Urinary system Flashcards
What are the four main organs of the urinary system?
- Kidneys
- Ureters
- Urinary bladder
- Urethra
What is the function of the kidneys
- Filter waste products from the bloodstream and convert the filtrate into urine
- returns needed substances to the blood
What do the ureters do?
transport urine from kidney to bladder via peristalsis
What is the function of the urinary bladder
Storage of urine
What is the function of the urethra?
transports urine from bladder to the outside of the body
What is the renal hilum?
Where vessels, nerves and ureters enter and leave the kidney
What are the three things the kidneys regulate?
- blood volume and pressure: filtering role
- Blood’s inorganic ion balance: sodium, potassium and phosphate ions
- Erythrocyte production via erythropoietin
How does the kidney maintain an acid-base balance
Through changes in the rate of hydrogen and ammonium secretion
What are the four protective coverings of the kidney?
- fibrous capsule
- Perirenal fat capsule
- Renal fascia
- Pararenal fat capsule
What side is the ureter on?
On the posterior, medial surface
What does the renal sinus contain?
minor/major calices, renal pelvis, renal fat, blood vessels
Where does the kidney receive blood from?
Renal artery (branch of abdominal aorta)
How does blood drain from the kidney
Drains via veins into renal vein and then the inferior vena cava
What is the flow of blood through the kidney
Renal artery -> segmental arteries -> interlobar arteries -> arcuate artery -> cortical radiate artery
What is the pneumonic for the flow of blood through the kidney?
Really Smart Instructor At Class
How does the blood flow out of the kidney?
Cortical radiate vein -> arcurate vein -> interlobar vein -> renal vein
What is the nephron composed of?
Renal corpuscle - first part of nephron where filtration occurs
Renal tubule - long tubular secretion of proximal tube, loops of henle, distal tubule and collecting duct
What are the major renal processes of urine formation
- glomerular filtration
- Tubular resorption
- Tubular secretion
What is glomerular filtration?
Filtrate of blood leaves kidney capillaries
What is tubular resorption
Most nutrients, water and essential ions reclaimed
What is tubular secretion?
Active process of removing undesireable molecules
What are the 2 parts of the renal corpuscle?
- Glomerulus - tuft of capillares
2. Bowman’s capsule
What are the 4 parts of the renal tubule?
- Proximal convoluted tubule
- Loop of Henle
- Distal convoluted tubule
- Collecting duct
What occurs in the proximal convoluted tubule?
- entirely in renal cortex
- reabsorbs ions, nutrients, plasma proteins, vitamins and water
- filtrate is called tubular fluid
What occurs in the loop of henle?
- in the renal medulla
- reabsorption of ions and water
What occurs in the distal convoluted tubule?
- entirely in renal cortex
- secretes ions into the tubular fluid and reabsorbs water
- less active in resorption than proximal
What occurs in the collecting duct?
- each received urine from several nephrons
- ducts join to form larger papillary ducts
What are the two types of nephrons?
Cortical nephrons
Juxtamedullary nephrons
What is the difference between cortical and juxtamedullary nephrons?
Cortical have short nephron loop compared to a long nephron loop in justamedullary nephrons with contribute to kidneys ability to concentrate urine
What are the capillary beds in cortical nephrons?
Peritubular capillaries
What are the capillary beds in justamedullary nephrons?
Vasa recta
What are the three layers of the ureters? innermost -> outermost
- mucosa
- muscularis
- adventitia
What is the mucosa in the ureters?
- transitional epithelium to allow passage of urine
How do the ureters enter the bladder and why is this important?
Enter on an oblique angle to prevent backflow
What is muscularis in the ureter?
2 smooth muscle layers: inner longitudinal and outer circular
What does the adventitia in the ureter do?
areolar connective tissue which anchors the ureter to the posterior abdominal
How does the urinary bladder receive blood?
By the internal iliac arteries
What are the three layers of the urinary bladder?
- Mucosa
- Thick muscular layer (detrusor)
- Fibrous adventitia
What paraympathetic axons innervate the bladder?
- come from the micturition reflex centre located in spinal cord segments S2-S4
STIMULATE URINATION
What sympathetic axons innervate the bladder?
Come from the T11-L2 segments of the spinal cord
- inhibit innervation
Name four structural differences of the female urethra
- 3-5 cm long
- smooth muscle and inner mucosa layer
- internal urethral sphincter (involuntary)
- external urethral sphincter (voluntary)
What does the internal urethral sphincter do in the female urethra?
Keeps urethra closed when urine is not being passed
What does the external urethral sphincter do in the female urethra?
Inhibits urination until the proper time
What are the three parts of the male urethra?
- Prostatic urethra
- Membranous urethra
- Spongy urethra
What is the important function of the internal urethra sphincter of the male urethra?
Prevents the simultaneous passage of sperm and urine through the male urethra