6. Respiratory System

Question 1

Describe how air enters the body

Answer 1

Air goes through nares –> filtered through mucous membranes and vibrissae & lysozyme in nasal cavity –> passes into pharynx and larynx –> into trachea –> then into one of two mainstem bronchi —> bronchioles —> alveoli

Question 2

What and where is the pharynx?

Answer 2

Lies behind nasal cavity at back of mouth. Common pathway for air going to lungs and food going to esophagus

Question 3

What and where is the larynx?

Answer 3

Lies below pharynx and is only for air to lungs. The epiglottis covers the opening of larynx (glottis) when swallowing. Larynx contains 2 vocal cords maneuvered by skeletal muscle and cartilage

Question 4

Why do bronchi and trachea have ciliated epithelial cells?

Answer 4

To filter anything that passed vibrissae

Question 5

What do bronchi further divide to?

Answer 5

Bronchioles and divide further into tiny balloon-like structures called alveoli

Question 6

Each alveolus is coated with what? Each alveolus is surrounded by what? How is elasticity of alveoli determined?

Answer 6

Surfactant, a detergent that lowers surface tension at air-liquid surface to prevent alveolus from collapsing on itself. Network of capillaries surround each alveolus to carry oxygen and carbon dioxide. Pressure of fluid, not radius of airway (radius = determined by bronchioles)

Question 7

Visceral vs parietal pleura

Answer 7

Membrane adjacent to lung vs membrane surrounding visceral pleura. Intrapleural space in b/w visceral and parietal pleura

Question 8

What is the diaphragm?

Answer 8

Thin, muscular structure that divides thoracic cavity and abd cavity; ONLY innervated by phrenic nerve; ONLY consists of skel muscle

Question 9

Is inhalation an active process? What muscles control inhalation?

Answer 9

Yes it’s an active process. Diaphragm and external intercostal muscles (muscles b/w ribs) expand thoracic cavity –> inc the space in the pleural cavity –> lowering its pressure relative to atmospheric pressure. This forces air down into the lungs and expands the lungs, forming the basis of ‘negative pressure’

Question 10

What is intrathoracic volume?

Answer 10

The volume of thoracic cavity

Question 11

Is exhalation an active process? What muscles control exhalation?

Answer 11

No it does not have to be an active process; diaphragm and external intercostal muscles relax. For it to be active, internal intercostal muscles and abd muscles pull rib cage down.

Question 12

Total lung capacity (TLC) vs residual volume (RV) vs vital capacity (VC) vs tidal volume (TV)? Know what these look like on a graph on pg 333

Answer 12

Max vol of air during complete inhalation, usually 6-7 liters vs vol of air left after exhaling vs difference b/w TLC and RV vs vol of air in/exhaled under nml breath

Question 13

Expiratory reserve volume (ERV) vs inspiratory reserve volume (IRV)? Know what these look like on a graph on pg 333

Answer 13

Vol of air forcibly exhaled after nml exhalation vs vol of air forcibly inhaled after nml inhalation

Question 14

How is ventilation/respiration regulated by the brain?

Answer 14

Ventilation/respiratory center = located in medulla oblongata, it’s a collection of neurons; AND PONS - resides in hindbrain, connects cerebrum to hindbrain, responsible for respiration

Question 15

Central chemoreceptors vs peripheral chemoreceptors vs mechanoreceptors

Answer 15

Central chemoreceptors neighbor around resp center in brain, carry info about CO2 and pH vs peripheral chemoreceptors are outside the brain, carry info about O2, CO2 and pH vs carry info about pressure, sound, touch and motion

Question 16

What happens when CO2 rises (hypercarbia/hypercapnia/hypoxemia) in blood?

Answer 16

Respiratory rate inc to exhale CO2

Question 17

Describe where de/oxygenated blood comes from

Answer 17

Deoxygenated blood moves from right heart ventricle to pulmonary arteries to capillaries –> CO2 diffuses from blood to lungs, O2 diffuse from lungs to blood –> Oxygenated blood moves from capillaries to pulmonary veins to left heart atrium

Question 18

What is thermoregulation? How is it regulated? What does resp system have to do with it?

Answer 18

Regulation of body temp. Heat = regulated by vasodilation or vasoconstriction. If blood vessels expand –> more blood goes through –> larger amounts of thermal energy can be dissipated; if blood vessels constrict –> less blood goes through –> thermal energy conserved. Resp system = highly vascular —> does vasodilation/constriction

Question 19

What is mucociliary escalator?

Answer 19

When cilia in respiratory tract move pathogens into mucus and to oral cavity to be expelled or swallowed

Question 20

What is the bicarbonate buffer system?

Answer 20

CO2 + H20 H2CO3 H + HCO3

Question 21

What happens when body pH is lower than 7.35 (acidemia)?

Answer 21

Acid-sensing chemoreceptors send signals to inc respiratory rate –> more CO2 blown off –> push bicarbonate buffer system to left

Question 22

What happens when body pH basic (alkemia)?

Answer 22

Dec respiratory –> you need to retain CO2 –> push bicarbonate buffer system to right to reabsorb and produce more H ions and bicarbonate ions

Question 23

What can’t a spirometer measure?

Answer 23

Residual vol, and consequently TLC

Question 24

People with IPF have what decreased vol?

Answer 24

TLC, inspiratory vol, and RV

Question 25

What does passive recoil of lung tissue do?

Answer 25

Dec lung vol —> exhale completely