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Clin Sci IMS, Respiratory, Renal, Cardiovascular, Nutrition & Energy > Renal > Flashcards

Renal Flashcards

1
Q

What are the main functions of the kidney?

A
  • Remove waste products
  • Regulate fluid balance and blood pressure
  • Regulate electrolytes
  • Regulate body fluid pH
  • Regulate blood cell count
  • Contribute to calcium homeostasis
  • Detoxify free radicals
  • Gluconeogenesis in times of starvation
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2
Q

Describe the general size of the kidney - mass, length and width

A

130-160g
10-12cm long
5-7cm wide

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3
Q

Describe the deep layer of renal capsule

A
  • Smooth and transparent
  • Dense irregular connective tissue
  • Continuous with outer layer of ureter
  • Trauma barrier
  • Maintains kidney shape
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4
Q

Describe the middle layer - adipose capsule of kidney

A
  • Fatty tissue
  • Trauma barrier
  • Maintains kidney position
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5
Q

Describe the superficial layer of the kidney - renal fascia

A
  • Dense irregular connective tissue

- Anchors kidney to abdominal wall surrounding structures

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6
Q

Describe the renal lobes

A
  • 1 renal pyramid
  • Overlaying area of renal cortex
  • 1/2 of each adjacent renal column
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7
Q

What is the order of renal arteries / vessels?

A 
Renal artery 
segmental arteries 
Interlobar arteries 
Arcuate arteries 
Interlobular arteries 
Afferent arterioles 
Glomerular capillaries 
Efferent arterioles
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8
Q

What is the order of renal veins /capillaries? Smaller to large

A 
Peritubular capillaries 
Interlobular veins 
Arcuate veins 
Interlobar veins 
Segmental veins 
Renal veins 
Inferior vena cava
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9
Q

Describe the nephron

A
  • Functional unit of the kidney
  • Each afferent arteriole supplies one nephron
  • Blind ended tubes - renal corpuscle and renal tubule
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10
Q

Describe the glomerulus

A
  • Ball of capillaries supplied by afferent arteriole
  • Initial site of urination production
  • Drained by efferent arteriole
  • 200um
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11
Q

Describe the bowmans capsule

A
  • Site of blind end nephron
  • Outer parietal layer that is continuous with renal tubule outer layer
  • capsular space - where filtrate collects
  • Inner visceral layer composed of podocytes with envelope glomerular capillaries
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12
Q

Describe the renal tubule

A
  • PCT
  • Loop of henle
  • Distal tubule
  • Collecting duct
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13
Q

Describe cortical nephrons

A
  • Glomeruli in outer 2/3 of cortex

- Short loops of henle

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14
Q

Describe the juxdamedullary nephron

A
  • glomeruli in inner 1/3 of Cortex

- long loops of henle which pass into deep medulla

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15
Q

Describe the PCT

A
  • Early part is convoluted
  • Late part is straight
  • 15 mm long
  • Outside diameter 70um
  • Columnar/cuboidal epithelium
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16
Q

Describe the loop of henle

A
  • U shaped loop
  • Descending / ascending limbs
    Thick segments
  • Simple cuboidal epithelium
  • initial part of descending limb
  • all of ascending limb
  • metabolically active
    Thin
  • Simple squamous epithelium
  • Lower part of descending limb
  • low metabolic activity
  • High permeability to water
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17
Q

Describe the juxtamedullary apparatus

A
  • Macula densa - thick ascending limb

- Juxtaglomerular cells - afferent arteriole smooth muscle cells

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18
Q

Describe the DCT

A
  • Early part of thick ascending loop of henle

- Late part cuboidal - principal cells - ADH, intercalated cells, Aldosterone

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19
Q

Describe the collecting ducts

A
  • Cells very similar to late distal convoluted tubule
  • Receives fluid from approx 6 distal tubules
  • In medulla pair to form ducts of belini which drain into minor calyces
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20
Q

Describe body fluid components and their percentages

A

Extra cellular 35%

  • Interstitial fluids 25%
  • PLASMA 8%
  • Transcellular fluid 2%

Intracellular 65%

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21
Q

Describe the intracellular fluid component (ICF)

A
  • Virtual - made of cells (lots of )
  • Unifying similarities
  • contained. by cell membranes
  • K+ = major cation
  • proteins and phosphate are major anions
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22
Q

Describe the extracellular fluid component (ECF)

