Urinary System (LAB PRACTICAL) Flashcards
Homeostatic regulation aspects of the urinary system
-Water balance
-Acid-base balance in blood
-Plasma ionic composition
-Blood pressure & volume
-Stimulates blood cell production
-Activates vitamin D3
Kidneys
Produce urine as a result of carrying out the major functions of the urinary system
Ureters
-Transport urine from kidneys to bladder.
-Continuous with renal pelvis
-Enter posterior aspect of bladder
-Runs behind peritoneum
-Uses peristalsis & gravity
Bladder
-Temporary storage reservoir of urine, usually holds 500 mL of urine and is ~5 inches long when moderately full
-Smooth, collapsible, muscular sac
-Contains trigone (Triangular region) at the base
-3 openings: 2 from ureters, 1 from urethra
Blood vessels of the kidney at the hilum
-Renal arteries deliver blood to kidneys for processing
-Renal veins carry blood away from kidneys
Urethra
-Thin-walled tube that carries urine from the bladder to the outside of the body by peristalsis
-Urine release controlled via control 2 sphincters
Difference between male and female bladder
In males prostate gland surrounds bladder neck
Urinary bladder wall
-3 layers of smooth muscle collectively called detrusor muscle
-Mucosa made of transitional epithlium
-Walls are thick and folded in an empty bladder
-Bladder can expand without increasing internal pressure due to folded cells
2 sphincters controlling urine release
-Internal urethral sphincter: Involuntary and made of smooth muscle
-External urethral sphincter: Voluntary and made of skeletal muscle
Male vs Female urethra
-Length: 20cm in Males, 2-4cm in Females
-Location: male through prostate & penis, female next to wall of the vagina
-Function: Male carries urine and sperm, female only carries urine
Kidney location
-Against dorsal body wall
-At the level of T12 to L3 vertebrae
-Right kidney is slightly lower than left
Renal cortex
Outer region of the kidney
Renal medulla
Region inside the cortex
Renal pelvis
Inner collecting tube
Renal hilam
Medial indentation where several structures enter or exit the kidney
Adrenal gland
Gland that sits above the kidney
Renal/Fibrous capsule
Most superficial covering surrounding each kidney
Renal fascia
Outermost capsule that helps hold the kidney in place against the muscles of the trunk wall
2 layers of fat surrounding kidney
-Inside of renal fascia: Perirenal fat between capsule of the kidney fascia. Surrounds kidney and cushions against blows
-Outside renal fascia: Pararenal fascia
Nephroptosis/Renal ptosis
The change of position of kidneys where they drop in the body cavity. May be due to loss of perirenal fat
Blood supply and flow through kidneys
-25% of total bodys volume passes through the kidneys each minute
-Renal artery branches from abdominal aorta and provides arterial blood supply to kidney
-Renal vein drains blood from the kidneys to inferior vena cava
Nephron
-Structural & functional unit of the kidney responsible for forming urine
-Associated with the glomerular capillary bed and peritubular capillaries
-2 major structures of the nephron
-Renal corpuscle: Glomerular capillary bed & glomerular capsule
-Renal tubule
Renal tubule extension from glomerular/bowmans capsule
-Glomerular/Bowmans capsule
-Proximal convoluted tubule
-Nephron loop
-Distal convoluted tubule
Renal corpuscle
Site of filtration: Portion of blood passes from glomerular capillaries into the glomerular capsule
Glomerulus
-Knot of capillaries
-Supplied by afferent arterioles & drained by efferent arterioles
-Under high pressure to force fluid and small solutes out of blood and into bowmans capsule
-Covered by podocytes of the visceral layer of glomerular capsule
Glomerular capsule
-Beginning of the renal tubule
-Encloses glomerulus
-Visceral layer: podocytes with foot processes that form the part of the filtration membrane
-Parietal layer: Outer impermeable wall
Peritubular capillary bed
