Physiology Unit 6: Urinary System

What is urine and where does it come from?

Urine is processed plasma. It comes from blood plasma that is filtered in the kidneys (glomerus) the modified by reabsorption. What remains is urine!

How can urine be used in clinical diagnosis?

Can be tested for diabetes (glucose), possible injury and disease (blood), hydration status (color), and kidney function issues

What is the difference between the ureters and urethra?

Ureters are tubes from the kidneys to the bladder and it moves urine peristalsis(active smooth muscle contractions). Urethra are tubes from the bladder to outside body and responsible for urine elimination.

What is the function, location and cellular composition of the urinary bladder?

The function of the urinary bladder is it stores urine until elimination. It is inferior to the peritoneal cavity and in the retroperitoneal region. the cellular composition are Transitional epithelium which stretches as bladder fills, Lamina propria & submucosa and Detrusor muscle (SM)

What does retroperitoneal means anatomically?

Retro = behind. Organs located behind the peritoneal membrane which includes kidneys and bladder.

What is peritoneum and its role?

A membrane lining the abdominal cavity containing mesothelial cells and connective tissue. It provides lubrication, supports organs, serves a pathway for blood vessels and nerves and form mesentery & omentum

What is the sphincter system of the bladder in the micturition reflex (peeing)?

The internal urethral sphincter have involuntary smooth muscle that relaxes during urination. The external urethral sphincter have involuntary skeletal muscle that is controlled by somatic neurons. During micturition, detrusor muscle contracts and the sphincters relaxes.

How does urine makes its way from the kidneys to the bladder?

Urine flows from Kidneys → ureters → bladder. This flow is drivers by peristaltic contractions of smooth muscle in ureters and NOT on gravity.

What is the position and main anatomical regions of the kidney?

The kidney is located in the retroperitoneal region which is slightly protected by ribs and surrounded by fat. The regions are the cortex (outer) that contains nephrons, medulla (inner) that contains pyramids (important for water balance)

What is the general composition of the functional unit of the kidney?

In the nephron, the composition is the Renal corpuscle and Tubular system surrounded by peritubular capillaries. Its function is to filter blood and balances fluid, electrolytes and wastes.

What are the two capillary vascular system of the nephron?

Glomerulus (high pressure filtration) and Peritubular capillaries (Reabsorption and exchange)

What is the difference between afferent and efferent arterioles?

Afferent arteriole carries blood into the glomerulus. Efferent arteriole carries blood away from the glomerulus. After filtering, it then continues to the second capillary for processing