Introduction Flashcards
3 major functions of the kidney
1) Secrete wastes and foreign substances
2) Homeostasis
3) Endocrine
What wastes and foreign substances do the kidneys secrete?
Wastes: urea, creatinine, and uric acid
Foreign Substances: drugs and food additives
What are the kidney’s roles in homeostasis?
Regulate pH, water, and electrolyte balance
What endocrine functions do the kidneys have
Secrete renin, erythropoietin, and activate Vitamin D3
Function of Renin Secretion
Blood pressure regulation
Function of Erythropoetin Secretion
RBC production
Function of activating Vitamin D3
Regulate calcium and phosphorus levels
3 General parts of a nephron
Vascular, Tubular, and Combined Vascular/Tubular components
What structures make up the vascular component of the nephron
Afferent arteriole, Glomerulus, Efferent arteriole, and Peritubular capillaries
Function of the afferent arteriole
To carry blood to the glomerulus
Function of the Glomerulus
A group of capillaries that filter protein-free plasma into the tubular component
Function of the Efferent arteriole
To carry blood away from the glomerulus
Function of the peritubular capillaries
To supply the renal tissue with blood; play a role in tubular resorption and secretion
What structures make up the tubular component of the nephron
Bowman’s capsule, Proximal Tubule, Loop of Henle, and Distal tubule and collecting duct
Function of Bowman’s capsule
To collect filtered fluid from the glomerulus
Function of the Proximal Tubule
Site of uncontrollable reabsorption and secretion of selected substances
Function of the Loop of Henle
Establish an osmotic gradient in renal medulla that is important in the kidney’s ability to produce urine with varying concentrations
Function of the Distal Tubule and Collecting Duct
Site of variable, controlled resorption of sodium and water; secretion of potassium and hydrogen ions; fluid exiting is urine
What makes up the Combined vascular/tubular component?
Juxtaglomerular apparatus
Function of the Juxtaglomerular apparatus
Prod. Substances involved in kidney function
What are the two types of nephrons?
Cortical and Juxtaglomerular nephrons
What are the two regions of the kidney?
Cortex and the Medulla
Where do the Cortical nephrons lie?
Outer cortex
How does the Loop of Henle make contact with the cortical nephron?
It dips slightly into the medulla
What do the peritubular capillaries present as in the cortical nephron?
Complex network woven around the tubule
Where do the Juxtaglomerular nephron lie?
In the inner part of the cortex, next to the medulla
How does the loop of Henle make contact with the juxtaglomerular nephron?
Its long loops plunge deep into the medulla
What do the peritubular capillaries in the Juxtaglomerular nephron present as?
They form hairpin loops called vasa recta
What are the three basic renal processes involved in urine prod.
Tubular Secretion, Tubular Resorption, and Glomerular Filtration
What is Glomerular Filtration
Process where protein free plasma is filtered from the glomerulus into Bowman’s capsule
All blood constituents except______ & ______ non-selectively enter the tubular component of the nephron
Plasma proteins and Blood cells
How much glomerular filtrate is produced from a 10 kg Beagle in a minute
37ml (3.7 ml/kg/min)
How much glomerular filtrate per minute and per day are produced
125mL per hour and 180 Liter per day
Tubular resorption is
The selective movement of filtered substances from the tubular lumen into the peritubular capillaries
How much filtered substance is resorbed and excreted?
99% is resorbed, 1% is excreted as urine
Tubular secretion is
Selective movement of substances from the peritubular capillaries into the tubular lumen
What is the best way to measure Kidney function
GFR (Glomerular Filtration Rate)
What substance gets filtered but not resorbed nor secreted?
Insulin
If 100% of insulin is not filtered out, what condition will be caused?
Diabetes
What substance gets filtered and completely resorbed but not secreted?
Glucose
What substance gets filtered and partially resorbed, but not secreted
Urea
What substance gets filtered and secreted, but not resorbed
H+ Ions
