963106
Description
Flashcards by Hannah Tribe, updated more than 1 year ago
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Created by Hannah Tribe
almost 10 years ago
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| Question | Answer |
| How does urine travel from the kidneys to the bladder? | By myogenic peristaltic waves along the ureters. |
| How do the ureters enter the bladder, and how is back flow prevented? | Ureters enter obliquely on the posterior surface of the bladder, in the trigone region. Passive flap-valves prevent back flow of urine. |
| What are kidney stones? | Crystals that have precipitated out of the urine within the urinary tract, usually calcium oxalate or maybe calcium phosphate. |
| What can cause kidney stones? (5) | 1. Poor urine output/obstruction 2. Altered pH of urine 3. Low concentration of stone-inhibiting substances (e.g. citrate) 4. Infection 5. Excess intake of stone-forming substances (in diet) |
| What are the symptoms that a kidney stone can cause? (4) | 1. Painful urination (dysuria) 2. Haematouria 3. Pain in the loins or back (referred) 4. Reduced urine flow |
| What feature of the bladder allows stretch? | Transitional epithelium can flatten out, and epithelium is not tightly attached to the detrusor muscle, which itself is overlapping and concentric, allowing for more stretch. |
| What is the internal sphincter? | It is an extension of the detrusor muscle and is not under voluntary control. |
| What is the external sphincter? | 2 striated muscles surrounding the urethra, which are under voluntary control. |
| What are the differences between the female and male bladder and urethra? (4) | 1. Female bladder is more spherical 2. Female urethra is shorter 3. Female urethra only carries urine, male also carries semen 4. Female external sphincter is poorly developed, so can easily be damaged in childbirth, whereas males do not have to rely on the external sphincter for urinary continence, as muscles in the penis also aid urination. |
| How is innervation to the bladder both sensory and motor? | Sensory, because we are able to detect when the bladder is full. Motor, because the detrusor muscle can contract and internal sphincters relax to allow micturition. |
| Which 3 sets of nerves innervate the lower urinary tract? | Sympathetic nerves from the hypogastric nerve (T11 - L2), Parasympathetic nerves from the pelvic nerve (S2-S4), Somatic nerves from the pudendal nerve (S2-S4) |
| What are the afferent (sensory) pathways? | Afferent fibres are mainly parasympathetic, A fibres that sense the tension in the detrusor muscle, and unmyelinated C fibres near epithelium that detct pain on over stretching, or in response to infection. Sympathetic (hypogastric) and somatic (pudendal) afferents also detect pain via nociceptors. |
| What is the motor innervation of the bladder? | Parasympathetic neurones (pelvic nerve) to stimulate urination by contracting the detrusor muscle and relaxing the internal sphincter (NO). Sympathetic neurones (hypogastric nerve) to stimulate relaxation of the detrusor (directly through beta receptors, indirectly by blocking parasympathetic fibres [alpha receptors]) and contraction of the internal sphincter (alpha receptors), promoting storage of urine in the bladder. Somatic neurones (pudendal nerve) cause contraction of the external sphincter to prevent micturition. |
| Micturition is an _________ reflex for babies and adults with spinal injury, but can be modified to be under _____________ ________ as we grow. Once we have this, higher centres allow us to switch between __________ and ______________. | autonomic, voluntary control, storage, elimination |
| How can we modify the micturition reflex voluntarily? | Consciously contracting the external sphincter and levator ani muscles can trigger increased sympathetic control of the internal sphincter (contracting it). |
| Why is it important to empty the bladder? | To maintain sterile environment and prevent infection. If urine remains in the bladder for too long, bacteria can grow and infect fresh urine too. |
| Name 3 types of UTI | 1. In the kidney - pyelonephritis 2. In the bladder - cystitis 3. In the urethra - urethritis |
| Why are UTIs more common in women? | Women have a shorter urethra |
| Why can they become common in men over the age of 40? | Enlarged prostate can cause urinary retention in the bladder and therefore is at a higher risk of becoming infected. |
