The total force opposing LV con-. traction (i.e., the afterload) is the product of the LV. pressure and the internal surface area of the LV. cavity. In hypertensive subjects, of course, the arterial and. LV pressures are abnormally high during systole and, therefore, the LV afterload tends to be high.
Sincerely, Dick Montgomery A Most of the North American Hummingbirds migrate. The ones that go the farthest are the Rufous and the Ruby-throat. They may make trips to destinations which are as far as 2000 miles away.The hummingbird you have in northern Wisconsin is the Ruby-throated.n spring the birds probably follow the same route to come back north. A Ruby-throated Hummingbird flies at about 27 miles per hour if there is no tail wind or head wind. This would mean that long 500 mile flight across the Gulf of Mexico would take about 18 1/2 hours.
The average ruby-throated hummingbird weighs 3 grams. In comparison, a nickel weighs 4.5 grams. It would take more than 150 ruby-throated hummingbirds to weigh one pound. From 25-30 percent of a hummingbirdâs weight is in its pectoral muscles. These are the broad chest muscles principally responsible for flight.