Urinary System Flashcards
Describe the structure of the kidney
Located retroperitoneally in perirenal capsul
What are the functions of the urinary system
Dispose of metabolic waste and excess substances through formation of urine + filters the blood: gets rid of nitrogenous waste ammonia etc. salts glucose vitamins.
Regulate fluid electrolyte balance. Regulate acid-base balance in blood. Produce hormone erythropoietin
What are the three regions of the kidney
Cortex, medulla and pelvis
What is the cortex of the kidney
Outer region. Lightly colored and granular
Describe the medulla
Darker, reddish brown. Contains cone shaped renal pyramids that are striated. Composed of parallel bundles of urine collecting tubules. The renal pyramid and surrounding cortical tissue constitutes a lobe
Describe the pelvis of the kidney
Flat, funnel shaped tube continuous with ureter and exits out the hilium
What are the major calyces
Large branches of the renal pelvis that are subdivided into several minor calyces. Collect urine draining from papilla of each renal pyramid. Empty urine into the renal pelvis
How does the urine flow through the pelvis and ureters to the bladder
By peristalsis
What are ureters
Tubes connecting the renal pelvis to the bladder. Ureters enter bladder at an oblique angle and when bladder is full shape changes and pinches off ureters to prevent backflow of urine
What are the three tissue layers that the wall of the ureter is composed of
It are mucosal layer is transitional epithelium. Middle layer is smooth muscle. Outer layer is fibrous
Describe the urinary bladder
Stores urine until a limitation. Stretching of wall makes it thinner and more susceptible to rupture. Stretch receptors trigger contractions. Involuntary sphincter control is urine flow into urethra.
Describe the urethra
Tube connecting bladder to outside of body. Typically longer in males but not true and cats.
What does the urethra carry in females
Urine
What does the urethra carry in males
Urine and semen
Describe kidney filtration
Kidneys receive one fourth of aortas blood at any given time. All of body’s blood is filtered every five minutes. 25% of blood plasma enters the nephron as filtrate. All but one percent of filtrate is reabsorbed back into the blood by capillories surrounding the nephron that are called peritubular capillaries. Remaining filtrate enters calyces as urine.
Describe blood flow to and from kidneys
Aorta ➡️ renal artery➡️afferent arteriole ➡️glomerulus ➡️peritubular capillaries ➡️renal vein ➡️inferior vena cava
How is the kidney capillary bed and the regular capillary bed different
This capillary bed is different because it is forced movement not by concentration gradient.
What is the renal corpuscle
The glomerulus and the Bowmans capsule
What is a nephron
Structural and functional renal unit. Forms urine
What does the nephron consist of
Glomerulus
Bowmans capsule
Renal tubule
Describe the glomerulus
Capillary bed. Blood enters under high-pressure. Endothelium is fenestrated. Filtration of blood is selective only by size. Filtrate enters the renal tubule after the glomerulus
What can pass through the glomerulus
Plasma + dissolved solutes
What shouldn’t pass through the glomerulus
Proteins, cells. Too large to be re absorbed and will Be thus present in urine
Describe the Bowmans capsule
Surrounds glomerulus and is continuous with the renal tubule. Odor parietal layer is simple squamous epithelium. Inner visceral layer consists of podocytes that cling to basement membrane. Filtrate passes through fenestrations between the feet in the capsule