PS 3: Urinary System - Organization and Nephron Function

1. Removes waste products generated by cells of the body

2. Regulates blood volume and blood pressure

3. Regular plasma concentrations of ions

4. Helps stabilize blood pH

5. Conserves valuable nutrients eg glucose and amino acids

6. Eliminates nitrogenous wates eg urea

What are the 6 key functions of the urinary system?

cortex; medulla

The kidney is comprised of an outer ____ and inner ____.

renal pyramids

The medulla of the kidney contains conical ____ ____

renal columns

____ ____ extend from the cortex inwards

renal pelvis

____ ____ is a funnel-shaped chamber connected to the ureter

nephron

What is the functional unit of the kidney?

single layer of epithelial cells

What is the nephron composed of?

renal corpuscle'; bowman’s capsule; glomerulus

____ ____ is a cup-shaped chamber (also called ____ ____) containing a capillary network (____)

afferent arteriole

Blood originating from the renal artery reaches the glomerulus via an ____ ____

proximal tubule; thin descending limb; loop of henle; thick ascending limb; early distal tubule; collecting duct

What are the major components of a nephron?

renal artery, afferent arteriole, glomerular capillary, efferent arteriole, peritubular capillary, renal vein

What is the pathway of blood to and from the kidney?

filtration; secretion; reabsorption

All adaptations for maintaining salt and water balance and for excreting nitrogen wastes employ ____ of body fluids and active ____ and ____ of specific ions.

glomerular capillaries; Bowman’s space

Blood pressure forces fluid and dissolved solutes out of the ____ ____ into ____ ____.

protein

Filtration produces a ____-free solution.

renal tubule

Filtrate enters the ____ ____ from the renal corpuscle.

urine

Ions, solutes, and water are reabsorbed at various sites along the nephron resulting in production of ____ in the collecting duct

1 million

How many nephrons are there per kidney?

deaminates; urea

The liver ____ amino acids and the resulting ammonia is combined with carbon dioxide to form ____, a water-soluble molecule that is excreted in urine

nephron; glomerulus; tubule

The ____, the functional unit of the kidney, consists of a ____, in which blood is filtered across the walls of a knot of capillaries, and a renal ____, while processes the filtrate into urine

peritubular capillaries

A system of ____ ____ serves the tubule

secondary active transport with Na+

Glucose is reabsorbed in the proximal tube by ____

active

____ transport of Na+ and K+ occurs across the basal side of the proximal tubule cell.

bicarbonate converted to co2, diffuses into proximal tubule cell, converted back to bicarbonate, diffuses to blood stream

How is bicarbonate reabsorbed in the proximal tubule to the blood stream?

more

Normally urine is ____ concentrated than tissue fluids

1. isosmotic fluid leaving proximal tubule becomes more concentrated in descending limb

2. Removal of solute in thick ascending limb creates hypoosmotic fluid

3. Hormones control distal nephron permeability to water and solute

4. urine osmolarity depends on reabsorption in the collecting duct

List the four changes in osmolarity as fluid flows through the nephron

countercurrent multiplier mechanism

The loops of Henle create a concentration gradient in the extracellular fluids of the renal medulla by a ____ ____ ____

ADH

In the presence of ____, urine flowing down collecting ducts of the ureter is concentrated by osmotic loss of water caused by the concentration gradient in surrounding tissue fluid

ADH; vasopressin

____ or ____ controls the permeability of the collecting duct to water, thus amount of water reabsorbed from urine

aquaporins

ADH stimulates incorporation of proteins called ____ that serve as water channels in the collecting duct cell membranes (apical side)

increased urine output due to defective ADH receptor or defective aquaporin

What is nephrogenic diabetes inspidus?

rise in blood osmolarity leads to osmoreceptors detecting an increase stimulating ADH release. ADH increases permeability of collecting duct cells to H20, decreasing blood osmolarity due to more water reabsorption, inhibiting more ADH release.

How does ADH regulate blood osmolarity?

Low blood pressure causes stretch receptors to detect decrease and stimulate ADH release. ADH cause blood vessels to construct in periphery, elevating blood pressure, inhibiting ADH release.

How does ADH regulate blood pressure?

autoregulatory mechanisms

Kidney function in mammals is controlled by ____ ____ that maintain a constant high glomerular filtration rate even if blood pressure varies

renin

An important autoregulatory mechanism is ____ release by the kidney when blood pressure falls.

angiotensin; aldosterone

Renin activates ____, which causes constriction of peripheral blood vessels, causes release of ____ (which enhances water resorption), and stimulates thirst

Decrease blood to kidneys, decreased filtration/urine production, production of renin increased triggering formation of angiotensin which constricts peripheral arterioles, increased glomerular pressure and return to homeostasis

Describe the Renin-Angiotensin System and regulation of GFR

decreased BP leads to increased renin secretion from kidney leading to angiotensin leading to increased aldosterone secretion leading to increased Na+ and water reabsorption resulting in increased BP

What effect does aldosterone have on salt and water regulation?

atrial natriuretic peptide

The atria of the heart release ____ ____ ____ (ANP) when blood pressure becomes high.

decreases reabsorption of sodium causing an increased loss of sodium and water, which lowers blood volume and pressure

What does ANP do in the kidney?

more carbonic acids leading to more release of H+ ions and pH goes down

What does increased carbon dioxide do to plasma pH?

disorder caused by hyperventilation and CO2 buildup in tissues and blood; improve ventilation

What is respiratory acidosis? What is the treatment for respiratory acidosis?

disorder caused by buildup of metabolic acid, impaired H+ excretion at kidneys, or bicarbonate loss in urine; administration of bicarbonate

What is metabolic acidosis? What is the treatment?

uncommon disorder causes by hyperventilation and reduction in plasma CO2 levels; reduce respiratory rate

What is respiratory alkalosis? What is the treatment?

rare disorder caused by prolonged vomiting and associated acid loss; administration of ammonium chloride

What is metabolic alkalosis? What is the treatment?