Podcast
Questions and Answers
What are the main components of the urinary system?
What are the main components of the urinary system?
Kidneys, ureters, urinary bladder, urethra
Which of the following is the main function of the kidneys?
Which of the following is the main function of the kidneys?
The kidneys are positioned in a ______________ position.
The kidneys are positioned in a ______________ position.
retroperitoneal
The adrenal glands cap the superior surface of the kidneys.
The adrenal glands cap the superior surface of the kidneys.
Signup and view all the answers
What are the three distinct regions revealed in a frontal section through a kidney?
What are the three distinct regions revealed in a frontal section through a kidney?
Signup and view all the answers
What is the function of the minor calyces?
What is the function of the minor calyces?
Signup and view all the answers
Renal corpuscles consist of glomerulus and Bowman's capsule.
Renal corpuscles consist of glomerulus and Bowman's capsule.
Signup and view all the answers
Nephrons are the structural and functional units of the kidneys, with over 1 million ______ in each kidney.
Nephrons are the structural and functional units of the kidneys, with over 1 million ______ in each kidney.
Signup and view all the answers
Match the following components of a nephron with their description:
Match the following components of a nephron with their description:
Signup and view all the answers
What is the function of the Macula densa in the Juxtaglomerular Complex?
What is the function of the Macula densa in the Juxtaglomerular Complex?
Signup and view all the answers
What is the role of Granular/Juxtaglomerular cells in the kidney?
What is the role of Granular/Juxtaglomerular cells in the kidney?
Signup and view all the answers
What is the function of Extraglomerular mesengial cells in the kidney?
What is the function of Extraglomerular mesengial cells in the kidney?
Signup and view all the answers
What are the three layers of the bladder wall?
What are the three layers of the bladder wall?
Signup and view all the answers
What is the name of the area at the base of the bladder with 3 openings?
What is the name of the area at the base of the bladder with 3 openings?
Signup and view all the answers
The male urethra is approximately 8 inches long.
The male urethra is approximately 8 inches long.
Signup and view all the answers
What is the daily volume of glomerular filtrate in females?
What is the daily volume of glomerular filtrate in females?
Signup and view all the answers
What is the daily volume of glomerular filtrate in males?
What is the daily volume of glomerular filtrate in males?
Signup and view all the answers
Glomerular filtrate is heavily regulated.
Glomerular filtrate is heavily regulated.
Signup and view all the answers
What is the role of the Juxtaglomerular Apparatus?
What is the role of the Juxtaglomerular Apparatus?
Signup and view all the answers
Glomeruli generate about $180$ liters of filtrate per day, and approximately $______$% of it is reabsorbed in the renal tubules.
Glomeruli generate about $180$ liters of filtrate per day, and approximately $______$% of it is reabsorbed in the renal tubules.
Signup and view all the answers
What is the function of the internal urethral sphincter?
What is the function of the internal urethral sphincter?
Signup and view all the answers
Which segment of the urethra passes through the center of the prostate gland?
Which segment of the urethra passes through the center of the prostate gland?
Signup and view all the answers
The external urethral sphincter surrounds the urethra and is voluntarily ________.
The external urethral sphincter surrounds the urethra and is voluntarily ________.
Signup and view all the answers
The kidneys receive approximately 20-25% of resting cardiac output.
The kidneys receive approximately 20-25% of resting cardiac output.
Signup and view all the answers
Match the following kidney function with its description:
Match the following kidney function with its description:
Signup and view all the answers
What is a commonly used marker to estimate renal function?
What is a commonly used marker to estimate renal function?
Signup and view all the answers
What is GFR estimated by?
What is GFR estimated by?
Signup and view all the answers
What is the purpose of renal clearance?
What is the purpose of renal clearance?
Signup and view all the answers
Urine production is evidence of __________ kidneys.
Urine production is evidence of __________ kidneys.
Signup and view all the answers
What type of reabsorption routes exist in the renal system?
What type of reabsorption routes exist in the renal system?
Signup and view all the answers
Water follows salt in obligatory reabsorption.
Water follows salt in obligatory reabsorption.
Signup and view all the answers
Match the following functions with the Proximal Convoluted Tubules (PCT):
Match the following functions with the Proximal Convoluted Tubules (PCT):
Signup and view all the answers
What is the main function of the Loop of Henle?
What is the main function of the Loop of Henle?
Signup and view all the answers
What is impermeable to water in the Thick Ascending Limb of the Loop of Henle?
What is impermeable to water in the Thick Ascending Limb of the Loop of Henle?
Signup and view all the answers
The reabsorption in the Thin Descending Limb of the Loop of Henle is impermeable to water.
