Biology Chapter: Nervous System Functions

Channels in a cell membrane that open when a specific molecule binds to them.

Channels that open in response to physical pressure or distortion.

Channels that open when the membrane potential changes.

The difference in electrical potential between the inside and outside of a neuron's cell membrane when it is not transmitting a signal.

Unequal distribution of ions across the membrane, selective permeability of the membrane to certain ions, and the action of the sodium-potassium pump.

Small, localized changes in membrane potential that can vary in strength.

Graded potentials are produced when mechanically-gated or ligand-gated channels open.

Graded potentials decrease in strength as they travel away from the point of stimulation.

Excitable cells, like neurons, communicate using electrical signals. These signals can be either Action Potentials (APs) or Graded Potentials (GPs).

Action Potentials (APs) are rapid, short-lasting changes in membrane potential that travel long distances along the axon, allowing communication between neurons.

Graded Potentials (GPs) are localized changes in membrane potential that decay over short distances. They are important for communication within a neuron, but not between neurons.

The resting membrane potential is the electrical difference across the plasma membrane of a neuron when it is not actively transmitting signals.

Ion channels are proteins embedded in the cell membrane that allow specific ions to pass through. They are key for generating and transmitting electrical signals.

Leak channels are always open, allowing ions to flow passively across the membrane. They're important for maintaining the resting membrane potential.

Ligand-gated channels open in response to a chemical messenger (ligand) binding to a receptor. They are important for transmitting signals at synapses.

Voltage-gated channels open or close in response to changes in the membrane potential. They are crucial for generating and propagating action potentials along the axon.

The nervous system is responsible for detecting changes in the internal and external environments, processing this information, and generating appropriate responses to maintain homeostasis.

Sensory neurons transmit information from sensory receptors to the central nervous system. Motor neurons carry signals from the central nervous system to effectors, which carry out responses. Interneurons connect neurons within the central nervous system.

The central nervous system (CNS) consists of the brain and spinal cord. The peripheral nervous system (PNS) includes all the nerves outside the CNS. The PNS can be further divided into the somatic nervous system (voluntary control) and autonomic nervous system (involuntary control)

The nervous system is involved in detecting changes in the internal and external environments through sensory receptors. This information is then analyzed and interpreted by the CNS, leading to decisions regarding appropriate responses.

The CNS processes sensory information, stores memories, and makes decisions about how to respond. These decisions result in appropriate actions or behaviors.

The nervous system initiates and controls responses by sending signals to effectors, such as muscles and glands, which carry out the appropriate actions.

Neurons are specialized cells that transmit information throughout the nervous system through electrical signals called action potentials.

Neuroglia are supportive cells that provide structural support, insulation, and nourishment to neurons. They also play a role in maintaining the health of the nervous system.

The combined effect of multiple presynaptic neurons releasing neurotransmitters at the same time, leading to a postsynaptic neuron's depolarization.

The effect of a single presynaptic neuron repeatedly releasing neurotransmitters in a short timeframe, resulting in a postsynaptic neuron's depolarization.

The process of adding together the effects of multiple postsynaptic potentials, which can be either excitatory or inhibitory.

A type of neurotransmitter that is a small molecule or compound.

A type of neurotransmitter that is made up of a chain of amino acids.

A neurotransmitter that is involved in the transmission of pain signals.

A neurotransmitter that is involved in the inhibition of pain signals.

A neurotransmitter that is involved in the regulation of mood, pain perception, and memory.

Hypothalamic releasing and inhibiting hormones are produced in the hypothalamus and regulate the release of hormones by the anterior pituitary.

Angiotensin II is a peptide that stimulates thirst and may regulate blood pressure in the brain. It also acts as a hormone, causing vasoconstriction and promoting aldosterone release, which increases salt and water reabsorption by the kidneys.

Cholecystokinin (CCK) is a neuropeptide found in the brain and small intestine that may regulate feeding as a 'stop eating' signal. It also acts as a hormone, regulating pancreatic enzyme secretion during digestion and contraction of smooth muscle in the gastrointestinal tract.

A neural circuit is a group of neurons that work together to process specific types of information.

Simple series circuits involve neurons connected in a linear fashion, where information flows sequentially from one to the next.

In diverging circuits, a single neuron branches out to activate multiple other neurons.

Converging circuits receive input from multiple neurons, which converge onto a smaller number of neurons.

The change in membrane potential, often a small depolarization or hyperpolarization, is proportional to the strength of the stimulus. A stronger stimulus creates a larger graded potential.

Multiple graded potentials can add together, either by summation of several subthreshold stimuli or by the arrival of multiple stimuli close together in time. This combined effect may reach threshold, triggering an action potential.

A rapid, short-lived change in the membrane potential that travels along the axon of a neuron or muscle fiber.

The phase of the action potential that starts from the resting potential and rapidly rises to a more positive value. The rising phase is caused by an influx of positively charged sodium ions (Na+) into the neuron.

The phase that follows depolarization, and returns the membrane potential to its resting value. The falling phase is caused by an outward flow of positively charged potassium ions (K+) from the neuron. This results in a decrease in the membrane potential making it more negative.

An action potential will only be generated if the membrane potential reaches a certain threshold value. This threshold is determined by the balance of inward and outward current flow across the membrane. Below threshold, the neuron will not fire an action potential.

These channels remain closed at rest, but open when the membrane potential reaches a certain threshold. This opening allows sodium ions (Na+) to flow into the cell, causing depolarization.

These channels are also closed at rest, but open more slowly than sodium channels, during the depolarization phase. This opening allows potassium ions (K+) to flow out of the cell, contributing to repolarization.