Cervical effacement (also called cervical ripening) refers to a thinning of the cervix. It is a component of the Bishop score. It can be expressed as a percentage. Prior to effacement, the cervix is like a long bottleneck, usually about four centimeters in length. Throughout pregnancy, the cervix is tightly closed and protected by a plug of mucus. When the cervix effaces, the mucus plug is loosened and passes out of the vagina.
A reflex arc is a neural pathway that controls a reflex action. In higher animals, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord.hen the patellar tendon is tapped just below the knee, the patellar reflex is initiated and the lower leg kicks forward (via contraction of the quadriceps). The tap initiates an action potential in a specialized structure known as a muscle spindle located within the quadriceps.
1-7. REFLEX ARC An impulse follows a conduction pathway from its origin in the dendrites or neuron cell body in one part of the body to the impulse's end somewhere else in the body.One pathway is called a reflex arc and is a functional unit of the nervous system.The basic parts of a reflex arc are a receptor, a sensory neuron, a center, a motor neuron, and an effector. a. Function of Components of a Reflex Arc.Functions are: (1) Receptor. The receptor activates a nerve impulse in a sensory neuron in response to a change in the body's internal or external environment.(2) Sensory neuron. This neuron conducts the impulse from the receptor to its axonal end in the central nervous system.he receptor activates a nerve impulse in a sensory neuron in response to a change in the body's internal or external environment. (2) Sensory neuron. This neuron conducts the impulse from the receptor to its axonal end in the central nervous system.