BIOL 1002 Lecture Notes - Lecture 13: Pus, Multiple Sclerosis, Skeletal Muscle
Document Summary
Urine- watery uid contains waste products, foreign substances, some ions and nutrients that. The primary cell wastes in urine are nitrogenous wastes ammonia, urea, and uric acid. Homeostasis- adjusting the water content, ph and concentration of a variety of ions and small organic molecules in body uids. Organs involved- paired kidneys and ureters, bladder, urethra. These organs lter small molecules and ions out of the blood, return essential ions and nutrients, and collect and excrete substances and cellular wastes. Renal pelvis- collects urine and conducts it into the ureter. Ureter- muscular tube that contracts rhythmically to propel urine. Bladder- muscular chamber that collects and notes urine. Average adult bladder holds around a pint. Internal sphincter- located at the junction of the bladder and urethra- opens automatically. External sphincter- slightly below the internal sphincter, under voluntary control, allowing the brain to suppress urination.