight or flight).
- Parasympathetic nervous system: influences activity related to protection and rest (rest and digest).

Neural Plasticity

The brain's ability to create new synapses and change the strength of existing ones.

Brain Divisions & Structures

Hindbrain:
- Cerebellum: controls fine movements and coordinates cognitive processes.
- Medulla oblongata: regulates breathing, heart rate, and blood pressure.
- Reticular formation: regulates arousal and attention.
Midbrain:
- Substantia nigra: initiates smooth movements.
- Various nuclei: relay sensory signals to the forebrain and create automatic responses to stimuli.
Forebrain:
- Amygdala: connects sensations and emotions.
- Cerebral cortex: analyzes sensory information, controls voluntary movements, and supports abstract thinking and complex cognitive activity.
- Corpus callosum: transfers information between the two cerebral hemispheres.
- Hippocampus: forms new memories.
- Hypothalamus: regulates hunger, thirst, and sex drive.
- Thalamus: interprets and relays sensory information.

Neurotransmitters

Neurotransmitter | Normal function | Disorder
------------------------ | ------------------------ | -----------------------
Acetylcholine | Memory, movement | Alzheimer's disease
Norepinephrine | Mood, sleep, learning | Depression
Serotonin | Mood, appetite, impulsivity | Depression
Dopamine | Movement, reward | Parkinson's, Schizophrenia
GABA (inhibitory) | Sleep, movement | Anxiety, Epilepsy
Glutamate (excitatory) | Memory | Damage after stroke

Endorphins

A class of neurotransmitters that bind to opiate receptors and moderate pain.

Endocrine System

Hormones provide feedback to the brain and the pituitary gland, creating a negative feedback system.

Central Nervous System

Spinal cord
- Relays signals from peripheral senses to the brain.
- Conveys messages from the brain to the rest of the body.
- Afferent neurons: sensory neurons in the spinal cord.
- Efferent neurons: motor neurons in the spinal cord.
Reflexes are involuntary, unlearned behaviors directed by the spinal cord without instructions from the brain.

Brain

Hindbrain
- An extension of the spinal cord, containing nuclei that control vital functions (e.g., blood pressure, heart rate, and breathing) primarily in the medulla oblongata.
Reticular formation
- A network of cells and fibers in the hindbrain and midbrain involved in arousal and attention.
Locus coeruleus
- A small nucleus in the reticular formation involved in attention.
Cerebellum
- Controls finely coordinated movements and stores movement memories.
Midbrain
- Relays information from eyes, ears, and skin, and controls automatic behaviors.
Forebrain
- The most highly developed part of the brain, responsible for complex behaviors and mental processes.
Thalamus
- Relays sensory signals from most sense organs to higher brain levels, playing a key role in processing and making sense of information.
Hypothalamus
- Regulates hunger, thirst, and sex drive.
Amygdala
- Critically involved in fear and reward learning.
Hippocampus
- Plays a crucial role in forming new memories.
Limbic system
- A set of brain structures vital for regulating emotion and memory.
Cerebral hemispheres
- The left and right halves of the outermost part of the brain.
Cerebral cortex
- The outer surface of the brain.
- Sensory cortex:
  - Receives sensory stimulus information.
  - Visual cortex: in the occipital lobe processes visual information.
  - Auditory cortex: in the temporal lobe processes auditory information.
  - Somatosensory cortex: in the parietal lobe processes skin, touch, pain, and temperature.
- Motor cortex:
  - In the frontal lobe.
  - Controls voluntary movements in specific body parts.
- Association cortex:
  - Receives information from multiple senses.
  - Combines sensory and motor information to perform complex cognitive tasks.
Corpus callosum:
- Connects the right and left cerebral hemispheres, allowing communication.
Lateral dominance (lateralization):
- The tendency for one cerebral hemisphere to excel at specific functions compared to the other hemisphere.

Biological Psychology

Biological Psychology is the study of the physical and chemical processes that cause and occur in response to behaviour and mental processes.
Nervous System is a complex network of cells that allows organisms to receive information, process it and respond accordingly.
Neurons are the fundamental units of the nervous system.
Glial Cells support neurons and facilitate communication between them.
Axons carry signals from the neuron's body to other neurons.
Dendrites receive signals from other neurons' axons and carry them to the cell body.
Synapses are the gaps between neurons where communication occurs.
Action Potential is a wave of electrochemical changes travelling down an axon when a neuron is depolarised.
Myelin is a fatty substance that wraps around axons, increasing the speed of action potential.
Nodes of Ranvier are gaps in the myelin sheath that allow action potential propagation and regeneration.

