metabolism 3 Flashcards Preview

From Flashcardlet > metabolism 3 > Flashcards

Flashcards in metabolism 3 Deck (103)
Loading flashcards...
1
Q

List 4 functions of the kidneys

A

1) stability of body fluid composition and volume
2) regulation of body electrolytes through filtration, reabsorption
3) secretion with the formation of urine
4) regulation of blood pressure
5) acid base homeostasis
6) renal hormone production (prostaglandin, renin, erythropoietin)

2
Q

what is the basic unit of the kidney and what is it made up of

A

renal lobe made up of cortical cap that sits on a base of the medullary pyramid (papilla)
the papilla branches into the renal pelvis or a calyx

3
Q

define pelvis and calyx

A
Calyx = expansion/dilation of a branch or sub-branch of the ureter or a branch of the pelvis
Pelvis = dilation in proximal ureter
4
Q

List the 4 types of kidneys and examples of animals that display them

A

1) unilobar - rodents and rabbits
2) multilobar - ox
3) multilobar with fused cortex (no external lobation) - pig
4) multilobar with fused cortex and medulla - dog, cat, sheep, goat, horse

5
Q

what are some special characteristics of the multiocar cortical and medullary fusion type kidney

A
  • crest (the totally fused part of the medulla around the pelvis)
  • pseudopapillae, which look like papillae but have no openings
  • calyces are reduced/modified to form recesses (complex extensions of renal pelvis either side of the pseudopapillae)
6
Q

position of kidney relative to each other

A

the right usually cranial to left and right usually more tightly anchored to abdominal roof than left, which is somewhat mobile.

7
Q

what is the hilum and the sinus

A

○ The hilum is the opening into the sinus at the medial indentation.
○ The sinus is normally filled with fat and surrounds the renal pelvis.

8
Q

horse kidney shape and what is special about the ox kidney

A

right heart shape and left bean shape

ox - distinct lobation externally and no pelvis just major and minor calyces

9
Q

what does the renal cortex lobule comprise of and what are they

A

1) cortical labyrinth - the substance of a lobule, consists of renal corpuscles and convoluted tubules
- kidney has granular appearance due to presence of renal corpuscles
2) Medullary rays are groups of parallel straight tubules running between the cortex and the medulla

10
Q

urine flow from the collecting duct to the bladder

A

flows from collecting duct - papillary duct - papillary foramen - renal pelvis - ureter - bladder

11
Q

what are the stellate artery and veins

A

Stellate artery and vein - at the surface of the kidney in some animals which drain into the interlobular veins

12
Q

what are the vasa recta

A

blood supply to the medulla
descending vasa recta are arterioles that form capillary networks within the medulla, the capillaries drain into venules which ascend towards the cortex as ascending vasa recta which drain into arcuate veins

13
Q

what are the two layers of the glomerular capsule

A
  1. Outer layer = parietal epithelium - simple squamous epithelium with relatively think basement membrane
    Inner layer = visceral epithelium - podocytes, closely associated with capillaries - the basement membrane separates them
14
Q

what are the 4 things that make up the renal corpuscle

A

1) glomerulus
2) glomerular capsule
3) urinary pole
4) urinary space

15
Q

what forms the filtration slits in the glomerulus

A

The pedicles of adjacent podocytes interdigitate to form filtration slits.
Filtration membranes span these filtration slits

16
Q

histology features of the proximal convulted tubule and what is special in the cat

A
  • simple cuboidal epithelium
  • cells are large so only a few nuclei per profile and lumen is relatively small
  • apical surface has brush boarder (microvilli)
  • basal striations with mitochondria between infoldings
  • in cats these cells contain lipid which gives yellow colour to cortex
17
Q

histology features of proximal straight tubule

A

very similar to proximal convoluted tubule but in dogs have lipid so yellow not cats

18
Q

histology features of Loop of henle (thin ascending and thin descending)

