URINARY BLADDER.pptx

URINARY BLADDER

1. URINARY BLADDER PRESENTED BY: M.C.KNIRANDA ASSISTANT PROFESSOR SSNSR, SU.

2. Urinary bladder is a TEMPORARY RESERVOIR OF URINE . It is an inverted triangle shape . Its shape and size vary from individual to individual and also depends on the urine volume is stores. It receives urine from the kidneys via the Ureters - stores it within , and expels it during urination via Urethra . An empty bladder is about the size and shape of a pear , becomes more oval as it fills with urine . The normal capacity of the bladder is 400-600ml . URINARY BLADDER

3. It is a hollow muscular, and distensible (or elastic) organ, LOCATION – Pelvic cavity. (it is situated in the pelvic cavity behind the pubis, in front of the rectum in the male and in front of the anterior wall of the vagina in females ). When distended, the bladder rises into the abdominal cavity. SIZE and POSITION – vary, depending on the volume of urine it contains. STRUCTURE OF URINARY BLADDER

4. Filling beyond 220 ml causes micturition. Filling up to 500 ml may be tolerated , but beyond this it becomes painful.

5. The external features of the bladder are: Apex  – located superiorly. Body  – main part of the bladder, located between the apex and the fundus Fundus (or   base)  – located posteriorly. It is triangular-shaped. Neck  – the lowest and most fixed part of the bladder. It is situated where the inferolateral and the posterior surfaces of the bladder meet. It is continuous with the urethra.

6. LAYERS OF URINARY BLADDER The walls of the urinary bladder consists of three layers. Outer layer Middle layer Mucosa

7. The outer layer – loose connective tissue , containing blood and lymphatic vessels. The middle layer – consisting of interlacing smooth muscle fibres and elastic tissue loosely arranged in three layers. This is called the detrusor muscle and when it contracts, it empties the bladder. The mucosa – composed of transitional epithelium that readily permits distension of the bladder as it fills with urine. LAYERS OF URINARY BLADDER

8. LAYERS OF URINARY BLADDER

9. ORIFICES OF URINARY BLADDER There are three orifices of urinary bladder. These three orifices in the bladder wall form a triangle or trigone . The upper two orifices on the posterior wall are the openings of the uterus . The lower orifice is the opening into the urethra .

10. BLOOD SUPPLY OF URINARY BLADDER The  superior vesical artery   supplies blood to the upper part of the bladder. The lower part of the bladder is supplied by the  inferior vesical artery . ( Vesical artery - The superior vesical artery is a branch of the  umbilical artery . The inferior vesical artery is a pelvic branch of the internal iliac artery in men; and in women it branches from the vaginal artery ). ( iliac artery – large artery of the abdomen) ( umbilical artery – paired artery found in abdominal and pelvic regions) In females, the  uterine  and  vaginal arteries  provide additional blood supply.

11. Bladder receives blood supply from both the autonomic (sympathetic and parasympathetic) and somatic nervous system: Sympathetic – hypogastric nerve (T12 – L2). It causes relaxation of the detrusor muscle, promoting urine retention. Parasympathetic – pelvic nerve (S2-S4). Increased signals from this nerve causes contraction of the detrusor muscle, stimulating micturition. Somatic – pudendal nerve (S2-4). It stimulates the external urethral sphincter, providing voluntary control over micturition. NERVE SUPPLY OF URINARY BLADDER

12. FUNCTI O N S OF URINA R Y BLADD E R The bladder undergoes relaxation and contraction . At the time of relaxation , it becomes filled with the urine coming through the ureter. During contraction , the urine is squeezed out from the bladder into the urethra.