Ch. 26-27: The Kidneys and Blood Osmolality

What is the correct sequence of structures for urine flow starting from the kidney?

Calyx -> renal pelvis -> ureter -> urinary bladder -> urethra.

What are the three main processes performed by nephrons to form urine?

Filtration, reabsorption, and secretion.

What substances are filtered out of the blood by the glomerulus?

Water, ions, glucose, amino acids, and small wastes.

What substances are typically retained in the blood during glomerular filtration?

Large proteins and blood cells.

What is the primary function of the Proximal Convoluted Tubule (PCT)?

It is the major site of reabsorption, reclaiming glucose, amino acids, sodium, water, and bicarbonate.

How does the descending limb of the Loop of Henle affect the filtrate?

It is permeable to water, allowing water to leave the tubule, which concentrates the filtrate.

How does the ascending limb of the Loop of Henle affect the filtrate?

It is impermeable to water and actively pumps out sodium and chloride, which dilutes the filtrate.

What is the primary function of the Loop of Henle?

To create a concentration gradient in the kidney medulla for water conservation.

What is the role of the Distal Convoluted Tubule (DCT)?

It performs final adjustments to urine composition, regulating ions like Na+, K+, Ca2+, and pH.

Which hormone controls final water reabsorption in the collecting duct?

Antidiuretic hormone (ADH).

What are the main roles of proteins in the body?

Growth, repair, and the formation of enzymes.

What is the function of the Bowman's capsule?

It is a cup-shaped structure that collects the filtered fluid (glomerular filtrate) from the glomerulus.

What is the role of water in the body?

It is essential for chemical reactions, transport, and temperature control.

What is the primary function of the ureters?

To transport urine from the kidneys to the bladder using peristalsis and prevent backflow.

How does the body respond to high blood osmolality?

Osmoreceptors in the hypothalamus detect the concentration, triggering thirst and the release of ADH to retain water.

What is the physiological response to low blood pressure?

Baroreceptors detect the low volume, triggering thirst and activating the renin-angiotensin system to encourage fluid intake and retention.

What is the normal pH range of human blood?

Approximately 7.35-7.45.

How does the respiratory system regulate blood pH?

By controlling CO2 levels; increased breathing removes CO2 to raise pH, while decreased breathing retains CO2 to lower pH.

What role do the kidneys play in long-term acid-base balance?

They excrete hydrogen ions (H+) and reabsorb or generate bicarbonate (HCO3-) to adjust urine acidity.