A
  • Any non intracellular compartment
  • Na = major cation
  • Chloride and bicarbonate = major anions
    Has several sub compartments - plasma fluid
  • fluid within vasculature
  • 70ml per litre of plasma composed of protein and lipid
    ISF - interstitial fluid
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23
Q

Describe the interstitial fluid

A
  • Occupies interstitial space
  • Separated by plasma fluid by capillary endothelium
  • Bathes the cell and link between ICF and blood plasma
  • Virtual
  • Reasonably low in protein
  • Excess ISF drains into plasma fluid compartment via lymphatic system
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24
Q

Describe trans cellular fluid (TCF)

A
  • Separated by plasma by additional epithelial layer Specialised functions
  • urine
  • CSF
  • Lymph
  • GI contents and secretions
  • Synovial fluid
  • Compartments of eye
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25
Q

Describe the dilution principle

A

Use of known quantity of dye to target compartment

- After equilibrium measure the dye concentration

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26
Q

How do you measure dye concentration ?

A
  • Make solutions of known concentration
  • measure light intensity of solutions
  • Plot conc vs light intensity calibration curve
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27
Q

Describe osmoality

A

Analogues to the mole for non dissociating substances it is identical to the mole
Osmoality mosmol kg H2O = Number of ions a solution dissociates into x molar concentration

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28
Q

What are the osmoalities of glucose and NaCL ?

A 
Glucose = 1 mmol /kgH2O 
NaCL = 1 mmol /kgH2O x 2 as dissociates so 2 mosmol/kgH2O
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29
Q

Describe body fluid osmolality

A
  • Kept constant at around 280-300 mosmol/kg H2O
  • Kidney plays major regulatory role
  • ICF x ECF osmoalities are identical because H2O can readily cross cell membranes
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30
Q

What is osmotic pressure?

A

Equal to hydrostatic pressure and represents pressure required to prevent net movement of water across a semipermeable membrane

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31
Q

Describe isotonic and isomotic

A

Isotonic - does not cause change in cell volume

Isomotic - solutions have the same osmolality

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32
Q

What is plasma protein oncotic/ colloid pressure?

A
  • Osmotic pressure exerted by plasma proteins
  • Large impermeant anions
  • Important in transcapillary fluid dynamics
    Represented by pie symbol
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33
Q

Give the Gibbs donnas effect equation

A

(Diffusable cations x Diffusible anions ) for side one
Times
(Diffusible cations x Diffusible anions) for side 2

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34
Q

Describe bulk flow

A
  • Passive solute movement
  • Solvent drag
  • Occurs in vessels - vasculature, lymph vessels, renal tubules
  • occurs from filtration across capillary membranes
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35
Q

Describe starling forces

A

Forces determine capillary filtration and reabsorption

  • 90% due to diffusion
  • 10% starling forces
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36
Q

Describe the ideal capillary for starling forces

A
  1. Hydrostatic pressure dependent on -
    - Arterial blood pressure
    - Extent of transmission
    - Venous pressure - resistance to flow
  2. Plasma protein colloid pressure
    - 25 mmHg
    - constant as plasma proteins are effectively impermeable
    - plasma protein are effective osmoses as they are impermeant
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37
Q

Describe glomerular filtration

A
  • Produces ultra filtrate of plasma
  • Filtration is modified along renal tubule until it becomes urine in the collecting duct
    3 layered filter
  • Endothelium
  • basement membrane
  • Podocytes
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38
Q

Describe the endothelium of glomerular filter

A
  • Fenstrated capillaries - leakier than normal

- Blocks cells and platelets

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39
Q

Describe the basement membrane of glomerular filter

A
  • Secreted by podocytes
  • Main filtration barrier
  • Collagen and glycoproteins
  • Negatively charged
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40
Q

Describe the Podocytes of glomerular filter

A
  • Maintain basement membrane
  • Complex structures
  • Interdigitating foot processes - pedicles
  • Negatively charged glycocalyx coating
  • May act as supplementary filtration barrier via slit membranes
  • Phagocytic escaping cells and macromolecules
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41
Q

Describe filtration characteristics of glomerular filtrate

A
  • Free filtration below 7000Da
  • Virtually no filtration above 7000Da
  • Negative charges prevent filtration of most proteins
  • Glucose, amino salts and urea are freely filtered
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42
Q

Describe how to calculate net filtration pressure (NFP)

A

Because glomerular filtration rate is directly proportional to net filtration rate can sub equation with a filtration coefficient
= Kf (coefficient) Pcap - PColloid bowmans capsule (pie bc) - PColloid capillary (Pie cap)

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43
Q

What are the values for Pbc, Pcap and Pie cap

A

Pbc - bowmans capsule hydrostatic pressure - 10 mmHg
Pcap - capillary hydrostatic pressure - 45mmHg
Piecap - capillary protein colloid oncotic pressure - 25mmHg

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44
Q

What are the factors affecting glomerular filtration rate?

