Lab Exam 4 Flashcards
substances from the blood plasma that have been filtered out
urine
a nitrogenous waste product filtered out by the kidneys, it is a by-product of protein metabolism
urea
by-product of nucleic acid metabolism
uric acid
Definition of erythropoietin in regards to the kidneys:
When O2 is low, the kidneys will secrete erythropoietin, a hormone that stimulates red blood cell production in the bone marrow.
Definition of the nephron:
The functional unit of the kidneys.
blood flows from the renal arteries into this structure, then into the 1st capillary bed
afferent arteriole
blood leaving the glomerulus flows into this structure, then into the 2nd capillary bed
efferent arteriole
ball like network of capillaries in the kidney; site of filtration
glomerulus
capsule-shaped membranous structure surrounding the glomerulus of each nephron in the kidneys
bowman’s capsule
begins at the renal pole to the beginning of the loop of Henle, reabsorbs filtrate
proximal tubule
responsible for the regulation of K+, Na+, Ca2+, & pH.
distal tubule
consists of a series of tubules & ducts that physically connect nephrons to a minor calyx or the renal pelvis
collecting duct
peritubular capillaries in the kidney that dip into the medulla & then go back up to the cortex, forming hairpin loops
vasa recta
portion of the renal tubule that creates dilute urine & sets up the conditions needed to make concentrated urine
ascending limb of loop of henle
bulk movement of fluid from the blood into the nephron
filtration
returning substances from the filtrate back to the blood
reabsorption
movement of individual ions (H+, K+) from the blood into the nephron tubule
secretion
Increases Na+ reabsorption, increases K+ secretion
aldosterone
fluid that leaves the blood in the glomerulus & enters Boman’s capsule –> contains H2O, organic molecules, ions, and NO PROTEINS!
filtrate
How much filtrate does the kidney produce and excrete daily?
180L from the blood every day. Only 1-2L is excreted from the body daily
Definition of obligatory water loss:
a minimum of 400 mL per day must be excreted to remove waste products from metabolism.
Definition of hyperkalemia & hypokalemia:
When K+ levels are too high & above normal range. Hypo is below normal range.
Definition of vasopressin (AKA antidiuretic hormone):
will increase water reabsoprtion
Definition of atrial natriuretic hormone:
this is the agonist to vasopressing & aldosterone –> reduces water & Na+ reabsoprtion, and increases water excretion
Which 8 organic molecules get filtered out of the blood and become part of the filtrate?
- glucose
- Co2
- amino acids
- vitamins
- nitrogenous wastes
- small proteins
- bicarbonate
- lipids
Which category of molecules in the plasma is prevented from passing through the glomerular filter?
plasma proteins –> albumins, transferrin, fibrinogen
Which major component of the blood (plasma vs. formed/cellular elements) contains substances that are completely prevented from passing thru the glomerular filter?
Formed elements
Water will move across a membrane to a location with more of these.
osmotically active solutes
If only water is being reabsorbed (e.g., leaving) from the descending limb, what happens to the concentration or osmolarity of the filtrate from the top of the limb to the bottom?
Osmolarity increases in the filtrate
If only ions are being reabsorbed (e.g., leaving) from the ascending limb, what happens to the concentration or osmolarity of the filtrate from the bottom of the limb to the top?
Osmolarity decreases in the filtrate
Which must move first-water from the descending limb or ions from the ascending limb? Why?
Ions must enter the blood first because water always moves by osmosis towards solutes.
If the nephron is the effect, what are the stimuli? List all 3.
↑ or ↓ total blood volume
↑ or ↓ blood osmolarity
↑ or ↓ pH (H+ concentration)