| What are the 2 types of incontinence? | 1. Stress incontinence - caused by weakening of the sphincters (after childbirth, with age etc.) 2. Urge incontinence - caused by Overactive Bladder (OAB), where detrusor muscle contracts spastically. |
| What is atonic bladder? | The destruction of the sensory nerve fibres from the bladder to the spinal cord, so there is no contraction of the detrusor by micturition reflex. The bladder therefore fills to maximum capacity then overflows drops at a time into the urethra, causing overflow incontinence. |
| What is automatic bladder? | After injury to the spinal cord, trauma causes spinal shock, which causes suppression of the micturition reflex so that catheterisation is needed to prevent damage to the bladder. After the reflex returns, damaged nerves still cause the reflex to no longer be under voluntary control. |
| What is neurogenic bladder? | Damage that has occurred to the brain stem or the spinal cord which interrupts the inhibitory signals from the sympathetic nerves, causing continuous excitable impulses, resulting in frequent and uncontrolled urination. |
| Name 6 'renal syndromes'. | 1. Nephritic syndrome 2. Nephrotic syndrome 3. Acute Kidney Injury (AKI) 4. Chronic Kidney Disease (CKD) 5. Haematuria 6. Asymptomatic proteinuria |
| Why is it difficult to diagnose specific renal diseases? | Each disease can manifest itself with symptoms from multiple syndromes. |
| How could you give a definite diagnosis? | Take a renal biopsy. |
| What are the 3 sub-categories of AKI? | 1. Pre-renal 2. Renal 3. Post-renal |
| What are pre-renal causes? | Relating to the blood flow to the kidneys, e.g. Hypovolaemia (due to haemorrhage), Decreased perfusion (due to septic shock, cardiac failure etc.), or drugs (ACE inhibitors, NSAIDs). |
| How can NSAIDs affect the kidney? | NSAIDs prevent the synthesis of prostaglandins, which are the main vasodilators in the afferent arteriole, so without the prostaglandins, the afferent arteriole is constricted, resulting in further decreased renal perfusion. |
| What happens if the pre-renal causes of kidney injury are not corrected? | It becomes renal disease |
| What are 3 intrinsic renal diseases? | 1. Glomerulonephritis 2. Acute tubular necrosis 3. Interstitial nephritis |
| What are post-renal causes of AKI? | Caused by obstruction, such as by kidney stones or enlarged prostate. |
| How are the post-renal causes identified and treated? | Detected by ultrasound, can sometimes be treated by bladder catheterisation. |
| Why are renal patients disproportionately expensive? | Dialysis is expensive, and there is a lack of organ donors for transplants. |
| What other health conditions can CKD lead to? | Cardiovascular diseases such as atherosclerosis and arteriosclerosis, which can increase the risk of MI and stroke. |
| Why might dialysis not be a suitable treatment option for some patients? | In older patients, dialysis may not actually prolong life, and will significantly reduce the quality of life, so is not deemed in the patient's best interests. |
| How is the patient connected to the haemodialysis machine? | An arteriovenous fistula is created (connecting an artery and vein so the vessel is larger and stronger). 2 thin needles are inserted each dialysis session, one for blood entering the machine and one for blood returning to the body. |
| How does the dialysis machine filter the blood? | The dialyser has a semi-permeable membrane within it, across which waste molecules can diffuse out. The dialysate and blood flow in opposite directions, creating a countercurrent mechanism as is seen in the kidneys. The pressure of the blood drives diffusion and ultrafiltration, as well as the composition of dialysate being tightly regulated to create the concentration gradients. |
| How does peritoneal dialysis differ? | Peritoneal dialysis uses the peritoneal membrane as the semi-permeable membrane across which waste products can diffuse out. The peritoneal cavity is filled with dialysis fluid containing high concentrations of glucose, to encourage water to leave by osmosis (as there is no control over pressure). |
| Why is it important to limit fluid intake when patients are on dialysis? | Can cause fluid overload, putting pressure on the CVS. |
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