A
  • simple squamous epithelium
  • similar to capillaries but:
    1) wider lumen
    2) round nuclei (bulge into the lumen)
    3) few microvilli and basal striations
19
Q

histology features of distal straight tubule

A

same as distal convoluted tubule however can have presence of macula densa cells

20
Q

histology features of distal convoluted tubule

A
  • simple cubodial epithelium
  • lumen larger than PCT
  • no brush boarder and no striations
  • eosinophilic
21
Q

histology features of straight collecting tubules

A
  • simple cuboidal epithelium
  • centrally located round nucleus
  • pale staining cells bulge into the lumen
22
Q

epithelial layer of the papillary duct and foramina

A
  • epithelium is simple cuboidal/columnar and is continuous with the transitional epithelium lining the urinary pelvis and covering the surface of the medulla
23
Q

what are the 3 components of the juxtaglomerular complex/apparatus and their main functions

A

1) macula densa - chemoreceptor for NaCl concentration in tubular lumen
2) juxtaglomerular cells - release renin and involved with contraction and relaxation of afferent arteriole - act as baroreceptor
3) mesangial cells - close contact with macula densa cells act as chemoreceptors, phagocytosis, supportive, contractile

24
Q

urinary passages (ureter, bladder and urethra) what epithelium and muscle layers

A
  • transitional epithelium - maintain integrity under tension/expansion (expect end of urethra stratified squamous epithelium)
  • tunica muscularis - of generally 3 distinct layers of smooth muscle
  • inner longitudinal, middle circular, outer longitudinal (except bladder - only one muscular layer)
25
Q

ureter how enter bladder and how does it propel urine into bladder

A
  • Enters the bladder either side of the midline and passes obliquely through the wall creating a mucosal-flap valve, which prevents reflux of urine into the ureters.
  • propels via peristalsis
26
Q

what are the ligaments involved with stabilisation of the bladder

A

Two lateral ligaments, one either side extends laterally from the body, near the neck, to the walls.
One ventral ligament lies in the median plane and extends to the floor.

27
Q

how much blood flow does the nephron use

A

20% cardiac output

28
Q

what does the mesangial cells made up of and what they can do

A
  • bundles of microfilaments + contractile proteins in cytoplasm →contractile
    → change filtration slits & fenestrae
    → change Glomerular Filtration Rate (GFR)
29
Q

what cells produce angiotensin

A

proximal tubules

30
Q

what are the functions of the principle cells and intercalated cells in the collecting ducts

A

1) principle cells
- Reabsorb water and urea (medullary region) through aquaporins - ADH
- Reabsorb Na+ & Cl secrete K+ - Aldosterone
2) Intercalated cells
- Secrete H+ Reabsorb K+

31
Q

what are the 4 things that renal sympathetic nerves act upon and their function

A

1) Endings on afferent and efferent arterioles
- Noradrenalin acts on beta-adrenergic receptors
- Cause vasoconstriction and dilation which affects blood flow and therefore GFR
2) Podocytes
- Cause filtration slits to open and close
3) Proximal convoluted tubule
- Increase transport proteins present and therefore increase reabsorption
4) Juxtaglomerular cells
- Renin release

32
Q

List the 6 hormones that act on the kidney, where released from and function

A

1) Antidiuretic hormone.
➣ Released by posterior pituitary and promotes water reabsorption in collecting duct
2) Aldosterone.
➣ Steroid hormone produced by adreanal cortex and promotes sodium reabsorption in collecting ducts by the addition of Na+ channels
3) Atrial natriuretic peptides.
➣ Produced by cardiac cells and involved in sodium excretion.
4) Parathyroid hormone
➣ Produced by parathyroid gland and is involved in phosphate excretion, calcium reabsorption and calcitriol production.
5) Angiotensin II
➣ Promotes sodium retention
6) Vitamin D
➣ Vitamin D3 converted to Calcifediol in liver then is converted in the kidneys to calcitriol (1,25-(OH)2D3) the active form of vitamin D

33
Q

list the 3 basic renal processes

A

1) glomerular filtration
2) tubular secretion
3) tubular reabsorption - very important in homeostasis as many substances have around 99% reabsorption rate

34
Q

List and briefly describe the 4 factors that determine which molecules are filtered

