Bleeding or spotting later in pregnancy may be a sign of a serious problem, like: 1  Preterm labor. This is labor that happens too early, before 37 weeks of pregnancy. 2  Placenta previa. This is when the placenta lies very low in the uterus and covers all or part of the cervix. 3  Placental abruption.
Afferent definition, bringing to or leading toward an organ or part, as a nerve or arteriole (opposed to efferent). See more.
In a generalized pathway, the afferent neuron of the sensory unit is the first in a chain of neurons that relays information to the CNS (spinal cord and brain). The afferent neuron is the first order neuron. It synapses with a second order neuron that synapses in turn with a third order neuron in the thalamus. The third order neuron guides the impulse to the sensory cortex where it is perceived.