exam 4 review

• Gas solubility in the plasma makes up a portion of the total arterial oxygen content. Less than 2% of oxygen is dissolved in the plasma. Plasma O2 determines the percent saturation of hemoglobin
• • Oxygen dissolved in the plasma is influenced by: surface area, airway resistance, lung compliance, diffusion distance, and rate and depth of breathing
• Left shifts occur when there is an increase oxygen binding affinity, and less oxygen is released. An example is fetal hemoglobin.
• Right shifts occur when there is a decrease in oxygen binding affinity, and more oxygen is released
• Some things that can shift oxygen to the right are increased temperature, decreased ph, and increased PCO2 (flip these to get left shift)
• A right shift is caused by increased CO2, increased temp, decreased pH (increased amount of H+), and 2,3-DPG
• A left shift is caused by decreased CO2, decreased temp, increased pH (low amount of H+), and no 2,3-DPG
• The RCC is in the medulla as it (the medulla) initiates respiration
• The VRG has an area known as the pre-Bötzinger complex and has neurons that fire continuously similarly to baroreceptors in the heart.
• the firing of the pre-Bötzinger complex makes sure the airway remains open
• Central chemoreceptors in the medulla respond to H+ in the CSF (cerebrospinal fluid)
• The DRG deals with quiet breathing (inspiration) while the VRG deals with forced breathing (expiration)
• Plasma water and solute in glomerulus move into Bowman’s capsule and is a non-selective process. However if the solute is bigger than the endothelial pores in the capillary lumen it won't be filtered in
• The filtration barrier is made up of glomerular capillary endothelium, the basal lamina, and bowman’s capsule (w/ foot processes of podocytes between the basal lamina and lumen of bowman’s capsule epithelium)
• Solute passes through the pores of the endothelial cells to the basal lamina, then they pass through the filtration slits to get to the bowman’s capsule epithelium
• The epithelium does not allow red blood cells to pass and only allows plasma. If a person pees blood it means there is a kidney infection/puncture
• Local Control

  • Plays a more important role than systemic control
  • *Tubuloglomerular feedback *: includes the JG apparatus which is a negative feedback loop to maintain GFR by macula densa cells releasing paracrine signals to affect afferent arterioles diameter. This feedback is not 100%
  • Myogenic response (afferent arteriole)
• Systemic/ reflex control

  • Its main function is to keep water and maintain blood pressure
  • Neural: sympathetic , norepinephrine, alpha receptors (constrict afferent arterioles)
  • Hormonal: ANG II (vasoconstrictor) and ANP (dilates afferent, relax mesangial cells)
• 1. Hormones responsible for regulating water reabsorption.

  • ANG II and ANP
  • ANG II allows for vasoconstriction and Na+ reabsorption casing water reabsorption. ANP is a vasodilator (of the afferent*) relaxing mesangial cells
• Glucose in the kidney is reabsorbed along with Na+. This is done using the SGLT symporter and GLUT carrier protein
• Diabetes is a condition in which glucose is found in the pee (is secreted) which is not a good thing as the concentration of glucose in the pee should be 0
• Membrane protein responsible for glucose reabsorption

  • SGLT  ( glucose/ Na+ symporter) which uses secondary active transport and GLUT protein (glucose carrier) facilitated diffusion aka passive transport
• organic anion secretion

  • Uses tertiary transport (active transport) using the OAT
  • The goal is to move the anion out of cell (secretion) with energy from decarboxylate gradient
• Reabsorption is the process of moving substances from filtrate in lumen in tubule back to blood flowing in peritubular capillaries around the nephron
• Secretion selectively removes molecules from the blood and adds it to filtrate in the tubule lumen
• Excretion is the movement of substance out of the body through urination
• Filtration is the process by which fluid and solute are forced from glomerular capillaries into bowman’s capsule bc of pressure gradient across filtration membrane
• Tmax is the max rate where substances can be reabsorbed by tubules. Is a point where all carriers at the time are saturated
• Clearance is the amount of volume of plasma cleared at a certain point in time
• GFR is the amount of fluid filtered from glomerular capillaries to the bowman’s capsule per unit time. Measures kidneys ability to filter out waste from blood
• Renal calculations

  • Clearance = Ex / plasma [x]
  • Remember GFR = Clearance
  • Excretion (Ex) = urine flow x urine[x]
  • Excretion (Ex) = Filtration (Fx) - Reabsorption (Rx) + Secretion
  • Tmax = GFR x RT (renal threshold)
  • R = Filtration (Fx) - Excretion (Ex)
• Hormones responded to blood pressure change

  • Vasopressin (ADH): it causes the vasoconstriction
  • ANG II: increases BP
  • ANP: decreases BP
  • Aldosterone:Increases BP
  • Renin: is made because of low BP
• RAS Pathway

  • Was called Renin, ANG II, Aldosterone System
  • It is a pathway that responds to a low BP in aims to increase it

  A) Renin

  B) Aldosterone

  C) Vasopressin

  D) ANG II in plasma

  E) low blood pressure

  F) Aldosterone

  
• ADH function


  Causes vasoconstriction to promote water retention in kidneys, this increases blood pressure and increases blood volume. Is released by pituitary
• ANGII function


  Causes vasoconstriction which ends up increasing blood volume and blood pressure
• Aldosterone function

  • Aldosterone is the hormone released by the adrenal cortex and it targets P cells
  • It reabsorbs Na+ and it secretes K+ ( gets Na+/K+ pump to work), causing an increased blood volume and increased blood pressure
  • In all, it regulates blood pressure by regulating Na+ reabsorption
• ANP function

  • Inhibits renin and aldosterone that are found in the RAS Pathway
  • Promotes secretion of Na+ and water (increasing urine flow)
  • It decreases blood volume and blood pressure (vasodilation)
  • Comes from myocardium in the heart
• Severe dehydration map

  • Increased osmolarity and increased blood pressure
• Hypothalamic mechanism

  1. Increased osmolarity triggers vasopressin release

  2. Increased water reabsorption

  3. Decrease in osmolarity
• Severe Dehydration pathway

  1. Activated due to low blood pressure signal

  2. Aldosterone inhibited by high osmolarity

  3. Less aldosterone and low GFR

  4. Less sodium reabsorption

  5. Increases blood pressure & lowered osmolarity