Additional causes of bleeding in early pregnancy include: 1  Cervical changes. During pregnancy, extra blood flows to the cervix. 2  Infection. Any infection of the cervix, vagina, or a sexually transmitted infection (such as chlamydia, gonorrhea, or herpes) can cause bleeding in the first trimester.
A: Afferent neurons are special nerve cells that are responsible for carrying nerve impulses from the receptors to the central nervous system. Efferent neurons carry nerve impulses from the central nervous system to the muscles and glands. Continue Reading.
The neuron is a single nerve cell, and you have billions of them. There are three basic types of neurons: association, afferent, and efferent. The association neurons comprise the central nervous system (CNS) that is the brain and spinal cord.The afferent neurons are also known as the sensory neurons: they bring the stimuli from the sensors (e.g., skin, eyes, ears) to the CNS.here are three basic types of neurons: association, afferent, and efferent. The association neurons comprise the central nervous system (CNS) that is the brain and spinal cord.