A

1) filtration barrier - 4 layers for size and charge
2) starlings forces - bulk flow
3) autoregulation - vasoconstriction and vasodilation at the levels of afferent arteriole and macular densa
4) influence of hormones/nerves - regulates blood flow and GFR, can override the autoregulation mechanism

35
Q

List the 4 layers of the filtration barrier

A

1) capillary endothelium
2) glycocalyx on endothelial cells - negative charge
3) basement membrane - negative charge
4) filtration slits from podocytes

36
Q

what can and cannot be filtered through the glomerular filtrate

A

essentially protein free

  • water and small solutes freely filtered
  • 10,000DA freely filtered
  • if bound to protein not filtered (drugs, calcium)
  • anionic hardest to cross and cationic easiest to cross
37
Q

what is the formula for GFR and NFP (net filtration pressure)

A
GFR = NFP x Kf (permeability times surface area) 
NFP = (PGC (Glomerular capillary hydrostatic pressure) - PBC (hydrostatic pressure bowmans space) - πGC (oncotic pressure in glomerular capillary))
38
Q

how to increase Kf and what in turn does it increase

A

○ Relaxation of mesangial cells leads to an increase surface area
Relaxation of podocytes leads to an increase in slit size
increases GFR

39
Q

what occurs with a kidney stone in terms of bulk forces and what effect on GFR

A

PBC = Hydrostatic pressure Bowmans space

  • Increased intra-tubule pressure eg kidney stone
  • drop in GFR
40
Q

name the 4 factors that regulate hydrostatic pressure in the blood and how this occurs

A

1) sympathetic nerves
- vasodilation afferent decrease hydrostatic pressure
- vasodilation efferent increase hydrostatic pressure
2) angiotensin II - retain salt so decrease GFR and decrease hydrostatic pressure
3) Atrial natriuretic peptide - detects volume so when low volume vasodilation of afferent increase in hydrostatic pressure
4) disease - drop hydrostatic pressure due to haemorrhage, dehydration, vomiting, diarrhoea, ascites

41
Q

List and describe the 2 ways autoregulation of GFR is maintained

A

1) myogenic mechanism - intrinsic property of vascular smooth muscle which contracts when stretched (increase blood pressure) causes opening of Ca2+ ions that cause afferent arteriole constriction
2) tubuloglomerular feedback
- feedback via distal tubule macula densa that increase GFR by increasing delivery of NaCl
- can also decrease GFR - More Na+, K+, Cl- move in through the Na+/K+/Cl- pump in the apical membrane which flows through the Na+ K+ ATPase on basolateral membrane creating ADP which binds to A1 receptors which causes the release Ca2+ which in turn causes: a decrease in renin release and vasoconstrction of the afferent arteriole

42
Q

List 3 vasoconstrictors and 2 vasodilators and stimulus for release

A

vasoconstrictors
1) angiotensin II - decrease ECV (effective circulation volume) and renin
2) sympathetic nerves - decreased ECV
3) endothelin (made by kidneys) - ETA receptor on smooth muscle, shear force, angiotensin II, ADH
vasodilators
1) prostaglandins - angiotensin (bring back to normal), shear stress (blood pressure)
2) nitric oxide - shear stress, bradykinin, histamine, (drops Ca2+ level within cell)

43
Q

NaCl handling within the kidney

A

freely filtered in glomerulus

most reabsorption occurs in proximal tubule and loop of henle - dependent on Na+/K+ ATPase pump

44
Q

what occurs with early proximal tubule and late proximal tubule in terms of NaCl

A

EARLY PROXIMAL TUBULE - Na+ active secretion causes the blood to have a net positive charge favouring anion reabsorption (Cl-) through paracellular pathways
LATE PROXIMAL TUBULE - Cl- movement via paracellular channels causes the blood to have a net negative charge favouring cation reabsorption (Ca2+, Na+, K+, Mg2+) through paracellular pathways

45
Q

water reabsorption where occurs

A

proximal tubule - very permeable to water
distal tubule - very impermeable
descending loop of henle - permeable to water
ascending loop of henle - impermeable to water
collecting ducts - permeable to water subject to ADH control

