natremia The presence of sodium ions in the blood. Derived terms . dysnatremia; hypernatremia; hyponatremia; natremic; Translations
A reflex arc is a nerve pathway in the body of humans and some animals that connects certain muscle groups to others, without involving the brain. These sorts of pathways primarily control involuntary movements in response to some sort of stimulus.
Reflex Arc. 1  A sensory receptor detects a stimulus. 2  A sensory neuron conducts action potentials through the spinal nerve and dorsal root to spinal cord. 3  in the spinal cord,the sensory neuron synapses with an interneuron. 4  The interneuron synapses with motor neuron.