1 - Renal Anatomy Flashcards
What are the components of the renal system?
Kidneys
Ureters
Suprarenal gland
Urinary bladder
Male urethra
Female urethra
Prostate gland
Describe the position of the kidneys
- Lie on either side of vertebral column between T12 – L3
- Right kidney is usually 1.5-2 cm lower
- Transpyloric plane passes through upper part of left kidney
- Located in the RETROperitoneal space
Transpyloric plane = plane of the stomach
Describe the appearance of the kidneys
- Lateral surface is CONVEX
- Medial surface CONCAVE
Looks like a kidney bean
Describe the renal hilum
The only place that normally where the blood vessels come in or go out of the kidney
There are occasions that some of the blood vessels branch early and then enter right into the kidney and not through the hilum
Renal artery and vein go into the renal pelvis
Describe the renal sinus
Three parts
- Renal pelvis
- Major callices (3 or 4 of these that give rise to the big pelvis)
- Minor callices (12 or so of these, a few for each major)
The singular of callices is calyce
This is the collecting system of the kidney to take urine away from the kidney
Describe the renal papilla
- A small structure that is part of the renal pyramid
- Each pyramid is made up of the little collecting ducts which take urine and release it into the callices
- The little collecting ducts have a little opening into the papilla
- Glomeruli are found in the cortical part of the kidney and they are the organs that produce urine from blood
- Urine is then passed onto collecting ducts, papilla, minor papilla, major papilla then renal pelvis
Describe the cortex and medulla
Cortical region =
Medulla =
What do we find in the perirenal region?
Fat
Can see a lot of fat in this region
There are no bones (ribs) to protect the kidneys on the back - only protected by muscle and a lot of fat ***
What are the two capsules and two types of fat that surround the kidneys?
- Renal capsule surrounds the kidney and within that capsule there is a layer of fat
- -> This fat is called perirenal fat
- Renal fascia (part of deep fascia) surrounds the kidney and the renal capsule, has a layer of fat in this
- -> The fat in this area is called pararenal fat
Describe the blood supply further?
Listen?
Describe the ureters
- Muscular tubes which carry urine to the bladder
- About 25 cm long
- Also located in the RETROperitoneal space
Describe the path of the ureters
- Descends vertically anterior to the transverse processes of L2 – L5 vertebrae
- Crosses brim of pelvis and external iliac artery to enter pelvis
Describe the 3 main sources of blood to the ureters
It is so long that one artery cannot do all of the blood supply
- Renal artery
- Superior vesical artery
- Common iliac or the aorta
Where are the 3 areas of the ureters where they become more narrow and they tend to catch renal stones?
- Renal pelvis where the ureters begin
- When it crosses the illiac artery
- When the ureter enters the bladder
What are suprarenal glands?
There are two names
- Suprarenal glands (better descriptive names)
- Adrenal glands
Describe the shape of the right suprarenal gland
Right
- Triangle
Describe the shape of the left suprarenal gland
Left
- Semilunar shape
Describe the attachment of the suprarenal glands to the kidney
They are actually NOT attached to the kidney, there is a fascial layer in between
The fat around the suprarenal gland and the gland are hard to differentiate
Describe the blood supply to
1 - Superior suprarenal arteries
2 - Middle suprarenal arteries
3 - Inferior suprarenal arteries
Endocrine glands in general have a lot of blood supply
Describe the position of the urinary bladder
- In adults, lies in the true pelvis when empty, then pushes up into the abdomen ONLY when it is full ***
- In infants, bladder protrudes into the abdomen NORMALLY because it is larger ***
Bladder is a RETROperitoneal organ
“Good to remember this”
Describe the shape and structure of the urinary bladder
- Bladder is a hollow muscular bag covered by smooth muscle known as DETRUSOR muscle ***
- Mucus membrane of the urinary bladder is firmly attached to underlying tissue at trigone (transitional epithelium, just an FYI)
- Empty bladder is shaped like a triangular pyramid containing
What are the components of the urinary bladder
Remember, shaped like a triangular pyramid, which contains:
- An apex (attached to umbilicus via muscle)
- Superior surface
- Two inferolateral surfaces (one on each side)
- Base (where ureters come in on the back wall)
- Neck (where it starts to narrow before the urethra starts)
What is the urinary trigone?
