PBL 8 kidney n bladd

PBL 8 kidney n bladd

Question Answer
Give three functions of the bladder Temporarily store urine at low pressure (without sensitisation), Empty fully (at a socially convenient time), reciprocal contraction/relaxation of the bladder/urethra
what is the urinary bladder? a hollow, muscular organ that serves to temporarily store urine
what can the size of the bladder change with? whats the max? size changes with the amount of urine it holds (up to a max of 1L)
name two ligaments of the bladder the median umbilical ligaments (extends from the anterior, superior border towards the umbilicus) and the lateral umbilical ligaments (pass along the sides of the bladder to the umbilicus)
what do the umbilical arteries run in conjunction with? the median and lateral umbilical ligaments
what does the median umbilical ligament extend from? the anterior, superior border towards the umbilicus
where does the lateral umbilical ligaments go? pass along the sides of the bladder to the umbilicus
what is the superior part of the bladder covered by? peritoneum
where do the anterior, posterior, and inferior parts of the bladder sit outside? the peritoneum – in these areas, tough ligamentous bands anchor the bladder in the pelvic cavity
what is the mucosal lining of the bladder? rugae, which disappear as the bladder fills
whats the trigone? the triangular area bounded by the opening of the ureters and the entrance of the urethra. Here the mucosa is smooth and thick.
what does the trigone act as? a funnel that channels urine into the urethra then the urinary bladder contracts
what is detrusor muscle lined with transitional epithelium
what is the body of the bladder? the portion of the bladder situated between the fundus and the apex – fundus is inferior posterior surface
in males what is the urinary bladder fundus closely related to? anterior wall of the rectum – in females the fundus is closely related to the anterior wall of the vagina
what does the fundus contain? the trigone of the bladder
where is the trigone of the bladder found? the internal surface of the fundus – its a triangular area of smooth muscle.
what are the ureteric orifices? the openings of the two ureters in the bladder
what lies between the ureteric orifices? a membranous fold called the interureteral fold
where is the neck of the bladder situated? at the base of the trigone and is therefore the most inferior aspect of the back. Inferiorly, the neck of the bladder is continuous with the proximal urethra
how long is the female urethra? 4cm long – its external opening is situated between clit and vagina
how long is the male urethra and what parts can it be divided into? The male urethra is much longer than the female urethra (which is 4cm) and can be divided into 4 parts – pre-prostatic urethra (continuous with neck of bladder), prostatic urethra, membranous urethra, spongy urethra
what is the pre-prostatic urethra surrounded by? an involuntary muscle called the internal urethral sphincter muscle
what is the membranous urethra surrounded by? the external urethral sphincter muscle
what part of the male urethra is longest? the spongy urethra – contains the external urethral orifice
where does the urinary bladder receive its arterial blood supply from? 2 branches of the internal iliac artery – the superior vesical artery and the inferior vesical artery (supplies fundus and neck)
where is venous blood from the urinary bladder drained to? the vesical venous plexus
what is innervation of the urinary bladder provided by? the vesical nervous plexus
Name the four layers of the bladder wall Mucosa, Lamina Propria, Musuclaris, Adventitia
describe the mucosa of the bladder a mucous membrane with transitional epithelium (able to stretch). Mucous secreted by goblet cells of the mucosa prevents the cells from coming in contact with the urine
describe the bladders lamina propria areolar connective tissue with considerable collagen, elastic fibres and lymphatic tissue
describe the bladders muscularis also called the detrusor muscle – consists of three layers of smooth muscle; inner longitudinal, middle circular, and outer longitudinal layers
describe the adventitia of the bladder a superficial coat of areolar connective tissue containing blood vessels, lymphatic vessels, and nerves that serve the muscularis and mucosa. The adventitia blends in with the surrounding connective tissue and anchors the ureters in place
what anchors the ureters in place the adventitia
what three layers of smooth muscle does the detrusor muscle have inner longitudinal, middle circular, outer longitudinal
what sort of control does the internal urethral sphincter have involuntary
what sort of control does the external urethral sphincter have voluntary
describe the internal urethral sphincter smooth muscle fibres found at the neck of the bladder, providing involuntary control of urine discharge. In men it is known as the pre-prostatic sphincter (bladder neck)
describe the external urethral sphincter voluntary control, skeletal muscle fibres found distally. Intramural striated muscle (rhabdosphincter) and periurethral striated muscle (pelvic floor muscles)
venous drainage of the bladder x surrounding the bladder is a rich plexus of veins that ultimately empties into the internal iliac veins.
