28 Flashcards
How much of our bodies are water - male and female
Our bodies are 60% (male)
and 55% (female) water
How much of the total body water is in the ECF vs ICF
Total body water =
extracellular fluid (1/3) (fluid between cells and fluid in blood vessels) and
intracellular fluid (2/3)
Balance of _____ (and ______) in the body is crucial
Balance of water (and
solutes) in the body is
crucial
Role of the urinary system
Balance of water (and
solutes) in the body is
crucial
(If ICF not regulated tissues of cells could sell up)
(If ECF not regulated could cause high blood pressure)
How die the urinary system maintain balance
• By filtering the blood and expelling:
– Excess water
– Excess salts (too much K+ is bad so expelled in urine)
– Wastes of metabolism (nitrogenous waste can be toxic, metabolising proteins produces ammonia which is toxic and our liver then converts it to something less toxic but kidney gets rid of it)
– Many toxins and drugs (such as urea and pencillan)
In order for the urinary system to achieve balance via filtering the blood and expelling…. What’s needed….
In order to achieve this, 1200ml of blood flows through the kidneys per minute. A typical person produces 800-2000ml urine/day.
(20% of cardiac output)
(- without good blood supply can go into renal failure)
What is urine?
Waste product excreted
to maintain balance
within the body
What does normal urine contain ?
• Water
• Salts
• Urea
• Metabolites, hormones, small proteins
Ph of urine? What’s the ph influenced by?
Urine pH is not tightly regulated (pH ~4.6 - 8) and is influenced by what is excreted
Urine can be a useful diagnostic tool for:
Disease states
Features of abnormal urine
•Large proteins (too big to be filtered so u shouldn’t see them in urine - problem with filtration barrier)
•RBC (too big to be filtered in glomerus )
•Glucose (filtered, but completely reabsorbed)
To be effective, the urinary system needs:
• Delivery system for blood
• Selective filtration system
• Filtrate recovery mechanism (such as glucose and water and salts)
• System to return recovered, filtered fluid to body
• System to remove filtrate from body
• Protection (of kidneys etc)
• Ability to communicate with relevant parts of the body
• Adaptable to meet the body’s changing needs
Main components of the urinary system
• 2 kidneys • 2 ureters • Urinary bladder • Urethra
Which kidney is lower
Right
Why is the right kidney lower
- liver pushes it down
Inferior vena cava is to the _____ of the midline
Right
Which kidney is closer the the inferior vena cava
Right
What’s on top of kidneys
Adrenal glands
What happens at the Hilum?
- where renal vein leaves and where renal artery arrives and where urticaria leaves and where renal nerve and lymphatics enter too
URita vs urithra
Urita carries urine to bladder
Urithrea carries from bladder to external environment
The structure of the kidneys allows:
• Blood to be brought into close proximity with the nephron, for filtering (reabsortion useful substances from filtrate)
• Blood that has been filtered to leave the kidney
• A pathway for urine to be removed from the kidney, stored and then excreted
• Protection
The kidneys location and oritation
• T12-L3
• 11 th and 12th ribs
• Convex side faces laterally
• Medial surface has a concave notch called the hilum
• renal blood vessels, lymphatics, nerves and the ureter
(Hilum is located at L1)
What helps protects the kidneys
11th and 12th ribs (floating ribs) - protecting form the back
Kidneys location within the abdominopelvic cavity - what surrounds it?
Retroperitoneal: Located on posterior
abdominal wall, covered on anterior side by
peritoneum
- Surrounded, supported and protected by (perirenal) fat
Adhered to and surrounding the kidney is a_____ heat does this do?
Fibrous capsule
- holds kidney in its shape - prevents it from rupturing
- prevents infection in surrounding tissue from getting into kidney itself
Renal fascia is…. With the peritoneum (anterior) and the…… lumbar muscles facia (posterior
Fused / continuous
Three regions of the kidney
cortex, medulla and pelvis
Gross strucuture of the kidney
- cortex, medulla and pelvis
- fibrous capsules
- inner medulla
- divided into pyramids
- each medullary pyramid ends in a papilla
- outer cortex
- continuous layer
- renal columns
- cortex and medulla:
- multiple functional lobes
- 5-11 lobes per kidney
How many lobuels per kidney
5-11
Lobule is comprised of
- medulla and surrounding cortex
Why is pyramid stripeY?
- many tubules in their
- collecting ducts
- Nephron loops
Fluid flows down towards? - ya-
Papilli
- paili drain into the calyces
- 2 or 3 minor calyces drain into a major one
- thus then empties into renal pelvis
- urine can then leave via the Hilum into the ureter
What is a kidney lobe ? What is is made of ?
- One medullary pyramid
- All cortex that surrounds it (including renal columns, not shown here)
- Made up largely of nephrons- tiny tubes that filter from blood and create urine
Functional unit of kidney
Nephron
Pathway of urine out of the kidneys
• Urine drains from each papilla and collects in a calyx
• Calyces join to form renal pelvis
• Pelvis narrows as it exits the hilum to become the ureter
Urine travels into: papilla —> minor calyx —> major calyx —-> renal pelvis —-> ureter
Three structures that provide external protection for the kidneys
11th and 12th ribs
Renal fat pad
Fibrous capsule
How is urine product produced
- by filtering waste from the blood into the nephron
Where does filtration occur - in the kidneys?
In the cortex of the kidneys
Where does the renal artery arise form?
The abdormanal aorta
What happens to arteries as the reach the cortex ?
Branching arteries get smaller and smaller until they reach the cortex
What is filtered in the kidney?
Blood
Veins return filtered blood from the cortex goes where?
to the renal vein, then to the Inferior vena cava
Renal artery enters at the
Hilus
Renal vein exists at the
Hilum
What happens to blood in the cortex
- The afferent arteriole delivers blood from the arteries to the glomerulus
- The glomerulus is made of glomerular capillaries and is where filtration occurs
- The efferent arteriole carries blood from the glomerulus to the peritubular capillaries
- The peritubular capillaries carry blood to the veins
(Periteubulat cappilaries wrap around the nephron and supply them with oxygen and also collects substances that have been reabsorbed from the nephron and return it to the venous system)
Flow of blood through the kidneys
blood supply into the cortex to be filtered
- Abdominal aorta
- renal artery
- series of arteries
- afferent arteriole
- glomerular capillary
Blood supply away from the cortex after being filtered
- Glomerular capillary
- efferent arteriole
- peritubular capillaries
- series of veins
- renal vein
- inferior vena cava
Nerve supply of the kidneys
- Innervation is from a network of autonomic nerves and ganglia called the renal plexus
• Sympathetic nerves act to adjust diameter of renal arterioles and thus regulate blood flow.
What is a nephron
Microscopic functional unit of the kidney
Bull of kidney is made of of…
Nephrons
1.2 million of them
