Urinary Flashcards
(101 cards)
1
Q
How much of the body is made up of water? Intracellular? extracellular?
A
60%
ICF 40%
ECF 20%
2
Q
How much water is roughly taken in by food and metabolism (ml/day)
A
food = 500 metabolism = 400
3
Q
How much water output is from skin, respiration and faeces (ml/day)
A
skin = 400 respiration = 400 faeces = 100
4
Q
What is water intake variation
A
type of food
water availability
5
Q
What is water output variation
A
lactation
exercise
environmental conditions
disease/infection
6
Q
What are four common causes of fluid loss
A
diarrhoea/vomiting
hyperventilation
fever
sweating
7
Q
Most abundant cation in extracellular fluid? anion?
A
cation = Na+ Anion = Cl-
8
Q
Nine symptoms of dehydration
A
extreme thirst dark coloured urine/zero output fatigue dizziness/headache dry mouth, lips and eyes poor skin turgor low blood pressure rapid heart beat slow capillary refill
9
Q
What happens to the plasma osmolarity, plasma Na+, ECV, and ICV when you lose equal amounts of water and salt (isotonic) and what is the typical cause
A
Plasma osmolarity = normal Plasma Na+ = normal ECV = decreases ICV = normal Causes = acute diarrhoea
10
Q
What happens to the plasma osmolarity, plasma Na+, ECV, and ICV when you lose more water than salt (hypertonic) and what are the typical causes
A
Plasma osmolarity = increases Plasma Na+ = increases ECV = Decreases ICV = decreases Causes = burns/fever/respiratory infection
11
Q
What happens to the plasma osmolarity, plasma Na+, ECV and ICV when you lose more salt than water (hypotonic) and what are the typical causes
A
Plasma osmolarity = decreases Plasma Na+ = decreases ECV = decreases ICV = increases Causes = chronic vomiting/diarrhoea
12
Q
Typical concentration of electrolytes in extracellular fluid: sodium, osmolarity, chloride, bicarbonate, potassium, calcium and pH
A
Sodium ~142mmol/l Osmolarity ~290mosmol/l Chloride ~102mmol/l Bicarbonate ~25mmol/l Potassium ~4.2mmol/l Calcium ~1.2mmol/l pH ~7.4
13
Q
How many nephrons in a singular kidney
A
about 1 million (each 5 cm long)
14
Q
What does a nephron do
A
contains a glomerulus that filters your blood and a tubule which returns needed substances to your blood and pulls out additional waste
15
Q
What is the renal pelvis, what is it lined with and what does it do
A
Where two or three major calyces join
Lined with mucous membrane covered with transitional epithelium
Acts as a funnel for urine flowing to the ureter
16
Q
What are the ureters and how do they function
A
Narrow tubes carry urine from the kidney to the bladder
Muscles in their walls contract and relax to force urine down (if urine backs up, or is allowed to stand then a kidney infection can occur)
17
Q
Two roles of bladder, and how much can it store
A
temporary storage of urine and assists in expulsion of urine
Holds 400-600ml
18
Q
Four parts of male urethra
A
pre-prostatic, prostatic, membranous, spongy
19
Q
What is the glomerular filtration rate
A
test used to see how well kidneys are working
20
Q
What is the typical rate at glomerular filtration occurs
A
~90-125ml/min (across both kidneys)
21
Q
What does the glomerular filtrate contain
A
no cells
trace amount of protein
ions and small organic substances in same concentrations as plasma
22
Q
What does the renal artery branch into and what do they branch into
A
branches into segmental arteries which branch into interloper arteries which branch into arcuate arteries, cortical radiate arteries, afferent arterioles
23
Q
What is the blood supply to the nephrons
A
afferent arterioles
24
Q
What does the rate of filtration of a given substance depend on
A
its molecular weight
electrical charge
shape
25
What happens at the glomerulus
main function is to filter plasma to produce glomerular filtrate which passes down the length of the nephron tubule to form urine
26
What is tubular reabsorption
process by which the nephron removes water and solutes from the tubular fluid and returns them to the circulating blood
27
What is tubular secretion
used to remove drugs, toxins, or other natural compounds in excessive amounts (K+, H+, urea) out of blood plasma
28
What is hyperkalaemia
higher potassium than normal
29
ECG changes with hyperkalaemia
tall, peaked T waves with a narrow base, shortened QT interval, and ST depression
30
What are starling forces
opposing forces that affect glomerular filtration: hydrostatic and oncotic pressure
31
What is autoregulation
ability to maintain relatively constant blood flow despite changes in perfusion pressure
32
Where are sodium ions most likely to be reabsorbed
proximal convoluted tubule
33
Definition of paracellular
transfer of substances across an epithelium by passing through the intercellular space between the cells
34
Definition of transcellular
substances travel through the cell, passing through both apical and basolateral membranes
35
What are some general properties of the proximal convoluted tubule
```
longest segment of nephron
contain brush border microvilli
lots of mitochondria (active-transport)
reabsorbs 60-70% glomerular filtrate
Reabsorption is isosmotic
```
36
What does isosmotic mean
having the same osmotic pressure