46
Q

as move along proximal tubule what occurs with bulk flow

A

starlings forces favor reabsorption back into the blood due to

  • increase oncotic pressure capillary (reabsorption)
  • decrease hydrostatic pressure capillary (loss at glomerulus)
  • increase hydrostatic pressure interstitial fluid (movement water and Na+
47
Q

reabsorption of glucose in the nephron and what is special about it and a disease associated

A

limited number of specific carries so transport maximum which can be exceeded with diabetes mellitus - dehydration as glucose and water goes out in urine

  • Apical membrane - via a co-transporter with Na+
  • Basolateral membrane - via passive carrier transport
48
Q

reabsorption of protein (small amino acids, dipeptides, oligopeptides, large proteins

A

○ Small amino acids are reabsorbed via co-transport with Na+ across the apical membrane
○ Dipeptides enter via symporter carriers with H+ ions and then broken down by intracellular peptidases
○ Oligopeptides broken down by extracellular peptidases and then brought in via co-transport with Na+
○ Large proteins bind to receptors on the apical membrane and are endocytosed. The endosomes bind with lysosomes and the proteolytic enzymes within the lysosomes degrade the reabsorbed proteins and the resulting amino acids are transported into the interstitial fluid and then the blood.
- process can be saturated and is ATP dependent

49
Q

tubular secretion what mainly is secreted why and generally how occurs

A

Secretion of organic ions and drugs can occur as they may be bound by plasma proteins and poorly filtered in glomerulus
- anions - passive movement basolateral and active apical
cations - active process low specificity may be helped by conjugation in the liver

50
Q

what is hypoosmotic and hyperosmotic to plasma

A

hypo osmotic - dilute

hyperosmotic - concentrated

51
Q

countercurrent multiplication what is its function and how it achieves this and what occurs at the end of the loop of henle

A
  • Need to establish hyperosmotic interstitial fluid so water and solute reabsorption can be separated
  • NaCl transported out of thick ascending limb and into the medullary interstitium which increase the Osmolarity that draws water out of the descending limb
  • end get hypoosmotic fluid 100mOsm/L
52
Q

if want dilute urine what occurs and if want concentrated urine what occurs

A

Hypoosmotic
- No reabsorption of water down the collecting ducts which maintains the 100mOsm/L Osmolarity and results in dilute urine
Hyperosmotic
- Reabsorption of water down the collecting duct needs to take place so the Osmolarity can be 1200mOsm/L and produce concentrated urine - ADH

53
Q

Antidiuretic hormone (vasopressin) what act upon and what occurs, additionally mechanisms that are important and what disease prevents this

A

1) principle cells - V2 (G-protein receptor) basolateral membrane - increase cAMP - increase aquaporin 2 on apical membrane
2) urea absorbed due to ADH dependent urea transporter in collecting duct (contributes to 50% osmolarity in medullary gradient to drive water reabsorption from descending limb)
3) V1 receptor smooth muscle periphery vasoconstriction through PIP2 pathway to maintain flow to central areas in hypovolaemia
diabetes insipidus - no ADH so get dilute urine

54
Q

what are the 2 major stimulus for ADH secretion and what detected by and what occurs and how sensitive

A

1) Hyperosmolarity
- detected by osmoreceptors in the brain (hypothalamus)
- very sensitive responding
2) Effective circulating volume depletion
- Receive input from carotid sinus baroreceptors
○ Decrease in firing due to decrease stimulation from afferent neurons results in increase secretion of ADH
○ Increased firing due to increase stimulation from afferent neuron results in decrease ADH secretion
- Less sensitive 10-15% reduction in volume needed
transmit signal via vagus nerve

55
Q

what is the functions of the vasa recta, how does it achieve this and what occurs with increase blood pressure

A

1) Provide nutrients and oxygen to tubules in medulla
2) Return reabsorbed water and solutes back to circulation
3) Maintains osmotic gradient
- As it flows down into medulla » NaCl flows into vasa recta and H2O out.
- After bend on ascending loop NaCl moves out and H2O in
Medullary washout - blood flow is slower to permit adequate diffusion in and out if increase flow inappropriate exchange resulting in medullary washout reducing medullary osmotic gradient and decreasing efficiency to concentrate urine

