The Urinary System - Flashcards

These flashcards cover key concepts from the lecture on the urinary system, focusing on anatomy, functions, processes, and hormonal regulation.

What are the six organs of the urinary system?

Two kidneys, two ureters, urinary bladder, and urethra

What are the main functions of the kidneys?

Filter blood plasma, excrete toxic wastes, regulate blood volume, pressure, and osmolarity, regulate electrolytes and acid-base balance, secrete erythropoietin, regulate calcium levels, clear hormones, detoxify free radicals, synthesize glucose during starvation.

What is considered a waste in biological terms?

Any substance that is useless to the body or present in excess.

How is urea formed in the body?

Proteins are broken down into amino acids, NH2 is removed forming ammonia, which is converted to urea by the liver.

What does BUN stand for and what does it indicate?

Blood Urea Nitrogen; indicates levels of nitrogenous waste in the blood.

What are the symptoms of uremia?

Diarrhea, vomiting, dyspnea, and cardiac arrhythmia due to toxicity from nitrogenous waste.

What is excretion?

The process of separating wastes from body fluids and eliminating them.

Which systems in the body carry out excretion?

Respiratory, integumentary, digestive, and urinary systems.

What is the position of the kidneys in the body?

Lie against the posterior abdominal wall at T12 to L3; the right kidney is slightly lower than the left.

What are the protective coverings of the kidney?

Renal fascia, perirenal fat capsule, and fibrous capsule.

Describe the renal parenchyma.

Glandular tissue that forms urine and appears C-shaped, encircling the renal sinus.

What is contained in the renal sinus?

Blood vessels, lymphatic vessels, nerves, and urine-collecting structures.

What are the two zones of renal parenchyma?

Outer renal cortex and inner renal medulla.

What are renal pyramids?

Triangular structures in the renal medulla with broad bases facing the cortex.

What is the function of minor calyxes?

They collect urine from the renal papillae.

What does the renal pelvis do?

Drains urine down to the ureter.

What is renal circulation?

The blood flow through the kidneys, supplying them with oxygenated blood and helping in filtration.

How much of the cardiac output do the kidneys receive?

About 21%.

What is glomerular filtration?

The process by which the kidneys filter blood, removing waste and excess substances to form urine.

What is the glomerulus?

A ball of capillaries where blood filtration occurs.

What is the function of the renal corpuscle?

Filters blood plasma.

What is the role of the nephron loop?

Generate a salinity gradient that enables the collecting duct to concentrate urine.

What are the effects of aldosterone in the kidneys?

Stimulates reabsorption of Na+ and Cl− and promotes water retention.

What triggers the release of renin?

A drop in blood pressure detected by baroreceptors.

What is the renin-angiotensin-aldosterone system (RAAS)?

A hormonal system that regulates blood pressure and fluid balance.

What is ADH and what is its function?

Antidiuretic hormone; makes the collecting duct more permeable to water for reabsorption.

What is the primary function of the proximal convoluted tubule (PCT)?

Reabsorbs about 65% of glomerular filtrate.

What happens in the distal convoluted tubule (DCT)?

Variable reabsorption of water and solutes under hormonal control.

What is glycosuria?

The presence of glucose in urine due to exceeded renal transport maximum.

What is the countercurrent multiplier system?

A mechanism that establishes a vertical osmotic gradient in the renal medulla.

How does the loop of Henle contribute to urine concentration?

By reabsorbing NaCl and water differently in the descending and ascending limbs.

What role do vasa recta play in kidney function?

They provide blood supply to the medulla and maintain osmotic gradient without removing NaCl and urea.

What substances are primarily secreted in the urine?

Urea, uric acid, ammonia, bile acids, and creatinine.

What would occur if the glomerular filtration rate (GFR) is too high?

Increased urine output and risk of dehydration and electrolyte depletion.

What is the significance of the filtration membranes in glomerular filtration?

They selectively filter substances based on size and charge.

What is tubular reabsorption?

The process of reclaiming water and solutes from tubular fluid and returning them to the blood.

What is obligatory water reabsorption?

Water reabsorption that occurs at a constant rate in the PCT.

What is the primary driver of sodium reabsorption?

The sodium-potassium pump in the basal surface of epithelial cells.

What happens to excess glucose in the renal tubules?

If the tubular transport maximum is exceeded, excess glucose is excreted in urine.

How does dehydration affect urine concentration?

Leads to production of hypertonic urine with high concentration of solutes.

What does the term 'collecting duct' refer to?

A duct that receives fluid from multiple nephrons and reabsorbs water.

What factors influence the reabsorption of water in collecting ducts?

ADH and the osmolarity of the interstitial fluid.

What is the surprise role of the nephron loop in urine concentration?

It actively transports salts and is impermeable to water, affecting tubular fluid concentration.

How is blood flow to the kidneys regulated?

By changes in blood pressure and hormonal signals that affect afferent and efferent arterioles.

What is the impact of antidiuretic hormone (ADH) on urine production?

Reduces urine volume by enhancing water reabsorption in the collecting duct.

What role do natriuretic peptides play in the body?

Help regulate blood pressure by promoting salt and water excretion.

What is countercurrent exchange in the renal medulla?

The process by which vasa recta maintain the osmotic gradient while supplying blood to the medulla.

What are the main components filtered by the glomerulus?

Electrolytes, glucose, amino acids, vitamins, waste products such as urea and creatinine.

What happens to the osmolarity of tubular fluid as it moves through the nephron?

It changes based on the reabsorption of water and solutes.

What is the role of water channels (aquaporins) in the nephron?

Facilitate water reabsorption during obligatory water reabsorption.

What condition occurs if blood pressure in the glomeruli is too high?

May lead to nephrosclerosis and renal failure.

What defines the net filtration pressure (NFP) in the kidneys?

The difference between outward and inward pressures in the glomerulus.

Which part of the nephron is responsible for most of the tubular secretion?

The proximal convoluted tubule (PCT).

What condition leads to a low glomerular filtration rate (GFR)?

Severe dehydration or blood loss.

How do the kidneys protect against water loss?

By reabsorbing water from the renal tubules back into the bloodstream.