Physio Exam 3 Study Guide.pdf - Lecture 1 – Cardio Flow 1....

Lecture 1 – Cardio Flow
1. What is the function of desmosomes?
2. What is the function of gap junctions? 3. What is the equation for resistance?
4. What are the equations for blood flow and flow rate?
5. Flow calculation. Use the Flow and Resistance equation to compare the flow
rate and resistance of two blood vessels.
Lecture 2 – Electrical Events
1. Know the mechanism of the neuromuscular junction and cross bridge cycle.
(Start with the motor neuron releasing neurotransmitter)
a. Somatic motor neuron releases ACh at neuromuscular junction
b. Net entry of Na+ (depolarization) through ACh receptor-channel initiates a
muscle action potential
c. AP in T-tubule alters conformation of DHP receptor (type of calcium
channel)

d. DHP receptor opens the RyR releasing Ca2+ into the cytoplasm
i. RyR is a Ca2+ release channel in the sarcoplasmic reticulum (SR)
e. Ca2+ binds to troponin, allowing actin-myosin binding
i. Troponin shies away
ii. Myosin comes together- cross bridge
f. Myosin heads execute power stroke
g. Actin filaments slide toward center of sarcomere
i. Muscle contracts and becomes shorter
h. Sarcoplasmic Ca2+ -ATPase pumps Ca2+ back into SR
i. Decrease in free cytosolic Ca2+ concentration causes Ca2+ to unbind
from troponin
j. Tropomyosin recovers binding site.
k. When myosin heads release, elastic elements pull filaments back to their
relaxed position