1. Abdo 10 Renal and Urinary Flashcards
Functions of the renal and urinary system
The kidneys maintain homeostasis by the production of urine, which is the removal, from the circulating blood, of excess water and electrolytes, and toxic, metabolic waste products such as urea and creatinine.
The kidneys monitor and affect acid/base balance by excreting hydrogen ions during acidosis, or bicarbonate ions during alkalosis.
The kidneys secrete renin, which (indirectly) raises blood pressure, and erythropoietin, which accelerates red blood cell production.
The ureters conduct urine to the bladder, where it is stored.
The urethra is for the passage of urine out of the body.
What layers encapsulate the kidneys?
They are encapsulated and protected by layers - firm (perirenal/nephric) fat and then renal fascia, derived from extra-peritoneal fascia (and inc. the suprarenal gland), then pararenal/nephric fat
Kidney position?
Bean shaped Retroperitoneal Extend from T12 - L3 Right lower than the left Left kidney longer
Anterior and posterior relations of the kidney?
Anterior: Duodenum, liver, suprarenal glands, stomach, pancreas, Lt colic flexure, Rt colic flexure
Posterior: Ribs 10-12, Diaphragm medially, transversus abdominus, quadratus lumborum, psoas major
The functional unit within the kidney is the nephron that consists of?
- Renal corpuscle; (glomerulus)
- Proximal convoluted tubule (PCT);
- Loop of Henlé;
- Distal convoluted tubule (DCT);
- Collecting duct
A section through the kidney shows its cortex and medulla, with the renal ______ (housing the nephrons with their function of filtration and reabsorption) projecting as renal papillae into the _____ of the collecting system
Minor calyces converge on major calyces, which themselves form the ____ _____ that tucks in to the sinus of the kidney
At the hilum, the pelvis becomes the ______ that transports urine to the bladder
A section through the kidney shows its cortex and medulla, with the renal pyramids (housing the nephrons with their function of filtration and reabsorption) projecting as renal papillae into the calyces of the collecting system
Minor calyces converge on major calyces, which themselves form the renal pelvis that tucks in to the sinus of the kidney
At the hilum, the pelvis becomes the ureter that transports urine to the bladder
Renal hilum, ant to post?
Vein, Artery, Pelvis of ureter
Arterial supply of kidneys?
Renal arteries, from Ao at L 1, 2 (left higher than right), divide at hilum, usually ant and post, often additional, accessory, extrahilar arteries from Ao
The renal vein all receives which two veins?
Suprarenal
Gonadal
Shorter renal vein?
The right is shorter as it’s closer
What are the stages of renal artery division?
Each renal artery usually divides into five segmental arteries that enter the kidney at its hilum
Lobar arteries arise from each segmental artery, one for each renal pyramid
Before entering the renal substance, each lobar artery gives off two or three interlobar arteries
The interlobar arteries run toward the cortex on each side of the renal pyramid
At the junction of the cortex and the medulla the interlobar arteries give off the arcuate arteries, which arch over the bases of the pyramids
The arcuate arteries give off several interlobular arteries that ascend in the cortex
The afferent glomerular arterioles (that give blood directly into the renal corpuscle) arise as branches of the interlobular arteries
Kidney nerve supply?
Derived from T 12 and L 1, referring pain to the back and lumbar region, as well as loin to groin. Afferents in the vagus may cause the nausea and vomiting associated with such pain
Ureter narrowings?
Pelvi-ureteric junction
Crossing the pelvic brim
Passing through the bladder wall
Relations of the ureter?
The ureters lie anterior to psoas major, and therefore anterior to the branches of the lumbar plexus; they cross the bifurcation of the common iliac artery
Inc. the gonadal and left and right colic vessels
But lie posterior to everything else
Difference between pelvic relations of the ureter in males and females?
Male, between vas and seminal vesicle
Female, posterior to ovary, inferior to uterine artery, passing cervix and lateral fornix of vagina
Relations of ureter in pelvis?
Medial to:
- Internal iliac vessels and branches
- Lumbosacral trunk
- SI joint; Ischial spine
- Must also pass the rectum
Vascular and lymph supply of ureter?
Vascular:
- Aorta
- Renal
- Gonadal
- Common and internal iliac
- Uterine, vaginal
- Vesical
Lymph to para-aortic and iliac nodes
What is the relevance of the ureters oblique entry into the bladder?
