Smooth Muscle

Question 2

What are the three types of cellular communication?

Answer 2

Endocrine, Paracrine, Autocrine

Question 3

What are the characteristics of a receptor and how does it recognize chemical signals?

Answer 3

Receptors have high affinity for chemicals and can quickly saturate due to limited capacity. They recognize specific chemicals through conformational changes that activate intracellular responses.

Question 4

Explain receptor-effector responses, including G protein-coupled second messenger signaling.

Answer 4

G protein-coupled signaling involves second messengers transmitting signals inside the cell. G-protein stimulatory (Gαs) activates adenylyl cyclase to generate cAMP, while G-protein inhibitory (Gαi) inhibits it.

Question 5

What is the macroscopic and cytoskeletal structure of smooth muscle?

Answer 5

Smooth muscle contains actin and myosin for contraction. Unlike skeletal muscle, it lacks sarcomeres, leading to a non-striated appearance and sustained contraction ability.

Question 6

What are the distinguishing characteristics of multi-unit and unitary smooth muscle?

Answer 6

Multi-unit smooth muscle cells are individually excited, lacking gap junctions (e.g., vas deferens), while unitary smooth muscle cells have gap junctions for synchronized contraction (e.g., intestines).