BIO3303 - Nervous System and Endocrinology Quiz

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What is the key difference between the nervous and endocrine systems?

Nervous system cells release hormones into the circulatory system to target tissues
Endocrine cells release hormones into the circulatory system to target tissues (correct)
Endocrine cells release electrical signals into the synapse to communicate with target cells
Nervous system cells release neurotransmitters into the synapse to communicate with target cells

What type of channels open when there is a specific change in membrane potential?

Hyperpolarization-gated channels
Ligand-gated channels
Voltage-gated (VG) channels (correct)
Depolarization-gated channels

What happens if the combined depolarization in a neuron exceeds threshold?

Rapid depolarization occurs until the membrane potential repolarizes
An action potential is generated and travels down the axon (correct)
The resting potential is restored
The electrical signal travels down the axon and triggers neurotransmitter release

What is the function of the inactivation gate of the Na+ ion channel?

It prevents the generation of action potentials immediately after an AP has occurred (B) Signup and view all the answers

What is the significance of the absolute refractory period?

It prevents the generation of action potentials immediately after an AP has occurred (B) Signup and view all the answers

How does tetrodotoxin (TTX) affect action potential generation?

It prevents the generation of action potentials by blocking voltage-gated ion channels (D) Signup and view all the answers

What is the main purpose of habituation in the Aplysia Gill-Withdrawal Reflex?

To decrease the tendency to respond to a stimulus (C) Signup and view all the answers

What is the mechanism behind sensitization of the Gill-Withdrawal Reflex in Aplysia?

Facilitating interneurons (D) Signup and view all the answers

How does the structure of a neuron relate to its function?

Dendrites receive input, Axon hillock generates action potentials, Terminals release neurotransmitters (B) Signup and view all the answers

What is the difference between an electrical and chemical synapse?

Electrical synapses allow direct electrical coupling between neurons (D) Signup and view all the answers

What causes the inactivation gate of the Na+ ion channel to close?

Depolarization at -55mV (D) Signup and view all the answers

What prevents backward transmission of action potentials down the axon?

Absolute refractory period (A) Signup and view all the answers

What is the effect of tetrodotoxin (TTX) on voltage-gated ion channels?

It prevents action potential generation (D) Signup and view all the answers

What is the role of the myelin sheath in signal transmission?

It increases resistance and reduces capacitance, resembling insulation on an electrical wire (C) Signup and view all the answers

What is the main characteristic of saltatory conduction?

Action potentials jump from node to node along the axon (D) Signup and view all the answers

What distinguishes ionotropic receptors from metabotropic receptors in synaptic transmission?

Ionotropic receptors are ligand-gated channels causing rapid changes in postsynaptic membrane potential, while metabotropic receptors trigger intracellular transduction pathways for slower changes (B) Signup and view all the answers

What is the main purpose of sensitization in the Aplysia Gill-Withdrawal Reflex?

To increase the response to a gentle stimulus after exposure to a strong stimulus (D) Signup and view all the answers

Which process leads to a decline in the tendency to respond to a stimulus due to repeated exposure in the Aplysia Gill-Withdrawal Reflex?

Habituation (B) Signup and view all the answers

What is the effect of partial inactivation of voltage-gated channels in the axon terminal of the sensory neuron in the Aplysia Gill-Withdrawal Reflex?

Causes an increase in the release of neurotransmitters (C) Signup and view all the answers

What does sensitization of the Gill-Withdrawal Reflex involve?

Facilitating interneurons (D) Signup and view all the answers

What are the two types of cells that wrap axons in the nervous system and produce myelin?

Schwann cells and oligodendrocytes (OLs) Signup and view all the answers

What is the function of the nodes of Ranvier in signal transmission along the axon?

Nodes of Ranvier contain lots of Voltage-gated Na+ channels and facilitate saltatory conduction. Signup and view all the answers

What are the two types of cell-to-cell communication at synapses, and how do they differ?

The two types are electrical and chemical. Electrical synapses use gap junctions for fast ionic transmission, while chemical synapses involve neurotransmitter binding to receptors, leading to slower changes in membrane potential and intracellular signaling cascades. Signup and view all the answers