Urinary System 2

Question 1

Describe ureters

Answer 1

25-30cm in length with diameter of 1-10mm along their length, retro-peritoneal, pass medially and obliquely through the posterior wall of the body, as bladder fills with urine, it exerts a pressure on the openings causing them to close and prevent backflow

Question 2

Describe the main role of the ureters

Answer 2

to transport urine from the renal pelvis to the bladder via peristaltic actions (1-5 per min), this pushes the urine through to the bladder, also helped by gravity

Question 3

Name the 3 key layers of the ureters

Answer 3

mucosa
muscularis
adventitia

Question 4

Describe the mucosa layer of the ureters

Answer 4

made of transitional epithelium - which is able to stretch and accommodate the passage of urine and of lamina propia - areolar connective tissue
goblet cells within the mucosa secrete mucus to prevent the cell walls from being damaged by the urine

Question 5

Describe the muscularis layer of the ureters

Answer 5

causes peristalsis - inner longitudinal and outer circular fibres of smooth muscle (opposite to GIT)
distal 1/3 of ureter has further longitudinal outer layer

Question 6

Describe the adventitia layer of the ureters

Answer 6

outer coat made of connective tissue containing blood vessels, lymphatics and nerves, blends into surrounding tissue and anchors the ureters in place

Question 7

Describe the urinary bladder

Answer 7

hollow, distensible, muscular organ in the pelvic cavity, anterior to vagina/inferior to uterus (females)
anterior to rectum (males)
spherical, then pear shaped as it fills with urine, holds 700-800 mls

Question 8

Describe key identifications of the bladder

Answer 8

triangular area on the floor of the bladder = trigone
2 posterior corners which are the urethral openings
anterior corner opens into the interior urethral orifice

Question 9

Name the 4 layers that make up the urinary bladder

Answer 9

mucosa
muscularis
adventitia
serosa

Question 10

Describe the mucosa layer of the urinary bladder

Answer 10

internal layer, made of transitional epithelium and lies in folds called rugae - allows for expansions the bladder fills, also made up of lamina propia which is areolar connective tissue containing elastic fibres and veins

Question 11

Describe the muscularis layer of the urinary bladder

Answer 11

called the detrusor muscle (push down) made up of 3 fibres - inner longitudinal, middle circular, outer longitudinal
circular fibres form the internal urethral sphincter
inferior to this is external urethral sphincter - composed of skeletal muscle

Question 12

Describe the adventitia layer of the urinary bladder

Answer 12

made of connective tissue continuous with the ureters

Question 13

Describe the serosa layer of the urinary bladder

Answer 13

outer layer, layer of visceral peritoneum

Question 14

Describe Micturition

Answer 14

when the bladder exceeds 200-400mls, the stretch receptors in the bladder wall send impulses to the sacral spinal cord and trigger the micturition reflex -causes contraction of the detrusor muscle and relaxation of the internal sphincter muscle and external sphincter muscles allowing micturition - the cerebral cortex learns to control this action through voluntary action (only for limited time)

Question 15

Describe the urethra

Answer 15

small tube allowing passage of urine from the inferior aspect of the bladder to the exterior, female urethra = 4cm
male urethra = 20cm - passes from bladder through prostate and deep muscles of the perineum to the exterior

Question 16

Describe the tissue layers of the urethra

Answer 16

deep mucosa composed of epithelium and lamina propia which is areolar connective tissue containing elastic fibres and veins, muscular layer contains circularly arranged fibres and is continuous with the bladder

Question 17

Describe the difference in tissue layers between males and females

Answer 17

Similar but their arrangement varies in males due to the reproductive organs associated with it

Question 18

Describe the 6 main roles of the kidneys

Answer 18

regulate the volume, composition and pH of bodily fluids - by removing waste and excess substances

contribute to synthesis of vitamin D - to allow absorption of dietary calcium

adjust levels of calcium - for muscle contraction and ca & K for extracellular bone matrix

perform gluconecogenesis - helps in neuron production during fasting/starvation

release erythropoietin hormone - to stimulate RBC production

adjusts volume of interstitial fluid and lymph - by increasing/decreasing reabsorption of water

Question 19

Give 6 changes to the urinary system that come with age

Answer 19

kidneys shrink and have decreased blood flow/filtration

glomeruli decrease in number with 40% non-functioning

mass decreases from 300g in 20yr old to 200g in 80yr old

bladder decreases in size and muscular walls weaken

reduction in thirst sensation = dehydration

more prone to infections