Human and Animal Physiology 2024 PDF

Here is the conversion of the document/images into a structured markdown format. ```markdown BSc in Biology – 5. Semester Human and Animal Physiology 2024 # Human og Zoofysiologi * Sara Abreu DVM MSci (Aalborg Zoo) – [[email protected]](mailto:[email protected]) * Trine H. Jensen (Dyrlæge, PhD)...

Here is the conversion of the document/images into a structured markdown format. ```markdown BSc in Biology – 5. Semester Human and Animal Physiology 2024 # Human og Zoofysiologi * Sara Abreu DVM MSci (Aalborg Zoo) – [[email protected]](mailto:[email protected]) * Trine H. Jensen (Dyrlæge, PhD) & * Aage Aalstrup (Dr. Med. Vet, PhD) --- # 06. URINARY SYSTEM AND OSMOTIC BALANCE **LEARNING OBJECTIVES** * Explain the interaction between physiology and anatomy in the larger animal orders. * Explain acid / base regulation, kidney function and water / salt balance in the larger animal orders. * Explain the anatomical-physiological adaptations to life in aquatic environments * Explain the basic functions of the excretory system of the larger animal orders. --- ## Water and Salt Balance * **Kidney:** * Tubular structures that discharge directly or indirectly to the outside world * Production and elimination of aqueous solutions derived from the blood plasma or other extracellular body fluids. Excretion of nitrogenous waste products * Regulation of the composition and volume of the blood plasma and other extracellular body fluids by means of controlled excretion of solutes and water * “Kidney" like organs (= function): gills, salt glands, malpighian tubules * **Urine:** complex solution containing multiple inorganic and organic solutes. * All the constituents of the urine – including the water are drawn from the blood plasma (osmosis!) --- The following describes a diagram (image). The diagram is about urine production. * (A) - shows the Malpighian tubules of insects which relies on Secretion and reabsorption kidney. * (B) - shows the vertebrate kidney relies on filtration and reabsorption **Aqueous solution** at the beginning of "kidney” Most vertebrates, some invertebrates (molluscs, crabs) --- The following describes various diagrams and images: * Diagram A is a basic diagram of the frontal section through left kidney * Diagram B is a frontal section of the cadaver left kidney. * Diagram C is A flowchart of renal circulation Labeled items in the kidney illustration include Renal Cortex, Renal Medulla, Renal Pyramid, Renal pelves etc --- The following describes the functional unit of Mammal Kidney = Nephron * Blood plasma filtration: ultrafiltrate in the Bowman's Capsule lumen * Tubular reabsorption of ~99% of water and most electrolytes. Urea remains * Tubular secretion of various substances via active transport --- The following describes diagrams that represents a Nephron and Collecting System. * Diagram a) Nephron consist of sections colored in purple * Diagram b) Collecting System consist of sections colored in tan. --- The following is a description of illustration titled **Glomerular Filtration, Renal Corpuscle = Bowman's Capsule + Glomerulus** * (B) A human glomerulus positioned in a Bowman's capsule * a Important structural features of a renal corpuscle. * b This cross section through a portion of the glomerulus shows the components of the filtration membrane of the nephron. --- ## Colloid Osmotic Pressure (or Oncotic Pressure) = PCOP * Formed as a result of ultrafiltration, resulting in the accumulation of plasma proteins and other macromolecules in glomerular capillaries. * Pulls water into the capillaries * Filtration of fluid from blood plasma along the capillaries increases the colloidal osmotic pressure in the glomerular capillaries * Pcop increases non-linearly along glomerular capillary --- The following describes the **Glomerular filtration** illustration, including labelled pressures. * The glomerular hydrostatic pressure (GHP) is the blood pressure in the glomerular capillaries. * The net filtration pressure (NFP) is the net pressure acting across the glomerular capillaries. --- ## Kidney facts! * Human kidney form 180 L of filtrate / day! * Humans excrete approx. 