Lab 7 - heart lab

Question 1

ECG:

Answer 1

Electrocardiogram. It’s the same thing as an EMG except with the heart instead of skeletal muscle.

Question 2

Human heartbeat:

Answer 2

P wave - atrial depolarization
QRS complex - atrial repolarization (smol) and ventricular depolarization (BIG)
T wave - ventricular repolarization

Question 3

Initiation of heart contraction occurs where?

Answer 3

Myocardial cells

Question 4

ANS can directly influence heart rate.

Answer 4

ACh from vagus nerve slows heart.

Epinephrine from adrenal glands speeds it.

Question 5

Baroreceptor reflex:

Answer 5

Keeps central arterial blood pressure high enough for metabolic activities but low enough to avoid rupture from vessels or excess fluid leakage from the capillaries.

Question 6

Diving bradycardia:

Answer 6

Thermo/mechanoreceptors in the face activate survival mode. Vasoconstriction occurs, which raises central arterial blood pressure dangerously. Heart rate is slowed to avoid danger.

Question 7

How is increased heart rate accomplished?

Answer 7

More beats per time (T-P), faster cycle time (P-T)

Question 8

Experiment 1: exercise and heart rate

Answer 8

Measure heartbeat pattern and pulse amp. Exercise. Repeat step 1.

Question 9

Phys sig, experiment 1:

Answer 9

Heart rate increases, pulse decreases (because blood is going to the legs).

Question 10

Experiment 2: dive

Answer 10

Measure heart rate and pulse amp. Face in water. Recover.

Question 11

Heart rate (beats/min) equation:

Answer 11

(60 seconds/minute) / (seconds/beat)

Question 12

Units:

Answer 12

Calibrating pulse plethysmograph is timeconsuming, so it’s incorrectly in mV.

Question 13

Phys sig, experiment 2:

Answer 13

Pulse decreases (blood goes to heart and brain). Overrides need for air and stimulates parasymp, releasing ACh from vagus nerve to drop heart rate. After the dive, pulse increases past normal because ACh gets used up and vasodilation occurs.