Podcast
Questions and Answers
What is the approximate percentage of cardiac output that the kidneys receive?
What is the approximate percentage of cardiac output that the kidneys receive?
What is one of the endocrine functions of the kidneys?
What is one of the endocrine functions of the kidneys?
Which condition is considered a pre-renal cause of impaired renal function?
Which condition is considered a pre-renal cause of impaired renal function?
What happens to renal function if pre-renal causes are not adequately treated?
What happens to renal function if pre-renal causes are not adequately treated?
Signup and view all the answers
What determines the impermeability of glomeruli to macromolecules?
What determines the impermeability of glomeruli to macromolecules?
Signup and view all the answers
What type of substances are glomeruli permeable to?
What type of substances are glomeruli permeable to?
Signup and view all the answers
Which hormone stimulates angiotensogen to help with blood pressure regulation?
Which hormone stimulates angiotensogen to help with blood pressure regulation?
Signup and view all the answers
Which of the following is a consequence of renal vasoconstriction due to hypovolaemia?
Which of the following is a consequence of renal vasoconstriction due to hypovolaemia?
Signup and view all the answers
What could be a renal cause of kidney issues?
What could be a renal cause of kidney issues?
Signup and view all the answers
Which substance is commonly used to estimate glomerular filtration rate (GFR) in clearance tests?
Which substance is commonly used to estimate glomerular filtration rate (GFR) in clearance tests?
Signup and view all the answers
What does creatinine clearance primarily depend on?
What does creatinine clearance primarily depend on?
Signup and view all the answers
What is the formula for calculating creatinine clearance?
What is the formula for calculating creatinine clearance?
Signup and view all the answers
What is the normal creatinine clearance rate for healthy adults?
What is the normal creatinine clearance rate for healthy adults?
Signup and view all the answers
Why is inulin clearance not suitable for routine clinical use?
Why is inulin clearance not suitable for routine clinical use?
Signup and view all the answers
What condition can cause damage to the kidney in the context of post-renal issues?
What condition can cause damage to the kidney in the context of post-renal issues?
Signup and view all the answers
When can the clearance formula for creatinine be considered valid?
When can the clearance formula for creatinine be considered valid?
Signup and view all the answers
Study Notes
Kidney Functions
- The kidneys perform three critical functions: excretion, homeostasis, and endocrine functions.
- Excretion: The kidneys remove waste products from the body, such as urea and creatinine.
- Homeostasis: The kidneys regulate the volume and composition of extracellular fluid (ECF) by controlling water, electrolyte, and acid-base balance.
- Endocrine: The kidneys produce hormones like renin, activate vitamin D, and produce erythropoietin.
Renal Function Unit (Nephron)
- Each kidney contains approximately 1 million nephrons, which are the functional units of the kidney.
- Glomeruli act as filters, allowing water and low molecular weight substances to pass through but blocking macromolecules.
- The tubules reabsorb essential nutrients, fluids, and substances back into the blood. The remaining fluid and waste form urine.
Causes of Impaired Renal Function
- Pre-renal causes: Reduced renal perfusion, often due to hypovolemia or a drop in blood pressure, leading to decreased glomerular filtration rate (GFR) but preserved tubular function.
- Renal causes: Acute kidney injury or chronic kidney disease, directly impacting glomerular filtration.
- Post-renal causes: Obstruction of urine flow due to conditions like renal stones, prostatism, or genitourinary cancer, potentially leading to kidney damage.
Tests of Glomerular Function
- Glomerular function tests are essential in diagnosing and managing kidney disease.
- Inulin clearance: Gold standard for measuring GFR, but requires intravenous infusion of inulin, making it unsuitable for routine use.
- Creatinine clearance: Widely used clinical test that estimates GFR by measuring creatinine in plasma and urine.
- Creatinine is an endogenous compound produced by muscle metabolism, and its clearance is relatively constant in healthy individuals.
- Creatinine clearance is calculated using the formula: Clearance = U × V/P
- U = urine creatinine concentration (μmol/L)
- V = urine flow rate (mL/min or (L/24 h)
- P = plasma creatinine concentration (μmol/L)
Normal Creatinine Clearance
- Normal creatinine clearance in healthy adults is approximately 120 mL/min.
- GFR values can be standardized to a body surface area of 1.73 m2 for better comparison between individuals.
- It's important to note that creatinine clearance calculations are only reliable when kidney function is stable.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the essential functions of the kidneys, including excretion, homeostasis, and endocrine activities. Understand the role of nephrons and glomeruli in filtering blood and producing urine. This quiz also delves into the causes of impaired renal function.
