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.
Overview of Excessive Drinking and Urinating in Cats. The term polydipsia refers to a cat's excessive thirst manifested by excessive water intake, which in turn usually leads to polyuria, which is the formation and excretion of a large volume of urine. Polydipsia and Polyuria is commonly abbreviated and discussed using the letters PU/PD.