The ureters pass through the bladder wall obliquely, creating a flap valve that prevents urine that is in the bladder from backing up and returning into the ureter (ureteric reflux)
Pressure of urine in the full bladder, forcing the ureters closed
The ureters pass 1.5 to 2 cms obliquely thro’ the bladder wall to prevent reflux
The walls of the ureters and bladder are essentially ________. Peristaltic waves propel urine down the ureter (hence the ____ pain of ureteric calculi) and the bladder fills by relaxation of its muscular wall (_______). Of course, bladder emptying is by muscular contraction, aided by raised ____-______ pressure.
The epithelial lining is ______ Epithelium, or urothelium, which is urine-proof and allows distension. The cells are _____ and piled on top of each other, but flatten and spread out to cope with distension.
The muscle is smooth and _______, controlled by the autonomic, particularly parasympathetic system. However, the external sphincter around the urethra is ______ and under voluntary control.
The walls of the ureters and bladder are essentially muscular. Peristaltic waves propel urine down the ureter (hence the colicy pain of ureteric calculi) and the bladder fills by relaxation of its muscular wall (detrusor). Of course, bladder emptying is by muscular contraction, aided by raised intra-abdominal pressure.
The epithelial lining is Transitional Epithelium, or urothelium, which is urine-proof and allows distension. The cells are rounded and piled on top of each other, but flatten and spread out to cope with distension.
The muscle is smooth and involuntary, controlled by the autonomic, particularly parasympathetic system. However, the external sphincter around the urethra is striated and under voluntary control.
Nerve supply of the ureter
Complex, autonomic supply, more at the lower end
Nerves are not required for peristalsis; there are many “pacemakers” in the renal calyces; muscle cell to muscle cell propagation of conduction, contraction; modulated by autonomics
Derived segmentally: T10, 11, 12, L1, S2,3, 4 from aortic, renal and pelvic plexuses
Referred pain is mainly T11 to L2: loin to groin and scrotum or labia
Filling and emptying of bladder controlled by?
Fills by its detrusor muscle relaxing, empties by its contraction
Detrusor is under the control of parasympathetic nerves derived from S2, 3, 4
Anatomically, how do men prevent semen back flow into bladder?
The male has a preprostatic, internal sphincter (sympathetic) to prevent semen backflowing into the bladder.
How does female anatomy relate to urinary continence
In the female the bladder neck is above the pelvic floor, so that pressure of pelvic organs, as well as levator ani contribute to urinary continence.
4 parts of male urethra?
- Preprostatic at bladder neck (position of smooth Internal Sphincter)
- Prostatic
- Membranous, surrounded by striated External Sphincter
- Spongy or Penile Urethra
Arterial supply of bladder and urethra?
Arteries: branches of the internal iliac artery - sup. and inf. vesical; internal pudendal; also branches from arteries to adjacent structures, e.g. vaginal, uterine
Venous drainage of bladder and urethra?
Veins: Vesical (and prostatic) plexuses converging on internal pudendal and internal iliac veins
Lymph drainage of bladder and urethra?
Lymph: to internal and external iliac nodes
From the prostate there are communications with the valveless veins of the vertebral plexuses (Batson) facilitating ______ _______
From the prostate there are communications with the valveless veins of the vertebral plexuses (Batson) facilitating tumour spread
Nerve supply of bladder and urethra
Require:
Somatic motor for control of striated muscle (ext. sph.)
Autonomic (motor) both sympathetic and parasympathetic (male pre-prostatic sphincter; detrusor)
Sensation:
S2, 3, 4 (Pudendal nerve and its branches)
Sympathetic and Parasympathetic in Pelvic Plexus
What are the 3 stages of micturition?
Simultaneous relaxation/contraction
1. Storage Parasympathetic to detrusor “switched off” in spinal cord to allow bladder to relax and fill Usual volume (male) about 400 ml, if reach 500 ml – pain in lower abdomen and perineum
- “Full”, causes desire to micturate
Afferents (sensory) to spinal cord, then “M” Centre in pons – stimulates preganglionic, parasympathetic neurones at S 2, 3, 4 - Void
1y neurones stimulate 2y neurones in bladder wall ganglia, causing detrusor contraction
Simultaneous relaxation of external urethral sphincter (striated muscle) – pudendal nerve (S 2, 3, 4) and contraction of abdo. wall; sensation of urine in urethra maintains the reflex