37
Describe tubular transport of sodium
most is done via secondary active transport
most reabsorbed in exchange for H+
driven by ionic gradients across apical membrane and ATPase on basolateral membrane
38
Describe tubular transport of calcium and potassium
most potassium ion reabsorption is via paracellular route passively down ionic gradient
Calcium reabsorption is via transcellular and paracellular routes down ionic gradient
39
Describe tubular transport of amino acids and glucose
occurs against concentration gradient via secondary active transport (co-transport)
dependent on sodium gradient on apical membrane
facilitated diffusion of basolateral membrane
when transport maximum is reached the rest is secreted in the urine
40
Describe tubular transport of water
occurs down osmotic gradient
transcellular reabsorption on apical and basolateral membranes via aquaporins
paracellular reabsorption via gap junctions
also occurs in loop of Henle, distal tubules, and collecting ducts
41
Describe tubular transport of bicarbonate and hydrogen
bicarbonate combines with hydrogen for indirect reabsorption in presence of carbonic anhydrase
In distal tubules new bicarbonate is formed and hydrogen is secreted via buffers
42
What do longer loops of Henle create
create a larger osmotic gradient so their parent kidney can produce more concentrated urine
43
What is the distal nephron composed of
distal convoluted tube
cortical portion of collecting duct
medullary portion of collecting duct
44
What does aldosterone do in the plasma concentration of potassium
targets the distal nephron where it increases K+ secretion (secreted to the urine)
45
What is hypovolaemia
decrease of blood volume and venous return
46
What does hypovolaemia decrease
Stroke volume, cardiac output and hence arterial blood pressure
47
How do kidneys deals with hypovolaemia
sense reduced blood pressure and reduced renal blood flow
they reduce sodium loss in urine
reduce, by osmotic retention, water loss in urine
48
What are the high blood pressure sensors
```
arterial baroreceptors (carotid sinus/aortic arch)
juxtaglomerular apparatus of kidney
```
49
What are the low blood pressure sensors
(useful for excretion of excess, retained plasma fluid)
cardiac atria
pulmonary vasculature
50
Explain juxtaglomerular apparatus and renin
complex structure where distal tubules makes close contact with the glomerulus and its vasculature
juxtaglomerular secrete a hormone renin, in response to low blood flow
Renin has a direct role in Na+ secretion and hence water reabsorption in the distal tubules
51
Describe the renin-angiotensin-aldosterone system (RAAS)
key in regulating blood volume by controlling NaCl and hence water reabsorption by the nephron
Renin is a proteolytic enzyme its substrate is circulating angiotensin produced by the liver
the result is angiotensin I
angiotensin I is converted into angiotensin II by an angiotensin converting enzyme (ACE)
52
What 3 things does angiotensin II do
exerts a vasoconstrictor response
stimulate ADH release and hence water reabsorption by the kidney
stimulates aldosterone release from the adrenal cortex to increase Na+ retention by the kidney
53
What is aldosterone
steroid hormone secrete from the zona glomerulosa of the adrenal glands under the stimulation of angiotensin II
54
What happens when there is an increase in circulating aldosterone
they bind to a receptor which forms a complex that stimulates transcription of apical Na+ channels
Increases NaCl reabsorption via principal cells in the distal tubules/collecting ducts
Na+ uptake from the lumen is enhanced, Cl- and then water follow
55
What does atrial natriuretic peptide (ANP) do ?
causes natriuresis=excretion of Na+ as NaCl and hence water
56
Why is plasma osmolarity regulated
to stop cells shrinking or swelling
57
How is plasma osmolarity regulated
by controlling water influx and efflux
58
What is normal plasma osmolarity
290mosmol.kg^-1
59
What happens if there is a change in plasma osmolarity
osmoreceptors in hypothalamus detect the change
hypothalamus initiates changes to pituitary gland and/or thirst centre
pituitary gland releases ADH and thirst centre changes the thirst response
Release of ADH changes the urine concentration and changes in thirst response changes water intake
60
Where is ADH secreted from
posterior pituitary gland
61
Alternative name for ADH
vasopressin
62
3 actions of ADH on the kidney
increases water permeability at the collecting duct
increases NaCl reabsorption in the thick ascending limb of the loop of Henle
increases urea permeability in the inner medullary region of the collecting duct
63
Where is ADH produced
in the supraoptic and paraventricular nuclei neurones
64
What portion of the nephron is impermeable to water
the ascending limb of the loop of Henle
65
What is the net result of the counter-current mechanism in the loop of Henle
osmolarity gradient is generated in the medullary
interstitium
fluid entering the distal tubules and collecting duct is hypo-osmotic
66
What is diabetes insipidus caused by
abnormality in the functioning of the ADH hormone
67
What is plasma concentration of H+ like?
