Description

BISC 104
Session 6

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• Please read the manual!

• Please read the manual! • Activity 1: Direct heart stimulation
• Please read the manual!
• Activity 1: Direct heart stimulation
• Activity 2: Indirect heart stimulation
• Please read the manual!
• Activity 1: Direct heart stimulation
• Activity 2: Indirect heart stimulation
• Activity 3-6: Effect of chemicals on heart rate
• Please read the manual!
• Activity 1: Direct heart stimulation
• Activity 2: Indirect heart stimulation
• Activity 3-6: Effect of chemicals on heart rate
• Activity 7: Effect of Temperature
• Please read the manual!
• Activity 1: Direct heart stimulation
• Activity 2: Indirect heart stimulation
• Activity 3-6: Effect of chemicals on heart rate
• Activity 7: Effect of Temperature
• Activity 8: Effect of Ions
• Please read the manual!
• Activity 1: Direct heart stimulation
• Activity 2: Indirect heart stimulation
• Activity 3-6: Effect of chemicals on heart rate
• Activity 7: Effect of Temperature
• Activity 8: Effect of Ions
• Please read the manual!

Cardiac Muscles
• Autorhythmicity: Heart’s ability to trigger its own contraction
• Two type of nervous systems acting: symphathetic and parasymphathetic
• Symphathetic affect the pacemaker cells =⇒ Increased heart rate
• Parasymphathetic counters symphathetic by decreasing the heart rate
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Cardiac Muscles have long refractory period
Unlike skeletal muscles, summation is not always possible

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Effect of chemicals, temperature, ions
• Heart rate can be modulated by varying the temperature, ions
• Chemicals also affect by inhibiting/mimicing/enhancing the action of organic chemicals such as acetylcholine
• NA+, K+ decrease the strength of contraction, Ca+2 increases
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Signup for presentations
• Sign-up with your topics
• 10 minute presentation followed by Q & A on topic of your choice
• Topic needs to pertain to physiology/biology • Examples: Pancreatic cancer, muscular diseases etc.
• Sign-ups on first come basis.
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Saket Choudhary skchoudh@usc.edu
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