The Biological Bases of Behaviour - Chapter 3

Flashcards covering the biological bases of behavior, including neuron structure and function, neural impulses, neurotransmitters, brain anatomy and functions, and methods for studying the brain.

What are the four main parts of a neuron?

Cell body (soma), Dendrites, Axon, and Axon Terminals.

What is the function of dendrites in a neuron?

Dendrites receive signals from other cells.

What is the primary function of an axon?

The axon conducts electrical impulses away from the cell body (soma).

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

Glial cells hold neurons in place, make and move nutrients, form the Myelin Sheath, remove toxins, and form the blood-brain barrier.

What are the two basic functions of neurons?

Neurons generate electricity (create nerve impulses) and release chemicals (communicate with other cells).

Describe the first step of neural activation.

The cell is at rest with an electrical resting potential, typically -70mV, due to a higher concentration of sodium ions outside and negative protein ions inside.

What is an action potential in a neuron?

An action potential is a neural impulse produced when a cell is stimulated, causing electrical charges (ions) to flow across the cell membrane and reverse the charge of the resting potential.

What is the absolute refractory period in neural impulses?

It is a period during which a neuron cannot fire again, limiting how often nerve impulses can occur and ensuring impulses travel in a single direction.

Explain the All-or-None Law related to action potentials.

Action potentials occur at a uniform and maximal intensity, or they do not occur at all. Stronger signals do not cause stronger action potentials, but rather create more action potentials (increase the rate of cell firing).

What is the function of the Myelin Sheath?

The Myelin Sheath is a fatty, whitish insulation layer derived from glial cells that insulates neurons and speeds up signal conduction.

What are Nodes of Ranvier?

Nodes of Ranvier are places where the myelin sheath is either extremely thin or absent, allowing electrical conduction to 'skip ahead' for faster signals.

What is a synapse?

A synapse is a functional (not physical) connection between neurons and their target cells, where neurons communicate across gaps called synaptic clefts.

What are neurotransmitters?

Neurotransmitters are chemical substances that carry messages across the synapse to either excite other neurons or inhibit their firing.

List the five stages of chemical communication by neurotransmitters.

Synthesis, Storage, Release, Binding, and Deactivation.

How does an inhibitory neurotransmitter affect a postsynaptic neuron?

An inhibitory neurotransmitter increases the resting potential of the postsynaptic neuron (hyperpolarization), decreasing the likelihood of an action potential.

How does an excitatory neurotransmitter affect a postsynaptic neuron?

An excitatory neurotransmitter decreases the resting potential of the postsynaptic neuron (depolarization), increasing the likelihood of an action potential.

Why are there different types of neurotransmitters sensitive to specific brain systems?

This 'chemical specificity' avoids 'crosstalk' between different brain areas, ensuring precise communication.

What is the primary function of Glutamate?

Glutamate is an excitatory neurotransmitter expressed throughout the brain, involved in the control of behaviors, especially learning and memory.

What is the primary function of GABA (gamma-aminobutyric acid)?

GABA is an inhibitory neurotransmitter expressed throughout the brain, involved in the control of behaviors, especially anxiety and motor control.

Which neurotransmitter is primarily involved in muscle movement and memory, with its decline linked to Alzheimer's disease?

Acetylcholine (ACh).

What are some functions associated with Norepinephrine?

Norepinephrine is involved in learning, memory, wakefulness, and eating, and its dysfunction can be related to depression and panic disorders.

What roles does Serotonin play in the body?

Serotonin is mostly inhibitory and functions at various sites, involved in mood, eating, sleep, and arousal, linked to depression, sleeping, and eating disorders.

Which neurotransmitter is involved in voluntary movement, learning, motivation, and pleasure?

Dopamine, which is also implicated in depression, Parkinson's disease, and Schizophrenia.

What is the effect of an oversupply of Endorphins?

An oversupply of endorphins can lead to insensitivity to pain.

What is the function of sensory neurons?

Sensory neurons carry input messages from the sense organs to the spinal cord and brain.

What is the function of motor neurons?

Motor neurons transmit output impulses from the brain and spinal cord to muscles and organs.

What is the role of interneurons?

Interneurons perform connective or associative functions within the nervous system and are the most common type of neuron.

