Chapter 12: Urinary System Flashcards
Regulates aspects of homeostasis
🔹blood vol / blood pressure 🔹electrolytes 🔹acid-base balance in blood 🔹red blood cell production (EPO) 🔹activation of vit.D
Elimination of waste products
🔹nitrogenous wastes
🔹Toxins
🔹Drugs
Roles of elimination of wastes?
🔘lungs (C02/H20)
🔘sweat glands (N2, H20, electrolytes)
🔘digestive system ( bile, minerals)
🔘kidney (have most responsibility)
Organs of the Urinary System
🔘kidneys
🔘ureters
🔘urinary bladder
🔘urethra
kidney located against the dorsal body wall
Retroperitonial
Kidney at the level of the
🔘T12 to L3 vertebrates
Kidney anchored to surrounding structures by ___________
Right kidney slightly lower than left due to __________
🔘 renal fascia
🔘 liver
In the middle of each kidney is a indentation called:
🔘 renal hilum
👁🗨at site of HILUM (the ureters, renalblood vessels & nerves (parasympathetic) enters and exit the kidney
Atop each kidney are the:
Adrenal Glands
Coverings of the kidneys:
1️⃣fibrous capsule - surrounds each kidney
2️⃣perirenal fat capsule - surrounds the kidney and cushions against blows
3️⃣renal fascia - outermost capsule that helps hold the kidney and adrenal gland in place against the muscles of the trunk wall
Regions of the kidneys:
- Renal Cortex 🔹outermost region
- Renal Medulla 🔹deep to the cortex
🔘renal (medullary) pyramids
🔘 renal columns - extensions of cortex-like materials that separate the pyramid - Renal Pelvis 🔹 inner flat, funnel shape
🔘Calyces - cup-shaped structures towards the renal pelvis
____________ of Total blood supply of the body passes through the kidneys each minute
One-quarter (1/4)
Renal artery provide each kidney with _______ blood supply
Arterial
Blood Flow in the Kidneys:
Aorta➡️renal artery➡️segmental artery➡️interlobar artery➡️arcuate artery➡️cortical radiate artery➡️afferent arteriole⤵️
Glomerulus ⤵️
Efferent arteriole ➡️peritubular capillaries➡️cortical radiate vein➡️Arcuate vein➡️Interlobar vein➡️Renal vein➡️Inferior vena cava
Each kidney contains ________ of nephron. (Cannot be replaced when damaged)
Millions
____________ are the structural and functional units of the kidneys. Responsible for forming the urine.
Consists of a glomerulus and glomerular capsule
Nephrons
Main structures of the nephrons:
- Renal corpuscles (glomerulus + bowman’s capsule)
2. Renal tubules
Renal tubules extends from _______ _______ and ends when it empties into the ________ _____
🔘 glomerular capsule
🔘 collecting ducts
The subdivision of the renal tubules are:
- Proximal convoluted tubele (PCT)
- Nephron Loop (Loop of Henle)
- Distal Convoluted Tubule (DCT)
Circulation to a Nephron:
Start: afferent ➡️ efferent ➡️ peritubular capillaries
Juxtamedullary Nephron are:
🔘 Proximal Convoluted Tubule
🔘 glomerulus
🔘 distal Convoluted Tubule
Nephron is composed of:
- Renal Corpuscle
- Proximal Convoluted Tubule
- Nephron Loop
- Distal Convoluted Tubule
_________ is a specialized capillary bed which is fed by arterioles from renal artery 🔜sits within Bowman’s (glomerular) capsule
Keeps the blood at high pressure to force fluids/so lures (smaller than proteins) out of blood into the glomerulus.
Glomerulos
🔘arise from the efferent arteriolar of the glomerulus
🔘normal, low-pressure, porous capillaries
🔘adapted for absorption instead of filtration
🔘cling close to the renal tubule to reabsorb (reclaim) some substances from collecting tubes
Peritubular capillary beds
🔘. Collects filtrate from the glomerulus 🔘 consists of a continuous tube: 1. Bowmans capsule 2. Proximal Convoluted Tubule 3. Loop of Henle 4. Distal Convoluted Tubule 5. Collecting Tubule
Renal Tubules
Not part of Nephron!
Collecting System
Carries tubular fluid through renal Medulla towards renal pelvis and ureters
Collecting duct
Types of Nephrons
- Cortical Nephron - 85%
2. Juxtamedullary nephrons - 15%
Located entirely in the cortex
Cortical Nephron
🔘Found at the boundary of the cortex and Medulla
🔘long Nephron loops extending deep into renal Medulla
🔘most important: essential for conserving water (regulating water balance) and concentrating urine
Juxtamedullary Nephron
Water and solutes smaller than proteins are forced through the capillary walls and pores of the glomerular capsule into the renal Tubule.
*protein and blood cells are normally too large to pass through the Filtration membrane
Glomerular Filtration
Water, glucose, amino acids, and needed ion are transported out of the filtrate into the Tubule cells and then enter the capillary blood
Tubular Reabsorption
Creating, and drugs are removed from peritubular blood and secreted by the tubule cells into the filtrate
Tubular Secretion
Each kidney has about ____ million Nephron
1.25
Both cortical and juxtamedullary Nephrons inner acted by:
Renal Nerves
Most Renal nerve fibres are sympathetic or parasympathetic nerves?
Sympathetic nerves
🔘 adjust blood flow and blood pressure at glomeruli
🔘 stimulates release of Renin
Urine Formation occurs through 3 steps:
- Glomerular Filtration
- Tubular Reabsorption
- Tubular Secretion
Urinary system maintains homeostasis by regulating:
🔘Volume and composition of blood
🔘also excrete solutes, especially nitrogenous wastes:
✔️urea
✔️creatinine
✔️ Uric acid
Produced by the liver as an end product of protein breakdown (amino acid catabolism).
50% reabsorb but remainder is excreted in urine.
Urea
Low level of urea indicate:
🔘 malnutrition (inadequate protein in the diet)
🔘 kidney dysfunction
High level of urea indicate:
🔘 excessive protein intake
🔘 increased protein breakdown in the body
Produced from the breakdown of the body’s cells and food (DNA, RNA)
Completely reabsorbed. About 10% of the reabsorbed ends up in urine bcoz it is so created in the renal tubules
Uric Acid
🔘 Breakdown product of creatine, w/c is an important part of muscle energy supplies
Creatinine
✔️kidneys maintain the blood creatinine in a normal range
Three (3) processes in Urine Formation
- Filtration
- Reabsorption
- Secretion
In the Renal corpuscle, Filtration produces ______L/day of filtrate
180 L/day
🔘BV is 5L
If arterial blood pressure is __________, filtrate formation stops because glomerular pressure will be too low to form filtrate
too low