The smooth muscle type found in the walls of digestive and urinary system organs and that exhibits gap junctions and pacemaker cells is a. multi unit, b. unitary.

Video transcript

Hey, everyone. Let's take a look at this question together which of the following statements about smooth muscle types is true. Is it answer choice. A multi unit smooth muscle is found in organs such as the bladder and uterus. Answer choice B unitary smooth muscle is found in organs such as the digestive and urinary systems. Answer choice C unitary smooth muscle is innervated by the autonomic nervous system. While multi unit smooth muscle is innervated by somatic nerves or answer choice D multi unit smooth muscle exhibits pacemaker and gap junctions. Let's work this problem out together to try to figure out which of the following statements about smooth muscle types is true. So we know that when it comes to smooth muscle types, we know that there are two main groups of smooth muscle which are multi unit as well as unitary. And in order to determine which of the following statements about those smooth muscle types is true, we have to recall what we've learned about each individual group to determine which statement is true. So starting off with multi unit, we know that multi unit smooth muscle is found in organs such as the iris of the eye as well as the walls of large blood vessels. We also note that it does not exhibit gap junctions or pacemaker cells and we note that it is innervated by the autonomic nervous system, specifically the sympathetic nerve fibers. And on the other hand, we have the unitary smooth muscle type and we note that the unitary smooth muscle type is found in organs such as the digestive and urinary system. And it exhibits gap junctions and pacemaker cells as well as being innervated by the autonomic nervous system. Specifically the sympathetic and parasympathetic nerve fibers. And the name unitary comes from the fact that the cells in the unitary smooth muscle contract together as a single unit, which is where the uni comes from in unitary. So looking at our answer choices, which of the following statements about these two smooth muscle types is true. We know that answer choice A is incorrect since it is not the multi unit smooth muscle that is found in the organs such as the bladder and uterus. And instead it is the unit that is found in the digestive and urinary system. And answer choice C is incorrect since both the multi unit and unitary smooth muscle types are innervated by the autonomic nervous system and not somatic nerves. And lastly answer choice D we know is also incorrect since the multi unit smooth muscle does not exhibit pacemaker cells and gap junctions. And it is the unitary smooth muscle type that exhibits the pacemaker cells and gap junctions, which leaves us with the correct answer, which is answer choice B since unitary smooth muscle is found in the organs such as the digestive and urinary system, which is the only true statement about smooth muscle types here. So it is the correct answer. I hope you found this video to be helpful. Thank you and goodbye.