Brothers Lecture 1

The kidneys are vital organs that filter waste products from the blood, regulate blood pressure, and maintain fluid and electrolyte balance.

The process of removing waste products, excess water, and electrolytes from the blood and excreting them as urine.

A measure of the kidneys' ability to filter waste products from the blood.

A measure of the concentration of dissolved substances in the blood.

The kidneys regulate sodium (Na+) levels in the blood, which plays a crucial role in maintaining fluid balance and blood pressure.

The kidneys regulate water balance in the body, preventing dehydration or overhydration.

The body's internal environment must be maintained within a narrow range to ensure optimal cell function. This involves maintaining a stable internal temperature, pH, fluid volume, and electrolyte concentration.

The kidneys are essential for maintaining acid-base balance (pH), which is crucial for many bodily processes.

The process where cells in the nephron tubule actively remove substances from the blood and transfer them into the urine.

The ability of the kidneys to cleanse the blood by removing waste products.

The process by which the body returns most of the filtered solutes and water to the bloodstream.

Maintaining a balance between the amount of substances entering and leaving the body.

The process of excreting substances from the body through the kidneys.

The ability of the kidneys to regulate the amount of water and solutes in the body by adjusting reabsorption and secretion.

The kidneys' ability to control the amount of solutes and water excreted is influenced by diseases that affect the tubules.

The first part of the nephron tubule where approximately 50% of filtered sodium and water is reabsorbed.

The segment of the nephron where approximately 40% of filtered sodium and chloride is reabsorbed in the ascending limb.

The rate at which creatinine is produced and excreted by the kidneys.

A byproduct of muscle metabolism that's filtered by the kidneys and excreted in urine.

A lab test that estimates GFR based on serum creatinine, age, sex, and race.

A formula used to estimate GFR in patients with chronic kidney disease.

A formula used to estimate GFR in patients with acute kidney injury.

A formula used to estimate GFR in children less than 18 years old.

A formula used to estimate GFR in adults and stage chronic kidney disease (CKD).

The kidneys are responsible for maintaining fluid balance by regulating the amount of water and electrolytes excreted in urine.

The kidneys filter waste products from the blood, such as urea, creatinine, and uric acid, and excrete them in urine.

The kidneys maintain acid-base balance by regulating the excretion of hydrogen ions (H+) in urine.

The kidneys contribute to blood pressure regulation by controlling sodium and water excretion.

The kidneys produce erythropoietin, a hormone that stimulates red blood cell production.

The kidneys activate vitamin D to its active form, calcitriol, which is essential for calcium absorption in the intestines.

The kidneys maintain a relatively stable extracellular environment, crucial for cell function.

The kidneys produce hormones that influence systemic and renal hemodynamics, red blood cell production, and mineral metabolism.

The kidneys filter and excrete metabolic waste products, adjusting the excretion of water and electrolytes to match intake and production.

The kidneys regulate water and solute excretion, particularly sodium, potassium, and hydrogen, through alterations in tubular reabsorption or secretion.

The kidneys develop and secrete hormones that influence blood pressure regulation, red blood cell production, and bone health.

The kidneys receive 25% of the cardiac output, filtering approximately 180 liters of plasma per day.

The kidneys have a large functional reserve, meaning they can function effectively even with a significant loss of kidney tissue.

The nephron is the functional unit of the kidney, responsible for filtering blood and producing urine.

Urine formation involves three major processes: filtration, reabsorption, and secretion.

Effective circulating volume (ECV) is an unmeasurable parameter that represents the volume of fluid in the arterial system effectively perfusing the tissues. It's not the same as total blood volume or extracellular fluid volume, but rather the volume that matters for tissue oxygenation and function.

High sodium intake causes water retention due to its osmotic effect, leading to increased blood volume in arteries, raising blood pressure.

Heart failure reduces cardiac output, leading to decreased ECV. This triggers sodium-retaining hormones to increase perfusion, but this can cause fluid buildup (edema).

Hypovolemia, a condition of low blood volume, can occur due to conditions like vomiting, leading to decreased ECV, reduced extracellular fluid, lower plasma volume, and reduced cardiac output.

Heart failure causes decreased ECV due to reduced cardiac output, but it leads to increased extracellular fluid and plasma volume as the body tries to compensate.

Hepatic cirrhosis leads to decreased ECV despite increased extracellular fluid and plasma volume due to impaired liver function affecting blood flow.

Kidney disease may present with a variety of symptoms, either directly related to the kidney (hematuria, pain) or due to extrarenal implications (edema, hypertension).

Routine exams can identify kidney disease by abnormal urinalysis or elevated creatinine levels. After diagnosis, the severity and progression are assessed alongside the underlying cause.

Kidney disease is understood by understanding basic kidney physiology and functions. Fluid balance relies on a complex interplay of water, sodium, and hormones. Osmotic, hydrostatic, and oncotic pressures are crucial in renal osmoregulation and volume control. eGFR is used for assessing kidney filtration, but it's imperfect.

eGFR (estimated glomerular filtration rate) is a practical measure of kidney filtration, but limitations exist due to potential inaccuracies in serum creatinine estimation.

The process of reducing the dosage or frequency of medications that are primarily eliminated by the kidneys. This is necessary when kidney function is impaired to prevent medication accumulation and toxicity.

Plasma creatinine levels may not always reflect the severity of kidney function decline, especially in patients with GFR above 60 mL/min.

A measure of the kidney's ability to filter waste products from the blood.

A concentration measure of dissolved substances in a solution, expressed as the total number of solute particles per kilogram of solvent.

A concentration measure of dissolved substances in a solution, expressed as the total number of solute particles per liter of solution.

The force exerted by a solute to draw water across a semipermeable membrane.

The pressure exerted by proteins in the blood, primarily albumin, to draw water back into the capillaries.

The pressure exerted by the blood against the walls of blood vessels, pushing water out into the surrounding tissues.

The process of regulating sodium levels in the blood, which affects the balance of water and blood pressure.

The process of regulating the balance of water in the body, preventing dehydration or overhydration.

The ability of the body to maintain a stable internal environment despite external changes, keeping critical variables like temperature, pH, and fluid levels within a narrow range.

The process of regulating acid-base balance (pH) in the body, critical for many biochemical reactions.

The state of having a low plasma sodium concentration. It's often caused by imbalance in water and/or sodium levels.

The state of having a high plasma sodium concentration. It's often caused by dehydration or excessive sodium intake.

The state of increased fluid volume in the body, often characterized by swelling or edema.