Chapter 17 Renal Physiology Flashcards
What are some broad functions of the kidneys?
- Regulate volume and components of extracellular fluid (plasma and interstitial fluid) by filtering the blood plasma into urine.
- Regulate blood pressure through volume of blood plasma
- Regulate the concentration of waste products in the blood
- Regulate the concentration of electrolytes (Na+, K+, H+, HCO3-)
- Regulate pH of body fluids
- Secrete erythropoietin
What stimulates secretion of the hormone erythropoietin from the kidneys and what does it cause?
They kidneys secrete the hormone erythropoietin in response to hypoxia (low oxygen conditions). This hormone stimulates the production of red blood cells in the bone marrow. This increases oxygen-carrying capacity.
Trace the path of urine formation from the glomerulus to the toilet bowl. This includes the
nephron.
- Nephron
- Minor calyces -> major calyx
- Renal Pelvis
- Ureters
- Bladder
- Urethra
Two layers of kidney
- Outer cortex
- Inner Medulla
The outer cortex of the kidneys contains many _________.
Capillaries
The Inner Medulla of the kidneys is composed of 7-18 renal _______ which are separated by renal ______.
-7-18 renal pyramids
-separated by renal columns
The collecting ducts of nephrons empty into ______ which unite to form a ________.
minor calyces unit to form a major calyx
What structures in the kidneys form the renal pelvis?
Major renal calyces
The renal pelvis collects _____ and transports it to ______.
urine; ureters
What are the 3 muscles involved with the bladder and urethra, and what type of muscle is each one?
When is each one constricted vs. relaxed during bladder filling and micturition?
- Detrusor (bladder wall)- smooth muscle
-contracts: Micturition
-relaxes: filling of bladder - Internal Urethral Sphincter- smooth muscle
-contracts: filling of bladder
-relaxes: micturition - External Urethral Sphincter- Skeletal Muscle
-contracts: filling of bladder
-relaxes: Micturation
The three muscles during micturition
Once the bladder is full and it is time to urinate:
-detrusor contracts
-internal + external urethral sphincter relax
The three muscles during filling of the bladder
While the bladder is filling with urine:
-detrusor is relaxed
-internal urethral sphincter is constricted
-external urethral sphincter is constricted
What are parts of the
nervous system contribute to
-Bladder filling
-Bladder emptying/ urination
Bladder filling:
-Sympathetic nervous system relaxes detrusor and constricts internal urethral sphincter
-Somatic nervous system stimulates external urethral sphincter to constrict (voluntary)
-Norepinephrine
Bladder emptying:
-Parasympathetic nervous system contracts detrusor and relaxes internal urethral sphincter
-somatic nervous system signals eus to relax
The volume of plasma (blood) delivered to kidneys over time (mL/min) is called ______________.
What % is this of total cardiac output?
Renal plasma (blood) flow (RPF)
RPF is 22% of cardiac output
What is the renal plasma/blood flow?
The volume of blood that gets delivered to the kidneys over time?
What are the units of measurement of renal plasma/blood flow?
mL/min
How much cardiac output do the kidneys get?
22%
How much of renal plasma/blood flow do the glomeruli get?
The glomeruli receive approximately 20% of the renal plasma flow, which is about 1/5th of the total renal blood flow and 4-5% of cardiac output.
Trace the path of renal blood flow starting on the arterial side with the afferent arteriole to
the venous side
Afferent arteriole -> glomerulus (1st capillary) -> efferent arteriole -> peritubular capillaries (2nd capillary)
How many nephron units are in each kidney?
10^6
The vascular component of the kidneys is the __________. All of the renal plasma flow passes through this.
glomerulus
Tubular components of the Nephron
Glomerular (Bowman’s) Capsule -> proximal convoluted tubule (PCT) -> Loop of Henle (LOH– descending limb -> thin ascending limb -> thick ascending limb) -> Distal convoluted tubule (DCT) -> Collecting duct (cortical then medullary) -> empties into calyx
Loop of Henle is composed of
- Descending Limb
- Thin Ascending Limb
- Thick Ascending Limb
The Renal Corpuscle includes
(1) Glomerulus
(2) Bowman’s Capsule
Nephrons are situated in the _______ descending down into the renal ______.
Situated in cortex and descend down into the renal pyramids.
The collecting ducts from nephrons drain into the _______.
Minor calyces
Types of Nephrons
- Cortical Nephrons
- Juxtamedullary Nephron
Cortical Nephrons originate in _________.
Juxtamedullary Nephrons originate in _______.
Outer 2/3 of cortex
Inner 1/3 of cortex
How does the loop of henle differ between cortical and juxtamedullary nephrons
-Cortical nephrons have a short, thick loop of henle that is mainly located in the cortex but a small portion of it dips into the medulla.
-Juxtamedullary nephrons have long, narrow loops of henle that extend deep into the medulla.
Cortical nephrons are more involved in ______.
Reabsorption of ALL solutes and waste secretion.
Juxtamedullary nephrons are important for producing _________ via _______.
Producing concentrated urine via salt and water reabsorption.