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.
When a female enters his territory, the male performs a courtship display. The Ruby-throated Hummingbird male will flash his red throat feathers and perform a dive display, rising 8 â 10 feet (2.5 â 3 m) above and 5 â 6 feet (1.5 â 1.8 m) to each side of the female in looping dives.