It has been shown in the literature that many MAC protocols for wireless networks, such as the IEEE 802.11 MAC, have a considerable control overhead, which limits their achievable throughput and delay performance. In this paper, we study the problem of improving the efficiency of MAC protocols. We first analyze the popular p-Persistent CSMA scheme which does not achieve 100% throughput. Motivated by insights from polling system theory, we then present three polling service-based MAC schemes, termed PSMAC, for improved performance. The main idea is to serve multiple data frames after a successful contention resolution, thus amortizing the high control overhead and making the protocols more efficient. We present analysis and simulation studies of the proposed schemes. Our results show that the proposed algorithms can effectively improve the throughput and delay performance of p-Persistent CSMA, as well as providing energy savings. The proposed schemes are more efficient for handling bursty traffic typically found in wireless networks. Finally, we observe that the proposed PSMAC schemes significantly outperform p-Persistent CSMA with respect to fairness.