Lecture 28-An overview and structure of the Kidney Flashcards
What is the role of the urinary system?
Balance the water (and solutes) in the body via filtering blood and expelling excess substances
How much of the body is water and what explains the difference between males and females?
- 60% (male) and 55% (female
- Difference because males have more muscle and females have more fat/adipose
What is the ratio of water between ECF and ICF?
Total body water is= extracellular fluid (1/3) and intracellular fluid (2/3)
What are some examples of things that the urinary system filters from the blood?
- Excess water
- Excess salts
- Wastes of metabolism
- Many toxins and drugs
How much blood flows through the kidneys per minute?
1200ml
How much urine on average is produced per day?
800-2000ml
How can urine be defined and what is typically in it?
- Waste product excreted to maintain balance within the body
- Contains, Water, Salts, Urea, Metabolites, hormones, small proteins
Is the pH of urine tightly regulated? What is the result of this?
-No, (pH ~4.6 - 8) and is influenced by what
is excreted
-Means pH is a useful diagnostic tool
What might be found in abnormal urine?
- Large proteins (too big to be filtered)
- RBC (too big to be filtered)
- Glucose (filtered, but completely reabsorbed)
To be effective the urinary system needs…
- Delivery system for blood to where it is filtered
- Selective filtration system
- Filtrate recovery mechanism
- System to return recovered, filtered fluid to body
- System to remove filtrate from body
- Protection
- Ability to communicate with relevant parts of the body
- Adaptable to meet the body’s changing needs environment changes, diet changes etc.)
What are the main components/ structures invovled in the urinary system?
- 2 kidneys
- 2 ureters
- Urinary bladder
- Urethra
What does the structure of the kidneys allow?
- Blood to be brought into close proximity with the nephron, for filtering
- Blood that has been filtered to leave the kidney
- A pathway for urine to be removed from the kidney, stored and then excreted
- Protection
Where are the kidneys located and what is there shape?
- T12-L3
- At level of the 11th and 12th ribs
- Convex side faces laterally
- Kidney bean shaped
- Medial surface has a concave notch called the hilum
What does the hilum of the kidneys contain?
- Renal blood vessels
- Lymphatics
- Nerves
- Ureter
Where are the kidney’s in relation to the peritoneal cavity?
- Retroperitoneal
- On the posterior adnominal wall
- Covered on anterior side by the peritoneum
What are the kidneys surrounded by and what does this provide?
Adipose (fat) tissue (pictured yellow) and provides support/cushioning
What are the three regions of the kidney?
- Cortex
- Medulla
- Pelvis
What are three things that protect the kidney?
- 11th and 12th ribs (bones)
- Layer of fat providing support
- Fibrous connective capsule (last line of defense)
What is the inner medulla like?
- Divided into pyramids called medullary pyramids
- Each medullary pyramid ends in a papilla
What is the outer cortex like?
- Wraps all the way around the medulla in a continuous layer
- Renal columns separate the individual pyramids
What is the lobe like structure of the kidneys and what does this allow?
- Exists as multiple functional lobes
- 1 lobe consists of 1 medulla pyramid and all the cortex that surrounds it (including renal columns)
- The number of lobes per kidney varies between people usually from around 5-11
- The functional unit structure means if one area fails other units can take over
What are kidney lobes largely made of? What are the function of these?
- Nephrons: tiny tubes that filter from blood and create urine
- Wiggly parts in the cortex and long parts that sit in the medullary Pyramid
What is the sequence of structures urine drains from after its made in the nephrons?
- papilla
- minor calyx
- major calyx (join together)
- renal pelvis (narrows as exits the hilum)
- ureter
What is a pyelogram?
- Type of x-ray where patient drunk something with contrast dye in it
- Can see the structure of the renal system in it
Where does the filtration of blood occur in the kidney?
The glomerulus within the cortex
How is blood supplied to the cortex of the kidney?
-Renal artery arises from the abdominal aorta
-It branches getting smaller and smaller until it reaches
the cortex
How is blood returned from the cortex of the kidney once filtered?
Veins return filtered blood from the cortex to the renal
vein, then to the inferior vena cava to return to the heart and circulate
What is the glomerulus and how is blood delivered there?
-The afferent arteriole delivers blood from the arteries
to the glomerulus
-The glomerulus is made of glomerular capillaries and is where filtration occurs
How does blood leave the glomerulus?
- The efferent arteriole carries blood from the glomerulus to the peritubular capillaries
- The peritubular capillaries carry blood to the veins
Why does blood in the urinary system go from atereriole capillaries and then arteriole (no venules)?
Arteriole means resistance can be altered and flow adapted which is important in the urinary system
Put these in order of blood flood into the cortex to be filtered…
- Renal artery
- Afferent arteriole
- Abdominal aorta
- Glomerular capillary
- Series of arteries
- Abdominal aorta
- Renal artery
- Series of arteries
- Afferent arteriole
- Glomerular capillary
Put these in order of blood flood out of the cortex once filtered…
- Series of veins
- Efferent arteriole
- Inferior vena cava
- Peritubular capillaries
- Renal vein
- Glomerular capillary
- Glomerular capillary
- Efferent arteriole
- Peritubular capillaries
- Series of veins
- Renal vein
- Inferior vena cava
What is the nerve supply of the renal system like and its basic function?
- 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 nephron and its basic function?
- Microscopic functional unit of the kidney
- Bulk of kidney made up of nephrons
- Filters blood
- Selectively reabsorbs or secretes
- Produces urine
Name the 5 basic parts of the nephron…
- Renal corpuscle
- Proximal convoluted tubule
- Nephron loop
- Distal convoluted tubule
- Collecting duct
What’s the renal corpuscle?
- Made of glomerular capsule and glomerulus
- Where the blood and nephron meet
What’s the collecting duct?
-Where you find the papilla of medullary pyramids ——-Shared between multiple nephrons
Which kidney is most inferior and why?
The right due to the liver being above
