Urinary System: Anatomy Review
1. Name the organs in the urinary system:
1. 2 kidneys
2. 2 ureters
2. The kidneys are retroperitoneal (behind the peritoneum), lying against the dorsal body wall in the upper abdomen.
3. The adrenal gland sits atop the kidneys. Blood vessels enter and leave the kidney at the renal cortex.
4. The functional units of the kidney are the nephrons. They are called renal pyramids if they are located mainly in the cortex. They are called renal pyramids if they are located in both the cortex and the medulla.
5. Blood enters the kidney through the hilus artery. The artery branches into smaller and smaller arteries and arterioles. Complete the sequence below: ______________ arteriole ______________ capillaries ______________ arteriole ______________ capillaries and vasa recta
6. Complete the sequence below showing all parts of the nephron: Glomerular (Bowman’s) capsule proximal convoluted tubule loop of henle (both descending and ascending limb) distal convoluted tubule collecting duct (both cortical and medullary sections)
7. The renal corpuscle consists of two parts: glomerular capillaries and the Bownan’s capsule.
A portion of the plasma is filtered into the capsular space due to the hydrostatic pressure of the blood.
8. The filtration membrane consists of fenestrated capillary endothelium, porous basementmembrane, and the photocyte (which contain filtration slits). This filtration membrane permits (large or small) molecules to be filtered.
9. Proximal tubule: The simple cuboidal cells of the proximal tubule are called brush border cells because they contain numerous microvilli. The microvilli increase the surface area for reabsorption. The proximal tubule cells are highly permeable to water and many solutes. The tight junctions permit the movement of water between the cells.
10. Loop of Henle: The thin descending limb of the loop of Henle is highly permeable to water but not to solutes. The thick ascending limb of the loop of Henle is highly permeable to ___________________ but not to ___________________.
11. The thick ascending limb of the loop of Henle runs back between the afferent and efferent arterioles as they enter and leave the glomerular (Bowman’s) capsule. The juxtaglomerular apparatus consists of the macular densa cells of the tubule and the granular (modified smooth muscle) cells of the afferent arteriole. Granulerutal cells serve as baroreceptors sensitive to blood pressure within the arteriole. Macular densa cells monitor and respond to changes in the osmolarity (or electrolyte composition) of the filtrate in the tubule.
12. After the juxtaglomerular apparatus, the tubule becomes the distal tubule, which merges with the cortical collecting duct. The cortical collecting duct contains two functional types of cells: Principal cells—hormones regulate their permeability to water and solutes. Intercalated cells—secrete hydrogen ions for acid-base regulation.
13. The medullary collecting duct is composed of principal cells.
Their permeability to urea and water is hormonally regulated. Urinary System: Glomerular Filtration
1. What force drives filtration at the glomerulus? Blood pressure
2. Glomerular filtration is a process of bulk flow driven by the hydrostatic pressure of the blood.
3. Common components of the filtrate are divided into four categories on the CD program. These include: 1. water 2. ions 3. notrogenous waste 4. organic molecules
4. Blood pressure in the glomerulus is about 60 mmHg.
5. What two pressures oppose filtration and what are their values?
1. hydrostatic 15mmHg
2. osmotic 28mm Hg
6. What is the normal net filtration pressure? 7 mmHg
7. With a glomerular filtration rate of 125 ml/min, how much plasma would be filtered per day? 180L In 24 hours? _____
8. In an exercising individual the afferent arteriole will (dilate or constrict) to avoid excess fluid loss.
9. Two mechanisms that provide autoregulatory control over renal processes include: 1. myogenic 2. tubuloglomer
10. High osmolarity (or high Na+ and Cl–) in the ascending loop of Henle will cause afferent arterioles to (dilate or constrict) by releasing vasoconstrictor
11. In periods of extreme stress, the sympathetic nervous system will override autoregulation.
An increase in sympathetic flow to the kidney will result in what two important effects that will aid maintenance of blood pressure?
2. Urinary System: Early Filtrate Processing
1. What are the two reabsorption pathways through the tubular cell barrier?
2. How can we cause water to diffuse from the lumen into the interstitial space? An increase in the osmolarity of the interstitium
3. Transport of what ion could cause the diffusion in question 2?
4. Summarize reabsorption in the proximal tubule. 85% of reabsorption of all useful substances occur here
5. What percent of the filtrate is reabsorbed in the proximal tubule? 99%
6. The simple squamous cells of the thin descending loop are permeable to __________________ but impermeable to ________________.
7. The ascending limb of the loop of Henle is permeable to Water but impermeable to solutes.
8. What is the role of the loop of Henle? Facilitated diffusion
9. What is the role of the vasa recta? Blood capillary which collects the filtered blood capillary which collects the filtered blood from afferent arterriole
10. From the Quiz section, what does furosemide do? Increases your water output to decrease fluid retention through urination
Urinary System: Late Filtrate Processing
1. Name the two types of cells in the cortical collecting ducts and describe their function.
2.a. Aldosterone is stimulated by an increase or decrease in what ions?
b. What does aldosterone increase in the basolateral membrane?
3. What does antidiuretic hormone (ADH) increase in the luminal membrane? Vasopressin
4. In dehydration and overhydration, what would be the levels of: a. ADH? v dehydration ___? ___ overhydration (? or ) b.
Aldosterone? ___ v ___ dehydration __? ____ overhydration (? or )
5. Describe what move(s) out of the tubule and what the osmolarity would be in the following nephron segments: a. Proximal tubule______ move(s) out______ mOsm b. Descending limb______ move(s)out______ mOsm c. Ascending limb______ move(s)out______ mOsm d. Late distal tubule______ move(s)out______ mOsm
6. a. By the medullary collecting duct, only _____% of the filtrate remains. b. Under the following conditions, report the levels of ADH and subsequent urine osmolarity and flow rate
7. a. Urine with a “high normal osmolarity” and containing RBCs and protein would indicate: _______________ b. Urine with a very high osmolartiy and glucose would indicate: _______________ c. Urine with a very low osmolarity and high volume would indicate: _______________
8. An increase in plasma potassium levels would lead to what changes in the following? (? or ) a. _____aldosterone levels b. _____potassium excretion c. _____sodium excretion d. _____interstitial osmolarity e. _____urine volume