SUGER Flashcards
What is neurourology?
Management of neuropathic bladder, bowel and sexual function
What are the types of incontinence?
Stress incontinence, urge incontinence, retention with overflow
What is the function of the urinary tract ?
Collect the urine, store it and void it when socially appropriate
What are the key factors of filling in a normal bladder?
Continence, sensation of bladder volume and receptive relaxation
What are the key factors of voiding in a normal bladder?
Voluntary initiation and emptying completely
What are the consequences of rtinary tract dysfunction?
Infections, bladder stone and upper tract injury
What in the function of the upper urinary tract?
Prevention of reflux and active peristalsis
What are the urethral sphincters?
Distal urethral sphincter (smooth muscle, intrinsic striated sphincter and extrinsic strained sphincter) and urethral sphincter, which is only used during ejaculation
What is the rhabdosphincter made of?
Intrinsic striated distal urethral sphincter. It is a slow twitch striated muscle.
What are the local afferents in the bladder?
The guarding reflex
Where does the Onuf’s upper motor neurone come from?
The motor cortex, it travels in the cortico-spinal tracts
What is the bladder made of?
It is composed of multiple segments of smooth muscle with their associated ganglia. Each segment exhibits spontaneous activity (micromotions)
Can the bladder be denervated?
No
What does the sacral micturition centre control?
Parasympathetic control of the bladder, with C fibre local afferents. Causes reflex bladder contractions
What do A delta fibres do?
Control normal sense of bladder fullness
What is sympathetic control of the bladder?
The bladder has receptive relaxation, the bladder neck during ejaculation and the smooth muscle sphincter
What does the pontine micturition centre do?
Possible medial (micturition) and lateral (storage) centres. It is the motor centre for the autonomic control of the lower urinary tract
What happens in the periaqueductal gray do?
It has the visceral and somatic control centre for the lower urinary tract. It receives A delta fibre input and communicates with conscious centres
How does the cerebral cortex affect the bladder?
It receives sensation and voluntary initiation
How does the midbrain affect the bladder?
It had the periaqueductal gray and the pontine micturition centre. It controls coordination and completion of voiding
What are the spinal reflexes involved in passing urine?
The reflex bladder contraction in the sacral micturition centre (coordination of micromotions); guarding reflex in Onuf’s nucleus
What does neuropathic mean?
Disorder of function due to nervous system dysfunction
What does atrophy mean?
Decrease in size or wasting away of a body part or tissue
What makes up the urinary system?
Kidneys, ureters, urinary bladder and urethra
What is the function of the kidney?
To filter the blood
What is the function of the ureter?
To transport the urine to from the kidney to the urinary bladder
What is the function of the urethra?
Conduct the urine from the bladder to the exterior atmosphere
How much of the cardiac output do the kidneys receive?
About 1/5th
What is the blood supply of the kidneys?
The renal arteries
Where do the renal arteries arise from?
Directly from the abdominal aorta
What hormones do the kidneys produce?
Erythropoietin and renin
What is the function of erythropoietin?
Controls red blood cell production
What is the function of renin?
It regulates water and salt concentrations
What are the two divisions of the kidney?
A pale coloured outer cortex and the darker regoins of central medullary tissue
How many medullary pyramids does each kidney contain?
10-15
What does the cortex of the kidney contain?
All the glomeruli, the convoluted (coiled) parts of the proximal and distal tubes, and the proximal parts of the collecting ducts
What do the medullary pyramids of the kidney contain?
The straight portions of the proximal and distal tubules, the loops of Henle and teh distal parts of the collecting ducts
What enters and leaves the kidney hilum?
The renal artery and vein
What does the renal artery divide into?
5 or 6 main branches that give off arcuate arteries at the corticomedullary junction. From these arise the interlobular arteries
What is the path of the interlobular arteries?
The interlobular arteries penetrate the cortex at regular intervals diving the cortex into lobules. They give off afferent arterioles that supply the glomeruli
Where is the blood filtered in the kidney?
The glomeruli
How does the filtered blood leave the glomeruli?
