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Flashcards in The urinary bladder Deck (31)
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1
Q

What is the basic flow of urine from the kidneys to being excreted?

A

It flows from the kidneys through the ureters into the bladder and is then eliminated via the urethra.

2
Q

What is the detrusor muscle?

A

Smooth muscle found in the bladder that can contract and relax.

3
Q

What parts of the bladder are important in retaining and holding urine?

A

The internal and external sphincters.

4
Q

How is urine moved into the bladder?

A

Peristaltic contractions of the walls of the ureter.

5
Q

How do male and female urinary tracts differ?

A

Females have an external sphincter and a smaller urethra - the urinary tract is shorter.

6
Q

What does a smaller female urethra impose?

A

There is a higher chance that they will develop a UTI.

7
Q

What is the capacity of the bladder?

A

600 and 800ml.

8
Q

What is the detrusor composed of?

A

Three layers of smooth muscle. The fibres in each layer are arranged differently - spiral, longitudinal and circular.

9
Q

What control is the internal sphincter under?

A

Involuntary control via smooth muscle.

10
Q

What control is the external sphincter under?

A

Skeletal muscle.

11
Q

What is tonic contraction?

A

Contractions that are maintained from several minutes up to hours at a time.

12
Q

What receptors are found on the bladder?

A

Muscarinic receptors (M3) and beta adrenergic receptors (B3).

13
Q

What receptors does the internal sphincter contain?

A

M3.

14
Q

What receptors are found on the external sphincter?

A

B3.

15
Q

Where does direct motor control of the bladder occur?

A

The pons, which is part of the brainstem.

16
Q

How does the detrusor muscle contract?

A

The pelvic parasympathetic nerve releases ACh which binds to the M3 receptor.

17
Q

What is the mechanism for “holding in” urine?

A

The pudendal nerve is a somatic nerve under our control. It releases ACh and acts on the A3 receptor on the internal sphincter, which binds and causes the external sphincter to contract.

18
Q

What is the hypogastric nerve responsible for?

A

Urine retention.

19
Q

What is the parasympathetic nerve responsible for?

A

Urination.

20
Q

What is released from the post sympathetic nerve involved in?

A

Releasing noradrenaline that binds to the B3 receptor on the detrusor muscle to relax it, and binds to the A1 receptor on the internal sphincter to contract it.

21
Q

What is the trigone muscle?

A

The bladders stretch receptor.

22
Q

What is the neural regulation method of bladder function?

A

It is an involuntary spinal micturition reflex arc. Stretch receptors in the wall of the urinary bladder, afferent sensory nerve fibres (convey impulses to the spinal cord) and efferent PS nerve fibres (convey impulses to the detrusor and internal sphincter)

23
Q

What is involved in the voluntary control exercised by the CNS and when does it develop?

A

The cortex, cerebellium and micturition centre are located in the pons that are developed in early childhood - full control is usually present between 3 and 5 years.

24
Q

What part of the spinal cord is involved in micturition.

A

The sacral portion.

25
Q

What are the two key processes for micturition to occur?

A

The detrusor muscle must contract and the internal sphincter must relax.

26
Q

What conscious part of the process is necessary for micturition to occur?

A

The cerebral cortex must allow the external sphincter to relax.

27
Q

What happens when the bladder is in terms of the brain?

A

Signals are sent to stimulate the hypogastric nerve to retain urine.

28
Q

What happens to prevent urination?

A

The sympathetic nerve is stimulated which allows us to hold in urine, and the parasympathetic nerve is inhibited so we don’t contract the pertrusor muscle.

29
Q

What happens when the bladder is full?

A

There is lots of stretching in the muscle and the sensory nerve in the pertrusor muscle will increase its firing to the sacral region.

30
Q

What is the voiding reflex?

A

The idea that if urination starts, urination will continue and will not stop.

31
Q

What is the basis of the voiding reflex?

A

The pelvic afferent nerve fibres will keep sending impulses to the sacral region of the spinal cord which works on a neurone that connects to the parasympathetic efferent nerve fibres. The pertrusor muscle will contract and cause a loop.