Chapter 17 - Physiology of the Kidneys Flashcards

Vocabulary flashcards for reviewing the physiology of the kidneys.

Renal

Pertaining to the kidneys.

Extracellular Fluid (ECF)

The fluid environment in the human body that the renal system regulates through urine formation.

Urea

An organic waste product of protein breakdown eliminated by the renal system.

Uric Acid

An organic waste product of nucleic acids eliminated by the renal system.

Creatinine

An organic waste product of muscle creatine eliminated by the renal system.

Gluconeogenesis

The synthesis of glucose from amino acids during prolonged fasting, which occurs in the kidneys (and liver).

Micturition

The process of urine storage in and flow from the urinary bladder via the urethra. Occurs in urinary bladder

Renal Cortex

The outer layer of the kidney; the site of glomerular filtration and convoluted tubules.

Renal Medulla

The inner layer of the kidney; the location of the longer loops of Henle and collecting ducts.

Detrusor Muscle

Smooth muscle in the bladder walls; contraction of this muscle produces micturition.

Internal Urethral Sphincter

Smooth muscle at the base of the bladder.

External Urethral Sphincter

Skeletal muscle surrounding the urethra below the internal urethral sphincter; its contraction can prevent urination.

Nephron

The functional unit of the kidneys, consisting of a renal corpuscle (glomerular capsule + glomerulus) and tubule.

Afferent Arterioles

Branches of the renal artery that bring blood to the glomeruli.

Glomerulus

A capillary network in the renal corpuscle where filtration occurs.

Glomerular Capsule

Surrounds the glomerulus; fluid filters out of the glomerulus into this capsule.

Proximal Convoluted Tubule

The first segment of the renal tubule where filtrate from the glomerulus enters and reabsorption/secretion occur.

Peritubular Capillaries

Capillaries surrounding the tubule; reabsorption of salt, water, etc. occurs into these capillaries.

Descending Limb of Loop of Henle

Part of the nephron tubule involved in water reabsorption.

Ascending Limb of Loop of Henle

Part of the nephron tubule where Na+ is actively pumped into the ISF.

Distal Convoluted Tubule

A segment of the nephron tubule that empties into the collecting duct.

Collecting Duct

The final segment of the nephron tubule that drains into the renal pelvis and then into the ureters.

Fenestrae

Large pores in glomerular capillaries through which filtrate is filtered.

Filtrate (Ultrafiltrate)

Cell-free and mostly protein-free fluid filtered from the blood in the glomerulus; similar composition to plasma.

Reabsorption

The return of filtrate from the tubules to the peritubular capillaries.

Countercurrent Multiplier System

System where fluid is hypertonic due to countercurrent flow (opposite direction flow) in ascending and descending limbs in nephrons and close proximity of limbs that allow them to interact to create high osmotic pressure in ISF.

Secretion

The movement of substances from the peritubular capillaries into the tubular fluid for excretion in the urine.

Renal Plasma Clearance

Volume of plasma that is 'cleared' of a substance by kidneys per unit time.

Glucosuria

The excretion of excess glucose in the urine when the transport maximum of glucose transporters is exceeded.

Renin-Angiotensin-Aldosterone System

System activated by decreased plasma [Na+] which then stimulates secretion of aldosterone from the adrenal cortex.

Acidosis

A condition where blood pH is less than 7.35.

Alkalosis

A condition where blood pH is greater than 7.45.

Ureters

Carry the urine to the bladder.

Glomerular filtration

The process where the kidneys filter blood to produce urine.

Urination

Another word for Micturition

Renal Artery

The blood vessel in which the blood flows through to enter the kidney.

Renal Vein

The blood vessel in which the blood flows through to exit the kidney.

180 L

How many Liters do your kidneys filter (Glomerular filtrate)?

1-2 L

How much urine do you usually excrete?

Proximal tubule

Where most salt and water in the filtrate gets reabsorbed.

Filtration

Refers to the movement of fluid and solutes from the glomerulus into the capsule and then into the tubules.

Osmoreceptors

Sense the changes in water intake and also controls how much ADH is secreted to maintain blood balance and regulate osmolarity of body fluids.

ADH

Affects the volume of urine excreted, to maintain blood volume. This basically tells your kidney to absorb more or less water.

Cortical Collecting Ducts

Where the Aldosterone stimulates/maintains Na+ reabsorption (Where the aldosterone tells the kidneys to save more Na+).