1. Frog Heart Muscle

2. Contraction Pathway SA node Atria Ventricles AV node Gap Junctions
Increases in Na+ conductance; causes AP; autorrhythmic
Slows transmission of AP
Ventricles
AV node
Bundle of His
Purkinje fibers

3. Heart rate Frequency of AP created by the SA node
Fires 100x/min on own
Adult heart rate is about 70 bpm. WHY?

4. Regulated by: Sympathetic neurons Parasympathetic neurons
Levels of circulating epinephrine

5. PNS
Sensory neurons
Motor neurons
Autonomic NS
Parasympathetic NS
Sympathetic NS
Somatic NS

6. Autonomic Nervous System
Parasympathetic NS
Sympathetic NS
Rest and Digest
Decrease HR, BP, contraction strength/rate, increase systole duration
Fight or Flight
Increase HR, BP , contraction strength/rate, decrease systole duration

7. SA Node Firing Rate Altered by:
Changes in autonomic nerve activity
Sympathetic
Vagal
Circulating hormones
Hyperthyroidism
Hypothyroidism
Serum ion concentration
Hyperkalemia
Hypokalemia
Cellular hypoxia
Usually from ischemia
Drugs

8. Drugs Ca 2+ channel blockers β blockers Atropine
Nightshade plant (tomato family)

9. Amphibian Heart 2 atria 1 ventricle
O2 and deO2 blood separated by conus arteriosis and timing of atrial contractions.
Pressure differences is systemic and pulmonary circuits can allow O2 and deO2 blood to mix via an intercardiac shunt. Helps stabilize O2 content in blood, thermoregulate, and allow the skin to be used as a respiratory organ.
Sinus venosus = SA node in mammals.

10. Homework Write a Results, and Discussion for this lab.
Answer ALL questions within the text.

11. Course Reviews Please do them ASAP. Print the confirmation at the end.
5 extra credit points for completing this!!
Please provide constructive criticism if you have any. I’m always trying to improve my teaching!