Select all that applyDescribe the muscarinic receptors in cardiac muscle cells.Multiple select question.They bind epinephrine.They bind ACh.When activated, they act as potassium ion channels.When activated, they act as sodium ion channels.They employ a secondary messaging system.

The muscarinic receptors in cardiac muscle cells have the following characteristics:

• They bind ACh (Acetylcholine). This is a neurotransmitter that binds to muscarinic receptors, which are a type of cholinergic receptor.

• When activated, they act as potassium ion channels. This means that when ACh binds to these receptors, it causes an increase in the permeability of the cell membrane to potassium ions, which leads to a slowing of the heart rate.

• They employ a secondary messaging system. This is because the binding of ACh to the muscarinic receptors activates a G-protein, which then activates other molecules inside the cell to carry out various functions.

The statements "They bind epinephrine" and "When activated, they act as sodium ion channels" are not correct. Epinephrine (also known as adrenaline) binds to adrenergic receptors, not muscarinic receptors. And while sodium channels do play a role in the action potential of cardiac muscle cells, they are not directly activated by the binding of ACh to muscarinic receptors.