1 L of urine per day * All plasma water in a person's body filtrated every 30 min! --- ## Glomerular Filtration Rate (GFR) * The amount of filtrate the kidneys produce each minute * Species differences in single nephron glomerular filtration rate: * The permeability of glomerular capillaries for water * Net filtration pressure * Mammals have relatively high arterial blood pressure compared to non-mammalian vertebrates (fish, amphibians, reptiles, birds) * The size of the glomerulus --- ## Glomerular Filtration Rate (GFR) in non-Mammals * Non-mammalian vertebrates can increase or decrease the number of functional nephrons * Affected by: * Internal changes in blood pressure * Environmental factors that affect fluid and salt balance * Aquatic – in non-mammals acclimatized to different salinities GFR is usually higher than in animals acclimatized to fresh water --- ## Auto-regulation of GFR in Mammals and Birds * Relatively independent of changes in blood pressure, due to adaptation mechanisms within the kidneys * Afferent arterioles are primarily responsible * Rapid renal myogenic response – vasoconstriction * Slower tubulo-glomerular feedback * Protects against high blood pressure, for example due to disease or training --- The following describes information contained in a graph The Mean arterial blood pressure (mmHg) is plotted against GFR (mL min-1) and Renal Blood flow (L Min-1) --- ## Macula densa in the distal tubular epithelium The provided diagrams represents tubular flow from the Glomerulus, distal nephron and the Efferent arteriole * Macula densa releases vasoactive substances which act on the afferent arteriole * Distal nephron * Macula densa cells are sensitive to sodium chloride concentraions of tubular fluid * Efferent arteriole --- ## Macula densa in the distal tubular epithelium * Detects NaCl * Releases vasoactive substances that control vascular tone * Controls renin excretion from the granules of the walls of afferent arterioles **Renin-Angiotensin-Aldosterone System** --- The following describes the diagram related to the **Renin-Angiotensin-Aldosterone System** Various effects on the body are depicted in the diagram, which ultimately leads to homeostasis after the signal “stimulus” --- ## Water and Salt Balance * Anti-diuretic hormone (ADH) = vasopressin * Regulates water turnover in mammal kidneys (stimulates the absorption of water) * Aldosterone * Increases reabsorption of sodium * Atrial Natriuretic Peptide (ANP) (counteracts aldosterone) * Decreases reabsorption of of sodium * Parathyroid hormone * Excreted when $Ca^{2+}$ decreases * Calcitonin * Excreted when $Ca^{2+}$ increases * Calcitonin prevents hypercalcemia and dissolution of the skeleton --- ## Proximal and Distal Convoluted Tubules * Reabsorb all the useful organic nutrients in the filtrate; * Reabsorb more than 90% of the water in the filtrate; * Secrete into the tubule lumen any waste products that did not pass into the filtrate at the glomerulus * Thin segment – only in mammals and birds The diagram provided illustrates the general section and some detailed sections of the Proximal Segment and Distal segment of a Nephron Loop. --- Fig 26-12. - Active reabsorption: Glucose, other simple sugars, amino acids, vitamins, ions (including sodium, potassium, calcium, magnesium, phosphate, and bicarbonate) - Passive reabsorption: Urea, chloride ions, lipid-soluble materials, water - Secretion: Hydrogen ions, Ammonium ions,creatinine, drugs and toxins --- **Proximal and Distal Convoluted Tubules – Permeability to Water** The diagram describes the urine formation in amphibians during diuresis (rapid urine flow) Fluid was sampled for analysis by use of minute pipettes inserted into the nephrons --- ## Distal Convoluted Tubules * Fish, amphibians and reptiles can produce urine with an osmolality that is less than 10% of the plasma osmolality (0.1 vs 0.3 in mammals) * The diagram provided describes Tubular Secretion and Solute Reabsorption by the Distal Convoluted Tubule (DCT). * Reabsorption: Sodium ions (variable), chloride ions, Calcium ions (variable), Water (variable) * Secretion: Hydrogen ions, ammonium ions, Creatinine, drugs, toxins --- ### Collecting Duct * Receives tubular fluid from many nephrons and carries it toward the renal sinus. * Water permeability and solute loss in the collecting system is hormonally regulated by aldosterone and antidiuretic hormone. * Important reabsorption and secretions to control pH