Physiology of Kidney Function

The process by which the kidneys maintain a stable blood flow and glomerular filtration rate (GFR) despite fluctuations in blood pressure.

A test that measures the pressure inside the bladder as it fills with urine. It helps diagnose bladder dysfunction.

The ability of the kidneys to maintain blood pH within a narrow range despite changes in body fluids.

The negative logarithm of hydrogen ion concentration in a solution.

The kidneys maintain pH balance by reabsorbing bicarbonate (HCO3-), excreting non-volatile acids, and producing ammonia (NH3).

The process of urination, involving the coordinated contraction of the bladder and relaxation of the urethral sphincters.

The bladder is filled with urine, which stretches its walls. Stretch receptors send signals to the spinal cord, triggering a reflex that either causes micturition or a conscious desire to urinate.

Disruptions in the nervous system's control of the bladder can lead to various dysfunction, including atonic bladder, automatic bladder, and uninhibited neurogenic bladder.

A condition where the bladder muscles are unable to contract due to damage to the sensory nerves, resulting in overflow incontinence.

A condition where the bladder empties automatically without voluntary control due to damage to the spinal cord above the sacral region.

A condition where the bladder contracts uncontrollably due to damage to the inhibitory pathways from the brain.

The myogenic hypothesis suggests that the afferent arterioles contract in response to stretch, increasing renal vascular resistance, while the juxtaglomerular hypothesis attributes autoregulation to changes in renin secretion.

The kidneys help regulate blood pH by reabsorbing bicarbonate ions, excreting non-volatile acids, and generating ammonia.

The process by which the kidneys remove waste products and excess fluids from the blood, forming urine.

The kidneys excrete non-volatile acids like sulfuric acid (H2SO4) and phosphoric acid (H3PO4) to maintain pH balance.

Ammonia (NH3) is produced in the kidneys and combines with hydrogen ions (H+) to form ammonium ions (NH4+), which are then excreted in the urine.

In urine, sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), and ammonium (NH4+) are the major cations.

In urine, chloride (Cl-), sulfate (SO42-), dihydrogen phosphate (H2PO4-), and hydrogen phosphate (HPO42-) are the major anions.

The pH of urine can fluctuate due to the presence of various ions, including bicarbonate (HCO3-) in alkaline urine.

The formation of slightly soluble alkaline phosphates, such as Ca2H2(PO4)2 and Mg2H2(PO4)2, in alkaline urine can cause turbidity (cloudiness).

Urea, a major component of urine, can be converted to ammonia by bacterial action, making the urine alkaline and potentially causing precipitation of phosphates, leading to cloudiness.

The kidneys use a combination of hydrogen ions (H+), sodium ions (Na+), and phosphate buffer system to maintain pH balance.

The process of emptying the bladder involves the coordinated contraction of the detrusor muscle, relaxation of the internal urethral sphincter, and voluntary relaxation of the external urethral sphincter.

The detrusor muscle is innervated by parasympathetic nerves, which stimulate contraction, while the internal urethral sphincter is innervated by sympathetic nerves, which cause contraction.

The external urethral sphincter is under voluntary control, allowing conscious control over urination.

The micturition reflex is a spinal cord reflex that is triggered by stretch receptors in the bladder wall. It can be influenced by centers in the brain stem and cerebral cortex.

Various tests, including urinalysis, clearance tests, IVP, kidney biopsy, and autopsy, can help assess kidney function.