Not well or not in good health. Ailing, sick, or indisposed. For example, “I am well-nigh choked with the sulfurous heat of the weather — or I am unwell.” (1826, Journal of Sir Walter Scott)
- Upper GI series
A series of x-rays of the esophagus, stomach, and small intestine (upper gastrointestinal, or GI, tract) that are taken after the patient drinks a barium solution. (Barium is a white, chalky substance that outlines the organs on the x-ray.)
- Upper leg
More properly called the thigh, the upper leg is the area between the knee and the hip. It has only one bone, the femur, which spans the distance from the hip to the knee.
- Upper motor neuron
A neuron that starts in the motor cortex of the brain and terminates within the medulla (another part of the brain) or within the spinal cord. Damage to upper motor neurons can result in spasticity and exaggerated reflexes. There is no standard laboratory test for upper motor neuron disease.
- Upper respiratory infection
An infection of the upper part of the respiratory system which is above the lungs. An upper respiratory infection can be due to any number of viral or bacterial infections. These infections may affect the throat (pharyngitis), nasopharynx (nasopharyngitis), sinuses (sinusitis), larynx (laryngitis), trachea (tracheitis) or bronchi (bronchitis). Upper respiratory infection is commonly abbreviated URI.
An increase in the number of receptors on the surface of target cells, making the cells more sensitive to a hormone or another agent. For example, there is an increase in uterine oxytocin receptors in the third trimester of pregnancy, promoting the contraction of the smooth muscle of the uterus.