Via the efferent arterioles and passes through thin walled vesseles between the tubules. Here it acquires fluid and ions recovered by the nephrons.
What do the efferent arterioles in the kidney drain into?
They drain into the arcuate veins for return to the systemic circulation
What blood vessel supplies the medulla of the kidney?
Near the cortico-medullary junction the arcuate arteries give off straight arteries that penetrate deep into the medulla
What is the path of the blood entering the kidney to be filtered?
First it goes to the glomeruli to be filtered. The primary filtrate is passed to the rest of the nephron for selective re-absorption of certain solutes
What does the glomerulus consist of?
A parallel array of fenestrated capillaries ensheathed by specialised endothelial cells called podocytes
Where is the filtration barrier of the kidney?
It is the basement membrane between the endothelial cells of the capillaries and the podocytes of the epithelium
Where are mesangial cells and what do they do?
They are between the coiled loop of the glomerular. They are important in forming the matrix
Where are the specialised renin-producing cells in the kidney?
In the wall of the afferent arteriole
Where is the macula densa of the kidney?
It is a specialised palisade of cells in a segment of distal tubule alongside the glomerulus
What does the glomerular tuft made up of?
Capillary loops supported by podocytes. It is surrounded by the urinary space that separates it from the glomerular capsule
What is the function of the mesangial cells?
They are responsible for providing the overall framework of the glomerulus
What is the first segment of the tubule of the nephron?
The proximal tubule. It is the most highly coiled segment. The cells have a prominent brush border and complex invaginations of their baso-lateral membrane
What takes place in the proximal tubules?
Extensive re-absorption of the filtrate. Na+, glucose and amino acids are actively transported in. Proteins and polypeptides are transported by endocytosis and lysozymes in their break them down.
What are the sections of the loop of Henle?
A thick straight descending portion, a thin loop and a thick ascending portion
Which loops of Henle have the longest and most penetrating thin loops?
The ones belonging to nephrons whose glomeruli lie close to the cortico-medullary junction
What does the ascending portion of the loop of Henle do?
It retains (is impermeable to) water although chloride and sodium are re-absorbed. This results in the production of a dilute filtrate but an interstitium that is hyper tonic
What does the descending portion of the loop of Henle do?
It has a low permability to ions and urea but is highly permeable to water so water is reabsorbed
What is the path of the distal tubule?
It follows on from the loop of Henle. It returns to the medulla to the cortex and then to the vascular pole of its own glomerulus.
How does aldosterone affect the distal tubules?
It increases sodium and bicarconate reabsorption and potassium and H+ excretion. This means the urine is acidic
List two important proteins that normally pass from the blood into the primary filtrate but are then reabsorbed:
Almost any small negatively charged protein can enter the glomerular filtrate but will be reabsorbed. Proteins such as albumins and Hb are too large to enter the filtrate
What is the difference between the proximal and distal tubules?
The proximal tubule is normally longer and more tightly coiled than the distal tubule
Are proximal or distal tubules more numerous type of tubules within the cortex?
The proximal tubule appear more numerous than those of the distal tubule
Where is the collecting duct in the nephron?
It is the final part of the nephron
What is the path of the collecting duct?
It starts in the cortex and filtrate from the distal tubule passes first into collecting tubules and thence into larger collecting ducts
How are medullary rays formed?
The collecting tubules from several nephrons coalesce to form larger ducts that pass into the medulla and from visible streaks known as medullary rays
Do collecting ducts have lots of mitochondria?
They have a high concentration of mitochondria
How does ADH affect the kidneys?
ADH increases the permeability of the collecting ducts cells and as a consequence water is re-absorbed to interstitium thereby concentrating the urine
What does the juxta-glomerulus apparatus consist of?
It consists of the afferent and efferent arterioles, the macula densa and specialised cells of the glomerular matrix known as lacis cells
What in the kidney produces renin?
Cells in the walls of the afferent arteriole are adapted to produce renin that appears as granules in the cytoplasm
What does renin do?
Renin when released, catalyses the conversion of angiotensin to angiotenis 1, the first step in the stimulation of aldosterone release by the suprarenal glands
Where is angiotensinogen produced?