56
Q

How to override a low ECV

A
  • Need to increase Na+ to increase amount of water and therefore volume in extracellular fluid
  • Therefore Na+ excretion is reduced
    ○ Drop GFR
    Increased reabsorption of Na+ via principle cells
57
Q

When is RAAS is activated and what does it result in

A

RAAS is activated in response to decrease blood volume or effective circulating volume (ECV)
Results in increase resorption of both Na+ and water in the kidneys

58
Q

what are the 3 controls of renin release and what are their stimulations

A

1) renal sympathetic nerves - baroreceptors sense reduction in body sodium and plasma volume
2) intrarenal baroreceptors within juxtaglomerular cells themselves - ECV decrease
3) macula densa - senses decrease in Na+ and/or Cl- concentration in distal tubule - decrease GFR

59
Q

what is the major functions and list the 6 functions of angiotensin II

A

sodium and water retention and vasoconstriction

1) Raises blood pressure via arterial vasoconstriction.
2) Stimulates aldosterone secretion by the adrenal cortex.
3) Enhances of NaCl reabsorption by proximal tubule.
- Activates Na+/H+ antiporter via stimulation of inhibitory G protein pathway that drops cAMP which normally acts to inhibit this antiporter
4) Alters renal hemodynamics by vasoconstriction of efferent arterioles and mesangial cells (reduction Kf)
5) Stimulation of ADH secretion and thirst.

60
Q

aldosterone where produced, function and what are the 4 things that regulate the secretion

A
  • Steroid hormone released from zona glomerulosa within the adrenal cortex
    Function - regulates Na+ reabsorption
  • Stimulates Na+ reabsorption and K+ secretion in principle cells of collecting ducts by increasing Na+/K+ ATP pump activity and sodium permeability by increasing number of Na+ channels (Aldosterone induced proteins)
    Regulation of secretion
    1) Angiotensin II - primary stimulation and most important signal
    2) Decrease in Na+ - second most important signal
    3) Increase in K+
    4) Increase in ACTH
61
Q

What are the 4 roles sympathetic nerves have in Na+ reabsorption

A

1) Drop GFR
- Vasoconstriction of afferent arterioles - less Na+ filtered and excreted
2) Stimulates renin secretion
- Via afferent arterioles stimulates renin
- Therefore stimulates Angiotensin II
3) Na+ tubular reabsorption
- Is enhanced as Na+/H+ transport is enhanced
4) Increase heart rate
- Increasing heart rate increases cardiac output which helps to restore blood pressure

62
Q

Atrial Natriuetic peptide where secreted and what is stimulus for release

A
  • Secreted from myocardial cells in the atria
    Stimulus for release
  • Increased effective circulating volume
  • Distention of atria
    Atrial stretch
63
Q

what is the function of the atrial natriuetic peptide and list 4 ways it achieves this

A

1) Increases GFR and filtered load of Na+
- Vasodilation of afferent arterioles and relaxes glomerular mesangial cells (Kf)
2) Inhibits aldosterone secretion
- Inhibits renin secretion
- Inhibits aldosterone secretion directly via action on adrenal cortex
3) Inhibits Na+ reabsorption by medullary collecting duct via cGMP
- Inhibit formation and movement of Na+ channels in apical membrane
4) Inhibits ADH secretion by posterior pituitary and collecting tubule response to ADH

64
Q

K+ filtration, secretion and absorption where occurs

A

○ K+ is freely filtered in glomerulus and almost all filtered K+ is reabsorbed before reaches collecting ducts
○ Distal tubule and collecting duct can reabsorb or secrete K+
- Proximal tubule most is reabsorbed via paracellular route

65
Q

List 4 things that alter K+ secretion and therefore K+ concentration

A

1) Aldosterone released by adrenal cortex (increased [K+] or Angiotensin II)
- Stimulating the production of » Na+,K+-ATPase pumps and K+ channels.
2) [K+] inside principal cells
» Increases concentration gradient
3) Tubular flow rates
- Increases local gradient for K+
○ Increased delivery of Na+ to collecting duct & its reabsorption leaves Cl- behind favouring electrochemical gradient for K+
4) Acidosis reduces K+ secretion
- pH alters K+ channels & Na+,K+-ATPase pumps
Possible that K+/H+ ATPase (intercalating cells) pumps increase.