Neuron Communication

Neurotransmitters are chemicals that facilitate signal transfer between neurons.
Neural Receptors are specialised cells that detect specific forms of energy and convert them into nerve cell activity.
When a neurotransmitter binds to its receptor, it stimulates channels on the postsynaptic cell membrane to open, allowing ion flow.
Postsynaptic Potential is the change in the membrane potential of a neuron that has received stimulation from another neuron.
Excitatory Postsynaptic Potential depolarises the neuronal membrane, increasing the likelihood of firing an action potential.
Inhibitory Postsynaptic Potential hyperpolarises the neuronal membrane, making a cell less likely to fire an action potential.

Nervous System Organisation and Functions

Neural Networks are groups of neurons that collaborate to perform complex functions.
Peripheral Nervous System connects the CNS to the rest of the body, consisting of two subsystems.
- Somatic Nervous System transmits sensory information to the CNS and sends signals from the CNS to skeletal muscles.
  - Sensory neurons provide information to the brain.
  - Motor neurons control muscles and other organs.
- Autonomic Nervous System carries messages between the CNS and internal organs.
  - Sympathetic Nervous System prepares the body for vigorous activity - 'fight or flight'.
  - Parasympathetic Nervous System influences activities related to protection - 'rest and digest'.
Central Nervous System includes the spinal cord and brain.
- Spinal Cord relays signals between peripheral senses and the brain, and vice-versa.
  - Afferent neurons are sensory neurons.
  - Efferent neurons are motor neurons.
- Reflexes are involuntary, unlearned behaviours controlled by the spinal cord without brain input.

Brain Structures and Functions

Hindbrain is an extension of the spinal cord, containing nuclei for regulating vital functions like blood pressure, heart rate, and breathing.
- Medulla Oblongata plays a key role in regulating these vital functions.
- Reticular Formation is involved in arousal and attention.
- Locus coeruleus is a nucleus within the reticular formation associated with attention.
- Cerebellum controls fine movements and stores movement-related memories.
Midbrain relays information from senses and controls automatic behaviours.
Forebrain is responsible for the most complex aspects of behaviour and mental life.
- Thalamus relays sensory signals to higher brain areas and processes sensory information.
- Hypothalamus regulates hunger, thirst, and sex drive.
- Amygdala plays a crucial role in fear and reward learning.
- Hippocampus is associated with the formation of new memories.
- Limbic System regulates emotions and memory.
- Cerebral Hemispheres are the left and right halves of the outermost part of the brain.
- Cerebral Cortex is the outer surface of the brain.
  - Sensory Cortex receives stimulus information from the senses.
  - Visual Cortex (occipital lobe) receives visual information.
  - Auditory Cortex (temporal lobe) receives auditory information.
  - Somatosensory Cortex (parietal lobe) receives touch, pain, and temperature information.
  - Motor Cortex (frontal lobe) controls voluntary movements.
  - Association Cortex combines information from different senses or sensory and motor information for complex cognitive tasks.
- Corpus Callosum connects the two hemispheres and facilitates communication between them.
- Lateral Dominance (Lateralisation) is the tendency of one hemisphere to excel in a specific function compared to the other.
- Neural Plasticity is the brain's ability to create new synapses and modify the strength of existing synapses.

Neurotransmitters and Their Functions

Neurotransmitters are chemical messengers involved in communication between neurons.
Acetylcholine is involved in memory and movement. Its deficiency is linked to Alzheimer's disease.
Norepinephrine affects mood, sleep, and learning. Its depletion is associated with depression.
Serotonin influences mood, appetite, and impulsivity. Low levels are linked to depression.
Dopamine plays a role in movement and reward. Dysfunction is implicated in Parkinson's disease and schizophrenia.
GABA (gamma-aminobutyric acid) is inhibitory and is involved in sleep and movement. Its deficiency is associated with anxiety and epilepsy.
Glutamate is excitatory and is crucial for memory. Excessive glutamate release can cause brain damage after a stroke.
Endorphins are a class of neurotransmitters that bind to opiate receptors and moderate pain.