Elimination

Question 1

What is micturition?

Answer 1

The release of urine from the urinary bladder into the urethra so that it can be eliminated via the urethral meatus

Question 2

How does formed urine leave the kidney?

Answer 2

It travels down the ureters by wave of peristalsis into the bladder

Question 3

How long is each ureter approximately?

Answer 3

30cm long

Question 4

Why does the ureters enter the bladder wall at an acute angle?

Answer 4

It prevents reflux of urine from the bladder back into the ureter

Question 5

How do we know we need to micturate (pass urine)?

Answer 5

Stretch receptors are stimulated until a conscious awareness to urinate is formed

Question 6

What is the bladder wall made up of?

Answer 6

Layers of smooth muscle called detrusor muscle

Question 7

What allows the bladder to expand on filling?

Answer 7

The lining of the bladder made up of stretchy epithelium called transitional epithelium

Question 8

What are the two important functions of the urinary bladder?

Answer 8

Storage of urine

Eliminating urine

Question 9

Where is the bladder closure mechanism located?

Answer 9

The base of the bladder surrounding the urethra

Question 10

What does the bladder closure mechanism do?

Answer 10

Allows automatic closure preventing urinary leakage

Question 11

What is the internal urinary sphincter?

Answer 11

Made up of smooth muscle, under the control of the Autonomic Nervous System (involuntary)

Question 12

What is the external urinary sphincter?

Answer 12

Made up of striated muscle, under the control of the Somatic Nervous System

Question 13

Where are the micturition centres located?

Answer 13

Spinal cord
Pons
Cerebral Cortex
Hypothalamus (integrates with micturition centre but is under hormonal control)

Question 14

In the control of micturition what does the spinal micturition centre (SMC) do?

Answer 14

Acts a relay centre that organises incoming sensory information from the bladder and outgoing motor responses to the brain.

Question 15

In the control of micturition what does the pontine micturition centre (PMC) do?

Answer 15

Receives signals from SMC to store or void urine in the bladder

Question 16

In the control of micturition what does the cerebral cortex do?

Answer 16

Relay centre that allows voluntary inhibition of the micturition reflex

Question 17

State the steps of normal voiding

Answer 17

1) . Bladder fills (stimulating stretch receptors)
2) . Afferent signals to spinal cord via pelvis nerves
3) . Integration of signals in spinal cord
4) . Efferent signals from spinal cord to bladder
5) . Efferent impulses cause bladder contraction and internal and external sphincters to relax
6) . Urinary bladder contracts and empties

Question 18

Which nervous controls the contraction of the external sphincter during the filling of the bladder?

Answer 18

Somatic nervous system

Question 19

Which nervous controls the contraction of internal sphincter during the filling of the bladder?

Answer 19

Sympathetic impulses

Question 20

Which nervous controls the inhibition of detrusor activity during the filling of the bladder?

Answer 20

Sympathetic impulses

Question 21

During micturition what nervous controls the relaxation of the external sphincter?

Answer 21

Somatic nervous system

Question 22

During micturition what nervous controls the relaxation of the lnternal sphincter?

Answer 22

Parasympathetic impulses

Question 23

During micturition what nervous controls the contraction of detrusor muscle?

Answer 23

Parasympathetic impulses

Question 24

What are the two main functions of the pelvic floor muscles?

Answer 24

It provides support for the contents of the abdominal cavity

It contributes to maintaining continence by supporting closure of the urethra and anus.

Question 25

Which division of the nervous system controls the pelvic floor muscles?

Answer 25

Somatic nervous system

Question 26

What is urinary continence dependent upon?

Answer 26

Bladder relaxation as it fills
Inhibition of bladder contractions during filling
Creation of a higher urethral closing pressure
Pelvic floor muscles

Question 27

How long is the female urethra?

Answer 27

3-5cm long

Question 28

How long is the male urethra?

Answer 28

20cm long

Question 29

What type of muscle is in the internal anal sphincter?

Answer 29

Smooth

Question 30

What type of muscle is in the external anal sphincter?

Answer 30

Striated

Question 31

What nervous control is used for the internal anal sphincter?

Answer 31

Autonomic nervous system

Question 32

What nervous control is used for the anal sphincter?

Answer 32

Somatic nervous system

Question 33

What does the colon do?

Answer 33

Exhibits slow waves of peristalsis that gently moves the faecal mass along the length of the bowel.

Question 34

Explain the sequence of events during normal defecation.

Answer 34

1) . Mass peristaltic waves advance stool through the colon to the rectum
2) . Recto-anal inhibitory reflex relaxes internal anal sphincter
3) . External anal sphincter and puborectalis muscle contract until its convenient to pass stool
4) . External anal sphincter and puborectalis muscle relax until its convenient to pass stool
5) . Levator ani muscle contracts, abdominal pressure increases creating downward pressure
6) . Muscles of sigmoid colon and rectum expel stool

Question 35

What factors can affect faecal continence?

Answer 35

Integrity of anal sphincters
Pelvic floor muscles
Anal cushions
Nervous control of the anal control and pelvic floor
The consistency of faeces
A healthy rectum

Question 36

What can happen if a woman has oestrogen deficiency following the menopause?

Answer 36

Contributing to incontinence