lymphatic drainage of the bladder x lymphatics drain into the vesical, external iliac and common iliac lymph nodes
what is chronic obstruction of bladder outflow due to? BPH (enlarged prostate compresses the urethra, making it difficult to urinate and empty the bladder), bladder stones, kidney stones, bladder tumours
what does reduced urine outflow cause – what happens to the ureters? backflow up the ureters and build up of urine. The ureters become dilated and lose their peristaltic function. Thus, urine can only flow down the ureters by the force of gravity
what's hydronephrosis? dilation of the renal pelvis and calyces
what can untreated hydronephrosis lead to? progressive atrophy of the kidneys, thus leading to kidney impairment
where is the external urethral sphincter? in an area known as the urogenital diaphragm
why are females more likely to get a uti? because there urethra is shorter (about 4cm)
name two receptors found on the bladder Muscarinic M3 receptor and Beta B3 receptor
what receptor is found on the internal sphincter muscle? the alpha 1 receptor
what receptor is found on the external urethral sphincter? the nicotinic receptor
name a parasympathetic nerve that supplies the bladder the pelvic nerve
what does the pelvic nerve do releases Ach, which binds onto the M3 receptor on the detrusor muscle – this causes contraction of the detrusor muscle.
which region does the pelvic nerve come from? the sacral region
where does the pudendal nerve come from sacral region
what sort of nerve is the pudendal nerve? a somatic nerve – it is under our control
what does the pudendal nerve do? releases Ach and acts on the nicotinic receptor found on the external sphincter
what happens when Ach from the pudendal nerve binds onto the nicotinic receptor of the external urethral sphincter? causes the external sphincter to contract – firing pudendal nerve when u are trying to hold in urine
which region does the hypogastric nerve come from? the thoracolumbar region
what does the bladders nerve impulses do during the micturition reflex? cause contraction of the detrusor muscle and relaxation of the internal urethral sphincter muscle
what does the hypogastric nerve target releases noradrenaline (its a post sympathetic nerve), which binds to the M3 receptor on the detrusor muscle and causes relaxation of the detrusor muscle. noradrenaline also binds to alpha 1 receptor on internal sphincter – causes contraction
what is the hypogastric nerve responsible for? urine retention, holding in urine, whereas the parasympathetic nervous system is responsible for voiding/pissing
name a 4th afferent nerve that's involved with the bladder a sensory pelvic nerve coming from the detrusor muscle – afferent nerve, is stimulated when the bladder is stretched
where is the micturition centre located? the pons
what does the increased build-up of urine in the pelvis and calyces cause? a pressure backlog, thus REDUCING THE GFR, due to the loss of a concentration gradient for solutes to filter out of the glomerulus into the tubules
what can a reduced GFR lead to? The buildup of systemic toxicity due to reduced toxin clearance
what might no improvement of serum creatinine after hydronephrosis suggest? the damage to the kidneys has been done. The GFR is not improving and thus creatinine is still not being cleared as efficiently as it should be
why might there be increased serum urea and creatinine? due to decreased urea/creatinine clearance through glomerulus (lack of diffusion gradient)
why might there be a slight increase in K+? due to impaired kidney function
what does reduced GFR lead to? reduced formation of primary filtrate, and thus, less filtrate reaching the PCT/DCT for reabsorption
what's the normal pH range? 7.35-7.45
what is GFR measured in? mL/min/1.73m2
GFR for stage 1 kidney failure above 90 mL./min/1.73m2
GFR for stage 2 kidney failure 60-90 mL/min/1.73m2
GFR for stage 3 kidney failure 30-60mL/min/1.73m2
GFR for stage 4 kidney failure 15-30mL/min/1.73m2
GFR for stage 5 kidney failure less than 15 mL/min/1.73m2
Name the three buffer systems acid-base regulation is controlled by? renal, pulmonary, chemical buffers
what does the renal buffer system do? regulation of HCO3- and H+ reabsorption and secretion
what does the pulmonary buffer system do? control of CO2 levels by hyper/hypo-ventilation
what does the chemical buffer system do? phosphate, proteins, BICARBONATE (most important physiological buffer)
what do buffers mainly focus on? buffers mainly focus on ensuring that the H+ concentration is not too extreme, thus maintaining pH within its 7.35-7.45 range. Hence H+ conc can be normal during acid-base imbalance – this is usually done at the expense of other blood chemicals (CO2, HCO3
what happens to volatile acids produce CO2, these can be eliminated from the body as a gas
what's a fixed acid acids that are produced by anaerobic respiration (lactic acid) and cannot be blown off
