Case Study I

Question 1

What is a heart murmur and how can it be caused?

Answer 1

• An abnormal heart sound caused by turbulent flow
• can result from an obstruction or valve failure

Question 2

What would be causing a heart murmur in this case?

Answer 2

• Worms in the heart causing turbulence
• abnormal function of the valves

Question 3

What is preload?

Answer 3

• the volume of blood present in the ventricles at the end of diastole
• diastole is the filling of the heart with blood
• preload is another name for EDV (end of diastolic volume)

Question 4

What is after load?

Answer 4

• The volume of blood contained in the ventricle after systole
• Systole is contraction of the heart
• Afterload should be a small amount as it indicates the majority of blood was ejected from the heart

Question 4

What will be the impact on preload and after load on violets case?

Answer 4

• After load and preload will increase, due to the obstruction and valve insufficiency that the worms cause, the blood is not properly ejected from the heart. This will cause an increase in the after load which ultimately causes an increase in preload

Question 5

Why is the right ventricle enlarged in this case/

Answer 5

• Pulmonary artery obstruction –> pulmonary hypertensions = increased after load in the right ventricle= right ventricular hypertrophy
• the myocardium (wall) of the right ventricle causes enlargement because it is working harder therefore cause more muscle to build increasing its size

Question 6

Why would a dog with heart failure have abnormal fluid?

Answer 6

• Due to the backlog of blood in the venous system
• The right side of the heart increases pressure, all the way down to the capillary level. This increase in hydrostatic pressure increases filtration pressure and loss of fluid

Question 7

What is Myasthenia Gravis (MG)

Answer 7

• autoimmune neuromuscular disorder in which circulating antibodies block nicotinic acetylcholine receptors

Question 8

Where is Ach found?

Answer 8

• The somatic nervous system at neuromuscular junction in skeletal muscles & the ganglionic synapse and the target organ synapses of the parasympathetic nervous system

Question 9

What type of receptors does Ach use?

Answer 9

• Nicotinic and muscarinic

Question 10

Where are Nicotinic receptors found

Answer 10

• found at ganglionic synapses of the autonomic nervous system and at the neuromuscular junction of skeletal muscles

Question 11

Where are muscarinic receptors found

Answer 11

• found on the effector tissue of the ANS
• the receptors for epinephrine and nor-epinephrine are alpha and beta-adrenergic receptors

Question 12

How does the tension test work?

Answer 12

• increases half life of Ach in the synaptic cleft

Question 13

What would a drug need to do to help Jake

Answer 13

• Slow Ach destruction allowing longer action at the NMJ