Anatomy - Urinary system Flashcards
What is urology
it is the specialty that focuses on the urinary system and its disorders and it also includes the make reproductive system.
What does the urinary system consist of
two kidneys
two ureters
the bladder
the urethra
how do the urinary and reproductive system relate
they are closely linked. In human males, sperm and seminal fluids are emitted through the urethra, therefore, sometimes the are put together as the urogenital system
What is the location of the urinary system
In the abdominopelvic cavity, the kidneys are high in the posterior abdominal wall and the left is slightly higher than the right.
The bladder is found in the lower pelvic cavity and the outlet is the urethra.
The ureters come out the hilums and pass inferiorly to enter posteriorly into the bladder.
What vessels supply the kidneys
renal artery and vein
What are the functions of the kidneys
Excretion of wastes Regulation of blood volume and pressure Regulation of osmolarity of body fluids Secretion of renin enzyme Secretion of erythropoietic hormone Regulation of concentration of pCO2 and acid-base (pH) of blood and body fluids Synthesis of calcitriol hormone Gluconeogenesis
Function of kidneys : Excretion of wastes
they filter the blood plasma and separate waste to make a proto urine while reabsorbing useful substances back to the bloodstream.
Function of kidneys :
Regulation of blood volume and pressure
because they control water conservation and elimination
Function of kidneys : Regulation of osmolarity of body fluids
because they control the reabsorption of non-diffusible solutes. (e.g. sodium and chloride ions)
Function of kidneys : Secretion of renin enzyme f
for the long term regulation of blood pressure and electrolytes
Function of kidneys : SEcretion of erythropoietin hormone
which stimulates the production of red blood cells
Function of kidneys : Regulation of pCO2 and acid-base balance (pH) of blood and body fluids
because they can secrete and reabsorb bicarbonate ions
Function of kidneys : Synthesis of calcitriol hormone
involved in calcium homeostasis (regulation of calcium)
Function of kidneys : Gluconeogenesis
make glucose from other types of molecules in conditions of extreme starvation
What is defined by waste
any substance that is useless to the body or present in excess of need
What is metabolic waste
wastes produced by the body during chemical reactions in cells (feaces in not metabolic waste)
What are nitrogenous waste
metabolic waste that nitrogen, they are among the most toxic metabolic wastes
What’s an example of nitrogenous waste
urea, 50% of which is produced by catabolism
What is produced in protein catabolism
Ammonia
Urea
What is produced in nucleic acid catabolism
Uric acid
Creatinine
What is excretion
The process of separating wastes from the body fluids and eliminating them.
What for systems carry out excretion
Respiratory system
Integumentary system (skin)
Digestive system
Urinary system
What does the respiratory system get rid of
CO2 and some water
What does the integumentary system get rid of
via sweat it gets rid of water, inorganic salts, lactic acid and urea
What does the digestive system get rid of
(gets rid of food residue, feaces, which isn’t excretion)
eliminates water, salts, CO2, lipids bile pigments, cholesterol and other metabolic wastes.
What does the urinary system get rid of
broad variety of metabolic wastes, toxins, drugs, hormones, salts, hydrogen ions and water.
Where are the kidneys positioned
The kidneys sit behind the peritoneal cavity (so its retroperitoneal) therefore, the peritoneal lining, the peritoneal lining, the peritoneum is anterior to both kidneys.
What are the layers of the kidney
renal fascia perirenal fat capsule fibrous capsule renal cortex renal medulla
What is the renal fascia
outermost layer, layer of connective tissue
What is the perineal fat capsule
a fat layer
What is the fibrous capsule
fibrous lining
What is the renal medulla
made of alternating structures, the renal pyramids, and renal columns (the renal columns are investing tissue from the cortex)
What percentage weight to kidneys represent in the body
0.4%
What percentage of cardiac output do kidneys get
21%
blood path from heart to glomerulus
Aorta Renal artery Segmental artery Interlobar artery Arcuate artery Interlobular artery Afferent arteriole Glomerulus
blood path from glomerulus to heart
corticoid nephrons
Glomerulus Efferent arteriole Peritubular capillaries Interlobular vein Arcuate vein Interlobar vein Renal vein Inferior vena cava
blood path from glomerulus to heart
juxtamedullary nephrons
Glomerulus Efferent arteriole Vasa recta Arcuate vein Interlobar vein Renal vein Inferior vena cava
What is a nephron
The functional unit of kidneys
How many nephrons are there
1.2 million per kidney
What two parts are kidneys composed of
renal corpuscle - filters blood plasma
renal tubule - converts the filtrate into urine
Where are nephrons located
largely in the cortex - cortical nephron
between the cortex and the medulla - juxtamedullary nephron
What does the loop of henle do
the are involved in water conservation
What is the most common type of nephron in humabs
cortical nephron
How does the nephron get its blood supply
the nephron gets its blood supply from the afferent arteriole, which goes into the nephron and form a ball of capillaries known as the glomerulus.
