Chapter 26 Study Guide: Urinary System

List the organs of the urinary system and briefly state their function.

Kidneys- produce urine

Ureters- tubes that carry urine from renal pelvis to urinary bladder

Urinary bladder- muscular sac that temporary stores urine prior to micturition

Urethra- tube that carries urine from urinary bladder to the exterior

Urination is the elimination of urine from the body. What is the medical term for urination?

micturition

Define excretion and elimination.

Excretion- removal of metabolic wastes from body fluids

Elimination- discharge of these wastes out of the body

Where are the kidneys positioned in the body?

On either side of the vertebral column, between vertebrae T12 and L3; left is slightly superior to right due to position of liver on right

What endocrine gland sits on top of each kidney?

adrenal glands

What condition can occur if the kidney's suspensory fibers break or become detached?

floating kidney

What is the hilum of the kidney?

A prominent medial indentation

What two structures enter the hilum?

Renal artery and renal nerves

What two structures exit the hilum?

Renal vein and ureter

What are the outer and inner regions of the kidney called?

renal cortex

Which region contains renal pyramids?

renal medulla

What are the functional units of the kidneys called? Hint: Microscopic structures that begin urine formation.

nephrons

What is another name for the glomerular capsule?

Bowwmans capsule

Which arterioles carry blood to the glomerulus?

afferent arteriole

Which arterioles carry blood away from the glomerulus?

efferent arteriole

What is glomerulonephritis?

Inflammation of the glomeruli that impairs filtration in the kidneys

Glomerulonephritis is often an immune complex disorder, but it may develop after an infection involving which genus of bacteria?

Streptococcus

What are three structures that comprise the filtration membrane?

Fenestrated endothelium, basement membrane, foot processes of podocytes

In which part of the nephron does filtration take place?

Renal corpuscle

What is filtrate? Does it contain protein?

Protein-free solution; no 

What occurs during reabsorption?

substance re-enters blood; movement of water/solutes from tubular lumen to peritubular interstitium

What occurs during secretion?

Enters tubular fluid from the blood; the movement of water and solutes from the peritubular interstitium to the tubular lumen

What is the primary function of the proximal convoluted tubule (PCT)?

Active reabsorption of critical ions from filtrate

What is the primary function of the distal convoluted tubule (DCT)?

Reabsorb water and selected ions, as well as secrete undesirable substances

The juxtaglomerular complex contains a structure called the macula densa. What do the cells of the macula densa function as? (Hint: receptors)

chemoreceptors or baroreceptors

Juxtaglomerular cells in the juxtaglomerular complex are modified smooth muscle cells in the wall of the afferent arteriole. These cells function as baroreceptors. What do they monitor? What hormones do they release?

Blood pressure in afferent arteriole; renin

What is the function of intercalated cells of the collecting duct?

Type A and B regulate acid-base balance in blood

Identify the two types of nephrons in the kidney. Which type constitutes ~85% of all nephrons?

cortical nephrons; the other is juxamedullary nephrons

What is the primary function of the ascending limb of the nephron loop?

Reabsorption of water from tubular fluid

What is the primary function of the descending limb of the nephron loop?

Reabsorption of ions; assists in creation of a concentration gradient in the renal medulla

List three important wastes produced during metabolism.

Urea, creatinine, uric acid

List the three distinct processes that form urine in the kidney.

Filtration, reabsorption, secretion

What two transport mechanisms are used during the reabsorption of substances in the renal tubule?

simple diffusion or carrier proteins osmosis used for water

What process is used for reabsorption of water?

secretion

Which four nutrients are not detected or are detected in very small amounts (<0.2 mg/dL) in urine from a healthy adult?

Glucose, lipids, amino acids, proteins

What is the physical reason why glomerular hydrostatic pressure (GHP) is greater than hydrostatic pressure in typical systemic capillaries?

the glomerular capillaries flows into an efferent glomerular arteriole, whose luminal diameter is smaller than that of the afferent glomerular arteriole. For this reason, the efferent arteriole offers considerable resistance. -high pressure helps with efficent filtration

What would happen if the glomerular hydrostatic pressure (GHP) and the hydrostatic pressure in typical systemic capillaries were equal?

Not be able to push water and solutes out of the bloodstream and into filtrate.

What causes capsular hydrostatic pressure?

Resistance to flow along the nephron and conducting system

How is net hydrostatic pressure (NHP) calculated?

Difference between glomerular hydrostatic pressure and capsular hydrostatic pressure --> NHP = GHP - CsHP

What organic molecule is responsible for blood colloid osmotic pressure (BCOP)?

Suspended proteins

How is net filtration pressure (NFP) calculated?

Difference between net hydrostatic pressure and blood colloid osmotic pressure acting across glomerular capillaries NFP = NHP - BCOP

Define glomerular filtration rate.

Amount of filtrate the kidneys produce each minute

Autonomic regulation of filtration is primarily maintained by which division of the autonomic nervous system?

sympathetic division

What process is regulated by hormones of RAAS and natriuretic peptides?

Glomerular filtration rate

Define renal threshold.

The plasma concentration at which a specific substance or ion begins to appear in the urine

Define glycosuria.

The presence of glucose in urine

Which part of the renal tubule normally reabsorbs 60-70 percent of the volume of the filtrate produced in the renal corpuscle?

proximal convoluted tubule

Which limb of the nephron loop is impermeable to water?

Ascending limb

Which part of the nephron is responsible for the active secretion of ions, acids, drugs, and toxins into the tubule?

Distal convoluted tubule (DCT)

The collecting system is important in controlling the pH of body fluids through the secretion or reabsorption of which two ions?

hydrogen

bicarbonate

What occurs during countercurrent multiplication. Which two segments of the nephron are involved in this process?

Filtrate flow in the nephron loop and blood flow in the vasa recta; exchange between fluids moving in opposite directions

descending and ascending limb

Which two microscopic kidney structures do ADH act on?

distal convoluted tubule and collecting duct

What would occur in the urine if ADH was not produced?

Water is not reabsorbed in these segments, so all the fluid reaching the DCT is lost in the urine

What is diabetes insipidus?

A disorder in which the body cannot conserve water properly, leading to excessive urination (polyuria) and excessive thirst (polydipsia)

Define urinalysis.

The analysis of urine by physical, chemical, and microscopic means

What test is used as an index to assess overall kidney function?

Creatinine clearance

What test measures the amount of urea in the blood?

Blood urea nitrogen (BUN)

What is a pyelogram?

An image of the urinary system obtained by taking an xray of the kidneys after a radiopaque dye has been administered intravenously

Urine produced by the kidney is directly emptied in what organ of the urinary system?

ureters

What is the function of the urinary bladder?

Serve as temporary storage for urine

What is the function of rugae in the urinary bladder?

Folds that allow the bladder wall to stretch and expand to hold volumes of urine

Which organ in the urinary system transports urine out of the body?

Urethra

What is the common name for renal calculi?

Kidney stones

What is nephrolithiasis?

The formation of calculi (kidney stones) in association of increasing age

What type of capillaries are glomerular capillaries?

Fenestrated capillaries