ABS 355 Exam 4, Elaborate and Detailed Questions
and Answers 2026
Gastralia (abdominal ribs) - Correct Answers a series of small dermal ossifications. These dermal
bones articulate to form an interlocking unit or 'basket' that is considered to protect the
abdomen.
Sternum - Correct Answers breastbone
birds breathe - Correct Answers -air passes over surface in ONE direction
needs 2 cycles, efficient for breathing in high elevations
-air doesnt mix
Air sacs in birds - Correct Answers - act as reservoirs for fresh air so lungs receive oxygen during
both inspiration and expiration
- air sacs can help cool the blood and regulate body temp
-O2 supply when diving and buoyancy in water
- also used to help the bird maintain flight.
Bird metabolism - Correct Answers -very high and requires a lot of food and oxygen
-endothermic
, Birds circulatory system - Correct Answers 4-chamber heart- 2 atria and 2 ventricles
-Birds' circulatory system goes though arteries to the veins in the extremities and flows near air
sacs.
-specifically, the dorsal aorta carries oxygenated blood from left ventricle and to other organs
and is returned to the heart via vena cava. Blood coming from tissues is then pumped to the
right ventricle and directly to the lungs for oxygenation
countercurrent heat exchange - Correct Answers -warm and cold blood flow in opposite
directions in two adjacent blood vessels to transfer heat via conduction
- the cold blood moving back towards the body's core is warm and the core does not go cold.
-This method also helps keep heat loss to a minimum and prevents their extremities from
freezing
Why do birds have a higher metabolism than mammals? - Correct Answers -the smaller the
animal, the faster their metabolism will be because animals with a smaller body size need to
continuously supply oxygen to the surrounding tissues- supported by lung ventilation.
Additionally, smaller organisms with a higher metabolism rate, including birds, will also exhibit a
higher body temperature.
-Birds also use a lot more energy, more than mammals, in comparison to their size, so
metabolism must be high to compensate for the difference and keep their temperature stable.
(Mammals also require 'x' amount of energy to maintain their temperature. However, most
mammals do not expend as much energy as birds do, so birds must increase their metabolism
higher than a mammal would to keep their temperatures stable)
and Answers 2026
Gastralia (abdominal ribs) - Correct Answers a series of small dermal ossifications. These dermal
bones articulate to form an interlocking unit or 'basket' that is considered to protect the
abdomen.
Sternum - Correct Answers breastbone
birds breathe - Correct Answers -air passes over surface in ONE direction
needs 2 cycles, efficient for breathing in high elevations
-air doesnt mix
Air sacs in birds - Correct Answers - act as reservoirs for fresh air so lungs receive oxygen during
both inspiration and expiration
- air sacs can help cool the blood and regulate body temp
-O2 supply when diving and buoyancy in water
- also used to help the bird maintain flight.
Bird metabolism - Correct Answers -very high and requires a lot of food and oxygen
-endothermic
, Birds circulatory system - Correct Answers 4-chamber heart- 2 atria and 2 ventricles
-Birds' circulatory system goes though arteries to the veins in the extremities and flows near air
sacs.
-specifically, the dorsal aorta carries oxygenated blood from left ventricle and to other organs
and is returned to the heart via vena cava. Blood coming from tissues is then pumped to the
right ventricle and directly to the lungs for oxygenation
countercurrent heat exchange - Correct Answers -warm and cold blood flow in opposite
directions in two adjacent blood vessels to transfer heat via conduction
- the cold blood moving back towards the body's core is warm and the core does not go cold.
-This method also helps keep heat loss to a minimum and prevents their extremities from
freezing
Why do birds have a higher metabolism than mammals? - Correct Answers -the smaller the
animal, the faster their metabolism will be because animals with a smaller body size need to
continuously supply oxygen to the surrounding tissues- supported by lung ventilation.
Additionally, smaller organisms with a higher metabolism rate, including birds, will also exhibit a
higher body temperature.
-Birds also use a lot more energy, more than mammals, in comparison to their size, so
metabolism must be high to compensate for the difference and keep their temperature stable.
(Mammals also require 'x' amount of energy to maintain their temperature. However, most
mammals do not expend as much energy as birds do, so birds must increase their metabolism
higher than a mammal would to keep their temperatures stable)
