Basic Physiology

Question 1

How is ACh synthesized? Where is it stored?

Answer 1

1. Acetyl CoA + Choline → choline acetyltransferase → ACh

2. Stored in the synaptic vesicles with ATP and proteoglycan

Question 2

How is ACh degraded? What happens to the degradation products?

Answer 2

1. ACh degraded to Acetyl CoA and choline by aceylcholinesterase
2. Occurs at the muscle end plate
3. 1/2 of the choline is taken back to the presynaptic cleft by Na-choline transport to make new ACh

Question 3

Botulinum Toxin

Answer 3

Blocks ACh release from presynaptic terminals → total blockade

Question 4

Curare

Answer 4

Competes with ACh for receptors on the motor end plate → decreased end plate potential

Question 5

Neostigmine

Answer 5

Inhibits acetylcholinesterase → prolongs action of ACh at motor end plate

Question 6

Hemicholinium

Answer 6

Blocks reuptake of choline into presynaptic terminal → depletes ACh stores

Question 7

Excitatory neurotransmitters

Answer 7

1. ACh
2. Norepinephrine
3. Epinephrine
4. Dopamine
5. Glutamate
6. Serotonin

Question 8

Inhibitory Neurotransmitters

Answer 8

1. GABA
2. Glycine
3. Nitrous Oxide

Question 9

Describe pathway for converting tyrosine into different neurotransmitters

Answer 9

Tyrosine → tyrosine hydroxylate → L-dopa → dopa decarboxylase → dopamine → dopamine β hydroxylase → norepinephrine → phenylethanolamine-N-methyltransferase → epinephrine

Question 10

What does serotonin form from? Where is the highest concentration of serotonin?

Answer 10

1. Tryptophan

2. Brainstem

Question 11

What metabolizes norepinephrine and dopamine?

Answer 11

1. Monoamine oxidase (MAO)
2. Catechol-O-Methyltransferase (COMT)
   * VMA metabolite of NE is increased in urinary excretion with pheochromocytomas

Question 12

What is the most prevalent excitatory neurotransmitter in the brain?

Answer 12

Glutamate

Question 13

GABA synthesis and receptors

Answer 13

1. Glutamate → glutamate decarboxylase → GABA
2. GABA(a) → Increase Cl conductance
   - Benzodiazepines and barbiturates act here
   GABA(b) → Increase K conductance

Question 14

Nitric oxide synthesis

Answer 14

Arginine → NO synthase → NO

Question 15

What is a major difference in myosin regulation between skeletal and smooth muscle?

Answer 15

Smooth has no troponin → Ca regulates myosin on the thick filaments

Question 16

Type 1 muscle fibers

Answer 16

1. Red, slow twitch
2. Small diameter
3. More mitochondria
4. More blood supply

Question 17

Type 2 muscle fibers

Answer 17

1. White, fast twitch
2. Large diameter
3. Extensive sarcoplasmic reticulum
4. Lots of glycolytic enzymes
5. Less extensive blood supply
6. Fewer mitochondria

Question 18

What can occur with repeated thoracocentesis in chylothorax?

Answer 18

1. Hyponatremia
2. Hyperkalemia
   * Third space loses of Na → subsequent decrease ECV and GFR causes increase K

Question 19

What is the order of half-life duration of AST, ALP, and ALT?

1. Dog
2. Cat

Answer 19

1. ALP>ALT»AST

2. ALP=ALT»AST

Question 20

Sensitivity and Specificity (High/Low): ALP

1. Dog
2. Cat

Answer 20

1. High sens (86%) but low spec (49%) for liver diseaes

2. Less Sens but more spec for liver disease

Question 21

Reasons for increase:

1. L-ALP
2. B-ALP
3. C-ALP

Answer 21

1. Cholestasis, Hyperadrenocorticism, and drug induction (phenobarb and steroids - ~24-48 hours after exposure)
2. Benign familial hyperphosphatemia in huskies and scotties results from increase B-ALP
3. Steroids (10 days after exposure), Diabetes mellitus, primary liver disease, and HAC

Question 22

Anion Gap Equation

Answer 22

(Na + K) - (Cl + HCO3)