of body fluids! The diagram provides an overview of the features of the structures associated with collection of urine. Proximal Convoluted tubule and renal corpuscles --- **(A) Initial condition** ## Effect of the Na/K pump (and K/Cl co-transport) in the Loop of Henle * The walls of the ascending limb are essentially impermeable to water and are drawn thick to symbolize that. * (B) - Processes that generate the single effect * Active transport of NaCl out of the fluid in the ascending limb dilutes that fluid and concentrates the interstitial fluid. The walls of the descending limb are permeable to water, so the fluid inside becomes concentrated by losing water osmotically to the interstitial fluid and sometimes by gaining Na+ and Cl by diffusion. * (C) - The single effective is the difference in Osmotic pressure --- ## Effect of the Na/K pump (and K/Cl co-transport) in the Loop of Henle. * Diagram depicts some of the osmotic balance of various elements and compounds with the Thick ascending limb being impermeable to water --- # LOOP OF HENLE **Countercurrent Multiplication!** --- This is the production of low volumes of hyperosmotic. Diagram illustrates sections that are permeable to water in collecting duct. --- Diagram shows graphs of the relation maximum urine concentration and relative medullary thickness across a range of mammals.. Diagram (A) shows cortex, medulla. renal pelvis and ureter --- Diagram provides a representation of **Nitrogen Excretion** for different types of animals. --- The following diagrams depict: * Left - Illustration of **Bird Kidney** * Right - mammalian-hype (looped) nephron --- The following diagrams illustrates, a diagram of Nephron segments labeled for different vertebre families --- ## Kidney in non-mammalian vertebrates * Hagfish (Slimål) * Glomeruli but no tubules, so Bowman capsule goes directly into collecting tube. The kidneys secrete ions, not much osmoregulation * Freshwater fish * Larger glomeruli than saltwater fish. * Some have no glomeruli, with only small amounts of urine, and ammonia excreted through the gills * Cartilaginous Fish * Urine not concentrated, retain urea (to remain hyperosmotic) * Amphibians and Reptiles * No loops of Henle --- The following compares saltwater and freshwater fish * **Challenges saltwater**: * Water in due to osmotic gradient * Salt loss to surrounding freshwater * **Characteristics saltwater**: * Skin - low permeability to salt and water * Does not drink water * Produces diluted urine * Gills (=kidneys) absorb Na+ and Cl- from water * saltwater * Hagfish and cartilaginous fish: plasma is iso-osmotic/slightly hyperosmotic vs seawater * Cartilaginous fish have lower concentrations of electrolytes compared to eels, but on the other hand, they have osmolytes such as urea and trimethylamine oxide * Bony fish are hypotonic to saltwater – they lose water through the gills, but they drink, thereby also gaining salt. They can excrete salt via the gills. --- Several Teleost Fishes are illustrated on the section of the kidney, including different kidney structures as well. * Active tubular secretion of MgSO4 (Magnesium Sulphate) in urine * Salts and Water in Seawater ingested. (source of net water gain) --- Diagram with illustration of water flow is different fish * **Saltwater**: Active chloride elimination, sodium diffuses from blood to sea water, through paracellular channels * **.**Freshwater: Active chloride uptake, sodium diffuses from water to blood, through proton pumps and Sodium channels in the apical membranes --- **Migrating fish - Gills** * When a fish moves from freshwater to saltwater, Na+ in plasma increases, which stimulates cortisol and growth hormone excretion * Cortisol causes the Na/K ATPase and NKCC (Na-K-2Cl cotransporter) activity in the gills to increase * This causes the Na+ secretion to increase from the gills until plasma levels are normal again * Hormone prolactin stimulates adaptations from salt to freshwater --- Diagram illustrates that acclimation of seawater vs freshwater impacts filtration rates --- * Water channels – aquaporins * Moist highly permeable skin water via passive diffusion, active transport of salts from the aquatic environment into the animal * Large volume lymphatic system and oversized bladder, the epithelium can transport Na+ and Cl-