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142 Cards in this Set
- Front
- Back
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Organs that form urine
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kidneys
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lead urine to the bladder
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ureters
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lead urine to the outside of the body
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urethra
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Roles of Urinary Homeostasis
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1.regulating composition of body fluids 2.remove wastes (from metabolism, etc.) 3.kidneys are minor endocrine organs
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location of kidneys
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between twelfth thoracic and third lumbar vertebrae
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What enters and exits the bladder?
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renal artery enters and renal vein and urethra exit
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outer portion of kidney
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renal cortex
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inner, triangular portion(s) of kidney
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renal medulla (renal pyramids)
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a sudden loss of kidney function, usually associated with shock or intense renal vasoconstriction, from a few days to a few weeks
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acute renal failure
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inflammation of the urinary bladder
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cystitis
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blood in the urine
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hematuria
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a method of clearing waste products from teh blood in which blood passes by the semipermeable membrane of the artificial kidney and waste products are removed by diffusion
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hemodyalysis
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night urination (during sleep)
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nocturia
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the condition of having urinary volumes of less than 500 ml/day (normal is 1000 ml/day)
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oliguria
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excessive urine output (as with diabetes insipidus)
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polyuria
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retention of urinary constituents in the blood owing to kidney dysfunction
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uremia
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functional unit of the kidney
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nephron
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T or F: one collecting duct serves one nephron
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F: one collecting duct serves several nephrons
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How many nephrons are there in each kidney?
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one million
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How many capillaries are there in the glomerulus?
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50 capillaries
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How much more permeable is the glomerulus than typical capillaries?
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100 to 1000 times more permeable
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feet processes that hold capillaries in place
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podocytes
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What is the purpose of brush border microvilli in the proximal convoluted tubule?
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increase surface area
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T or F: the nephron loop and distal convoluted tubule contain as much microvilli as the proximal convoluted tubule
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F: the nephron loop has NO microvilli and the distal convoluted tubule has much less
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empties into the collecting duct
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distal convoluted tubule
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the portion of the blood plasma that enters the capsule
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glomerular filtrate
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mechanisms that cause fluid to be filtered
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1. high hydrostatic pressure of blood (45 to 60 mmHg) 2.large number of pores
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How much blood plasma is filtered in a day?
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180 L or 45 gallons
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What is filtered and what is too big?
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water electrolytes, glucose, amino acids, urea, hormones and vitamins ARE filtered plasma proteins, RBC, WBC, and platelets are too big (albumin would be first to filter if something was damaged)
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What is the GFR or glomerular filtration rate?
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120 ml per minute
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How is GFR regulated?
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vasoconstrition or dilation of afferent arterioles by extrinsic and intrinsic mechanisms
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What are the extrinsic and intrinsic factors?
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extrinsic (sympathetic nerves) and intrinsic (locally produced chemicals)
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What is used to measure GFR?
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inulin
GFR (ml/min)= (urine volume ml/min x inulin conc. in urine mg/ml)/(inulin conc. in plasma mg/ml) |
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Where does reabsorption take place?
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in ALL parts of the nephron
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transfer of fluid and solutes out of the lumen of the nephron through the interstitial space and into peritubular capillaries
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tubular resabsorption
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How much filtrate is reabsorbed?
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99% we only produce 1 to 2 L of urine per day
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no energy required
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diffusion
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requires energy
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active transport
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sodium Na filtration
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99.5% reabsorbed, 67% in proximal tubule, 25% in loop of Henle, 8% in distal tubule
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What regulates sodium reabsorption?
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aldosterone of renin-angiotensin system
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Under normal conditions, how much of the glucose is reabsorbed?
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100%
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What is the transport maximum Tm for glucose?
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375 mg/minute filtered
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A glucose value above 375 will not be reabsorbed and will appear in the urine as a sign of what?
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diabetes
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the secretion of substances from the peritubular capillaries into the lumen of the tubule
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tubular secretion
(to selectively move substances into the lumen for excretion into the urine) |
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What are the most important substances excreted by the tubules?
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hydrogen ions, potassium ions, and some organic anions
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Why is H+ secretion important?
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acid-base balance in the body
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What does aldosterone stimulate?
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Pootassium secretion and sodium reabsorption
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How do the kidneys regulate acid-base balance?
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by secretion of H+ ions into the tubules and the reabsorption of bicarbonate
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the ratio of CO2 to bicarbonate in the extracellular fluid is increased because of the production of CO2 or an increase of H+ formation
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acidosis
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Renal response of acidosis?
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1)increased amounts of CO2 enter the tubular cells from EFC
2)increased amounts of H+ are secreted into lumen of nephron 3)bicarbonate in the lumen of nephron is reabsorbed into EFC |
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net result of acidosis
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H+ ions are secreted into the urine and bicarbonate ions are retained
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the ratio of bicarbonate increases as the pH rises
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alkalosis
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Renal response of alkalosis?
