Human Anatomy & Physiology II: Nervous Tissue

These flashcards cover key concepts in the Human Anatomy & Physiology II lecture, focusing on the nervous system and its components, functions, and mechanisms.

What is the primary function of the nervous system?

To keep controlled conditions within limits that maintain life.

What components make up the Central Nervous System (CNS)?

The brain and spinal cord.

What does the Peripheral Nervous System (PNS) consist of?

All nervous tissue outside the CNS, including cranial nerves and spinal nerves.

What are the two main divisions of the PNS?

Sensory (afferent) division and Motor (efferent) division.

What are neurons?

Excitable cells that generate and propagate action potentials.

What are neuroglia?

Supportive cells that do not generate action potentials and can multiply.

What are the three classifications of neurons?

Sensory (afferent) neurons, Interneurons, and Motor (efferent) neurons.

What are graded potentials?

Small deviations from the resting membrane potential that can be hyperpolarizing or depolarizing.

What is an action potential?

A sequence of rapidly occurring events that decrease and then reverse the membrane potential.

What is the all-or-none principle in relation to action potentials?

An action potential occurs completely or not at all and has a consistent amplitude.

What are electrical synapses?

Synapses where action potentials conduct directly through gap junctions between neurons.

What are chemical synapses?

Synapses where neurotransmitters are released from the presynaptic neuron to transmit signals to the postsynaptic neuron.

What is the role of neurotransmitter receptors?

They detect neurotransmitters in the postsynaptic neuron's membrane to facilitate communication.

What is resting membrane potential?

The electrical potential difference across the plasma membrane of an unstimulated cell.

What are the factors that contribute to resting membrane potential?

Inability of most anions to leave the cell, unequal distribution of ions, and electrogenic nature of Na+-K+ ATPases.

What is the difference between inhibiting and exciting postsynaptic potentials?

Excitatory postsynaptic potentials (EPSPs) depolarize the membrane, while inhibitory postsynaptic potentials (IPSPs) hyperpolarize it.

What occurs during a stretch reflex?

Contraction of a skeletal muscle in response to its stretching.

What is a reflex arc?

The pathway followed by impulses that produce a reflex, including sensory neurons, interneurons, and motor neurons.