Chapter 22 Signal Transduction Mechanisms

These flashcards cover key concepts and terminology from the lecture on signal transduction mechanisms, specifically focusing on neuronal signaling and the nervous system.

What are the three main functions performed by the nervous system?

1. Sensory input, 2. Integration, 3. Motor output.

What does the Central Nervous System (CNS) consist of?

The brain and spinal cord.

What are the two main components of the Peripheral Nervous System (PNS)?

Somatic (voluntary) and autonomic (involuntary) branches.

What do afferent signals do?

They carry information from receptors to the CNS.

What do efferent signals do?

They exit the CNS and travel to the PNS.

What is the role of myelin sheath?

It protects the axon and aids in the speed of signal transmission.

What is saltatory conduction?

The jumping of action potentials from node to node along myelinated axons.

What are astrocytes?

The most abundant glial cells in the CNS that provide support and help form the blood-brain barrier.

What is the typical resting membrane potential of a neuron?

Approximately -70 mV.

What triggers depolarization in a neuron?

The opening of voltage-gated Na⁺ channels.

What is the threshold potential needed to trigger an action potential?

Around -55 mV.

What occurs during the refractory period?

A neuron cannot fire or its ability is limited immediately after an action potential.

What do voltage-gated ion channels respond to?

Changes in membrane potential.

What are neurotransmitters?

Chemical messengers that transmit signals across a synapse.

What is temporal summation?

When multiple signals arrive at a neuron in rapid succession from the same presynaptic input.

What is synaptic cleft?

The small gap between neurons where neurotransmitters are released.

Describe myasthenia gravis (MG).

A chronic autoimmune disease causing muscle weakness due to blocking of acetylcholine receptors.

Describe multiple sclerosis (MS).

A chronic autoimmune disease targeting myelin, causing nerve signal blockage and permanent disability.