1 / 54

Osmoregulation

Osmoregulation. Chapter 44. Osmoregulation. Balance of water & solute concentration Intracellular & extracellular Ions (solutes) Na +1 , Cl -1. Osmolarity. Hyperosmotic Hypoosmotic Isoosmotic Normal saline (0.9%) 5% dextrose. Selectively permeable membrane. Solutes. Water.

bmark
Download Presentation

Osmoregulation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Osmoregulation Chapter 44

  2. Osmoregulation • Balance of water & solute concentration • Intracellular & extracellular • Ions (solutes) • Na+1, Cl-1

  3. Osmolarity • Hyperosmotic • Hypoosmotic • Isoosmotic • Normal saline (0.9%) • 5% dextrose

  4. Selectively permeablemembrane Solutes Water Hypoosmotic side: • Lower solute concentration• Higher free H2O concentration Hyperosmotic side: • Higher solute concentration• Lower free H2O concentration Net water flow

  5. Osmoregulation • Osmocomfomers • Body fluids have same concentration as environment • Ocean invertebrates • Osmoregulators • Constant blood osmolarity • Vertebrates

  6. Osmoregulation

  7. 50 µm (a) Hydrated tardigrade (b) Dehydrated tardigrade

  8. Nitrogenous wastes • Proteins, DNA & RNA contain nitrogen • Break downs-waste (NH2) • Aquatic animals • NH3 • Mammals, amphibians • Urea • Birds, reptiles, insects • Uric acid

  9. Nitrogenous wastes

  10. Urea • Uric acid

  11. Most aquatic animals, including most bony fishes Many reptiles (including birds), insects, land snails Mammals, most amphibians, sharks, some bony fishes Nitrogen wastes Ammonia Urea Uric acid

  12. Excretory process • Excretory systems • Regulate solute concentrations • Produce urine • Refine filtrate from body fluids

  13. Excretory process • Filtration • Blood (body fluids) is filtered • Forms filtrate (urine) • Reabsorption • Ions & nutrients are recovered • Returned to body from filtrate

  14. Excretory process • Secretion • Wastes/water from capillaries to filtrate (urine) • Excretion • Release filtrate (urine) from body • Release nitrogenous metabolites

  15. Filtration Capillary Filtrate Excretory tubule Excretion Reabsorption Secretion Urine Excretion

  16. Excretory Organs Kidney Structure Nephron Types Renalcortex Corticalnephron Juxtamedullarynephron Figure 44.12a Renalmedulla Posteriorvena cava Renalartery Renal arteryand vein Kidney Renalvein Aorta Renalcortex Ureter Ureter Urinarybladder Renalmedulla Urethra Renal pelvis

  17. Anatomy • Kidney • Ureter • Bladder • Urethra • Renal artery/vein • Blood supply of kidney

  18. Anatomy • Renal cortex • Outside of kidney • Renal medulla • Inside of kidney (hypertonic) • Renal pelvis • Funnel shaped • Ureter meets kidney

  19. Kidney

  20. Anatomy • Nephron: • Functioning unit of kidney • 1 million in each kidney • Glomerulus • Bowman’s capsule • Proximal (convoluted) tubule • Loop of henle • Distal (convoluted) tubule

  21. Nephron

  22. Kidney

  23. Kidney

  24. Pathway

  25. Pathway through kidney • Blood forced into glomerulus • Bed of capillaries • Blood cells & proteins are too large • Plasma goes through with minerals & water • Filtrate • Enters Bowman’s capsule • Proximal tubule • Located in renal cortex

  26. Pathway through kidney • Enters loop of Henle • In the loop goes deep in the renal medulla • Fluid returns • Distal tubule • Drains into collecting duct • Goes into renal pelvis (urine) • Ureter

  27. Pathway through kidney

  28. Juxtamedullary nephron Cortical nephron Nephron Renal cortex Collecting duct Renal medulla To renal pelvis (c) Nephron types