In the liver
Where is angiotensin 1 converted to angiotensin 2?
Mainly in the lungs
What does angiotensin 2 do?
It stimulates the release of aldosterone by glomerular cells in the cortex of the suprarenal gland
Where does aldosterone?
Cells of the distal tubules and collecting ducts where this hormone promotes the reabsorption of the sodium ions and water and thereby concentrates the urine and conserves body fluid
What is urothelium?
The ureters, bladder and most of the urethra are lined by a pseudo-stratified epithelium often referred to as urothelium
What happens to bladder epithelium when it is full?
As the bladder fills with urine the epithelium is stretched and the apparent number of layers of cells decreases
What are the layers of the ureter?
It has a star shaped lumen. The epithelial tube is surrounded by two helical layers of smooth muscle.
How do the muscle fibers of the ureter vary?
Toward the bladder the muscle fibres become predominantly longitudinal in orientation
What are the three points where the ureter is sharply constricted?
(1) at it’s origin in the pelvis of the kidney; (2) as it passes into the true pelvis anterior to the sacro-iliac joint; (3) as it enter the postero-inferior side of the bladder
How does the ureter prevent reflux of urine?
The compression of the ureter as it passes obliquely through the muscular wall of the bladder prevents reflux
What is the wall of the bladder made of?
It is composed of thick bundles of smooth muscle with no preferred direction except at the neck where the urether where it acts ac a sphincter
What is the bladder neck sphincter made of?
3 distinct layers of smooth muscle. The innermost longitudinal layer projects inferiorly and turns transversely to form a sphincter around the prostatic urethra (male) and the external meatus (female)
What is the main type of nerve supply to the bladder?
Parasympathetic from the sacral outflow. Sympathetic mainly affects the blood vessels of the bladder
Is the urethra longer in the male or female?
Male
What are the parts of the male urethra?
There are prostatic, membranous, bulbous and pendulous parts
How is blood flow of the glomerulus regulated?
By constriction of the afferent and efferent arterioles
Is the proximal convoluted or the distal convoluted tubule more tightly coiled?
Apart from the straight portions of these tubules, the proximal tubule is more tightly coiled than the distal tubule.
What is the result of the proximal convoluted tubule being more coiled than the distal convoluted tubule?
There are more transverse and fewer oblique sections through the proximal tubules than through the distal tubules
How do the loops of Henle differ in length?
Nephrons with glomeruli close to the medulla have long loops of Henle that project deep into the medulla. Ones close to the surface of the kidney have short loops that project to the outer medulla
Why is the wall of the ureter composed mainly of smooth muscle rather than of fibrous connective tissue?
The musclular wall of the ureter undergoes peristaltic contraction that helps to conduct the urine to the bladder
What causes the bladder to contract during micturition?
When the external sphincter of the bladder is relaxed (sympathetic stimulation) and detrusor muscle of the bladder wall contracts (parasympathetic stimulation)
Which glands drain into the prostatic urethra?
Most genital glands. Including the prostate, the seminal vesicles and the deferent duct.
What glands drain into the penile urethra?
The bulbo-urethral glands and other smaller mucous glands
What are the constituents of the male reproductive tract?
The testis, the epididymus, the vas deferens and the urethra
Where does the reproductive tract join the urinary tract?
Within the prostate gland and seminal fluid is expelled via the prostatic, membranous and penile urethra
What is the tunica albuginea?
A thick, dense collagenous capsule that encloses each testis
What do the seminiferous tubules drain into?
They drain into a network of channels (rete testis) that deliver sperm to the epididymis.
Where are and what is the function of Leydig cells?
They are between the seminiferous tubule in clumps and they produce testosterone
What is an exocrine gland?
pour’ secretions through a duct to site of action e.g. exocrine pancreas - amylase, lipase
What is an endocrine gland?
glands ‘pour’ secretions into blood stream e.g. thyroid, adrenal, beta cells of pancreas
What is in the major endocrine system?
Pituitary; Thyroid; Parathyroid; Adrenal; Pancreas; Ovary; Testes