how do you buffer a fixed acid ? buffering a fixed acid consumes HCO3- and the kidneys are important in the maintenance of HCO3- conc , and is via the excretion of H+ (in the form of NH4+ or H2PO4-) and subsequent reabsorption of HCO3-
name some sites of H+ secretion PCT, DCT, and collecting duct
name some sites of HCO3- reabsorption 90% in PCT, 10% in intercalated discs of DCT/collecting duct
what do renal tubule cells secrete and in exchange for what? renal tubule cells secrete H+ in exchange for Na+
what happens to CO2 in the renal tubule cell of the PCT? its converted back to HCO3- in the renal tubule cells
PCT renal tubule cell: what does the Na+/HCO3- symporter do? carries Na+ and HCO3- across basal membrane of tubule cell
phosphate buffer system: what's the anion The anion H2PO4- is a weak acid which is useful for buffering H+
what's the major non-bicarbonate buffer in the urine? phosphate
how much H+/day does phosphate account for? about 40mmol of H+/day
give the reversible equation for the phosphate buffer system H2PO4- -> H+ + PO42-
how is ammonium and NH3 released from tubular cells? The tubular cells use the enzyme glutamase to break down the amino acid glutamine, releasing ammonium (NH4+) and NH3
what happens to the NH4+ produced from glutamine break down? its released into the urine, in exchange for Na+
what happens to the NH3 produced from glutamine break down and why? the NH3 is highly volatile and toxic to cells, therefore it rapidly diffuses into the tubular fluid, then reacts with H+ to form NH4+
what happens to the remainder of the glutamine? it's converted to bicarbonate (HCO3-) and it is co-transported with Na+ into the extracellular fluid, then absorbed into the bloodstream
when does metabolic acidosis occur? it's a condition that occurs when the body produces excessive quantities of acid or when the kidneys are not removing enough acid from the body
whats the H+, HCO3, and CO2 conc like in metabolic acidosis? Increased H+ concentration, decreased HCO3- concentration, decreased CO2
compensatory mechanism for metabolic acidosis? increased ventilation, to blow off CO2
causes of metabolic acidosis build up of acid through metabolism e.g. muscle metabolism leads to lactic acid build up. ingestion of acid, e.g. methanol. Failure to excrete acid – renal tubular acidosis. Loss of HCO3- in the stool (diarrhoea) or urine (renal tubular acidosis)
whats the H+, HCO3-, and CO2 concs like in metabolic alkalosis ? decreased H+, Inc HCO3-, inc CO2
compensatory mechanism for metabolic alkalosis dec ventilation to raise CO2
causes of metabolic alkalosis vomiting – stomach acid contains a lot of acid (HCl), inc aldosterone production (maybe due to overuse of mineralocorticoids, or hyperaldosteronism) – this causes inc K+ excreted in the urine,. H+ used to compensate for the K+ lost via the H+/K+ antiporte
what are CO2 and H+ like in respiratory acidosis inc CO2 due to hypoventilation leads to inc H+ conc
compensatory mechanism for respiratory acidosis most of the inc H+ conc is buffered intracellularly, renal compensation – H+ ions are secreted and HCO3- ions are reabsorbed more. Resp comp – stimulation of arterial and CSF chemoreceptors causes an inc in breathing rate
what's CO2 and H+ like in respiratory alkalosis dec CO2 due to hyperventilation leads to dec H+
compensatory mechanism for respiratory alkalosis renal compensation – H+ ions are generated and HCO3- ions are secreted. Rsp comp – stimulation of arterial and CSF chemoreceptors causes a dec in breathing rate
what is chronic kidney disease defined as? a progressive, longstanding (more than 3 months) deterioration and impairment in renal function . CKD causes are varied and can be multifactorial
at what stage of kidney disease do symptoms start to appear? usually stage 4 – first symptoms often when GFR is less than 20
what problems are likely as the GFR falls? electrolyte problems
what do ckd patients typically present with? increased urea and increased creatinine. frequently accompanied by hypertension, proteinuria and anaemia
when do most ckd patients tend to be asymptomatic until GFR falls below 30mL/min/1..73m2, normally presenting with nocturia (urinating at night) due to the inability to concentrate urine at each nephron, therefore increasing the osmotic overload
what happens when gfr falls below 15mL/min/1.73m2 the patient will present with signs and symptoms that can affect all body systems – these include tiredness, breathlessness, anaemia, anorexia, weight loss, nausea, vomiting
what can patients experience with further renal deterioration deep respiration (Kussmaul's respiration) due to metabolic acidosis
when is the risk of CVD greatly increased? in CKD stage 3 or worse – hypertension occurs, and secondary to that, ventricular hypertrophy (can cause death). there's impairment in systolic and diastolic function. coronary artery calcification caused by inc Ca2+ levels, and may be due to hyperparathy

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