A
  • kf - filtration coefficient
  • Capillary hydrostatic pressure
  • Capillary oncotic pressure
  • Bowmans capsule hydrostatic pressure
  • Bowmans capsule oncotic pressure
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45
Q

Describe regulation of Renal blood flow

A
  • Renal blood flow is 1.1 litres /min
  • Not all of it is filtered
  • Only 600ml of 1.1 litres of blood is filterable as a rest of volume is cells
  • thus 600 ml represents renal plasma flow rate
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46
Q

Describe tubuglomerular feedback

A
  • Loop of henle/ DCT regions pass close to renal corpuscle
  • Contacts afferent and efferent arterioles -juxtaglomerular apparatus
  • High GFR
  • Sensed by macula densa
  • macula densa inhibits nitric oxide secretion
  • Decreased nitric oxide causes vasoconstriction of afferent arteriole
  • Returns GFR to normal range
  • Normal NaCL levels and fluid flow in distal tubules restored
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47
Q

Describe neural regulation of renal blood flow and glomerular filtration rate

A
  • Rich sympathetic innervation to kidney
  • Fibres to afferent arteriole wall
  • Tonic activity is low
  • Innervation has little effect
48
Q

Describe what increased nerve activation leads to for RBF and GFR

A
  • vasoconstriction of afferent arteriole
  • Reduces RBF and GFR
  • conservation mechanism
  • GFR can be as low as A FEW ML per min
49
Q

Describe medullary hypertonicity

A
  • Generated by countercurrent multiplication
  • INTERACTION BETWEEN LOOPS OF HENLE AND DISTAL TUBULES AND COLLECTING DUCTS
  • Facultative water handling in collecting ducts due to ADH
    Note to future Isabel - you couldn’t be bothered to retype the caps
50
Q

Describe the permeabilities of H2O of the ascending and descending loops of the loop of henle

A 
Ascending = not permeable 
Descending = Permeable
51
Q

Describe countercurrent multiplication

A
  • 200 mosmol/kg H2O difference between ascending loop and descending loop - small transverse osmotic gradient
  • Multiplied into larger longitudinal gradient by counter current arrangement via hairpin bend
52
Q

Describe Facultative H2O handling

A
  • According to need in DCT and collecting ducts
  • Collecting duct = cortical and medullary and DCT are relatively impermeable to water Urea and NaCl
  • ADH increases H2O permeability of segments according to need
53
Q

Describe what happens as ADH presence increases

A
  • Increases H2O reabsorption in cortical collecting duct, fluid osmolality increases from 90 to 290 mosmol/kg H2O
  • Remaining fluid enters medullary collecting duct for further h2O reabsorption
  • Too much reabsorption in medulla would negate medullary hypertonicity hence majority occurs in cortical collecting duct
54
Q

Describe urea countercurrent multiplication

A
  • Urea is freely filtered at glomerulus
  • 50% of urea passively reabsorbed in PCT
  • urea concentration increases in descending loop and along loop owing to passive diffusion from interstitium
55
Q

Describe the steps of urea recycling

A
  • H2O leaves cortical collecting duct urea conc increases
  • ADH activates urea uniporter in medullary collecting duct
  • Urea diffuses along gradient from medullary collecting duct into interstitium
  • Urea diffuses along gradient from interstitium into Thick ascending limb
  • Urea travels along tubule to DT / cortical collecting duct and cycle repeats
  • stimulates larger water reuptake by the descending limb
56
Q

Describe long vs short nephrons

A
  • 15% are long - juxtamedullary
  • 85% are short - cortical
  • all nephrons drain into collecting ducts which pass through medulla
  • Can achieve concentrated urine from all nephrons
57
Q

Describe proximal tubular function

A
  • Reclaims useful filtered substances

- Most reabsorption occurs in PCT involving Na transporters

58
Q

Describe Na symporters and anti porters

A

Symporters - two or more solutes cross membrane in same direction
Antiporters - Two or more solutes cross membranes ion opposite direction

