Heart Contraction

Question 1

The SNS has 2 effects on the heart, what are they?

Answer 1

Increases rate of heart contraction
Increases cardiac comtracility

Question 2

Where are baroreceptors located

Answer 2

Aortic arch
Carotid arteries
Heart chambers

Question 3

Where are chemoreceptors located

Answer 3

Medulla
Carotid arteries

Question 4

Where are chemoreceptors located

Answer 4

Medulla
Carotid arteries

Question 5

What is baroreceptor reflex if BP drops due to blood loss

Answer 5

1. Blood is lost
2. Baroreceptor which is a sensory cell detects it
3. Baroreceptor sends signal to CNS that BP is low
4. Increases HR
5. Vasoconstricyion occurs

Question 6

Where do the SNS fibres go

Answer 6

Post-G fibres go to the SA Node and AV Node (in the walls of the heart)

Post-G fibres also go to the myocardium  this controls the force of contraction

Question 7

Where are the sympathetic cardiac nerves found

Answer 7

Within the cardiac plexus

Question 8

How does the PSNS control the heart

Answer 8

Pre-G fibres travel in branches of the recurrent laryngeal and vagal nerves to the cardiac plexus. The post-G fibres end in the atrial walls.

Question 9

In both the sympathetic and parasympathetic system, what receptors are stimulated or inhibited in the lungs?

Answer 9

Nicotinic

Question 10

What is each sound of the horse heart contraction caused by

Answer 10

S1- left and right AV valve close
S2- SL valve close
S3- passive filling of ventricles as the AV valves open
S4- contraction of atria to fill ventricles with blood