Chapter 25: The Urinary System

**diuretic**

is a compound that increases urine volume.

**Parathyroid hormone**

(PTH) is an 84-amino acid peptide produced by the parathyroid glands in response to decreased circulating Ca++ levels.

**Natriuretic hormones**

are peptides that stimulate the kidneys to excrete sodium an effect opposite that of aldosterone.

**Endothelins**

21-amino acid peptides, are extremely powerful vasoconstrictors.

**Renin**

is an enzyme that is produced by the granular cells of the afferent arteriole at the JGA.

**tubuloglomerular feedback**

mechanism involves the JGA and a paracrine signaling mechanism utilizing ATP, adenosine, and nitric oxide (NO).

**myogenic mechanism**

regulating blood flow within the kidney depends upon a characteristic shared by most smooth muscle cells of the body.

**Autoregulation**

is a process by which an organism or system maintains its internal environment in a relatively constant state, regardless of external changes.

**juxtamedullary nephrons**

About 15 percent of nephrons have long loops of Henle that extend deep into the medulla and are called

**systemic edema**

This “plumps up” the tissues and cells, a condition termed

**Sympathetic nerves**

are part of the autonomic nervous system, which is responsible for the body's involuntary functions such as digestion, heart rate, and blood pressure.

**glomerular filtration rate (GFR)**

The volume of filtrate formed by both kidneys per minute is termed the

**Angiotensin II**

is a systemic vasoconstrictor that helps to regulate blood pressure by increasing it.

**juxtaglomerular cell**

A second cell type in this apparatus is the

**macula densa**

The wall of the DCT at that point forms a part of the JGA known as the

j**uxtaglomerular apparatus (JGA)**

* Lying just outside Bowman’s capsule and the glomerulus is the

**fenestration**s

prevent filtration of blood cells or large proteins, but allow most other constituents through.

**renal corpuscle**

The glomerulus and Bowman’s capsule together form the

**Nephrons**

are the “functional units” of the kidney; they cleanse the blood and balance the constituents of the circulation.

**renal hilum**

is the entry and exit site for structures servicing the kidneys: vessels, nerves, lymphatics, and ureters.

**renal columns**

are connective tissue extensions that radiate downward from the cortex through the medulla to separate the most characteristic features of the medulla, the **renal pyramids** and **renal papillae.**

**medulla**

inner region called the

**renal cortex**

A frontal section through the kidney reveals an outer region called the

**Micturition**

is a less-often used, but proper term for urination or voiding.

**detrusor muscle**

The bladder is a highly distensible organ comprised of irregular crisscrossing bands of smooth muscle collectively called the

**trigone**

The urethra in both males and females begins inferior and central to the two ureteral openings forming the three points of a triangular-shaped area at the base of the bladder called the

**urethra**

transports urine from the bladder to the outside of the body for disposal.

**Leukocyte esterase**

is released by leukocytes; if detected in the urine, it can be taken as indirect evidence of a urinary tract infection (UTI).

**polyuria**

Excessive urine production is

**Urinalysis**

**(urine analysis)** often provides clues to renal disease.

**urochrome**

This yellow pigment is

**oliguria**

Output below this level may be caused by severe dehydration or renal disease and is termed

**anuria**

The virtual absence of urine production is termed