Chapter F18 Urinary System

Front 1

Describe the location of the Kidneys, Ureters, Urinary Bladder, and Urethra

Back 1

Kidneys - located in the upper abdominal cavity on either side of the vertebral column, behind the peritoneum.
Ureters - Extends from the hilus of a kidney to the lower posterior side of the urinary bladder.
Urinary Bladder - Muscular sac below the peritoneum behind the public bones
Urethra - Carries Urine from the bladder to the exterior.

Front 2

Name the three areas of the kidneys, and state what each consists.

Back 2

Renal Cortex- the outer tissue layer, it is made of renal corpuscles and convoluted tubules. Part of the neohron
Renal Medulla - Inner tissue layer, made of loops of Henle and collecting tubules. Also part of the nephron. It consists of Renal Pyramids which are wedge-shaped.
Renal Pelvis - Not a layer of tissue but a cavity formed by the expansion of the ureter within the kidney at the hilus.

Front 3

Name the 2 major parts of a nephron. State the general function of nephrons.

Back 3

2 major parts of the nephron are a renal corpuscle and a renal tubule.
Renal Corpuscle consists of a glomerulus surrounded by a Bowman's capsule. Glomerulus is a capillary network that arises from an afferent arteriole and empties into an efferent arteriole.
Renal Tubule - continues from Bowman's capsule and consists of the following parts: Proximal convoluted tubule, loop of Henle, and distal convoluted tubule. All parts of the renal tubule are surrounded by peritubular capillaries which arise from the efferent arteriole.

Front 4

Name the parts of a renal corpuscle. What process takes place here?

Back 4

Glomerulus - a capillary network that arises from an afferent arteriole and empties into an efferent arteriole.
Afferent arteriole - the arteriole that takes blood from the renal artery into a glomerulus within its wall are juxtaglomerular cells that secrete renin
Efferent Arteriole - the arteriole that takes blood from a glomerulus to the peritubular capillaries that surround the renal tubule.
Bowman's Capsule - Expanded end of a renal tubule it encloses the glomerulus.
Podocytes - Inner layer of the Bowman's capsule. Means "foot cells" the foot of the podocytes are on the surface of the glomerular capillaries.
The process that takes place here is the Glomerular Filtration.

Front 5

Name the parts of a renal tubule. What process takes place here?

Back 5

Proximal convoluted tubule -(in the renal cortex)
Loop of Henle _(loop of the nephron - In the renal Medulla)
Distal Convoluted Tubule -(In the renal cortex). This tubule empty into a collecting tubule.
All parts of teh renal tubuke are surrounded by Peritubular Capillaries. The peritubular capillaries will receive the materials reabsorbed bu the renal tubules. As urine formation.
The process that takes places here is Tubular Secretion.

Front 6

Explain the importance of tubular secretion

Back 6

Tubular secretion changese the composition of urine. In tubular secretion substances are actively secreted from the blood in the peritubular capillaries into the filtrate in the renal tubules. Waste products such as Ammonia and some creatinine, and the metabolic products of medications may be secreted into the filtrate to be eliminated in urine. H+ ions may be secreted by the tubule cells to help maintain the normal pH of blood.

Front 7

Describe the pathway of blood flow through the kidney from the abdominal aorta to the inferior vena cava

Back 7

Blood from the abd aorta enters the Renal Artery, which branches within the kidney into several interlobar arteries. Each interlobar artery becomes an Arcuate artery, which branches into many interlobular arteries that enter the renal cortex. The interlobular arteries give rise to Afferent arterioles, blood flows into the Glomeruli to Efferent Arterioles, to Peritubular Capillaries, and to a series of veins. The Interlobar Veins all unite at the hilus to form the Renal Vein, which empties blood into the Inferior Vena Cava.
The exchanges that take place between the nephroms and the capillaries of the kidneys will form Urine from Blood plasma.

Front 8

Name the hormone that has each of these effects on the kidneys
a.) Promotes reabsorption of Na+ ions
b.) Promotes direct reabsorption of water
c.) Promotes reabsorption of Ca2+ ions
d.) Promotes excretion of K+ ions
e.) Decreases reabsorption of Na+ ions

Back 8

a.) Aldosterone - Stimulates the reabsorption of Na+ Ions.

b.) Antidiuretic hormone - Increase reabsorption of water from the filtrate to the blood

c.) Parathyroid Hormone - Increases reabsorption of Ca2+ ions from filtrate to the blood and excretion of phosphate ions into the filtrate,

d.) Aldosterone promotes excretion of K+ ions into the filtrate.

e.) Arterial Natriuretic Peptide (ANP) - secreted by the atria of the heart decreases the reabsorption of Na+ ions by the kidneys

Front 9

In what circumstances will the kidneys excrete H+Ions?
What ions will be returned to the Blood?
How will this affect the pH of blood?