The reabsorption in the Thin Descending Limb of the Loop of Henle is impermeable to water.
Signup and view all the answers
What is actively cotransported out of the tubule lumen into the interstitium in the ascending loop of the Loop of Henle?
What is actively cotransported out of the tubule lumen into the interstitium in the ascending loop of the Loop of Henle?
Signup and view all the answers
What is the main function of the Distal Convoluted Tubule (DCT)?
What is the main function of the Distal Convoluted Tubule (DCT)?
Signup and view all the answers
What percentage of the initial filtrate volume reaches the DCT?
What percentage of the initial filtrate volume reaches the DCT?
Signup and view all the answers
The DCT actively transports Na+ and Cl— out of the tubular fluid by Na+ - Cl– symporters.
The DCT actively transports Na+ and Cl— out of the tubular fluid by Na+ - Cl– symporters.
Signup and view all the answers
The Distal Convoluted Tubule is the primary site for _ reabsorption, regulated by parathyroid hormone (PTH) & calcitriol.
The Distal Convoluted Tubule is the primary site for _ reabsorption, regulated by parathyroid hormone (PTH) & calcitriol.
Signup and view all the answers
What accelerates H+ secretion in the DCT when blood pH falls?
What accelerates H+ secretion in the DCT when blood pH falls?
Signup and view all the answers
What are the three triggers that cause the Juxtaglomerular Apparatus to release renin?
What are the three triggers that cause the Juxtaglomerular Apparatus to release renin?
Signup and view all the answers
Which of the following are effects of Angiotensin II at the kidney? (Select all that apply)
Which of the following are effects of Angiotensin II at the kidney? (Select all that apply)
Signup and view all the answers
Aldosterone reduces sodium loss in urine. Is this statement true or false?
Aldosterone reduces sodium loss in urine. Is this statement true or false?
Signup and view all the answers
Match the following hormones with their actions:
Match the following hormones with their actions:
Signup and view all the answers
What triggers the release of Atrial Natriuretic Peptide (ANP)?
What triggers the release of Atrial Natriuretic Peptide (ANP)?
Signup and view all the answers
Study Notes
Objectives of the Urinary System
- Filter nearly 200 liters of fluid from the bloodstream
- Remove toxins, metabolic wastes, and excess ions from the body in urine
Kidneys - Anatomical Location and Structure
- Located in the retroperitoneal position
- Left kidney: around T12 to L3 vertebrae
- Right kidney: lower due to slight displacement by the liver
- Upper portions of the kidneys: protected by the eleventh and twelfth ribs
- Surrounded by a fibrous capsule
- Medial surface: concave and has a vertical cleft (renal hilum)
- Lateral surface: convex
- Renal sinus: internal cavity within kidney
- Renal pelvis: funnel-shaped tube that collects urine
Kidneys - Internal Anatomy
- Cortex: reddish-brown and granular (3 cm)
- Medulla: distinct granular texture
- Pelvis: internal cavity within kidney
- Renal columns: bands of cortical tissue that separate adjacent renal pyramids
- Renal pyramids: extensions of the medulla into the cortex
- Minor calyces: cup-shaped areas that enclose the papillae
- Major calyces: subdivisions of the renal pelvis
Nephron - Functional Unit of the Kidneys
- Renal corpuscle: spherical structure consisting of glomerulus and glomerular capsule (Bowman's capsule)
- Renal tubule: long tubular passageway that begins at the renal corpuscle
- Proximal convoluted tubule: located in the cortex
- Nephron loop/Loop of Henle: located partially in the medulla
- Distal convoluted tubule: located in the cortex
- Collecting duct: receives filtrate from many nephrons and delivers urine into minor calyces via papillae
Blood Vessels of Nephron
- Nephron capillary bed: glomerulus and peritubular capillaries
- Juxtamedullary nephrons: associated with special capillaries called the vasa recta
- Cortical nephrons: not associated with vasa recta
Classes of Nephron
-
Cortical nephrons: 85% of the nephrons in the kidneys, located in the cortex
-
Juxtamedullary nephrons: located near the cortex-medulla junction, associated with vasa recta### Kidney Structure and Function
-
Peritubular capillaries cling closely to adjacent renal tubules and empty into nearby venules.
-
The kidneys receive 20-25% of total cardiac output, or 1200ml of blood per minute.
-
Kidney receives blood through the renal artery and exits through the renal veins.
-
Renal plexus provides the nerve supply of the kidney and its ureter.
Juxtaglomerular Complex (JGC)
- Each nephron has a JGC, which regulates the rate of filtrate formation and systemic blood pressure.