59
Q

Describe transport maximum

A
  • Transports have upper capacity limit

- Measured in mg/min

60
Q

Describe solute reabsorption

A
  • H2O reabsorption occurs via osmosis
  • proximal tubule - H2O reabsorbed with solutes
  • Collecting ducts - H2O needs driven
61
Q

Describe Na handling in PCT

A
  • Na transporters achieve near 100% reabsorption of organic solutes
  • 80-90% bicarbonate
  • 65% H2O
  • 50% cl-
62
Q

Describe plasma osmoality

A
  • 280-290 mosmol/kg h2O
63
Q

Describe ADH

A
  • Vasopressin
  • Nonapeptide
  • Synthesised in supraoptic and paraventricular nuclei (SON and PVN) located in hypothalamus
  • 1/2 life 15 mins and degraded in the liver and kidneys
  • Part of precursor molecule 166a
64
Q

Describe ADH movement post synthesis

A
  • Moves from SON/ PVN to posterior pituitary - neurohypophysis
  • moves in axons of hypothalamohypopyseal tract
  • progressively cleaved during movement
  • strand with neurophysiology in nerve terminals
  • Released into blood system when required
    Plasma osmolality is main release stimulus
65
Q

Describe osmoreceptors

A
  • Located near SON
  • Threshold for activation is 280 mosmol/kg H2O
  • Small amount of ADH released if plasma osmoality rises linear response
66
Q

Describe haemodynamics as ADH stimuli

A
  • Via baroreceptors - low pressure/ volume
  • Less sensitive need 10-15% blood vol drop to activate
  • response is exponential
  • Drugs effect BP so can affect plasma ADH levels
67
Q

Describe nausea as ADH stimuli

A
  • Instant + profound

- Plasma ADH increases 100-1000 fold

68
Q

What are 5 stimuli for ADH

A
  1. Haemodynamics
  2. Nausea
  3. Hypoglycaemia
  4. Hypoxia
  5. Angiotensin
69
Q

Describe the mechanism of ADH action

A
  • principal cells V2 receptors on basal membrane
  • ADH occupies V2 receptor
  • Activates adenylate cyclase via Gs protein cAMP
  • cAMP activates protein kinase PKA
  • Pka phosphorylates and activates non functional aquaporin 2 water channels
  • Active aquaporin 2 channels inserted into apical membrane
70
Q

Describe aquaporin insertion and activation

A
  • Causes water permeability to increase
  • Water reabsorbed
  • Urine is concentrated
71
Q

Describe the pelvic nerve micturition reflex (wee)

A
  • Bladder fills - rugae unfold
  • pressure increases as urine vol increases
  • Stretch receptors in bladder activate pelvic nerve afferents
  • pelvic nerve efferent relax internal urethral sphincter
  • urination urge communicated to higher centres
72
Q

Describe voluntary control of micturition

A
  • achieved by integration with higher centres -pons - via pudendal nerves
  • Pudendal nerves keep external urethral sphincter closed
  • Voluntary inhibition of pudendal nerve activity releases external sphincter
  • urine flow
73
Q

Describe effective circulating volume (ECF)

A

Compartment of blood which is perfusing the tissue

74
Q

Describe renin release stimulation mechanism

A
  • Stored in juxtaglomerular apparatus
  • Increased sympathetic nerve activity initiated by baroreceptors
  • Decreased wall tension, afferent arteriole
  • Decreased Na delivery to macula densa
    Caused by decrease in ECV by decreased Na
75
Q

Describe the macula densa

A
  • Releases prostaglandins I2 (PI2)

- Stimulates granular cells to release renin into blood

76
Q

What is the primary hormone in Na regulation?

A

Angiotensin 2

77
Q

What are the 5 changes that occur with angiotensin 2 release?

A
  1. Vasoconstriction - infrarenal and systematic
  2. Increase of proximal tubular Na reabsorption
  3. Aldosterone release from zone glomerulosa in adrenal cortex which increases distal tubular Na reabsorption
  4. Increase thirst
  5. ADH release - water retention
78
Q

Describe the adrenal gland removal causes

A
  • Loss of Nacl from body via urine
  • Extracellular na content falls
  • ECF volume reduced
  • Circulatory collapse
79
Q

Describe aldosterone and stimuli for release

A
  • Synthesised by zone glomerulosa of adrenal gland
  • Steroid hormone synthesised from cholesterol
    Release
  • Decrease in plasma Na concentration
  • Increase in plasma K concentration
  • Decrease in ECV via angiotensin 2
80
Q

What are the effects of aldosterone?