66
Q

List some H+ producers and when does H+ change

A
  • Sulphur containing amino acids (methionine and cysteine),
  • Cationic amino acids (arginine and lysine)
  • CO2 produced by oxidative metabolism is normally excreted by the lungs
    » If not CO2 + H2O forms carbonic acid H2CO3
  • Therefore level of H+ will change with the diet
67
Q

How is H+ excess balanced and why is it important to control H+ concentration

A

H+ excess must be balanced by acid excretion
Why is H+ important
- H+ ions are highly reactive
○ relative small size - smaller than Na+, K+
○ strongly attracted to negatively charged portions of molecules due to their charge
- With a change in H+ concentration
○ proteins gain or lose H+ ions resulting in alterations in charge distribution, molecular configuration and consequently protein function.

68
Q

List the 3 stages in regulating H+

A

1) Chemical buffering by intracellular and extracellular buffers
2) Regulating partial pressure of CO2 in blood by altering alveolar ventilation
3) Control plasma HCO3 by changes in renal excretion of HCO3-.

69
Q

pH values for acidosis, alkalosis and death

A

Acidosis pH 7.45.

Death p H 8.0

70
Q

List the 3 types of buffers and which effected by dietary acid load

A

1) bicarbonate buffer system - increase
2) ammonia bufffers - increase
3) phosphate buffers

71
Q

Bicarbonate buffer system what is the equation, how is each molecule controlled and therefore what increases and decreases pH

A

H+ + HCO3- H2CO3 CO2 + H2O
H2CO3 - concentration is so small not considered
CO2 - lungs ensure that this concentration stays low to drive the reaction to the right
HCO3- - controlled by secretion in the kidneys
H+ α PCO2 / [HCO3-]
- Increases in CO2 increases H+ (reduces pH)
- Increases in HCO3 - drops H+ (increases pH)

72
Q

What is involved with the respiratory mechanism in regulating acid base balance

A
  • lungs regulate CO2 by removing it
  • [H+] detected by medulla oblongata which controls breathing so increase in [H+] increase in respiration and decrease in CO2
  • rapid response used to keep concentrations from changing too much until kidney mechanisms can start to work
73
Q

Describe the 3 renal mechanisms for regulating acid base

A

1) HCO3- reabsorption or excretion
- Every HCO3- reabsorbed is same as removing a H+ ion
2) Secretion of H+
- Needs to be closely controlled as if secrete too much H+ tubular fluid may become acidic and start to destroy epithelial cells reducing the ability to excrete and reabsorb solutes and buffers
3) Combination of excess H+ with tubular buffers
- Ammonia buffers (NH3 / NH4+).
- Phosphate buffers ( HPO4 2- / H2PO4- ).

74
Q

HCO3- filtration and reabsorption where does this occur and with combination of what

A
  • HCO3- is filtered by the glomerulus
  • Normally all HCO3- is reabsorbed in proximal tubule but also intercalated cells of collecting ducts
  • Balanced by the secretion of H+
  • Most of H+ does not leave body in urine but serves to reabsorb filtered HCO3
75
Q

How does secretion of HCO3- occur

A
  • Type B Intercalated cell in the collecting duct can secrete HCO3- via Cl- antiporter on apical membrane and maintain H+ concentration by secretion into the blood with a H-ATPase in the basolateral membrane
    ○ Directly opposite to Type A intercalated cell
  • used in alkalosis
76
Q

When all the HCO3- is reabsorbed what molecules are used as urinary buffers and when is secretion of H+ inhibited

A

HPO4^2-
NH3
at pH 4.4 as too acidic and will damage epithelial cells

77
Q

phosphate buffers what occurs in terms of filtration, secretion and reabsorption and when stops working

