M11S3: Urinary System: Urinary Tract

Question 1

Urinary tract overview and three parts

Answer 1

-transfers and stores the urine produced by kidneys until it is ready for excretion
3 parts:
Ureters
Bladder
Urethra

Question 2

Ureters

Answer 2

-2 long, thin, muscular tubes connecting the kidneys with bladder
-begin as continuation of renal pelvis and extend towards the pelvic cavity where they penetrate the posterior wall of bladder

Histology
-wall of ureter made up of three layers
-inner layer, mucosa, lined with transitional epithelium
*refer to goodnotes

Question 3

Bladder

Answer 3

-muscular, expandable, sac-like pelvic organ that functions to temporarily store urine
-smooth triangular area known as trig one overlies base of internal aspect of urinary bladder
-trigone enclosed by two uretheric openings superiorly and the internal ureteral opening inferiorly and acts as a funnel thwart directs urine into urethra
-trigone has a high density of afferent neurons that transmit urge to void
(The urinary bladder in average adult has a normal capacity of 400-600 mL, however, it can hold abnormally high columns grater than 1L in disease states)

Neck of urinary bladder
-constricted portion that connected to urethra inferiorly
-surrounded by an internal urethral sphincter that made up of smooth muscle and under involuntary control

Rugae
-inferior has folded appearance due to their presence
-unlike trigone which smooth as lack rugae
Function: allow bladder to expand in size to accommodate changes in volume, without damage to mucosa

Location of bladder
-sits pelvic cavity posterior to pubic bone
-spatial relationships of bladder differs in male and female due to differences in pelvic structure and organs
Female:
-posterior to pubic symphysis
-inferior to uterus
-anterior to vagina
Male:
-posterior to pubic symphysis
-anterior to rectum

Bladder histology
-mucosa composed of transitional epithelium and inner most layer of bladder wall
-muscularis made up of 3 laters that collectively called detrusor muscle (Latin for push down or to dislodge)

*refer to goodnotes

Question 4

Urethra

Answer 4

-muscular tube connecting neck of bladder with outside world at opening called external urethral meatus
-urethra differs in length and position between males and females
-epithelial lining of both male and female urethrae starts out as transitional, gradually becoming stratified toward the external opening

Features of male urethra
- 20 cm in length
-divided into 3 regions named after structure pass through

1. Prostatic urethra
   -3-4 cm passing through prostate gland
2. Membranous urethra
   -2 cm from prostate to the beginning of penis
   -voluntary external urethral sphincter surrounds the area far from the meatus (external urethral opening)
3. Penile (spongy) urethra
   -15 cm long through the penis
   *refer to goodnotes

*Features of female urethra
-3-5 cm long

Question 5

Micturition

Answer 5

-act of urination
-as urinary bladder contracts, the external urinary sphincter relaxes to expel urine from bladder into urethra, and then outside body
*refer to goodnotes

Question 6

Incontinence

Answer 6

-inability to voluntarily control the expulsion of urine
-urinate accidental and can cause neurological disorders
Sphincter involved= external urethral sphincter
Aspect of nervous system that innervate that sphincter = somatic motor