The Urinary System Flashcards
What does the urinary system comprise of
The urinary system is comprised of the kidneys, the ureters and the urethras
What is the function of the kidneys in the urinary system
Filters the blood
What is the function of the ureters in the urinary system
Ureters transport urine to the urinary bladder
What is the function of the urethras in the urinary system
They conduct the urine to the exterior during micturition
How much of the cardiac output does the kidneys receive
One fifth of the cardiac output
How does blood enter the kidneys
The renal arteries
Where do the renal arteries arise from
The abdominal aorta
What is the function of the nephrons in the kidneys
They regulate the fluid and electrolyte balance of the blood and removes waste products
What hormones are produced by the kidneys
Erythropoietin for the control of erythrocytes production and renin for the regulation of water and salt concentration
What is the kidney made up of
The pale outer cortex
Darker regions of the medullary tissue
In a healthy kidney how thick should the renal cortex be
At least 7mm
How many medullary pyramids does a kidney have
10 to 15 medullary pyramids whose apices point towards the hilum of the kidney
What does the cortex contain
The cortex contains the glomeruli of the kidney and the convoluted parts of the proximal and distal tubules
It also contains the proximal parts of the collecting ducts
What do the medullary pyramids contain
They contain the straight portions of the proximal and distal tubules, the loop of Henle and the distal parts of the collecting ducts
How does filtrate drain from each medullary pyramid
The filtrate is drained by up to 20 pores into a funnel-shaped calyx from where urine is collected into the widened pelvic portion of the ureter for transport to the bladder
Where does the nephron start and end
The nephron starts at the glomerulus and ends at the collecting duct
What are most of the cells in the glomerulus
Most cells in the glomerulus are capillary endothelial cells or mesangial cells which lie in between the capillaries
What are the mesangial cells in the glomerulus composed of
They are composed of smooth muscle
What is the function of the mesangial cells
They are able to reduce the filtration rate when the smooth muscle contracts and involved with the phagocytosis of the basement membrane cells
Where to the renal artery and renal vein enter and exit the kidney
They enter and exit at the hilum of the kidney
Describe the divisions of the renal artery
The Renal artery branches from the abdominal aorta, from this the renal artery divides into the segmental arteries which divide into the interlobar arteries which divides into arcuate arteries which divide into the interlobular arteries which divide into afferent arterioles
Describe the structures the venous blood from the kidneys get back to the inferior vena cava
The blood enters the efferent arterioles then to the peritubular capillaries then to the vasa recta into the renal veins and into the inferior vena cava
Where are straight arterioles found
Straight arterioles are branches of the arcuate arteries that penetrate deep into the medulla before returning blood to the arcuate veins
Blood entering the kidneys goes where first
Blood entering the kidneys passes first to the glomeruli where it gets filtered
Where does the primary filtrate pass from the glomeruli
The primary filtrate passes from the glomeruli to the rest of the nephron for the selective re-absorption of certain solutes
What does a glomerulus consist of
A glomerulus consists of a parallel array of fenestrated capillaries ensheathed by specialised cells called podocytes