A

HPO4^2- completely filtered in glomerulus, HPO4^2- + H+ in tubular lumen –> H2PO4^2- which is excreted
- stops working below pH of 5.7

78
Q

Ammonium buffers when used, how NH4+ generated and when

A

when pH below 5.7 as phosphate buffers can no longer be used
generated from urea in liver creating glutamine then converted to glutamate dehydrogenase when generates NH4+
enzymes in reaction are pH dependent so only occurs in acidosis

79
Q

what occurs in acid base metabolic disorders and respiratory disorders

A
  • In acid base metabolic disorders the levels of HCO3- are altered directly or via addition of acid or base
  • In respiratory disorders CO2 levels are altered via ventilation
80
Q

List 4 causes of metabolic acidosis and examples

A

1) Increased lactic acid
- anaerobic conversion during strenuous exercise
2) Increases in β-hydroxybutyric acid and acetoacetic acid
- diabetes mellitus & starvation
3) Loss of HCO3
- diarrhoea or diuretics eg carbonic anhydrase inhibitor
4) Renal failure
- Retention sulphuric acid

81
Q

What pH does acidosis and alkalosis occur

A

acidosis pH

82
Q

Respiratory acidosis what characterised by list some causes and response of body

A
  • characterized by a reduced plasma pH and elevated CO2.
  • It results from decreased gas exchange across the alveoli as a result of inadequate ventilation or impaired gas diffusion.
    cause
    1) paralysis respiratory muscle (ticks, polio)
    2) airway obstruction
    3) lung tissue damage (tuberculosis)
    response - kidneys excrete H+ and conserve HCO3
83
Q

characteristics of metabolic acidosis and response

A
Plasma pH drops and plasma HCO3- drops
Response 
- Via intra and extracellular buffers
- Hyperventilation that reduced CO2 
- Renal excretion of net acid is increased
84
Q

Metabolic alkalosis how characterised, 3 causes and response from body

A
  • occurs due to a loss of H+ (or gain of HCO3-) from a source other than CO2
    1) Persistent vomiting, with its associated loss of HCl from the stomach
    2) Massive blood transfusion ie increases HCO3
    3) Hypokalemia which causes movement of H+ into cells.
    Response
  • buffers
  • hypoventilation that increases CO2 (above 40 mmHg)
85
Q

Respiratory alkalosis what characterized by, 3 causes and response

A
  • characterized by an increased plasma pH and reduced CO2.
    Cause: increase in
    1) ventilation as a result of excessive artificial ventilation,
    2) hypoxia (due to anaemia or severe hypotension) or
    3) hyperventilation due to anxiety or pain.
    Response
  • Plasma HCO3- falls as result of decreased HCO3- reabsorption in the kidney (increase in urine)
86
Q

What are diuretics, what teat and generally how act

A
  • Drugs used to increase the volume of urine excreted
  • Used to treat diseases characterized by renal retention of NaCl & water
  • Act by inhibiting reabsorption of Na+ & Cl- &/or HCO3
87
Q

give an example of a diuretic and how it exerts its effects

A

Diamox

Inhibits carbonic anhydrase

88
Q

Size of normal kidney in a dog in a radiography and margination

A
  • In the ventrodorsal projection compare the length of the kidney to the length of the second lumber vertebra (L2)
  • Normal is 2.5-3.5 times the length of L2
    margination - smooth
89
Q

location of the kidney in terms of the spine and why might the right kidney be hard to visualize

A

○ Left kidney: level with 1st – 3rd lumbar vertebra
○ Right kidney: level with 13th rib (last rib)
difficult to fully visualise due to superimposition of liver and other abdominal structures: particularly on VD

90
Q

size of normal kidney in a cat, where are the kidneys located compared to spinal cord and each other