-Arise from efferent arteriole of the glomerulus
-Normal, low pressure capillaries
-Adapted for absorption instead of filtration
-Cling close to the renal tubule to reabsorb substances from collecting tubes
Path of filtrate through renal tubule
-Glomerular capsule
-Proximal convoluted tubule
-Nephron loop
-Distal convoluted tubule
Collecting duct
-Distal convoluted tubules empty into the collecting duct
-Receives urine from many nephrons
-Runs through the medullary pyramids
-Delivers urine into the calyces and renal pelvis
Nephron types
-Cortical nephrons: Located entirely in cortex. 85% of all nephrons
-Juxtamedullary nephrons: Found at boundary of cortex and medullar. Large role in concentrating urine
Basic renal processes (Filtration, reabsorption, secretion, excretion)
-Filtration: Glomerulus to glomerular capsule
-Reabsorption: Renal tubule to peritubular capillaries
-Secretion: Peritubular capillaries to renal tubule
-Excretion: Renal tubules out of the body
Urine formation steps
-Glomerular filtration: Water & solutes smaller than proteins forced through capillary walls and pores of bowmans capsule into renal tubule
-Tubular reabsorption: H2O, GLU, amino acids, and ions transported out of filtrate into tubule cells and then enter peritubular capillaries
-Tubular secretion: H+, K+ creatinine, and drugs removed from peritubular blood and secreted into filtrate
Urine characteristics
-1-1.8 Liters produced in 24 hrs
-Filtrate contains everything plasma does except proteins
-Urine is what remains after filtrate has lost most of its water, nutrients, and ions
-Contains nitrogenous wastes and useless substances
-Slightly aromatic
-Normal pH around 6
-Specific gravity of 1.001 to 1.030
Specific gravity
Relative weight of a specific volume of liquid compared with an equal volume of distilled water
-Dissolved solutes cause a given volume of urine to weigh more than the same volume of water
Solutes normally found in urine
-Sodium and potassium ions
-Urea, uric acid, creatinine
-Ammonia
-Bicarbonate ions
Solutes not normally found in urine
-Glucose
-Blood proteins
-RBC’s
-Hemoglobin
-WBC’s
-Bile
Glycosuria
-Glucose in urine
-Can be caused by uncontrolled diabetes mellitus or excessive carb intake
Proteinuria
-Presence of protein in urine. Albumin being most abdundant
-Increased permeability of glomerular filtration membrane
-Can be caused by ingestion of poison/toxins, hypertension, physical exertion, or pregnancy
Hematuria
-Presence of RBC’s in blood
-Irritation of urinary tract organs that can result in bleeding or leakage of RBC’s through damaged filtration membrane
-Can be caused by bleeding in tract, kidney stones, tract tumors, trauma to tract, damaged filtration membrane
Ketonuria
-Presence of ketone bodies in urine
-Excessive production of and accumulation of fat metabolism intermediates that can cause acidosis
-Can be called by diabetes mellitus, starvation, or low carb diets
Hemoglobinuria
-Presence of hemoglobin in blood
-Fragmentation of RBC’s can result in Hgb in plasma and filtrate
-Can be caused by hemolytic anemia, transfusion reactions, sever burns, poison snake bites, renal disease
Nitrituria
-Presence of nitrites in urine
-Results when gram negative bacteria reduce nitrates to nitrite
-Caused by UTI’s
Bilirubunuria
-Presence of bile pigments in urine
-Increase levels of bilirubin in the urine as a result of liver damage or blockage of bile duct
-Caused by hepatitis, liver cirrhosis, gallstones
Pyuria
-Presence of WBC’s in blood
-Presence of WBC’s or pus in urine caused by urinary tract inflammation
-Caused by UTI’s or gonorrhea
Path of blood from aorta to glomerulus
-Aorta
-Renal Artery
-Interlobar artery
-Arcuate artery
-Cortical radiate artery
-Afferent arteriole
-Glomerulus
Path of blood from glomerulus to inferior vena cava
-Glomerulus
-Efferent arterioles
-Peritubular capillaries
-Cortical radiate vein
-Arcuate vein
-Interlobar vein
-Renal vein
-Inferior vena cava