- The JGC consists of 3 populations of cells:
- Macula densa (distal convoluted tubule): a salt sensor that generates paracrine chemical signals to control vital kidney functions.
- Granular/Juxtaglomerular cells: smooth muscle cells that synthesize, store, and secrete the enzyme renin.
- Extraglomerular mesengial cells: involved in renal autoregulation of blood flow to the kidney and regulation of systemic blood pressure through the renin-angiotensin system.
Urinary Tract
- The urinary tract consists of the ureters, urinary bladder, and urethra.
- Ureters are pair of muscular tubes that continue from the renal pelvis and penetrate the posterior wall of the urinary bladder at an oblique angle.
- The urinary bladder is a hollow, muscular organ that can contain up to 1 liter of urine.
- The bladder wall has three layers: mucosa, muscularis, and adventitia.
Urethra
- The male urethra is approximately 20 cm long and has three regions: prosthetic urethra, membranous urethra, and spongy urethra.
- The female urethra is shorter, around 3-5 cm, and extends from the bladder to the vestibule.
- The external urethral orifice is near the anterior wall of the vagina.
Kidney Function and GFR
- Homeostatic functions of the urinary system include:
- Regulating blood volume and blood pressure
- Regulating plasma ion concentrations
- Helping stabilize blood pH
- Conserving valuable nutrients
- Assisting liver to detoxify poisons
- Regulating osmolarity
- Kidney functions include:
- Concentrating filtrate by glomerular filtration
- Absorbing and retaining valuable materials for use by other tissues
- The basic processes of urine formation are:
- Filtration
- Tubular reabsorption
- Tubular secretion
Forms of Membrane Transport
- Filtration: occurs at the renal corpuscle, where glomeruli produce about 180 L of filtrate per day (70 times plasma volume)
- Water and solute reabsorption: primarily occurs along proximal convoluted tubules
- Active secretion: primarily occurs at proximal and distal convoluted tubules### Glomerular Filtration
- Glomerular filtration is a passive process driven by hydrostatic pressure, which forces water and small solutes through membrane pores.
- The glomerular membrane has three components: capillary endothelium, lamina densa, and filtration slits.
- The filtration slits are the finest filters, preventing the passage of most small plasma proteins.
- Net filtration pressure (NFP) is the pressure needed to filter blood plasma from the glomerulus into the capsular space.
- NFP is calculated by the formula: NFP = GBHP - CHP - BCOP.
Glomerular Filtration Rate (GFR)
- GFR is the amount of plasma ultrafiltrate produced by the kidneys per minute.
- GFR averages 125 ml/min for males and 105 ml/min for females.
- Any factor that alters filtration pressure alters GFR.
- GFR is regulated by three levels of control: autoregulation, hormonal regulation, and autonomic regulation.
Regulation of GFR
- Autoregulation: local regulation of GFR through myogenic mechanisms and tubuloglomerular feedback.
- Hormonal regulation: initiated by the kidneys to regulate GFR through hormones such as angiotensin II and atrial natriuretic peptide (ANP).
- Autonomic regulation: regulated by the sympathetic division of the autonomic nervous system (ANS).
- Strong stimulation (e.g., exercise or hemorrhage) causes afferent arterioles to constrict, reducing GFR.
Reabsorption and Secretion
- Reabsorption: the process of recapturing useful materials from the filtrate into the bloodstream.
- Most of the filtered water (99%) and solutes are reabsorbed, especially in the proximal convoluted tubules (PCT).
- Reabsorption occurs through both active and passive processes.
- Small proteins and peptides are reabsorbed by pinocytosis.
- Reabsorption routes include paracellular reabsorption (50% of reabsorbed material) and transcellular reabsorption.
Secretion
- Secretion: the transfer of materials from the blood into the tubular fluid.
- Purpose: to eliminate toxic wastes and regulate blood pH.
- Eg., H+, K+, NH4-, creatinine, drugs.
- Secretion occurs through both active and passive processes.
Transport Mechanism
- Solutes move in one direction through the transport mechanism.
- Involves combination of diffusion, osmosis, channel-mediated diffusion, and carrier-mediated transport.
- Primary active transport uses ATP, e.g., Na+/K+ pumps.
- Secondary active transport involves facilitated diffusion, symporters, and antiporters.
Renal Transport Systems
- Lots of transporter proteins are involved in the transport of different molecules/ions.
- Each transporter protein has a maximum transport (TM) capacity, where transport saturates.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz covers the components of the urinary system, kidney function, and kidney structure. Test your knowledge of the urinary system and its parts!