A
  • In the ventrodorsal projection compare length of kidney to length of second vertebra (L2)
    Normal is 2.4-3 times length of L2
  • Both kidneys are at a similar location - level 1st and 4th lumbar vertebrae
    On lateral projection there is overlap between caudal pole of right kidney and cranial pole of left kidney
91
Q

how to access ureters on a radiograph

A
  • Normal ureters are not seen on radiographs
  • Can assess the retroperitoneum where the ureters are located
  • Only see if get calculi (metal opacity) or distention
92
Q

urinary bladder size, location and opacity and what does this compromise

A
  • Variable and depends on the time since the patient last voided
  • A normal distended urinary bladder may extend cranial to level with the umbilicus
    Opacity
  • Urine within the bladder is same radiographic opacity as urinary bladder wall cannot determine the thickness of the wall or asses the mucosa surface
93
Q

location of bladder and urethra in dog and cat

A

bladder
dog - caudal part located closer to the pelvic brim
cat - located further cranially in the abdomen
urethra
dog - majority of urethra is not included in abdominal
radiographs (need to take more caudal radiograph and move hindlimb to ensure see all urethra within pelvic rim)
cat - Longer proportion located cranial to pelvic brim and within abdomen

94
Q

List the 4 radio-graphic contrast study techniques

A

1) Excretory Urogram
2) Retrograde Cystogram
3) Retrograde Urethrogram
4) Retrograde Vaginourethrocystogram

95
Q

Excretory urogram what examined, what used and describe the 3 stages

A
  • Examination of the upper urinary tract - kidney and ureters
  • Use intravenous injection of iodinated contrast agent
    3 stages
    1. Nephrogram - contrast is within the kidneys
    2. Pyleogram - contrast concentrated in renal pelvis and moving down ureter
    3. Cystogram - when contrast is within the bladder - not the best for examining the bladder
96
Q

ectopic ureter what occurs, what normally see on radiograph and what results in on radiograph

A
  • when the ureter enters further distally into the urethra bypassing the bladder
  • Expect to see gaps in the ureter with the contrast as peristalsis is occuring
  • Causes large and distended ureters
  • No gaps in contrast down ureters as lost the active peristalsis
97
Q

Retrograde technique what examines, how works and what are the two contrasts used

A
  • Examination of the lower urinary tract:
  • Contrast moves retrograde (opposite to the flow of the urine)
    ○ Flow from tip of urethra to the bladder
  • Contrast administered via a urinary catheter
    ○ Positive contrast: iodinated contrast - most common look hyperechoic
    Negative contrast: gas - less common
98
Q

What are the 3 retrograde techniques what occurs and what examines

A

1) Retrograde Cystogram: place catheter in urinary bladder - just investigate the bladder
2) Retrograde Urethrogram: place catheter in distal urethra and investigate urethra +/- urinary bladder
3) Retrograde Vaginourethrocystogram: vagina, urethra +/- urinary bladder

99
Q

ultrasound of the urinary tract what can you see and what can’t you see

A

can see:
- internal architecture of the kidneys
- Contents of the urinary bladder
can’t see:
- Normal ureters are difficult to visualise
○ Unless have calculi or distention
- Limited portions of the urethra are able to be examined as ultrasound cannot travel through bone

100
Q

what are the two planes need to asses with ultrasound

A
  1. Longitudinal plane
    - Either sagittal or dorsal plane
  2. Transverse plane
101
Q

describe the echogenicity of the urinary bladder inner, middle and outer layers

A
Inner 
- Hyperechoic 
- Mucosa
Middle 
- Hypoechoic 
- Three muscle layers 
Outer 
- Hyperechoic 
- Serosa
102
Q

List and describe the 3 ways to sample the urinary tract, what needed, advantages and what used to examine

A

1) Cystocentesis: urine collection
- Needle into the urinary bladder through the abdomen wall
- Frequently performed using ultrasound guidance
- Advantage - not contaminated and will be sterile
2) FNA of the kidney
- Cells for cytology
- Just need to move needle around and bring out a small sample of cells - just need sedation
- inflammatory response (tumours)
3) Renal biopsy
- Core of tissue for histopathology
- More invasive, require a chunk of tissue need general anesthetic

103
Q

where to collect the kidney sample

A
  • Care needs to be taken with the needle as placement is important
  • Need to avoid: large arcurate vessels, large vessels in the renal hilus
  • Aim for the cortex