Question 23

Causes of increased calcium excretion

Answer 23

1. Decrease PTH
2. Increase ECV
3. Increase BP
4. Decrease P
5. Metabolic alkalosis
   * Opposites for decrease Ca excretion

Question 24

Ions associated with vasodilation

Answer 24

1. Increase Magnesium
2. Increased H (acidemia)
3. Acetate/Citrate
4. CO2
   - Vasodilate in brain
   - Vasoconstrict periphery to increase flow to the brain

Question 25

Ions involved in vasoconstriction

Answer 25

1. Increase Ca | 2. Decrease H (alkalemia)

Question 26

Total body water breakdown

Answer 26

TBW (60% BW) 1. 2/3 Intracellular (40% BW) 2. 1/3 Extracellular (20% BW) a. 3/4 interstitial fluid (15% BW) b. 1/4 plasma (5% BW) Blood volume = 10% BW → can take 10% of blood volume safely (1%)

Question 27

Transudate: 1. Sp. Gr. 2. Protein 3. Cells 4. Causes

Answer 27

1. <1.015 2. <2.5 3. 1500 4. Decrease osmotic pressure, early uroabdomen, Pre-sinusoidal or sinusoidal liver disease, right heart failure, liver failure

Question 28

Exudate: 1. Sp. Gr. 2. Protein 3. Cells 4. Causes

Answer 28

1. >1.025 2. >3 3. >7000 4. Usually infections and inflammation of viscera

Question 29

Chyle: 1. Sp. Gr. 2. Protein 3. Cells 4. Causes

Answer 29

1. >1.025 2. >2 3. 1000-7000 (small lymphocytes) 4. Trauma, neoplasia, infection, right heart failure

Question 30

What are the inducible liver enzymes?

Answer 30

1. GGT | 2. ALP

Question 31

ALP isotope concentrations in serum: 1. L-ALP 2. B-ALP 3. C-ALP

Answer 31

1. Majority % in dogs >1 year 2. 25% in dogs >1 year, 95% in dogs <1 year 3. 10-30%

Question 32

What can cause transiently high ammonia?

Answer 32

1. Irish Wolfhounds 2. Cobalamin deficiency (dog) 3. Arginine deficiency (cat)

Question 33

Function tests that would be indicative of liver disease/failure?

Answer 33

1. Decrease BUN 2. Hypocholesterolemia → may be increased in cholestatic disease 3. Hypoalbuminemia → when 70% of liver mass 4. Hyperammonia 5. Hypoglycemia → loss of 75% of hepatic mass 6. Increased t. bili

Question 34

Diseases with normal anion gap

Answer 34

1. Diarrhea 2. Renal insufficiency 3. Renal tubular acidosis 4. High chloride containing fluids 5. Compensation for respiratory alkalosis

Question 35

Complications of acidosis

Answer 35

1. Ventricular arrhythmias 2. Decrease cardiac contractility 3. Arterial vasodilation 4. Venous vasoconstriction 5. Insulin resistance

Question 36

What is the status of Ca in the sarcoplasmic reticulum?

Answer 36

Bound to calsequestrin

Question 37

Modified Transudate: 1. Sp. Gr. 2. Protein 3. Cells 4. Causes

Answer 37

1. 1.015-1.025 2. >2.5 3. 1000-7000 4. Post-sinusoidal portal hypertension, liver disease, HW/Caval syndrome, vascular permeability

Question 38

Diseases with decreased anion gap

Answer 38

1. Ketoacidosis 2. Uremia (renal failure) 3. Lactic acidosis 4. Toxins (ethylene glycol)

Question 39

Describe the differences between type A and type B hyperlactatemia

Answer 39

``` Type A → impaired tissue oxygenation - Hypoperfusion - Severe anemia - Excessive muscular activity - Seizures, trembling, exercise - Thromboembolic disease Type B → tissue oxygenation normal - Sepsis/SIRS - Neoplasia - Drugs - Severe Liver Failure ```

Question 40

Main causes of hypokalemia in cats

Answer 40

1. Chronic renal disease | 2. Burmese kitten syndrome

Question 41

How does insulin move K into cells?

Answer 41

Activates Na-K ATPase