Back 9

The kidneys will excrete H+ Ions when body fluids are becoming too ACIDIC

Causing the kidneys to secrete more H+ Ions into the renal filtrate and will return more HCO3- ions to the blood.

This will affect the pH of blood by raising the pH back to normal.

Front 10

In What circumstances do the kidneys secrete Renin, and what is its purpose?

Back 10

The circumstances that the kidneys secrete Renin is when the blood pressure decreases, the Juxtaglomerular cells in teh wall of the afferent arterioles secrete the enzyme Renin. The Renin initiates the Renin-Angiotensin mechanism to Raise Blood Pressure. The end product of this mechanism is Angiotensin 2 which causes Vasoconstraction and increases the secretion of Aldosterone, both which help raise blood pressure.

Front 11

In what circumstances do the kidneys secrete Erythropoietin and what is its purpose?

Back 11

The circumstance that the kidneys secrete Erythropoietin is when the blood oxygen level decreases ( a state of Hypoxia).
The Erythropoeitin stimulates the red bone marrow to increase the rate of RBC production. With more RBC in circulation the oxygen-carrying capacity of the blood is great and the Hypoxic state may be corrected.

Front 12

Describe the function of the ureters.

Back 12

Ureters - extend from the hilus of a kidney to the lower, posterior side of the urinary bladder.
The smooth muscle in the wall of the ureter contracts in peristaltic waves to propel urine toward the urinary bladder. As the bladder fills, it expands and compresses the lower ends of the ureters to prevent back flow of urine.

Front 13

Describe the function of the Urethra.

Back 13

Urethra - Carries urine from the bladder to the exterior.
External Urethral Sphincter - made of the surrounding skeletal muscle of the pelvic floor and is under Voluntary Control.

Front 14

With respect to the urinary bladder, describe the function of Rugae and the Detrusor Muscle

Back 14

Rugae - Folds of the mucosa of organs such as the stomach, urinary bladder, and vagina, permit expansion of these organs,

Detrusor Muscle - smooth muscle layer in the wall of the bladder. it is a form of a sphere, when it contracts it becomes a smaller sphere, and its volume diminishes.

Front 15

State the source of each of the Nitrogenous waste products:
a.) Creatine
b.) Uric Acid
c.) Urea

Back 15

a.) Creatine - Comes from the metabolism of creatine phosphate, an energy source in muscles

b.) Uric Acid - Comes from the metabolism of nucleic acids, that is the breakdown of DNA and RNA.

c.) Urea - formed by the liver cells when excess amino acids are deaminated to be used for energy production

Front 16

Describe the urination reflex in terms of stimulus, part of the CNS involved, effector muscle, internal urethral sphincter, and voluntary control.

Back 16

This reflex is a spinal cord reflex over which voluntary control may be exerted.
The STIMULUS for the reflex is stretching of the detrusor muscle of the bladder.
The stretching is sufficient to generate sensory impulses that travel to the sacral spinal cord.
Motor impulses return alon parasympathetic nerves to the detrusor muscle, causing contraction. At the same timethe internal urethral sphincter is Voluntarily relaxes.
If the external urethral sphincter is voluntarily relaxed urine flows into the urethra and the bladder is emptied.
Urination can be prevented by Voluntary contractin of the external urethral sphincter. However if the bladder continues to fill and be stretched voluntary control is eventually no longer possible.

Front 17

Describe the characteristics of normal urine in terms of
a.) appearance
b.) amount
c.) pH
d.) Specific gravity
e.) composition

Back 17

a.) Appearance - Typically yellow and is often referred to as straw or amber. Concentrated urine is a deeper yellow (amber) then is dilute urine. Freshly voided urine is clear rather then cloudy

b.) Amount - Normal urinary output per 24 hrs is 1 to 2 Liters. Excessive sweating or loss of fluid through diarrhea will decrease urinary output to conserve body water. Excessive fluid intake will increase urinary output. Alcohol will increase output because it inhibits the secretion of ADH and the kidneys will reabsorb less water

c.) pH - between 4.6 - 8.0 with an average value of 6.0. Diet has the greatest influence on urine pH. Vegetarian diet will be more alkaline whereas protein diet will be more acidic.

d.) Specific Gravity - Normal range is 1.010 to 1.025 this is a measure of dissolved material in urine. Distilled water is 1.000 meaning there is no solutes present. the higher the specific gravity the more dissolved material is present.

e.) Composition - 95% water, 5% salts and waste products.