The urinary system consists of the organs that produce urine (kidney), deduce it from the kidneys (ureters), collect urine (urinary bladder) and remo

Urinary system organs: anatomy of the kidney and urinary tract (ureter, bladder, urethra)

The urinary system consists of the organs that produce urine (kidney), deduce it from the kidneys (ureters), collect urine (urinary bladder) and remove from the bladder to the outside (the urethra).

Kidneys

Each person has two kidneys, which are placed on either side of the spine at the top of the abdominal cavity (diagram 97). Kidney length is 10-12 cm, width — 5-6 cm, weight — 120-200 grams, or about 0.5% of total body weight. By their form, they resemble bean seeds. Outside kidneys are covered with dense connective shell and embedded in a layer of fatty tissue — the adipose capsule. It firmly holds the kidney in a specific anatomical position. With a sharp human’s weight loss, when the adipose capsule is significantly reduced or disappears completely, the kidneys become mobile (floating kidney), which lead to various disorders of urination, the appearance of pain in the abdomen and lower back. On the cut of the kidneys may be seen two layers: the outer — cortex and inner — medulla, which is composed of multiple tapered segments — pyramids, and they, in turn, — of numerous uropoiesis units (nephrons).

Diagram 97. The anatomical structure of the kidneys and urinary tract: 1 — adrenal gland; 2 — kidney; 3 — kidney gates; 4 — renal artery; 5 — renal vein; 6 — abdominal aorta; 7 — lower hollow vein; 8 — the ureters; 9 — bladder; 10 — the sphincter of the bladder; 11 — the urethra; 12 — kidney bowl; 13 — cortex; 14 — medulla (renal pyramids); 15 — kidney poles

The duct of each nephron ends in uropoiesis tube, which opens into the cavity of the kidney — the renal pelvis (diagram 97).

Ureter

Ureter (fig. 97) begins directly in the renal pelvis of each kidney and ends in the bladder. Its function is urine abduction from the kidney to the bladder. The ureter has a length of 30-35 cm and a width of 5-6 mm. Taken from http://worldofschool.org

Bladder

The bladder (diagram 97) — is an unpaired hollow organ which serves as a urine container, from which it excrete to the outside. Filled bladder has a rounded shape. Its capacity in adults is 0.5-1 liters. The wall of the bladder has muscles; due to their contractions occurs excretion of urine from the bladder. Between the bladder and urethra, there is a thick circular muscle — sphincter (from Greek “to squeeze tight”): it prevents involuntary urination.

Urethra

Urethra (diagram 97) — is an unpaired tubular organ through which urine, during urination, excrete from the bladder to the outside. He opens as a small hole in the area of ​​the external genitalia.

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Questions:
  • What are the organs of the urinary system?

  • Explain the relationship of urinary system structure and functions.

  • Describe the relationship of kidneys structure and functions.

  • Explain the relationship of bladder structure and functions.