Avian Anatomy and Physiology Quiz

A single, unpartitioned cavity encompassing the avian thorax and abdomen, unlike mammals.

Four chambers: a thin-walled right ventricle, and a thick-walled left ventricle.

Rectangular, muscular atrioventricular valve on the right, aids complete right ventricle emptying.

High (108-250 mm Hg) due to stiff arteries, influenced by cardiac output and arterial impedance.

Nucleated, elliptical red blood cells, with functional mitochondria, involved in oxygen transport and more.

Includes nares, choana, infundibular cleft, glottis, and trachea with complete cartilaginous rings; syrinx as a vocal organ.

Composed of lungs, parabronchi, and air sacs; air sacs not for gas exchange, aid unidirectional airflow.

Occurs in air capillaries within parabronchi with a thin blood-gas barrier; cross-current flow enhances oxygen uptake.

Two-breath cycle: air first enters caudal air sacs; then moves from caudal to lungs; then enters cranial air sacs; exits through trachea.

Divided into cranial, middle, and caudal regions.

Nephrons in reptiles that lack a loop of Henle, and produce hypotonic urine.

Nephrons in mammals that have loops of Henle, enabling limited urine concentration.

A system receiving blood from caudal mesenteric, ischiatic, and internal iliac veins.

Composed of urine, urates (nitrogen waste), and feces.

The main nitrogen waste in bird droppings.

Hormone that promotes calcium mobilization in birds.

Hormone increasing calcium absorption.

Include germinal disc, yolk, albumen, and shell.

Testes in coelom, ductus deferens to urodeum.

Only left ovary and oviduct functional.

Avian arteries have lower peripheral vascular resistance compared to mammals. This means they require less pressure to push blood through them.

Avian arteries have a higher proportion of collagen fibers, making them 'stiffer' than mammalian arteries. This requires higher blood pressure to maintain circulation.

Avian blood pressure is determined by two main factors: cardiac output (how much blood the heart pumps) and arterial impedance (resistance to blood flow in the arteries).

High blood pressure in birds, due to stiff arteries, can lead to serious health problems like aortic rupture, heart failure, and internal bleeding, particularly when stressed.

Cardiac output in birds is measured as heart rate multiplied by stroke volume (amount of blood pumped per beat). This directly affects blood pressure.

Unlike mammalian RBCs, avian RBCs retain their nucleus, giving them an elliptical shape. They also have functional mitochondria.

While primarily involved in oxygen transport, avian RBCs also contribute to toxin metabolism and detoxification, likely due to their active mitochondria and enzymes.

Avian RBCs seem to respond to low oxygen environments, like high altitude flight, by adjusting their oxygen carrying capacity.

Avian RBCs can modulate the concentration of ATP (energy molecule) produced by their mitochondria to fine-tune their oxygen binding affinity. This allows efficient oxygen uptake and unloading according to the bird's needs.

Erythrocyte production (making red blood cells) and hemoglobin synthesis (making the oxygen carrier) are independently regulated in birds, unlike in mammals where they are coupled.

Birds have more dead space in their respiratory system than mammals, primarily due to their longer trachea. This means a larger volume of air doesn't participate in gas exchange.

To compensate for increased dead space, birds take deeper and slower breaths, maximizing the efficiency of gas exchange in their lungs.

These specialized bronchi in birds are responsible for gas exchange. Air flows through them in one direction, from the back to the front, maximizing gas exchange efficiency.

Atria, the expansions in the parabronchi walls of birds, are analogous to alveoli in mammals. These structures contain air capillaries where gas exchange occurs.

Neopulmonic are short, interconnected, and allow air to flow in both directions, unlike the parabronchi.