  29. Nephron

  30. Pathway through kidney • Capillaries surround the loop • Reabsorb water & ions

  31. Glomerulus Afferent arteriole from renal artery Bowman’s capsule 10 µm SEM Proximal tubule Peritubular capillaries Nephron Efferent arteriole from glomerulus Distal tubule Branch of renal vein Collecting duct Descending limb Loop of Henle Ascending limb Vasa recta (d) Filtrate and blood flow

  32. Pathway through kidney • 1000-2000L of blood flow through a day • 180 L of water a day • Urinate only 1.5 L per day • Reabsorb glucose, aa, vitamins & water • Excrete wastes, harmful substances, H+ & water • Maintain homeostasis (blood volume, pH electrolytes & BP)

  33. Regulation diagram

  34. Closer look • Proximal tubule • Most nutrients reabsorbed to blood • NaCl, H2O, HCO3-1 reabsorbed to blood • NH3, H+1 secreted into the tubule from blood

  35. Bowman’s Capsule and Proximal Tubule

  36. Closer look • Loop of Henle • Descending loop water is reabsorbed • Ascending loop NaCl is reabsorbed • Longer loop-more NaCl is absorbed

  37. Closer look • Distal tubule • Regulation of K+1 & NaCl here • Depends on body’s needs • K+ is secreted into tubule • NaCl reabsorbed into tubule

  38. Loop of Henle and Distal Tubule

  39. Closer look • Collecting duct • NaCl can be reabsorbed here • Some urea diffuses out of tube • Remaining filtrate passes as urine

  40. Collecting Duct

  41. Regulation diagram

  42. Proximal tubule Distal tubule NaCl Nutrients H2O HCO3– H2O K+ HCO3– NaCl H+ H+ NH3 K+ Filtrate Transport CORTEX Loop of Henle NaCl H2O OUTER MEDULLA NaCl NaCl Collecting duct Key Urea NaCl Active transport H2O INNER MEDULLA Passive transport

  43. Regulation of kidney • ADH (antidiurectic hormone) • Vasopressin • Released by posterior pituitary gland • Released in response to increased solute concentration in plasma • Dehydrated or eating salty foods • Distal tubule/collecting duct become more permeable to water • Decreases the amount of water in urine • Reabsorbs more water

  44. Osmoreceptors in hypothalamus trigger release of ADH. Thirst Hypothalamus Drinking reduces blood osmolarity to set point. ADH ADH Pituitary gland Increased permeability Distal tubule H2O reab- sorption helps prevent further osmolarity increase. STIMULUS: Increase in blood osmolarity Collecting duct Homeostasis: Blood osmolarity (300 mOsm/L) (a)

  45. ADHreceptor LUMEN Collectingduct COLLECTINGDUCT CELL ADH Secondmessenger cAMP ADH Proteinkinase A Storagevesicle Exocytosis Aquaporinwaterchannel H2O H2O

  46. Effect of ADH

  47. Regulation of kidney • Low blood volume • Juxtaglomerular apparatus • Tissue located near artery supplies blood to glomerulus • Secretes renin (enzyme) • Angiotensinogen to angiotensin I • Angiotensin I to angiotension II • Causes blood vessels to constrict • Causes release of aldosterone

  48. Regulation of kidney • Aldosterone • Released by the adrenal cortex • Due to low sodium levels • Due to low blood volume • Stimulates distal tubules/collecting ducts to reabsorb sodium • Chlorine & water follow • Stimulates potassium to be excreted

  49. Regulation of kidney • Aldosterone • Increases serum sodium levels • Increases water (blood volume) • Decreases serum potassium levels • ACE inhibitor • Blood pressure medication • Blocks the affects of aldosterone

  50. Liver Distal tubule Angiotensinogen Renin Aldosterone Angiotensin I Juxtaglomerular apparatus (JGA) ACE Angiotensin II STIMULUS: Low blood volume or blood pressure Adrenal gland Aldosterone Arteriole constriction Increased Na+ and H2O reab- sorption in distal tubules Homeostasis: Blood pressure, volume

More Related