Final answer:
Excitable cells like neurons contain voltage-gated, ligand-gated, and mechanically-gated ion channels, all of which contribute to the transmission of electrical signals in the form of action potentials.
Step-by-step explanation:
Excitable cells, such as neurons, have various types of ion channels. The types of channels found in these cells are: 1) Voltage-gated channels, 2) Ligand-gated channels, and 3) Mechanically-gated channels. Therefore, the correct answer to your question is 4) All of the above.
Voltage-gated channels are sensitive to changes in the cell's membrane potential and open or close in response to these changes. Ligand-gated channels, also known as ionotropic receptors, open in response to a specific chemical signal, such as a neurotransmitter, bonding to their extracellular region. Mechanically-gated channels respond to physical stimuli, such as pressure or stretch, that alter the cell's membrane, which can cause these channels to open.
The function of these gated ion channels is crucial for the transmission of electrical impulses. Action potentials in neurons involve the sequential opening and closing of these channels, allowing ions to flow into or out of the cell, leading to changes in the cell's membrane potential.