very low
68
3 reasons as to why it is important to regulate arterial pH
enzyme structure may be impaired
Acidosis can decrease cardiac contractility and lead to life-threatening arrhythmia's
handling of other cations (K+ and Ca2+) can lead to neuromuscular dysfunction
69
What is the bronstead and Lowry theory
than an acid is a proton donor and a base is a proton acceptor
and when an acid loses a proton it forms a conjugate base
70
Difference between strong and weak acids
strong acids fully dissociate in water and weak acids only partially dissociate
71
What do buffer pairs consist of
a weak acid and its conjugate base
72
What is the Henderson hasselbach equation
pH = pK + log [A-]/[HA]
73
What determines PaCO2
rate of carbon dioxide production by metabolism divided by rate of carbon dioxide removal by alveolar ventilation
74
Where is bicarbonate filtered
at the glomerulus
75
What does vomiting cause? how?
metabolic alkalosis
| by excessive loss of [H+]
76
What does diarrhoea cause? how?
metabolic acidosis
| by excessive loss of bicarbonate
77
what does insulin deficiency cause? how?
metabolic acidosis
| by excessive production of H+
78
What does shock cause? how?
metabolic acidosis
| by excessive production or ingestion of H+
79
When assessing renal function what 6 things should you assess?
```
production of urine
sodium and water homeostasis
filtration
blood flow
endocrine functions
information about other systems (glucose, bilirubin and ketones)
```
80
What should you look for on observation of urine tests
colour
clarity
volume
81
What are you looking for on a dipstick examination of urine
```
blood
ketone
nitrites
pH
glucose
proteins
```
82
What do lab tests look for on urine tests
omsolarity
sodium
creatine
83
Four tests on blood
```
U & E's (sodium, potassium, urea and creatine)
osmolarity
pH
bone profile
full blood count
```
84
What makes urine tests abnormal?
infection - kidney, UTI
Saturation of filtration system - glucose in diabetes
metabolism of fats - ketones
renal failure
85
What are the variables used in the CKD-EPI equation
gender
ethnicity
creatine
age
86
How do you perform a urine dipstick test
```
urine should be collected in sterile container
Urine should be collected midstream
do a visual analysis: colour and clarity
apply sample to dipstick
record results immediately
```
87
What are the endocrine functions of the kidney
aldosterone and ADH - water homeostasis
parathyroid hormone - increase calcium absorption and phosphate excretion
Erythropoietin - stimulates bone marrow to produce RBC
88
What does the parathyroid hormone (PTH) do in the kidney? in the bone?
```
Kidney:
increases calcium absorption in the distal tubules
increases phosphate excretion
increases formation of active Vit D
Bone:
stimulates bone resorption
```
89
What does vitamin D do in the bone? Intestine?
```
Bone:
stimulates bone resorption
Intestine:
stimulates calcium absorption
stimulates phosphate absorption
```
90
What are sunken fontanelles a sign of in children
dehydration
91
Why is creatinine used to assess renal function
because it is an easily measured byproduct of muscle metabolism that is excreted unchanged by the kidneys
92
What does U & E stand for
urea and electrolytes
93
During urine storage what nerves are suppressed/active?
```
pelvic nerve (S2-S4) is suppressed
Pudendal nerve is active (S2-S4) is active
```
94
During urine voiding what nerves are suppressed/active?
```
pelvic nerve (S2-S4) is active
pudendal nerve is suppressed (S2-S4)
```
95
What is nitrogen found in
```
mostly nucleic acids and proteins
but also:
cofactors such as NAD+
hormones such as adrenaline
neurotransmitters such as serotonin
```
96
what is a negative nitrogen balance and what is it indicative of
when you lose more nitrogen than you take in
| indicative of: malnutrition, or recent/ongoing trauma
97
What is a positive nitrogen balance and what is it indicative of
when you gain more nitrogen than you lose
| indicative of pregnancy, growth
98
Why does amino acid breakdown take precedence over breakdown of excess carbs and fat
because excess amino acids cannot be stored
99
How are amino acids transported to the liver
as alanine or glutamine
100
What is the toxic immediate product of amino acid breakdown
ammonium/ammonia
101
Difference between glucogenic amino acids and ketogenic amino acids
glucogenic amino acids can be converted into pyruvate and other glucose precursors
ketogenic amino acids can be converted into acetyl CoA and acetoacetyl CoA
