Lecture 17 - Kidney Flashcards
What are the dimensions of a kidney
- 6 cms in diameter
- 11 cms high in the
longest direction - 3 cms thick
How are kidneys described
Large, bean-shaped organs
What are the two sides of a kidney
- One side is concave and one side is convex
- Lateral = concave
- Medial = convex with a vertical cleft inside
What is the renal hilum
Where all your blood vessels go into the kidney and where your ureta comes out through renal pyramids
Where do ureter and renal blood supply join kidney
At Hilum
What sits on top of kidney
Adrenal gland
How can you access someones kidneys
Put someone on their front and cut open their back
Filtration, removal and drainage
- Filter blood plasma (~200 l/day) supplied by Renal Artery
- Remove excess water & waste solutes to produce urine (~2l/day), while returning ‘goodies’ to the systemic circulation
- Drained by Renal Vein
Functions of kidney - homeostasis of blood:
1) Osmoregulation, control of
total body water volume
2) Electrolyte balance
body fluid ‘osmolality’ - concentration of solutes e.g. urea, salts, KCl in blood = regulate electrolyte balance in body
3) Acid-base (pH) balance – regulate pH of blood, regulate molecules that can either make it acidic or basic e.g. urea
4) Toxic wastes Filter blood plasma (~200 L/day) supplied by Renal Artery = shows how much blood is being pumped around continuously
no alternative means of excreting metabolic wastes; urea, uric acid or creatinine = exit points for toxic wastes, some of the stuff that has been interconverted – modified by liver, put back out into blood and filtered by kidney = PROCESSES DETOXIFIED WASTES
Drugs
Other toxins
5) Produces erythropoietin & renin = regulate blood cell production & blood pressure systemically. These are hormones secreted by the kidney itself, not by the adrenal glands on top
6) Converts VitD to active form = use it throughout body
7) Starvation - metabolism and gluconeogenesis – if liver and muscles cant keep up to date with gluconeogenesis, exteme starvation, then kidney can help
What happens once liver has done its detoxification
Hepatocytes can either pump toxins into bile through bile cuniculi into bile duct into gall bladder or kick them back out into hempatic synosoids – exit into systemic circulation through central veins – go into kidneys – excreted into urine.
What is the only exit point for creatinine, urea and uric acid
Kindey
What are urea and uric acid and creatinine
- Urea and Uric acid = biproducts of protein metabolism in body, nitrogenous waste from amino acid & nucleic acid metabolism
- Creatinine = biproduct of specifically protein metabolism for skeletal muscles, muscle waste from ATP metabolism
Urinary system - organs and flow
Kidneys filter the blood and take out urine
That urine collects and goes down into ureter
Stored in bladder
Expelled through urethra when you want it
How can you regulate excretion rates of urine
Urethra has lots of sphincter muscles
Do all species have urethra
NO
Some species are continuously peeing e.g. mice
Why do we have a large bladder
Don’t continuously urinate, can selectively urinate – more socially acceptable
How does normal urine differ from filtered blood plasma
- 91-96% water content in urine & rest dissolved solutes (higher concentration than plasma) e.g. salt (Na+Cl-), other electrolytes (K+, H+, HCO3-)
- No cells, little nutrients or plasma proteins being excreted
- Slightly acidic (pH 5.5-6.0)
URINE DIFFERENT TO FILTERED BLOOD PLASMA AS IT CONTAINS NUTRIENTS AND ESSENTIALS
How much urine is produced per day by healthy adult
- 0.6L-2.6L Urine produced per day by healthy adult
- 6-8 urinations per day (~350ml bladder capacity) – depends on how much youre drinking.
Effects of urinating too much or too less
- Too much - signs of diabetes
- Too less - not drinking enough - dehydrated
How do babies get a nappy rash
pH slightly acidic = if constantly in contact with urine – irritate skin – slightly acidic
What colour should urine be
Nice straw light yellow colour
How do kidneys regulate blood volume and salt concs and waste disposal
By excereting what your body doesn’t need in the form of urine
What is urine
Filtrate of blood plasma
Why does kidney selectively filter
Don’t want all of the nutrients and essentials in urine to just flow out and exit body – losing a lot of vital stuff
What does it show if you have plasma proteins or nutrients being excreted in your urine
Indication that something is going wrong i.e. infection in urinary system or kidney failyure. Also should not see blood in urine ( dark red )
General structure of a kidney cross section - what are the 3 key regions
- Cortex = outer region
- Medulla
- Pelvis
What is the cortex
Outer region
Light appearance
What is the medulla
Darker triangles
Dark reddish brown
Striped
Contains bundles of capillaries, blood vessels and collecting tubes
What are renal pyramids/medulla separated by
Renal columns - made of cortex
What is Pelvis
- Funnel shaped tube
- Continuous with ureter
- Fed by Calyces - major calyx
- Where urine all collects – it feeds down into ureter
What is medulla also known as
Renal pyramids
Why do regions of kidney look striated
- Due to high density of blood vessels throughout the tissue = stripey appearance
- And nephrons have long collecting tube as they go out radially and there are lots of them
What is the – main entry and exit point if larger arterioles and venules ( larger blood vessels)
Running down renal columns
What is renal hilus
Where blood vessels are coming in and renal pelvis and ureter coming out
Process of what happens in kidney
- Blood comes in through these blood vessels, gets filtered by nephron and exits again through these renal column.
- The filtrate is turned into urine and comes down collecting duct and exits first into smaller tubes – minor calyx and then into larger tubes called your major calyx – calyces – filter into larger tube – renal pelvis – it feeds down into ureter
What does nephron do
Regulate urine and blood consituents