W8- Lecture 42- Urinary system Flashcards
what are the kidneys?
Organs that excrete urine
Paired, bean-shaped organs located in the posterior abdomen
Lateral surface is convex; medial surface is concave - Hilum
Right kidney is lower than left (due to liver)
Capped by the adrenal glands - on top (endocrine system)
where in the kidney would the find the renal pelvis, renal vein, renal artery and ureter?
the hilum
which organs form the urinary tract ?
- Ureters (paired tubes)
- Urinary bladder (muscular sac)
- Urethra (exit tube)
what are the three key functional roles of the urinary system?
Excretion
- Removal of waste from body fluids - Occurs in kidneys – the nephron is the functional unit for this process
Elimination
- Storage of urine (bladder) - Discharge of waste products (urination/micturition)
Homeostatic Regulation
- Blood plasma volume & pH - Plasma ion concentrations - Conservation of nutrients - Elimination of toxins
In the kidney what is the renal capsule?
Fibrous capsule that encases kidney and prevents infection
In the kidney what is the renal fascia?
Outer layer of dense fibrous connective tissue that anchors the kidney
In the kidney what is the perirenal fat ?
External to renal fascia + provides
Protection to kidneys
what is the renal hilum ?
The renal hilum is the indented part of the kidney, on the medial surface
Point of entry
- Renal artery - Renal nerves
Point of exit
- Renal vein - Ureter
In the kidney what is the cortex?
Granular superficial region.
Extends into medulla as renal columns
In the kidney what is the medulla ?
Subcortex, composed of six to eighteen triangular renal pyramids, separated by renal columns
make sure you can label a kidney
did you get all 10 ? 1- renal capsule 2- renal cortex 3- renal medulla 4- renal pyramids 5- renal columns 6- renal papilla 7- minor calyx 8- major calyx 9- renal pelvis 10- ureter
where would you find renal papillae?
what are they ?
At the base of renal pyramids
Openings into the minor calyx that channel urine towards the renal pelvis
what are the two types of renal nephrons ?
Cortical – Only just penetrating the medulla
Juxtamedullary – Reaching deep into the medulla
what structures are included in the renal corpuscle within the nephron?
Glomerular (Bowman’s) capsulecup-shaped chamber
- Glomerulus
a network of capillaries
what is the renal tubule ?
where does the renal tubule begin ?
length ?
long tubular passage in the nephron
begins at the renal corpuscle
about 50 mm long
what is the Proximal convoluted tubule (PCT)?
made from ?
First segment of renal tubule
Simple cuboidal cells with microvilli on the luminal surface
what is the nephron loop also known as ?
descending- location and structure
Ascending - location and structure
Loop of Henle
Descending limb (squamous) passes into medulla Ascending limb (cuboidal) re-enters cortex and transitions into distal convoluted tubule (DCT)
what is the Distal convoluted tube (DCT) ?
function
location
Empties urine into common collecting duct, leading to the papillary duct and renal papillae at the tip of the renal pyramid
what epithelial linings does each of these compartments of the renal tubule?
PCT
nephron loop- descending + thin ascending
nephron loop- thick ascending
DCT
last part of DCT and the collecting duct
PCT=simple cuboidal epithelial cells with prominent brush borders of microvilli
nephron loop- descending + thin ascending= simple squamous epithelial cells
nephron loop- thick ascending =simple cuboidal to low columnar epithelial cells
DCT=simple cuboidal epithelial cells
last part of DCT and the collecting duct= simple cuboidal epithelium consisting of principle cells and intercalated cells.
in the kidney what does the renal corpuscle include ?
what are the outer and inner layers formed of ?
glomerulus and Bowman’s capsule
Outer: Simple squamous epithelium
Inner: Specialised podocytes
what are podocytes ?
Cells with processes adhering to basal lamina over fenestrated capillary endothelium
Approximately% of systemic cardiac output flows through kidneys ?
does arterial flow differ to venous flow
25%
both follow similar paths
what is the incidence of horseshoe kidney?
how is it discovered ?
Incidence 1 in 600 births.
Asymptomatic and discovered on imaging.
what is the Ureter
Urine flows from renal pelvis through the ureter (1 per kidney) to the urinary bladder
Entrance into bladder is oblique
Ureters actively propel urine to bladder via peristalsis, in response to smooth muscle stretch
