phypa

• Kidney


  • Retroperitoneal Organ: Area outside or behind the peritoneum
  • Almost the size of a human fist
• Important Parts of the Kidney

  • Renal Cortex: Outer part
  • Renal Medulla: Inner part
• Composition of Medulla


  • Medullary Pyramid: Made up of nephrons
  • Hilum: bean-shaped configuration with a concave medial margin and a convex lateral margin
• Hilum


  • Renal Artery: Supplies blood
  • Renal Veins: Collects blood that has been filtered
  • Renal Pelvis: Fusion of collecting ducts would cause urine to flow via ureter, into a bladder, through urethra
• Micturation


  Also known as urination; Action or urinating
• Sterile urine comes into contact with the external environment
• Urethritis


  When things from the outside reach the urethra; infected urethra
• Cystitis


  When the infection climbs into the bladder (Worst case scenario: infection could climb back into the urether and into the kidneys)
• How to prevent infections

  • Don't inadvertently get pathogens into the urethra
  • Cleaning after urination
  • Urination after sexual intercourse can decrease infection
• Components of Micturation


  • Parasympathetic: Controls bladder contraction and the passage of urine
  • Sympathetic: Regulates the process of urine storage in the bladder
  • Somatic: Process of urination controlled by voluntary skeletal muscles
• Pontine Micturation Center


  Triggers the involuntary part of the micturation reflex
• Uretero-renal Reflex


  Reflexive response involving the ureters and the kidneys
• The ureter's ability to constrict (painful) helps protect the kidneys from harm due to urine backup, particularly when faced with conditions like kidney stones where pressure can become dangerously high
• The ureter can prevent the inadvertent release of pressure back to the renal pyramids, thus avoiding intense pain caused by kidney stone movement
• When urine backs up into the kidney, the ureter acts as a barrier to prevent damage. This is important because high ureteral pressure can potentially harm the kidneys. In cases of kidney stones, the ureter can constrict to prevent pressure buildup, thereby protecting the kidneys from damage caused by urine backup into the renal pyramids.
• Main concerns


  • Female urethera: Shorter
  • Male urethrea: Surrounded by the structure called prostate
• Benign Prostatic Hyperplasia (BPH)


  Enlargement of the prostate gland that can lead to compression of urethra, which is a common condition in aging men
• Glomerulus


  • Beginning part of nephron
  • Responsible for filtration of blood as it passes through the kidneys
  • Located within the Bowman's capsule of the kidney's nephron
• Urine Formation


  1. Blood from the renal arteries branches into numerous arterioles, eventually entering the afferent arteriole as it travels towards the glomerular capillaries

  2. Within the glomerulus, the capillaries possess a structure that allows for the movement of filtrate or plasma, facilitating the removal of waste products

  3. Blood then exits through the efferent arteriole
• Urine Formation Steps


  • Glomerular Filtration: Occurs in the renal corpuscle where substances are filtered from the blood into the renal tubules. It's non-discriminatory, meaning it doesn't selectively filter substances.
  • Tubular Reabsorption: Essential substances such as water, glucose, and ions are reabsorbed from the filtrate back into the bloodstream
  • Tubular Secretion: Actively transporting certain substances from the blood into the filtrate
• Urea


  • Product of the metabolism of amino acids, so anything that has nitrogen in general
  • When excreted is partially reabsorbed as well
  • Kidney maintains a level of urea (waste product) because it is a substance needed to concentrate the urine
  • Used as a salt in the kidney to reabsorb water back from the filtrate into the kidneys
• Azotemia


  Problem where the amount of urea being absorbed or retain is too much. "Azo" meaning a word related to nitrogen
• Uremia


  Problem where the amount of urea being absorbed or retain gets really extreme (Toxic)
• Afferent arteriole relaxed


  Glomerular Filtration Rate (GRF) increases when Renal Plasma Flow (RPF) increases
• Afferent arteriole constricted


  Glomerular Filtration Rate (GRF) decreases when Renal Plasma Flow (RPF) decreases
• Efferent arteriole constricted


  Increase in Glomerular Filtration Rate (GRF)
• Nephron


  • Functional unit of the kidney
  • Once destroyed, it cannot be regenerated
  • Physiological preservation: The ability of the remaining kidney to compensate for the loss or damage of the other kidney
• Types of Nephron


  • Cortical Nephrons: Has a length that only reaches mainly to the cortex, for efficient exchange
  • Juxtamedullary Nephrons: Its structure has a length that extends deeply into the medullary spaces of the kidney, capable of concentrating urine
• Main Structures of Nephrons

  • Proximal Convoluted Tubules (PCT)
  • Distal Convolutes Tubules (DCT)
  • Loop of Henle
  • Collecting Duct
• Bowman's Capsule


  Portion of the nephrons that receives the glomerulus, start of the functional unit (Structure above) known as nephrons
• Juxtaglomerular Apparatus


  Has censors for the particular composition of urine, when the composition changes, the juxtaglomerular apparatus would begin releasing a substance
• Kidney filters urine, and this urine is removed from the body via the urinary system
• Urine Formation Process


  • Filtration
  • Reabsorption
  • Secretion
• Secretion occurs on top of filtration to ensure that substances needing removal are extracted from the blood as it passes through the glomerulus
• Nephron is the portion of the kidney that does all of the removing of substances and all of the balancing of substances
• Two Main Transport Mechanism in Nephrons

  • Paracellular Transport: The movement of substance that passes through between the two cells
  • Transcellular Transport: The movement of substances across a cell, passing through its cytoplasm or cellular compartments
• Sodium Pump


  Uses ATP in order to keep on pumping sodium out into the portion called lumen
• Two Types of Transcellular Transport

  • Symporter: When a lot of sodium is introduced into the lumen (gutter), sodium ions tend to migrate back into the cell. This movement of sodium ions back into the cell often occurs alongside the transport of other substances such as glucose, amino acids, lactate, and phosphate.
  • Antiporter: As sodium enters hydrogen is removed
• Proximal Convoluted Tubules (PCT)

  • Responsible for the reabsorption of water, ions, glucose, and other nutrients from the filtrate back into the bloodstream
  • Sodium and water reabsorption (2/3)
  • Carbonic anhydrase (CA): Enzyme that converts CO2 and H2O into carbonic acid and vise versa
  • Brush Border Enzymes (e.g., Peptidases, Lipases, and Phosphatases): Involved in the breakdown of larger molecules such as peptides, lipids, and phosphates into smaller, absorbable components
• Distal Convolutes Tubules (DCT)

  • To absorb sodium, fluoride but not water
  • Inhibiting the sodium chloride cotransporter can lead to a lower calcium concentration in the urine, which can sometimes prevent the formation of kidney stones