How are the nephrons drained
the capillaries in the glomerulus re-form into an efferent arteriole that will form a secondary capillary network surrounding the renal tubule.
Where does the secondary capillary network form for cortical nephrons
around the proximal and distal convoluted tubules, and it’s called peritubular capillaries
Where does the secondary capillary network form for juxtacapillary nephrons
surrounding the loop, its known as the vasa recta
What composes the renal corpuscle
glomerulus and the glomerular capsule (Bowman’s capsule)
What does the renal capsule do
it is the filtration unit of the kidneys, so it filtrates the blood coming from the afferent arteriole and becomes the glomerulus.
What phenomena helps filtrate the blood at bowman’s capsule
hydrostatic pressure
What cells make up the leaky the inner or visceral layer of the bowmans capsule
podocytes
Where does the filtrate goes rigth after the visceral layer
the capsular space and into the first part of the renal tubule, the proximal convoluted tubule.
How long is the renal tubule
3cm
What are the four parts of the renal tubule
Proximal convoluted tubule (PCT)
Loop of henle (descendant and ascendant part)
Distal convoluted tubule (DCT)
Collecting duct (CD)
What is at the end of the collecting ducts
The renal pyramids, that open at the apex into the renal papilla. Then the the urine drips into the minor calyx, then major calyx, it goes into the renal pelvis and into the ureter.
Renal drainage: glomerular filtration
Creates a plasmalike filtrate of the blood
Renal drainage: tubular reabsorption and secretion
Removes useful solutes from the filtrate, returns them to the blood.
Removes additional wastes from the blood and adds them to the filtrate.
What vessels surround the renal tubule
Peritubular capillaries
Renal drainage: water conservation
removes water from the urine and returns in to blood; concentrates wastes.
What is the globular filtration rate (GFR)
the amount of filtrate produced per minute by the two kidneys
What is the GFR in a male
125 ml/min - 180 L/day
What is the GFR in females
105 ml/min - 150 L/day
What percentage of the filtrate is reabsorbed
99%
What hormone do the kidneys use to control blood pressure
renin aldosterone
Why does the PCT consumes so much ATP
because it filtrates the glomerular filtrate by active transport (6% of ATP usage)
What percentage of the glomerular filtrate does the PCT absorbe
65%
What does the PCT absorbe
65% of sodium, potassium, magnesium and phosphate
100% glucose
40%-60% of urea
67% of water
What does the PCT and the loop secrete
nitrogenous wastes, bile acids, catecholamines, prostaglandins, drugs (morphin, aspirin, penicillin), hydrogen and bicarbonate ions to regulate pH.
What does the loop reabsorb
25% of sodium, potassium and chloride
15% of water
What does the fluid arriving at the PCT contain
20% of water and 7% of the salts from the glomerular filtrate.
Water conservation
WAter is reabsorbed by the osmosis from the collecting ducts thanks to the concentration gradients generated by the nephron loops in the renal medulla. Longer loops can generate grater concentration gradients (the have greater ability to concentrate urine).
How long are the ureters
25 cm
How do the ureters connect the kidneys and the bladder
they form at the renal pelvis and connect to the urinary bladder; they are 1.7 cm in diameter at the entry and have a valve to prevent the reflux of urine.
What is the bladder
a muscular sac of a muscular layer called detrusor muscle and has a capacity of 700-800 ml
How long is the urethra
3-4 cm in females
18 cm in males
What is another name for urinating
micturition
How is urination controled
partly by a spinal reflex (involuntary)
partly by the CNS (Voluntary)