A smooth triangular region of the internal urinary bladder formed by the two ureteral orifices (coming from each kidney) and the internal urethral orifice (which the urine exits the body through)
The location where infections typically start in the bladder because it is pretty stable and bacteria can “take hold” here
What muscle forms a sphincter in the bladder?
The detrusor muscle contributes to a sphincter in the openings of the ureters into the bladder so urine doesn’t go back up to the kidneys from the bladder
What are the blood supplies to the urinary bladder?
- Superior vesical artery
- Inferior vesical artery
- Vesical venous plexus (drains into internal iliac)
Describe the nerve supply to the urinary bladder
Autonomic nerves because it is smooth muscle, not skeletal
S2, 3, 4 - sympathetics that constrict the sphincter
The bladder is emptied when the sphincter urethrae muscle (in the urethra) which is a SKELETAL muscle - voluntary release of this muscle leads to urination
Describe nerve damage to the spinal cord in relation to bladder voiding
- If the spinal cord is cut, the bladder fills up then the reflex automatically release the urine
- The sphincter urethrae muscle is paralyzed as well, so all you need is the reflex to urinate
- They will have to wear a diaper
Describe how the sphincter urethrae weakens as we age
- Sphincter urethrae weakens as you age
- Elders may have leaking or accidents and need to wear diapers
Describe the sphincter urethrae in babies
No voluntary control over sphincter urethrae muscle in children
Describe the male urethra
- 15-20 cm long
- Extends between the bladder and the external urethral orifice in glans penis
- Common passageway for urine and semen
What are the three parts of the male urethra
- Prostatic urethra
- Membranous urethra
- Penile urethra
Describe the female urethra
- 2-6 cm long
- Extends between the bladder and the external urethral orifice in the vestibule of vagina
What is the implication of a shorter urethra in females?
More infections (UTI, bladder infection, kidney infection)
Describe the prostate gland
Males only
- Shaped like an inverted pyramid
- Size of a walnut
- Composed of fibromuscular glandular tissue
- Lies between neck of bladder and urogenital diaphragm
Describe the components of the prostate gland
- Fibrous capsule
- Base
- Apex (rests on urogenital diaphragm)
- Anterior surface
- Posterior surface
- Ejaculatory duct
- Lobes
What are the 5 lobes of the brostate gland?
- Anterior
- Posterior
- Median
- Lateral (2)
Don’t pay too much attention to these lobe names because there are a lot of variation in how people label them
What is the lobe you want to pay attention to?
Between the ejaculatory duct and the urethra is the MEDIAN LOBE
This is the lobe that causes problems in benign prostatic hyperplasia
It enlarges and can block off the urethra
Which lobe of the prostate contributes to BPH (benigh prostatic hyperplasia)?
MEDIAN LOBE
What is the implication of BPH
- Retention of urine
- The bladder can’t completely empty out
- Have to urinate frequently
Describe the ejaculatory duct
- The duct starts in the seminal vesicles, goes through the prostate and then enters the urethra
- This is where the semen, prostatic fluid and sperm exits during ejaculation
Describe the difference between the two sphincters in the urinary system
The detrusor muscle forms a sphincter called the sphincter vesicle (AUTONOMIC - smooth muscle) at the bottom of the bladder before it becomes the urethra
The sphincter that is VOLUNTARY and is skeletal muscle is the sphincter urethrae
Describe the blood supply of the prostate
Arteries derived from
- Internal pudendal
- Inferior vesical
- Middle rectal
Describe the veins that take deoxygenated blood away from the prostate
Prostatic venous plexus drains into internal iliac veins
