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BIO 277 Unit 5a Homework (Cardiovascular Physiology)

Terms in this set (15)

Product of heart rate X stroke volume
Cardiac Output
Normally acts as a paracrine signal and causes vasodilation.
Histamine
Causes slowing of heart rate.
Increased permeability to potassium in autorhythmic cells
Caused by sympathetic activation of autorhythmic cells.
Increased permeability to Calcium during pacemaker potential
Factor that increases total peripheral resistance that is NOT a hormone.
Increased blood vessel length
Factor that increases total peripheral resistance that is NOT a hormone..
Autorhythmic cells controlling heart rate
Caused by sympathetic activation of myocardial pumping cells.
Increased Ca++ ATPase activity
This tissue is under tonic control by the autonomic nervous system
Vascular circular smooth muscle
When ligand-gated potassium channels open, what is the most likely consequence?
Potassium leaves the cell a graded hyperpolarization occurs.
Which is true about autonomic effects on heart rate?
Sympathetic activation increases heart rate because the autorhythmic cells get to threshold faster.
Which of the following is a direct consequence of sympathetic activation of myocardial pumping cells?
Increased calcium entry and faster calcium uptake into the sarcoplasmic reticulum.
For every system that we talk about moving forward, we will keep coming back to smooth muscle, so it is important to learn it really well now. Which statement below describes the correct order of events for the excitation-contraction coupling of smooth muscle?
Calcium enters the cytosol through a ligand-gated calcium channel and binds with calmodulin. The calcium-calmodulin complex activates myosin light chain kinase which phosphorylates the myosin head allowing myosin to bind with actin, and the cross-bridge cycle to proceed. For muscles to contract the amount of myosin kinase activity must exceed the amount of myosin phosphatase activity.
Which is the correct relationship between calcium levels, myosin kinase activity and contraction of smooth muscle?
increased Ca++leads to increased myosin kinase leads to increased contraction
Which is the correct statement about factors affecting the state of contraction of vascular circular smooth muscle?
Increased CO2 and H+ causes a decrease in myosin kinase activity.
Each of the following factors would increase peripheral resistance except one. Identify the exception.
Increased levels of ANP in the blood.
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