Excretory System (Kidneys & Nephrons) - Vocabulary Flashcards

Vocabulary flashcards covering key terms and definitions related to the excretory system, kidneys, and nephron function.

Nephron

The functional unit of the kidney that filters blood and forms urine, consisting of the glomerulus, Bowman's capsule, and renal tubule.

Glomerulus

A ball of capillaries where blood is filtered into Bowman's capsule under high pressure.

Bowman’s capsule

The cup-shaped structure surrounding the glomerulus that collects the filtrate filtered out of the blood.

Proximal tubule

The first part of the renal tubule with microvilli and thin, moist walls that provides a large surface area for reabsorption.

Renal tubule

The tube where filtrate passes and selective reabsorption of substances back into the blood occurs.

Filtration

The process by which small molecules pass from the blood in the glomerulus into Bowman's capsule, driven by blood pressure.

Reabsorption

The process of returning useful substances (e.g., glucose, amino acids, ions, water) from the filtrate back into the blood.

Filtrate

The fluid that enters Bowman's capsule during filtration, containing water, salts, glucose, urea, and amino acids.

Afferent arteriole

The small artery that brings blood into the glomerulus for filtration.

Renal artery

The artery that delivers blood to the kidneys from the heart.

Renal vein

The vein that carries filtered blood away from the kidneys back toward the heart.

Cortex (kidney)

Outer region of the kidney where many nephrons are located.

Medulla (kidney)

Inner region of the kidney containing the renal pyramids and collecting ducts.

Pelvis (kidney)

The funnel-shaped part of the kidney that collects urine before it moves to the ureter.

Kidney

A paired organ that filters blood, removes wastes, balances water and salts, and forms urine.

Ureter

The duct that transports urine from the kidney to the bladder.

Bladder

The organ that stores urine until it is excreted.

Urethra

The tube through which urine exits the body during urination.

Urea

A nitrogen-containing metabolic waste produced by the liver and excreted by the kidneys.

Metabolic wastes

Substances produced by metabolism that must be removed from the body (e.g., urea).

Excretion

The removal of metabolic wastes from the body.

Water reabsorption

The process by which water is reabsorbed from the filtrate back into the blood, mainly by osmosis.

Glucose reabsorption

The return of glucose from the filtrate to the blood to maintain blood sugar levels.

Amino acids reabsorption

The return of amino acids from the filtrate to the blood to use in the body.

Osmosis

Diffusion of water across a semi-permeable membrane from higher to lower water concentration.

Concentrated urine

Urine with a high concentration of solutes, produced when little water is available.

Dilute urine

Urine with a low concentration of solutes, produced when excess water is present.

Alveoli

Tiny air sacs in the lungs where gas exchange (CO2 and O2) occurs.

Carbon dioxide

A waste gas produced by respiration that is exhaled via the lungs.

Oxygen

Gas required for cellular respiration; absorbed into blood in the lungs and released to tissues.