Functions and Structure of the Renal System

Study Notes

Kidneys: two bean-shaped organs located in the upper back, responsible for filtering blood
Nephrons: functional units of the kidneys, consisting of:
- Glomerulus: a cluster of capillaries that filters blood
- Renal tubule: a tube where filtered substances are reabsorbed or secreted
Ureters: tubes that connect the kidneys to the bladder
Bladder: a hollow organ that stores urine
Urethra: a tube that carries urine out of the body

Renal blood flow: approximately 20% of total cardiac output
Glomerular filtration rate (GFR): the rate at which the kidneys filter blood
Ultrafiltration: the process of filtering blood in the glomerulus

Filtration: the process of filtering blood in the glomerulus
Reabsorption: the process of reabsorbing substances back into the bloodstream
Secretion: the process of secreting substances into the urine
Urine concentration: the process of concentrating or diluting urine

Renal autoregulation: the ability of the kidneys to regulate their own blood flow
Sympathetic nervous system: helps to regulate renal blood flow and GFR
Hormonal regulation: hormones such as aldosterone and antidiuretic hormone (ADH) help to regulate electrolyte levels and water reabsorption

The renal system filters waste and excess fluids from the blood, regulating electrolyte levels (e.g., sodium, potassium, calcium) and maintaining acid-base balance.
It produces hormones that regulate blood pressure and produce red blood cells, and helps to remove drugs and toxins from the body.

The kidneys are two bean-shaped organs located in the upper back, responsible for filtering blood.
A nephron is the functional unit of the kidneys, consisting of a glomerulus (a cluster of capillaries that filters blood) and a renal tubule (a tube where filtered substances are reabsorbed or secreted).
The ureters are tubes that connect the kidneys to the bladder, which is a hollow organ that stores urine.
The urethra is a tube that carries urine out of the body.

The renal system receives approximately 20% of total cardiac output, known as renal blood flow.
The glomerular filtration rate (GFR) is the rate at which the kidneys filter blood.
Ultrafiltration is the process of filtering blood in the glomerulus, resulting in a fluid that contains waste and excess substances.

Filtration is the process of filtering blood in the glomerulus, producing a fluid that contains waste and excess substances.
Reabsorption is the process of reabsorbing substances back into the bloodstream, while secretion is the process of secreting substances into the urine.
Urine concentration is the process of concentrating or diluting urine in response to changes in body water levels.

The kidneys have the ability to regulate their own blood flow through renal autoregulation.
The sympathetic nervous system helps to regulate renal blood flow and GFR in response to changes in blood pressure.
Hormonal regulation, including the actions of aldosterone and antidiuretic hormone (ADH), helps to regulate electrolyte levels and water reabsorption in the kidneys.