renal phys pt1

Question 1

what are the functions of the kidney?

Answer 1

A WET BED
1. Regulation of acid-base balance
2. Maintenance of water balance
3. Balance of electrolyte balance
4. Removal of toxins
5. Control of blood pressure
6. Erythropoietin production
7. Activation of vitamin D

Question 2

what are the 3 layers of the glomerular filtration barrier?

Answer 2

1. single-celled capillary endothelium (fenestrae, pores)
2. glomerular basement membrane
3. single-celled epithelial lining of Bowman’s capsule (podocytes, filtration slits)

Question 3

factors affecting glomerular filtration rate

Answer 3

1. glomerular hydrostatic pressure (increase)
2. capsular hydrostatic pressure (decrease)
3. plasma osmotic pressure (decrease)
4. activation of SNS (decrease)
   - activation of a1 receptors on afferent and efferent arterioles –> vasoconstriction
   - vasoconstriction of afferent arterioles (greater effect) –> decreased GFR
5. Atrial and brain natriuretic peptides
   - released upon increased blood volume –> dilates afferent arteriole and constricts efferent arteriole –> increased GFR

Question 4

what are the receptors on detrusor of bladder?

Answer 4

1. SNS - B3 receptors (relaxation)
2. PSNS - M3 receptors (contraction)

Question 5

what are the receptors found at the IUS?

Answer 5

a1 receptors (contraction)

Question 6

what is stress incontinence and its cause?

Answer 6

involuntary loss of urine with exertion such as coughing and sneezing

causes:
- damage to pelvic support structures
- neurogenic urethral sphincter incompetence –> sphincter becomes loose

Question 7

what is urge incontinence and its cause?

Answer 7

involuntary loss of urine associated with compelling desire to void

causes:
- uninhibited contraction of detrusor muscle –> overactive detrusor muscle

Question 8

what is deafferentation?

Answer 8

interruption of peripheral afferent nerves from bladder –> no sensory innervation to bladder when full –> prevents transmission of stretch signals from bladder –> atonic bladder –> overflow incontinence

Question 9

what is denervation?

Answer 9

interruption of both afferent and efferent nerves

upper motor neuron spastic neurogenic bladder
- hyper-reflexive bladder
- detrusor external sphincter dyssynergia (loss of coordination between detrusor contraction and sphincter relaxation)

lower motor neuron flaccid hypotonic bladder
- inability to void despite full bladder
- damage to peripheral nerves from spinal cord to bladder

Question 10

what is spinal cord transection?

Answer 10

inhibition of facilitatory and inhibitory pathways
- no voluntary control and no inhibition/facilitation from higher centres

Question 11

what are the three types of neurological interruptions that cause incontinence?

Answer 11

1. deafferentation
2. denervation
3. spinal cord transection

Question 12

what is the normal physiological pH?

Answer 12

7.35-7.45

Question 13

what is oliguria?

Answer 13

lower than normal urine ouput
<400ml/day

Question 14

what is polyuria?

Answer 14

higher than normal urine output
>2.5L/day

Question 15

what is volume status?

Answer 15

volume of blood in circulatory system

Question 16

Which of the following are TRUE of the micturition reflex? (Select all that apply)

a. Stretch in the bladder wall is detected by chemoreceptors
b. ↓ APs carried by pudendal nerve causes external sphincter to relax
c. Afferent pelvic nerves transmit APs to thoracic region of spinal cord
d. APs carried by PSNS leads to contraction of detrusor muscle

Answer 16

b. ↓ APs carried by pudendal nerve causes external sphincter to relax
d. APs carried by PSNS leads to contraction of detrusor muscle

wrong statements:
a. mechanoreceptors (transient receptor potential receptors)
c. sacral region of spinal cord