Muscle tone. Definition. noun. (1) The muscle in a steady partially contracted state caused by the successive flow of nerve impulses. (2) The amount of tension or resistance to movement in a muscle. Supplement. Muscle tone or tonus helps in maintaining body posture.
Hydronephrosis is the distention of the pelvis and calyces of one or both kidneys, resulting in thinning of the renal tubules because of obstructed urinary flow. When the obstruction is a stone or kink in one of the ureters, only one kidney is damaged.
Hydronephrosis is the swelling of the kidneys when urine flow is obstructed in any of part of the urinary tract. Swelling of the ureter, which always accompanies hydronephrosis, is called hydroureter. Hydronephrosis implies that a ureter and the renal pelvis (the connection of the ureter to the kidney) are overfilled with urine.