Urinary system Flashcards
Identify the following structures of the nephron: Bowman’s capsule, glomerulus, afferent arteriole, efferent arteriole, proximal convoluted tubule, loop of Henle, distal convoluted tubule and collecting tubule (collecting duct).
A = Renal Vein (Carries oxygenated depleted blood)
B = Renal Artery (Carries oxygenated blood)
C = Proximal Convoluted Tubule (PCT)
D = Afferent Arteriole
E = Glomerulus
F = Efferent Arteriole
G = Bowman’s Capsule
H = Distal Convoluted Tubule (DCT)
I = Collecting Tubule
J = Descending Limb of Loop of Henle
K = Ascending Limb of Loop of Henle
L = Loop of Henle
Identify the contents of urine.
95% water and 5% solutes
Explain the role of the kidney in the elimination of nitrogenous waste.
The kidneys remove nitrogenous wastes, urea, and ammonia. Urea is the main excretory product filtered and excreted from the blood by the kidneys. Ammonia is mostly converted into urea in the liver and excreted in the urine.
Discuss the role of the kidney in the regulation of pH.
· Acid-base regulation is one of the most important roles of the kidneys.
· pH is normally maintained using HCO3- buffer:
- The kidney maintains HCO3- concentrations in a normal range to regulate pH.
- The kidney can raise or lower HCO3- concentration to adapt to other changes in the body.
In the case of renal failure, patients become increasingly acidic, which causes a whole host of problems.
What is the structure and function of the kidneys?
Structure:
The kidneys lie against the back muscles in the upper abdomen. They have a layer of fat that’s called the adipose capsule. An outer layer of fascia anchors the kidneys.
They have an outer layer called the cortex, a middle layer called the medulla, and an inner layer called the pelvis.
Function:
To filter the blood, remove waste and produce urine.
Describe the function of the renal pelvis.
A large cavity that collects the urine as it is produced.
Describe the ureters. Explain how urine travels through them.
The ureters are 2 long and slender muscular tubes that use peristalsis and gravity to move urine along. They extend from the kidneys.
Describe the function of the urinary bladder.
The urinary bladder is a temporary reservoir for urine and has many layers. It’s lined with mucous membrane and transitional epithelium. When it’s empty, the bladder has rugae.
Describe the structure and function of the urethra.
The urethra is the tube that extends from the bladder, leading to the outside of the body, allowing urine to pass out.
Why does low BP affect the kidneys?
It’s blood pressure that drives that filtration process.
Describe the internal anatomy of the kidney.
A = Nephron
B = Renal Cortex
C = Renal Medulla
D = Renal Column
E = Renal pyramid in renal medulla
F = Renal sinus
G = Renal papilla
H = Fat in the renal sinus
I = Renal capsule
J = Papillary duct in renal pyramid
K = Minor Calyx
L = Renal pelvis
M = Ureter
N = urinary bladder
O = Renal artery
P = Renal vein
Filtration Process in the Nephron:
Describe the physiological processes of filtration with reference to the nephron. (blood flow to glomerulus)
Filtration Process in the Nephron:
Blood Flow to Glomerulus:
- Blood enters the glomerulus through the afferent arteriole.
- Hydrostatic Pressure: Blood pressure forces water and solutes into Bowman’s capsule through the glomerular capillary walls.
- Bowman’s Capsule: Collects the filtrate, which includes water, glucose, electrolytes, amino acids, urea, and other small molecules. Blood cells and large proteins are excluded from the filtrate.
Blood Exit from Glomerulus: - Efferent Arteriole: Takes filtered blood away from the glomerulus.
Describe the physiological processes of reabsorption with reference to the nephron.
Reabsorption Process in the Nephron:
- Proximal Convoluted Tubule (PCT):
Water, Sodium, Glucose and Amino Acids
Bicarbonate (HCO₃⁻), Chloride, and Potassium are reabsorbed.
- Descending Limb of Loop of Henle:
Water: Reabsorbed due to high osmolarity of the medulla (impermeable to solutes).
- Ascending Limb of Loop of Henle:
Sodium (Na⁺), Chloride (Cl⁻), and Potassium (K⁺): Reabsorbed (impermeable to water).
- Distal Convoluted Tubule (DCT):
Sodium (Na⁺): Reabsorbed, regulated by aldosterone.
Calcium (Ca²⁺): Reabsorbed, regulated by parathyroid hormone (PTH).
- Collecting Duct:
Water: Reabsorbed, regulated by antidiuretic hormone (ADH).
Sodium (Na⁺): Further reabsorbed, regulated by aldosterone.
Urea: Partially reabsorbed to maintain osmotic gradient in the medulla.
Describe the physiological processes of secretion with reference to the nephron.
Secretion in the Nephron:
- Proximal Convoluted Tubule (PCT):
Secretion of metabolic waste products, drugs, toxins, Hydrogen Ions and Ammonium.
- Loop of Henle:
Minimal Secretion: Most of the secretion processes occur in other parts of the nephron.
- Distal Convoluted Tubule (DCT):
Hydrogen Ions, Potassium Ions, Urea.
- Collecting Duct:
Hydrogen Ions, Potassium Ions and Ammonium
What is the main parts of the urinary system?
2 kidneys
2 Ureters
1 Urinary bladder
1 Urethra
What is a nephron?
A nephron is the functional unit of the kidneys. It does the kidneys work.
How many nephrons are contained in each kidney?
1 million
Describe how kidneys maintain blood pressure.
The juxtaglomerular apparatus controls the pressure of filtration.
When stimulated by low sodium volume in the blood, receptor cells secrete the enzyme renin, which initiates the process that activates angiotensin, a protein which elevates blood pressure.
Describe the pathway of urine elimination, beginning with the kidney.
Kidneys—>ureters—>bladder—>urethra—»outside of the body
List the major electrolytes needed by the body and their functions.
Sodium- maintains osmotic balance and body fluid volume. Required for nerve impulse conduction.
Potassium- helps transmit nerve impulses. Major cation of ICF.
Calcium- bone formation, muscle contraction, nerve impulse transmission, blood clotting.
Magnesium- muscle contraction
Bicarbonate- body fluid buffer
Chloride- formation of HCI in the stomach. It helps regulate fluid balance and pH. Major anion in ECF.
Phosphate- Carbohydrate metabolism, bone formation, pH. Found in nucleic acids (DNA, RNA) and ATP.
What are plasma proteins?
Plasma proteins are found in the plasma and never leave the plasma unless in diseased conditions.
What is the organic composition of urine?
urea, creatinine, uric acid, hippuric acid, other substances
What is the inorganic composition of urine?
sodium chloride, potassium, sulfate, phosphate, ammonium, magnesium, calcium
What is the normal pH of blood?
7.35-7.45 pH