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1)decreased amounts of CO2 enter tubular cells from EFC
2)decreased amounts of H+ are secreted into the lumen of the nephron 3) less bicarbonate is reabsorbed |
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net result of alkalosis
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H+ ions are retained and bicarbonate ions are excreted
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Where are the mechanisms that the kidneys use to regulate urine concentration?
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medullary interstitium, tubules, vasa recta (medullary capillaries)
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Which part of the nephron loop is permeable to water?
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the descending limb
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What part of the nephron loop is IMpermable to water?
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the ascending limb
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Where do sodium and chloride ions diffuse in and out of?
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Na+ and Cl- diffuse into the descending vasa recta and diffuse out of the ascending vasa recta
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What quantity of renal blood flow passes through the vasa recta?
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1 to 2 percent
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Net result of Regulation of Urine Concentration?
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high osmotic concentration ithe medulla
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Low levels of ADH?
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diluted urine because more water is produced in the urine
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High levels of ADH?
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concentrated urine because ADH inhibits formation of water in urine
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How is it decided which things will be retained and which will be expelled in the urine?
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it depends on the body's need to retain or eliminate that substance
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clearance (plasma clearance) of a certain substance
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Clearance (ml/min)= UxV / P
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If a substance is filtered and reabsorbed but not secreted...
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its plasma clearance rate is always less than the GFR (less than 120 ml/min)
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If a substance is filtered and secreted but not reabsorbed...
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its plasma clearance rate is always greater than the GFR (greater than 120 ml/min)
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length of the urethra in men vs. women
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it is significantly shorter in women than in men which means more urinary tract infections for women because bacteria doesn't have to travel as far
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where renin is produced and secreted
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juxtaglomerular apparatus
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kidneys play an important role in regulation of blood pressure via...
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the renin-angiotensin-aldosterone system
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Effects of renal failure
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water and salt retention
acidosis high plasma urea, creatine uric acid coma-due to acidosis death if below 6.8 anemia |
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What senses the need to release renin from the juxtaglomerular cells?
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macula densa (wall of the distal tubule)
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What causes release of renin?
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decrease in blood volume/pressure or an increase in sodium chloride concentration in the distal tubule
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action of hormones vs. nerves
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action of hormones is relatively slow and effects are prolonged, nerve impoulses are faste and effects are short
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Endocrinology
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the study of endocrine glands, the hormones they secrete, and th effects they have on their target cells, or target tissues
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How do hormones influence their target cells?
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chemically binding to integral membrane protein receptors that bind and recognize that hormone
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Generally, how many receptors for a particular hormone does a target cell have?
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2000-100,000
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down-regulation
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when a hormone is present in excess and the number of target cell receptors decreases
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up-regulation
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when a hormone is deficient and the number of receptors increases (makes target tissue more sensitive to hormone)
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Steroids
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all steroid hormones are lipids that are derived from cholesterol
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characteristics of steroids
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lipid soluble and enter cells rapidly
Ex: estrogens, progesterone, testosterone, aldosterone, cortisol |
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biogenic amines
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synthesized by modifying amino acids
Ex: T3 and T4, epinephrine, histamine, serotonin |
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Peptides and proteins
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consist of chaines of 3 to 200 amino acids, synthesized on rough endoplasmic reticulum
Ex: oxytoci, ADH, parathyroid hormone, calcitonin, CCK, gastin |
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Electrical vs. chemical communication of the brain
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nervous system vs. endocrine system, respectively
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General Characteristics of Hormones
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-physiological regulators
-effective in minute quantities -synthesized by living cells -secreted into and carried by the blood (some exceptions) -initiate specific actions |
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Neuroendocrinology
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the study fo the interactions between the nervous system and the endocrine system
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once called the master gland
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the pituitary gland, which is controlled by the hypothalamus
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anterior pituitary secretes 7 hormones
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growth hormone, ACTH, Thyroid stimulating hormone, prolactin, FSH, LH, melanocyte stimulating hormone
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posterior pituitary secretes 2 hormoes
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ADH and oxytocin (milk production)
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Where are the two hormones from the posterior pituitary made?
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in neurosecretory neurons (hormones from anterior pituitary are made in hypothalamus)
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Where are the hormones from the anterior pituitary made?
