A & P 2 - Renal 5

Front 1

Where is the Urinary Bladder located and what are some parts of it?

Back 1

pelvic cavity posterior to pubic symphysis

males - directly anterior to rectum

females - anterior to vagina and inferior to uterus

Trigone - triangular area in the flood
-corners: internal urethral orifice and 2 urethral openings

2 sphincters around opening of urethra:
-internal - smooth muscle
-external - skeletal muscle

Front 2

What is the structure of the urinary wall?

Back 2

mucosa - transitional epithelium

lamina propria

detrusor muscle - contracts to squeeze out urine

Front 3

What are the innervations of the urinary bladder?

Back 3

Sympathetic system:
-L1-L2 --> hypogastric nerves
-causes vasoconstriction

Parasympathetic system:
-S2-S3 --> pelvic N,
-stimulation cause relaxation of internal sphincter and contraction of detrusor

Somatic Nervous System:
-Pudendal Nerve (S3-S4) - external sphincter

Front 4

What happens in the different phases of the Micturation reflex?

Back 4

Collecting Phase:
Continence - abilitiy of bladder to retain urine
plasticity of the detrusor muscle - prevents rise in intravesicular P

Evacuation phase:
Spinal voiding reflex:
-increase in intravesicular P --> increase stretching of bladder wall --> afferent fibers of pelvic n --> contraction of detrusor and relaxation of internal sphincter
-voiding reflex is initiated at 300-400 ml
-high intravesicular P give rise to an inhibition of the external sphincter --> urination

Front 5

What is the Self-regenerative nature of the Micturation reflex?

Back 5

initial contraction of the bladder --> positive-feedback
-activation of bladder afferents by contractions of the detrusor
-reflex contractions of detrusor due to activation of receptors in urethra by urine flow
-self intensification of micturation reflex

Front 6

What is micturation controlled by in the brain?

Back 6

facilitatory centers - pons, posterior hypothalamus, cortex

inhibitory centers - midbrain, cortex

Front 7

What is the sequence in the development of the Urinary system?

Back 7

intermediate mesodrm during 3rd week

pronephros - degenerated by 6th week

mesonephros - degenerated by 8th week

metanephros

-begin excreting urine by end of 3rd month