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.
Sensory Neurons: Sensory neurons carry signals from the outer part of the body into the central nervous system. Motor Neurons: Motor neurons carry signals from the central nervous system to the outer parts of the body. Afferent/Efferent Pathways. Sensory Neurons: Sensory neurons follow the afferent pathway.