A
  • Stimulates na reabsorption in collecting duct
  • Stimulates K secretion in collecting ducts
  • Stimulates H+ secretion in collecting ducts
  • Promotes Na+ reabsorption in gut and sweat glands
81
Q

Describe atrial natriuretic peptide

A
  • 28 aa hormone from 126 aa pro hormone
  • release from atrial cells in response to atrial stretch
  • Act at ANP receptors
  • Promotes Na loss in urine
82
Q

Describe the mechanism of action for atrial natriuretic peptide

A
  • Inhibits collecting ducts Na-K ATPase
  • Inhibits aldosterone secretion
  • Reduced renin release, indirectly inhibiting aldosterone release
  • Promotes vasodilation ion afferent arterioles and increases GFR
  • Decrease in Na reabsorption
83
Q

Describe urodilation

A
  • Originates in kidney
  • Almost identical to ANP with 4 additional aa’s
  • Actions identical to ANP
  • Natriuretic
84
Q

Describe dopamine

A
  • Synthesised in proximal tubule
  • Inhibits Na-k ATPase
  • Inhibits Na-H anti port
  • natriuretic
85
Q

Describe adrenomedullin

A
  • 52 aa peptide synthesised in the kidney
  • Increase GFR
  • Decrease Na tubular reabsorption
  • Natriuretic
86
Q

Describe a small pH change effect on nerve excitability, enzyme activity and K+ homeostasis

A
  1. Nerve Excitability
    - Acidosis - decreases CNS
    - Alkalosis - Increases CNS
  2. Enzyme activity
    - r group amino acid chain vital to correct folding, pH change affects folding
  3. K+ homeostasis
    - Protein handling and K+ linked
    - Increase H+ (acidosis )
    - Decrease H+ leads to hypokalaemia (alkalosis )
87
Q

Describe three neutralisations of carbonic acid in the body

A
  1. Blood buffers
  2. Respiratory compensation
  3. Renal compensation
88
Q

What is blood pH dependent on?

A
  • HCO3- conc

- CO2 conc

89
Q

Describe the haemoglobin buffering system

A
  • Buffers metabolically produced CO2
  • H+ mopped up by reduced haemoglobin
  • Haemoglobin reduced after O2 delivery to cells
  • In lungs O2 = high, liberates CO2 remaining excess acid
90
Q

Describe the plasma protein buffering system

A
  • In ECF small buffering made by proteins
  • Proteins are amphoteric
  • Most important buffer in ICF where protein conc= high
91
Q

Describe the phosphate buffering system

A
  • Minor role in ECF due to low concentration
  • Second only two proteins in ICF acid-base balance
  • Good urinary buffer under normal conditions as little reabsorption
92
Q

What’s the Henderson hasselbalch equation?

A

Predicts if pH decreases PCO2 increases

- Most CO2 removed by lungs

93
Q

Describe acidosis

A
  • Plasma H+ increases
  • Less HCO3- filtered as it is buffering the H+
  • Renal H+ secretion increases
  • Urine is more acidic
94
Q

Describe alkalosis

A
  • Plasma H+ decreases
  • More HCO3- filtered as it is not required to buffer H+
  • Not all HCO3- is reabsorbed because H+ availability is limiting factor
  • Urine is more alkaline
95
Q

Describe H+ buffering with Ammonia

A
  • Ammonium ion formed, secreted in the kidney as weak base
  • Ammonia produced from glutamine metabolism
  • Up regulated during acidosis
  • Ammonia in collecting duct mops up urinary H+ during acidosis
96
Q

Describe H+ buffering with phosphate

A
  • capacity is limited unless in acidosis where capacity is exceeded
97
Q

Describe compensation vs correction

A

Compensation

  • Immediate
  • Corrects pH change only
  • PCO2 and HCO3- sacrificed to restore pH

Correction
- Complete restoration of pH, PCO2 and HCO3-

98
Q

What are 4 disorders of acid base balance?