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made by the hypothalamus and transported in small blood vessels
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releasing hormones or inhibitory hormones
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CRH-stimulates ACTH
TRH-stimulates TSH and prolactin GnRH-stimulates FSH and LH GIH or somatostatin-inhibits growth hormone secretion |
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Giantism and Agromegaly-excess GH
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giantism-excess before puberty
agromegaly-excess inadults |
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major source of IGF-I (insulin-like growth factor)
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liver
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pituitary dwarfism
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lack of GH or GRH before puberty, may also be hypothalamic pituitary tumor
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prolactin
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production of milk
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Thyroid stimulating Hormone-TSH
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T3 and T4
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Follicle Stimulating Hormone-FSH
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stimulates egg to maturity, estrogens, testicular growth
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Luteinizing Hormone-LH
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ovulation, corpus luteum, estrogen and progesterone, males-testosterone
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ACTH or adrenocorticotropin
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normal growth of adrenal cortex and secretion of glucocorticoids, increased lipids and skin pigmentation
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Oxytocin
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milk secretion and uterine contraction
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ADH or Vasopressin
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released in response to rising plasma tonicity or falling blood pressure
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diabetes insipidus
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lack of ADH due to damage of the pituitary or hypothalamus
symptoms: polyuria, polydipsia, dehydration, fever, dry tongue and delirium |
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pheochromocytoma
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tumor of the chromaffin cells in the medulla
symptoms: high blood pressure |
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location of adrenal gland
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on top of the kidney
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adrenal gland secretes?
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catecholamine hormones for sympathetic nervous system, mineral balance, energy balance, and reproductive function
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mineral corticoids (aldosterone)
sodium, potassium, and water balance |
zona glomerulosa
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glutocorticoids (cortisol)
anti-inflammatory, metabolism of carbs, proteins, and fats |
zona fasciculata
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gonadocorticoids (sex hormones)
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zona reticularis
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secretion of chromaffin cells in the adrenal medulla
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catacholamines, epinephrine (80%), norepinephrine (20%), dopamine (<1%)
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Inadequate secretion of glucocorticoids and mineralocorticoids = hypoglycemia, sodium and potassium imbalance, deydration, weight loss, weakness
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Addison's disease (President Kennedy had it)
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hypersecretion of corticosteroids usually from tumor or oversecretion of ACTH, puffy moon face, decreased antibodies, hyperglycemia
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Cushing's syndrome
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Alteration of enzymes required to produce mineralcorticoids, increase production of sex hormones, masculization of females
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Adrenogenital syndrome
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How many thyroid follicles do humans have?
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one million
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What do T4 and T3 make?
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a protein-rich fluid called colloid
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What do T4 and T3 do?
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regulate metabolism and body temperature, growth (hypothalamus and release of TSH regulate)
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What does Calcitonin do?
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lowers blood calcium by inhibiting the release of calcium from bone tissue
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insiffucient secretion of T4 and T3 in infants, stunted growth and thickened facial features
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cretinism (hypothyroidism)
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insufficient secretion fo T4 and T3 in adults
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myxedema
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pathological enlargement of the thyroid gland due to insufficient iodine intake
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goiter
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excessive secretion of T4 and T3, bulging eyes
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Graves' disease
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Calcium and...
1) bones 2) digestive 3) kidneys |
1)release
2)absorb 3)save Vitamin D helps to absorb |
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Calcium distribution in the body
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99% crystalline in bone, .9% in body cells, .1% in EFC
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How does calcitonin lower blood calcium?
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descreases bone resorption by inhibiting the activity of osteoclasts
stimulates urinary excretion of calcium and phosphate by inhibiting their reabsorption in the kidneys |
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T or F: PTH is essential for life
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TRUE!
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PTH increases blood calcium by...
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stimulating activity of osteoclasts to reabsorb bone
stimulates kidneys to reabsorb calcium from filtrate promotes formation of vitamin d |
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usually caused by a tumor in one of the parathyroid glands. characterized by hypercalcemia
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hyperparathyroidism
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used to be caused by remove of parathyroids during thyroid surgery
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hypoparathyroidism
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pancrease exocrine function
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secretion of pancreatic juice (enzymes) goes into intestinal tract
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pancreas endocrine function
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Alpha cells-secrete glucagon
Beta cells-secrete insulin |
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What does Glucagon do?
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elevates blood glucose stimulating glycogenolysis in the liver
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What does insulin do?
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promotes the cells to take up glucose (brain, kidney, intestinal and red blood cells don't need insulin) lowers blood glucose levels and stimulates glycolysis
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lack of ADH from the posterior pituitary
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diabetes insipidus
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insulin deficiency
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diabetes mellitus
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Juvenile onset
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Type I insulin-dependant
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maturity onset
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Type II noninsulin-dependant
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How can juvenile diabetes be complicated?
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by ketoacidosis
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glycosuria
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glucose in the urine
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polyuria
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increased urine volume
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polydipsia
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increased drinking
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What happens to the excess blood sugary during hyperglycemia?
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it is shunted to the polyol pathway, or the organs that don't need glucose
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reactive hypoglycemia
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caused by an exaggerated response of the beta cells to a rise in blood glucose
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gestational diabetes
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happens to 2 -5 % of pregnant women then disappears after delivery
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