What are the two main divisions of the nervous system?

The Central Nervous System (CNS) and the Peripheral Nervous System (PNS).

What are the components of the Central Nervous System (CNS)?

The spinal cord and the brain.

What is the function of the Somatic Nervous System?

The Somatic Nervous System brings information from sensory receptors and sends information to muscles, controlling voluntary muscle activation.

What is the primary role of the Autonomic Nervous System?

The Autonomic Nervous System regulates the internal environment, controlling involuntary functions such as respiration, circulation, digestion, and aspects of motivation, emotion, and stress responses.

What is the function of the Sympathetic Nervous System?

The Sympathetic Nervous System has an activation or arousal function, preparing the body for 'fight-or-flight' responses and tending to act as a total unit.

What is the function of the Parasympathetic Nervous System?

The Parasympathetic Nervous System slows down body processes, returning the body to a state of rest (e.g., 'feed-and-breed' system), and operates in specific organs at any given time.

What is a spinal reflex?

A spinal reflex is a simple stimulus-response sequence triggered at the level of the spinal cord, without direct brain involvement.

What are the three main anatomical divisions of the brain?

Forebrain, Midbrain, and Hindbrain.

What is the function of the cerebral cortex?

The cerebral cortex is the outer layer of the cerebral hemispheres, involved in thinking and mental processes.

What are the four lobes of the cerebral cortex?

Frontal Lobe, Temporal Lobe, Parietal Lobe, and Occipital Lobe.

What is the role of the basal ganglia?

The basal ganglia are collections of neurons crucial to motor function.

What are the key components and their functions within the limbic system?

The Hippocampus (memory), Amygdala (emotional response), and Nucleus accumbens (reward center).

What is the function of the thalamus?

The thalamus relays incoming sensory information through groups of neurons to the appropriate region in the cortex.

What is the function of the hypothalamus?

The hypothalamus regulates basic biological drives such as hunger, thirst, and sexual behavior.

What is the reticular formation primarily involved in?

The reticular formation is involved in the regulation of consciousness, conscious awareness, control, sleep, wakefulness, and attention.

What vital functions does the medulla control?

The medulla controls heart activity, breathing, swallowing, and digestion. All sensory and motor nerve tracts ascend from the spinal cord and descend from the brain through it.

What are the functions of the cerebellum?

The cerebellum controls bodily coordination, balance, muscle tone, and is involved in procedural memory (motor skills).

What is the primary function of the motor cortex?

The motor cortex controls the muscles involved in voluntary body movements.

What types of sensations does the somatic sensory cortex receive?

The somatic sensory cortex receives input for sensations of heat, touch, cold, and our senses of balance and body position.

Where are Wernicke's area and Broca's area located, and what are their respective functions?

Wernicke's area (temporal lobe) is involved in language comprehension, and Broca's area (frontal lobe) is involved in normal speech production.

What are some functions typically associated with the right hemisphere of the brain?

Feelings, intuition, humor, aesthetic appreciation, color perception, relationships, rhythm, physical senses, and motor skills (for the left side of the body).

What are some functions typically associated with the left hemisphere of the brain?

Analytical thinking, rules, logic, structure, mathematics, planning, speech, language, and time (for the right side of the body).

How is visual information typically processed in the brain?

The left visual field is processed in the right hemisphere of the brain, and the right visual field is processed in the left hemisphere of the brain.

What is the function of the corpus callosum and what happens if it is severed?

The corpus callosum bridges the hemispheres and transfers information between them. If severed (corpus callostomy), it results in 'split-brain' patients.

List three methods used to study the brain in live humans.

Surgical techniques, Electroencephalography (EEG), and various brain imaging techniques such as CT, PET, MRI, fMRI, DTI, NIRS, and TMS.

What does Electroencephalography (EEG) measure and what is its main advantage?

EEG measures electrical activity via electrodes. Its main advantage is very good time resolution (milliseconds).

How does Computer Tomography (CT) build an image of the brain?

CT builds a picture based on the differential absorption of x-rays, revealing gross features of the brain.

What specifically does functional Magnetic Resonance Imaging (fMRI) detect?

fMRI detects changes in blood oxygenation and flow, which are tied to neural activity; high activity corresponds to high oxygen use and high blood flow.