A
  1. Respiratory acidosis
  2. Respiratory alkalosis
  3. Metabolic acidosis
  4. Metabolic alkalosis
99
Q

Describe respiratory acidosis

Cause, Uncompensated result, compensated result and clinical cause

A 
Cause 
- retention of CO2 - hypoventilation 
Uncompensated result 
- pH decrease, HCO3- increase 
Compensated result 
-  Increases HCO3- reabsorption 
- Secretion of Ammonia 
- HCO3- remains elevated 
Clinical cause 
- Drug induced depression of respiratory centres 
- Pulmonary oedema 
- Emphysema
100
Q

Describe respiratory alkalosis

Cause, Uncompensated result, compensated result and clinical cause

A 
Cause 
- loss of CO2 - hyperventilation 
Uncompensated result 
- pH increase, HCO3- decrease
Compensated result 
- Decrease reabsorption of HCO3- 
- Decreased ammonia secretion 
- HCO3- remains depressed 
Clinical Cause 
- Anxiety 
- Aspirin poison 
- High altitude
101
Q

Describe metabolic acidosis

Cause, Uncompensated result, compensated result and clinical cause

A 
Causes 
- loss of HCO3- of H+ to plasma 
Uncompensated result 
- pH decreases, HCO3- decreases 
Compensated result 
- Respiratory compensation 
- Increased ventilation 
- Renal compensation completes in restoration of pH by increasing reabsorption of HCO3- 
Clinical Cause 
- Diabetic ketoacidosis 
- Diarrhoea - loss of HCO3- 
- Heavy exercise and lactic acid 
- Renal failure - reduced proton secretion
102
Q

Describe metabolic alkalosis

Cause, Uncompensated result, compensated result and clinical cause

A

Causes
- addition of HCO3- or loss of H+ from plasma
Uncompensated result
- pH increase, HCO3- increases
Compensated result
- Respiratory compensation increase in ventilation
- partially restores pH
- Renal compensation completes the restoration od pH by decreasing reabsorption of HCO3-
Clinical cause
- Ingestion of antacids
- Vomiting - loss of HCL

103
Q

Describe the negative feedback loop for erythropoietin increase caused by plasma hypoxia

A 
Plasma hypoxia 
Messangial/tubular cells 
Plasma erythropoietin 
Bone marrow stem cells 
pro erythroblasts 
Erythrocytes
104
Q

Describe renal failure

A
  • Less EPO produced
  • Anaemia developed
  • synthetic EPO available however costly £2500-£5000 per patient per year
105
Q

Describe erythropoietin

A
  • Hormone that stimulates erythropoiesis

- 80% produced in the kidney by mesangial and tubular cells

106
Q

Describe tubular handling of calcium

A
  • 50% of plasma Ca2+ bound to albumin
  • 5% of filtered ca2+ appears in urine
  • Rest is reabsorbed
107
Q

Describe Ca2+ handling in PCT

A
  • Ca2+ reabsorption parallels Na and H2O
  • 60% is passively reabsorbed
  • Pentubular transport not determined - Ca ATPase and Ca/Na anti port - 3Na for 1 Ca2+
108
Q

Describe ca2+ handling in the loop of henle

A
  • 20-25% is passively reabsorbed
109
Q

Describe ca2+ handling in DCT and collecting duct

A
  • 5-10% is reabsorbed
110
Q

Describe the regulation of calcium reabsorption

A

Regulated by parathyroid hormone and vitamin D
- PTH increases plasma ca2+
Raised by
- liberation of Ca2+ from bone
- indirectly decrease renal excretion of Ca2+
- indirectly increase intestinal ca2+ absorption

111
Q

Describe how ca2+ is directly liberated in bone

A
  • PTH increases number and activity of osteoclasts via action on osteoblasts
  • osteoclasts mediate bone resorption
  • bone resorption = breakdown of bone matrix and therefore elevating plasma Ca2+
112
Q

Describe how plasma Ca2+ is increased by decreases in excretion

A
  • Vitamin D3 steroid - active from calcitriol
  • Decreases Ca2+ excretion
  • Increases intestinal reabsorption and mediates indirect effects of PTH
113
Q

What are the most important effects of PTH and calcitriol?

A

PTH - effect on bone

Calcitriol - Intestinal

114
Q

Describe calcitromin / calcitriol

A
  • Peptide hormone
  • Synthesised in parafolicular cells of thyroid gland
  • Released when plasma Ca2+ is increased
  • Antagonises actions of PTH
  • promotes laying of bone
115
Q

What are some symptoms of osteomalacia and rickets caused by vitamin D deficiency?

A
  • Bone pain and tenderness
  • Skeletal deformities - bow legs, bony bumps on the ribs, skull and pelvic deformities
  • Increased tendency towards bone fractures
  • Enlarged joints
  • Dental deformities
  • Decreased muscle tone
  • Impaired growth and short stature

Clin Sci IMS, Respiratory, Renal, Cardiovascular, Nutrition & Energy (17 decks)

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