Exam 1: Lecture 2 Flashcards
Crucial functions of the kidneys?
maintaining overall fluid and electrolyte and acid-base balance
filtering waste materials and reabsorbing needed materials
creating hormones that help produce red blood cells, promote bone health, and regulate blood pressure
Where is the glomeruli located?
Cortex
The ________ contains the majority of the nephrons (tubules), the main functional component of the kidneythat filters fluid from blood.
medulla
enlarged, cup-like portion of the ureter. Renal artery enters and ureter leaves through the renal hilus.
The renal pelvis
There are about _______ million nephrons in each kidney.
1.3
Each __________ is composed of: arenal corpuscle(glomerulus within Bowman’s capsule)
nephron
______ % of the blood leaving the left ventricle of the heart enters the kidneys via the renal arteries.
20-25
Blood passes through the kidneys at a rate of __________ , or _____ ml/min/kidney.
~1200 ml/min
600
Your blood circulates through your kidneys many times a day. In a single day, your kidneys filter about
______ liters of blood. Most of the water and other substances that filter through your glomeruli are returned to your blood by the tubules.
Only ________ become urine.
140
600 – 1800 mL
Urine formation consists of what 3 processes?
-Plasma filtration at glomeruli
-Reabsorption
-selective secretion by renal tubules
After filtration, the fluid
is called the ….
ultrafiltrate
Hydration and Ion Balance depends on what system?
Renin/Angiotensin/Aldosterone System (RAAS)
What is the driving force behind glomerular filtration?
High hydrostatic pressure of afferent arteriole.
Works with Bowman’s capsule to create a shield of negativity to retain proteins.
______________ is where Needed components (water and solutes) are returned to the body
Reabsorption
wastes are removed from the bloodstream and excreted in urine after adjusting acid-base equilibrium.
Secretion
Both reabsorption and secretion involve what type of transport?
passive and active transport
Some substances are completely reabsorbed or secreted; other depend on plasma level – called ___________ substances.
threshold
what is needed for active transport?
carrier proteins and energy
Glucose does not appear in the urine until plasma concentration exceeds ________ mg/dL.
160 – 180 mg/dL.
Examples of threshold substances
potassium, amino acids, ascorbic acid, urea (low threshold), but we are usually referring to glucose (high threshold)
reabsorbs ions, water, nutrients: removes toxins and adjusts filtrate pH
Proximal convoluted tubule
selectively secretes and absorbs different ions to maintain blood pH and electrolyte balance
distal tubule
reabsorbs solutes and water from the filtrate
collecting duct
aquaporins allow water to pass from the filtrate into the interstitial fluid
descending loop of Henle
reabsorbs Na+ and Cl- from the filtrate into the interstitial fluid
ascending loop of Henle
-The most essential substances in the filtrate are reabsorbed in the first half of the proximal convoluted tubule along with 70% of the water, K, Cl and urea (passive).
-glucose, amino acids/proteins, phosphate, lactate and citrate, Mg2+ , Ca2+ are actively transported.
Reabsorption in the proximal convoluted tubule
uses sodium/proton exchangers to carry sodium coupled with another solute across cell walls using membrane proteins.
Indirect active transport or co-transport
> 80% of filtrate reabsorption here with 67% of water and almost all glucose, lactose, amino acids, bicarb and half of urea, 65% Na and K. Mostly active transport.
Proximal Convoluted tubule