Kidney/nephron HBS test

What is the outermost covering of the kidney?

renal capsule

Which structures are primarily located in the renal cortex?

Glomerulus, Proximal Convoluted Tubule (PCT), and Distal Convoluted Tubule (DCT).

Which structures are located in the renal medulla and renal pelvis?

Loop of Henle, collecting ducts, renal calyces. These structures are essential for urine concentration and transport.

Identify the capillaries surrounding the PCT/DCT versus those surrounding the Loop of Henle.

peritubular capillaries (pct/dct), Loop of Henle (vasa recta.)

What type of tissue composes the mucosa of the bladder?

Transitional epithelium

Where does the majority of reabsorption occur in the nephron?

The Proximal Convoluted Tubule (PCT).

What specific substances are reabsorbed in the PCT?

Glucose, amino acids, water, and NaCl (Salt).

How much fluid is filtered by the glomerulus daily compared to the amount excreted as urine?

About 180 liters filtered, 1-2 liters excreted.

What is the primary function of the descending limb of the Loop of Henle?

It concentrates urine by allowing water reabsorption as the renal pyramid gets saltier toward the tip.

What is a key characteristic of the ascending limb of the Loop of Henle?

It is impermeable to water.

Why does the glomerulus require higher pressure than the tubule?

To ensure effective filtration; if pressure backs up (e.g., from an enlarged prostate), filtration stops and the kidneys fail.

How does ADH (Antidiuretic Hormone) affect the collecting duct?

increases the permeability of the collecting duct to water, allowing more water reabsorption and concentrating the urine.

What is the source of ADH and what blocks its release?

produced in the hypothalamus and released by the posterior pituitary gland. Alcohol and certain medications can block its release.

When and why is Aldosterone released in the DCT?

It is released due to low blood pressure; it causes the body to reabsorb sodium and water, decreasing urine output.

How do ADH and Aldosterone respond to vomiting?

Both are released to regain lost electrolytes and water.

What substances are considered "normal" in urine?

Creatinine, uric acid, and urea.

What substances are "abnormal" if found in urine?

Red blood cells (RBCs) and glucose.

Why is creatinine used to estimate GFR (Glomerular Filtration Rate)?

It is filtered but not reabsorbed or secreted.

What are the origins of Urea and Creatinine?

Urea: Comes from protein metabolism. Creatinine: Comes from creatine phosphate (short-term energy for ATP).

What causes Gout and where does the substance originate?

Uric acid crystals in the joints. Uric acid comes from purines (seafood, organ meat, beer, sugar).

What do ketones in the urine indicate?

Excess lipid metabolism or starvation.

List the primary functions of the kidney.

Filter blood, excrete waste, balance electrolytes (Sodium), maintain pH, maintain blood pressure, and gluconeogenesis (during starvation).

What hormone do kidneys produce to stimulate RBC production?

Erythropoietin (EPO).

What is the path of urine formation from the nephron to the outside of the body?

Collecting duct → Papillae → Minor calyx → Major calyx → Ureter → Bladder → Urethra.

Describe Polycystic Kidney Disease (PKD) genetics.

primarily caused by mutations in the PKD1 or PKD2 genes, which lead to the formation of multiple cysts in the kidneys, impairing their function. can be inherited in an autosomal dominant or autosomal recessive pattern.

How does an enlarged prostate lead to kidney failure?

It prevents urination, causing pressure to back up into the glomerulus, which halts filtration.

How does vomiting affect urine pH?

increases blood pH (alkalosis); the kidneys must excrete bicarbonate to restore balance.

What is Polycystic Kidney Disease (PKD) and what are the kidneys filled with?

a genetic disorder characterized by the growth of numerous cysts in the kidneys, which can lead to kidney impairment and failure over time.

What are the primary risk factors for developing CKD?

diabetes, hypertension, cardiovascular disease, and a family history of kidney disease.

How do excess lipids or starvation affect urine?

Both states cause the body to burn fat for fuel instead of glucose, resulting in ketones appearing in the urine.

What is the "7 out of 8" rule for kidney transplants?

It refers to matching HLA (Human Leukocyte Antigen) markers. A match of at least 7 out of 8 markers, along with the same blood type, significantly reduces the risk of organ rejection.

Why do kidneys produce Erythropoietin (EPO)?

to stimulate red blood cell production in the bone marrow in response to low oxygen levels in the blood. In CKD, EPO production drops, often leading to anemia.

How does vasodilation-induced low blood pressure (under 110 mmHg) affect the kidneys?

reduces the hydrostatic pressure in the glomerulus, causing the eGFR (estimated Glomerular Filtration Rate) to drop, as there isn't enough pressure to "push" fluid through the filter.

What characterizes Gestational Diabetes Mellitus (GDM)?

It is characterized by glucose intolerance that is first recognized during pregnancy, often resolving after childbirth. It can lead to complications for both the mother and baby if not managed properly.

How does Diabetes Mellitus affect urine composition?

It leads to glycosuria (glucose in the urine) because blood glucose levels exceed the renal threshold for reabsorption in the PCT.

How does Dehydration affect the kidneys and urine?

Low blood volume triggers a massive release of ADH and Aldosterone. This leads to maximum water reabsorption, resulting in a very low volume of highly concentrated (dark) urine.

What are the markers and risks of Chronic Kidney Disease (CKD)?

Characterized by a prolonged decrease in eGFR (Glomerular Filtration Rate). Risks include hypertension and diabetes; late-stage CKD may require dialysis due to the kidney's inability to filter nitrogenous wastes like urea and creatinine.

How does Anorexia Nervosa impact renal function?

The body enters a state of starvation, leading to ketonuria (ketones in the urine) from the breakdown of lipids for energy. It can also cause severe electrolyte imbalances that may lead to heart failure.