structure of lower respiratory tract

Question 1

what does the lower respiratory tract consist of

Answer 1

• trachea
• the bronchi and bronchioles
• alveoli, which make up the lungs

Question 2

main function of the structures of the lower respiratory tract

Answer 2

gas exchange

Question 3

which structures support the lower respiratory tract

Answer 3

thoracic cage (or rib cage) and the diaphragm

Question 4

structure of trachea

Answer 4

• a tube less than an inch in diameter
• ## covered by cartilaginous rings

Question 5

location of trachea

Answer 5

extends from the bottom of the larynx down behind the sternum, until it branches into smaller tubes, the bronchi

Question 6

function of trachea during inhalation

Answer 6

air filtered and warmed by the upper respiratory system passes from the pharynx and larynx into the trachea, then down to the bronchi and into the lungs

Question 7

function of trachea during exhalation

Answer 7

deoxygenated air from the lungs passes back up through the trachea

Question 8

function of cartilaginous rings in trachea

Answer 8

support the tube of the trachea and prevent it from over-expanding or from collapsing

Question 9

strcuture of cartilaginous rings in trachea

Answer 9

C-shaped, with a gap on the posterior side

• allows the trachea to bend when the esophagus presses against it as food is swallowed.

Question 10

what are bronchi

Answer 10

Passageways That Bring Air In and Out of the Lungs

Question 11

what do bronchioles do

Answer 11

deliver oxygen-rich air from the trachea to the lungs

Question 12

what happens to bronchioles during exercise

Answer 12

• relaxation of smooth muscle in the bronchioles
• causes them to dilate.
• This bronchodilation allows greater ventilation.

Question 13

what causes bronchoconstriction

Answer 13

allergic reactions and histamines

Question 14

what happens to the lungs during inhalation

Answer 14

• air flows into the lungs through the bronchi and bronchioles
• Oxygen from the air is then absorbed into the bloodstream: it passes through the alveoli, into surrounding capillaries. - Carbon dioxide waste diffuses the opposite way, from the capillaries to the alveoli.

Question 15

what do the lungs do during exhalation

Answer 15

they expel the deoxygenated air during exhalation

Question 16

what are alveoli

Answer 16

• microscopic air sacs served by the bronchioles
• they are the terminal ends of the respiratory tract and the sites of external respiration

Question 17

what is external respiration

Answer 17

the exchange of gases between the air and the bloodstream

Question 18

what do the alveoli do during inhalation

Answer 18

the alveoli fill with air from the bronchioles

Question 19

what does the diaphragm do during inhalation

Answer 19

contracts and moves inferiorly, toward the abdominal cavity.

• allows the volume of the thoracic cavity and the lungs to increase.
• also explains why your abdomen puffs out when you take a deep breath

Question 20

what does the diaphragm do during exhalation

Answer 20

• diaphragm relaxes (along with the external intercostal muscles).
• The thoracic cavity and lungs decrease, and air is expelled

Question 21

arterial supply of lower respiratory tract

Answer 21

lower airways receive blood flow from two sources:
1. the pulmonary circulation
2. bronchial circulation

Question 22

what does pulmonary circulation provide

Answer 22

• provides blood from the heart for oxygenation through the right and left pulmonary arteries which follow a branching structure similar to that of the airways themselves.
• This blood returns as oxygenated blood through the pulmonary veins which follow an independently branching structure to return to the right ventricle

Question 23

what does bronchial circulation provide

Answer 23

• provides oxygenated blood to the airway structures themselves.
• These arteries arise independently from the systemic circulation

Question 24

venous drainage of lower respiratory tract

Answer 24

bronchial veins - drain blood from the trachea

azygous vein - drain blood from bronchi on the right

either the accessory hemiazygos veins or the intercostal vessels - drain blood from bronchi on the left

pulmonary veins - drain distal circulation

Question 25

lymphatic drainage of lower airways

Answer 25

through the deep lymphatic plexuses of the pulmonary lymphatic plexuses.

Question 26

innervation of pharynx

Answer 26

via cranial nerves VII, IX, X, and XII.

Question 27

innervation of pharynx

Answer 27

via cranial nerves VII, IX, X, and XII.