Perception and Interaction: Nervous System

These flashcards cover key concepts about the nervous system, its functions, the types of neurons, and the process of nerve impulse transmission.

What is the primary function of the nervous system in organisms?

To allow fast-acting and short-lived responses to changes in the internal or external environment.

What distinguishes a stimulus from a sensory receptor?

A stimulus is a change that can be detected, while sensory receptors are specialized cells that receive specific types of stimuli.

What are the five main types of sensory stimuli?

Vision, auditory (sound), olfactory (smell), gustatory (taste), and somatosensory (touch).

What role do sensory receptors play in the nervous system?

They detect changes in the environment (stimuli) and send signals to the central nervous system.

What is the main difference between myelinated and non-myelinated neurons?

Myelinated neurons have a myelin sheath that speeds up nerve impulse transmission, whereas non-myelinated neurons do not.

Define action potential in the context of nerve impulse transmission.

It is a wave of depolarization where the potential across the neural membrane changes from negative to positive and back to negative.

What is a reflex action?

A sudden, automatic, and involuntary response to stimuli that helps organisms quickly adapt to potential harm.

What are the three main types of neurons involved in a reflex arc?

Sensory neurons, motor neurons, and relay neurons.

How do excitatory neurotransmitters affect a neuron's action potential?

They cause depolarization, increasing the likelihood of the neuron firing an action potential.

Explain the concept of the all-or-nothing principle in nerve impulses.

An action potential is generated only if the stimulus is strong enough to reach a certain threshold; otherwise, no action occurs.

What happens during the refractory period of a neuron?

The neuron recovers from a previous stimulus and cannot be stimulated again until resting potential is restored.

Describe synaptic transmission in chemical synapses.

Nerve impulses cross a synapse using neurotransmitters that bind to receptors on the postsynaptic membrane, opening ion channels.

What are nodes of Ranvier and their significance in myelinated neurons?

Gaps in the myelin sheath that facilitate faster impulse transmission through saltatory conduction.

What is the function of the Na+-K+ pump in maintaining resting membrane potential?

It actively transports sodium out of the neuron and potassium into the neuron, creating a polarized membrane.

What types of synapses exist based on the conduction method?

Electrical synapses and chemical synapses.