University:
Texas A&M University
Course:
BIOL 319 | Integrated Human Anatomy and Physiology I
Academic year:

2024
Views:

88

Pages:

55
Author:

omiliar74be

Objectives: Part 2 Function and excretory ducts • Describe the structure of the kidney and distinguish between cortical and medullary organization. • Identify and differentiate between the portions of the nephron. • Trace blood flow through the kidney. • Describe the structural organization of the ureter, urinary bladder, and urethra. hilum kidney thin loop of Henle in cortex Thin loop of Henle in cortex kidney thin loop of Henle in cortex Thin loop of Henle in cortex The density of the cortex is dominated by the proximal convoluted tubules. 36727 However, the thin loop of Henle can be found in the cortex too. Flow rate The greatest change in flow rate occurs in the proximal tubule which reabsorbs 80% of the filtrate. Cortical nephrons Juxtamedullay nephrons Cortical nephrons Loop increases temperature over straight tube with same amount of heat Juxtamedullay nephrons Peritubular capillaries Capillaries of the vasa recta PERITUBULAR CAPILLARIES ABSORBS - 180 LITERS/DAY FROM INTERSTITIAL SPACES; THUS, ~4 TIMES REABSORPTION OF VENOUS END OF ALL OTHER CAPILLARIES OF BODY ENDOTHELIAL CELLS EXTREMELY POROUS COLLOIDAL OSMOTIC PRESSURE OF PLASMA PROTEINS LOW CAPILLARY PRESSURE PROXIMITY TO URINIFEROUS TUBULES PERITUBULAR CAPILLARIES peritubular fenestrated endothelium Rich blood supply of peritubular capillaries and vasa recta cortex 260 Arcuate arteries medulla Countercurrent exchanger Capillaries of the vasa recta Countercurrent Multiplier nephron Countercurrent Multiplier Countercurrent exchanger nephron Countercurrent Multiplier Countercurrent exchanger nephron WW Tuttle and BA Schottelius Textbook of Physiology C.V. Mosby Co. Juxtaglomerular apparatus Juxtaglomerular apparatus Juxtaglomerular apparatus Renin granules in JG cells of Kidney (PAS) Renin granules in JG cells of Kidney (PAS) Renin granules in JG cells of Kidney (PAS) ANGIOTENSINOGEN (PLASMA GLOBULIN) RENIN (ENZYME from JG cells) ANGIOTENSIN 1 (PLASMA ENZYME) ANGIOTENSIN II (MOST POTENT VASOCONSTRICTOR) INCREASED BLOOD PRESSURE ANGIOTENSIN II VASOCONSTRICTION ALDOSTERONE RELEASE FROM ADRENALS INCREASED BLOOD PRESSURE INCREASED SODIUM (WATER REABSORPTION BY DISTAL TUBULE) INCREASED BLOOD VOLUME Adrenal function Aldosterone stimulates Na+ resorption in: distal tubule of kidney gastric mucosa salivary glands sweat glands Proteinuria Several diseases may induce proteinuria: • In diseases such as diabetes mellitus and glomerulonephritis, the glomerular filter is altered and becomes much more permeable to proteins, with the subsequent release of protein into the urine • Proteinuria is an indicator of many potential kidney disorders. 0 to 8 mg/dL protein in urine is considered normal. kidney cortex medulla Minor calyx kidney Minor calyx Fluid transport and ureters All images Copyright McGraw-Hill Companies Ureter (upper 1/3) 1 2 3 4 1. Transitional epithelium 2. Lamina propria 3. Longitudinal smooth muscle 4. Circular smooth muscle 5. Adventia 5 Transitional epithelium Ureter – transitional epithelium and smooth muscle The shape of the urethral lumen is semi-lunar and slit-like Urinary bladder 6 5 4 3 Transitional epithelium 6. Serosa 2 1 5. Outer longitudinal smooth muscle 4. Middle circular smooth muscle 3. Inner longitudinal smooth muscle 2. Lamina propria 1. Transitional epithelium Urinary bladder, monkey Urinary bladder • Nerve and mesothelium Transitional epithelium Smooth muscle 160 Human Penis – transitional epithelium and surrounding spongy cavernous of penal urethra Penile urethra (monkey) Urethra Transitional epithelium Study Guide DIFFERENTIATING BETWEEN TUBULES IN THE CORTEX Proximal convoluted tubules • • • • most numerous around the renal corpuscle taller cuboidal cells brush border with small lumen intensely eosinophilic Distal convoluted tubules • • • • smaller cuboidal cells proportionally larger lumen less intensely eosinophilic macula densa Study Guide DIFFERENTIATING BETWEEN TUBULES IN THE MEDULLA Thick descending limb • • Intensely eosinophilic (resembles proximal convoluted tubule) More cuboidal than proximal convoluted tubule Thick ascending limbs • • • Cuboidal Less intensely eosinophilic (resembled distal convoluted tubule) Confused with collecting duct, but no distinct cell boundaries, no scalloped appearance Thin limb • • Simple squamous epithelium Nuclei often bulge into the lumen Capillaries • • • Simple squamous epithelium Nuclei do not bulge into the lumen Blood cells sometimes present Collecting ducts • • • • Tall cuboidal to columnar epithelium Light staining similar to distal convoluted tubule Apical surface often appears “scalloped” Distinct lateral cell boundaries Cortical nephrons Juxtamedullay nephrons Cortical nephrons Juxtamedullay nephrons Functions of the Urinary system