Bird dissection

Question 1

What is the crop?

Answer 1

an enlargement of the esophagus used to store food temporarily

Question 2

Where are most of the muscles concentrated?

Answer 2

around the centre of gravity - below the wings

Question 3

is the pectoral or the pelvic girdle more muscular?

Answer 3

pectoral - for the flight muscles

Question 4

What is the purpose of longer necks?

Answer 4

allow for things like grooming, food manipulation, and increased range of vision that are lost from the transition of forelimbs into wings and the reduced movement of eyes

Question 5

How does the avian gastrointestinal tract compare to that of mammals?

Answer 5

they are the same, except that birds have crops and their stomachs are different

Question 6

What are the 2 major sections of the bird stomach?

Answer 6

proventriculus (glandular), anterior

ventriculus (muscular), posterior

Question 7

what is the proventriculus?

Answer 7

the anterior most region of the bird stomach which functions in digestion

it is the glandular part of the stomach

Question 8

what is the ventriculus?

Answer 8

the posterior region of the stomach which is the muscular part

aka the gizzard

Question 9

T or F: extant birds are toothless

Answer 9

true

Question 10

What is the purpose of the ventriculus/gizzard?

Answer 10

acts as teeth, since extant birds do not have teeth, gizzards can mechanically digest food

Question 11

T or F: all birds have a crop

Answer 11

false

Question 12

why are small rocks often found in the gizzard?

Answer 12

to assist in digestion because birds don’t have teeth

Question 13

How is the respiratory system of birds unique to other reptiles and mammals?

Answer 13

one respiratory cycle includes 4 steps:

1 inhalation - 1 exhalation - 1 inhalation - 1 exhalation

air flow is continuous and unidirectional

Question 14

How many heart chambers do birds have?

Answer 14

4

Question 15

Do birds have single or double circulation?

Answer 15

double

Question 16

How does the circulatory system of birds compare to that of mammals?

Answer 16

pretty similar - both have 4 chambered hearts and double circulation, but bird circulation is more efficient

Question 17

What is the advantage of double circulation?

Answer 17

more efficient at transporting oxygen and nutrients throughout the body because more blood can be pumped per heart beat

Question 18

What is the difference between arteries and veins?

Answer 18

arteries: thicker, smoother tissue for faster blood flow and higher pressure leaving directly from the heart

veins: thinner, smaller because they are farther from the heart so pressure and speed is lower

Question 19

How do birds secrete waste? how does this compare to mammalian excretory systems?

Answer 19

birds have reduced excretory systems and secrete highly concentrated nitrogen metabolites (urates) which requires very little water

whereas mammals secrete urea, which requires a lot of water

Question 20

What is an adaptation to the excretory system of birds?

Answer 20

producing highly concentrated urates with little need for water means there’s no need for a urinary bladder = weight reduction

Question 21

how is uric acid/urates carried from the kidney to the cloaca of birds?

Answer 21

ureters

Question 22

describe the kidney of a bird

Answer 22

3-lobed

Question 23

What do the testes look like?

Answer 23

bean shaped, anterior to kidney

Question 24

What carries sperm to the cloaca? how does this differ from frogs and fish?

Answer 24

the vas deferens

frogs and fish do not have a vas deferens, but sperm is still transferred along a duct from the testes to the cloaca

Question 25

How has the female reproductive system in birds been modified? what are the benefits of this?

Answer 25

it has been reduced to only a left ovary and oviduct (other animals usually have 2 ovaries and oviducts)

reduces weight and prevents 2 eggs from being carried at a time