Ch. 6: The Respiratory System

Question 1

Thoracic Cavity

Answer 1

Structure designed to perform breathing, location of lungs and heart

Question 2

Air flow

Answer 2

Air is drawn into through the 1. Nares and through the 2. Nasal cavity (It is filtered by nasal hairs (vibrissae) and mucous membranes) and 3. Pharynx (common pathway for both food and air) where it is warmed and humidified 5. It then enters the larynx (only air, contains vocal cords which are maneuvered by skeletal muscle and cartilage, the glottis is the opening which is covered by the epiglottis to prevent food from entering the respiratory tract) 6. Followed by the trachea 7. Which divides into 2 mainstem bronchi, which divide into bronchioles 8. Which divide continually into smaller passages called bronchioles until reaching the alveoli

Question 3

Surfactant

Answer 3

In the alveoli, reduces surface tension @ the liquid gas interface preventing collapse

Question 4

Pleurae

Answer 4

Cover the lungs and line the chest wall, closed sac against which lung expands

• Visceral pleura: lies adjacent to the lung itself
• Parietal Pleura: lines the chest wall
• Intrapleural space: lies between these 2 layers and contains a thin layer of fluid which lubricates the 2 pleural surfaces

Question 5

Diaphragm

Answer 5

A thin skeletal muscle that helps to create the pressure differential required for breathing bc lungs do not fill passively– divides the thoracic cavity from abdominal cavity, under somatic control even though breathing is autonomic control

Question 6

Labored Breathing

Answer 6

Muscles of the chest wall, back and neck may also participate in breathing esp when breathing is labored due to pathogenic condition

Question 7

Inhalation

Answer 7

Active process. Diaphragm and external intercostal muscles expand the thoracic cavity increasing the volume of the intrapleural space first then the intrathoracic volume. This decreases the intrapleural pressure

Question 8

Negative-Pressure Breathing (part of inhalation)

Answer 8

The pressure differential ultimately expands the lungs, dropping their pressure and drawing in air from the environment. Boyles law– lower pressure in lungs causes atmospheric air to be drawn in to match atmospheric pressure

Question 9

Exhalation

Answer 9

May be passive or active. In passive exhalation relaxation of the muscles of inspiration and elastic recoil of the lungs allow the chest cavity to decrease in volume, reversing the pressure differentials seen in inhalation. In active exhalation the internal intercostal muscles and abdominal muscles can be used to forcibly decrease the volume of the thoracic cavity, pushing out air.

Question 10

Spirometer

Answer 10

Can be used to measure lung capacities and volumes

Question 11

Total lung capacity (TLC)

Answer 11

Maximum volume of air in the lungs when one inhales completely

Question 12

Residual Volume (RV)

Answer 12

Minimum volume of air in the lungs when one exhales completely

Question 13

Vital capacity (VC)

Answer 13

Difference between the minimum and maximum volume of the air in the lungs (TLC - RV)

Question 14

Tidal volume (TV)

Answer 14

The volume of air inhaled or exhaled in a normal breath

Question 15

Expiratory reserve volume (ERV)

Answer 15

Volume of additional air that can be forcibly exhaled after a normal exhalation

Question 16

Inspiratory Reserve Volume (IRV)

Answer 16

Volume of additional air that can be forcibly inhaled after a normal inhalation

Question 17

Ventilation Center

Answer 17

A collection of neurons in the medulla oblongata that regulates ventilation

Question 18

Chemoreceptors

Answer 18

Respond to CO2 concentrations, increasing the respiratory rate when there are high concentrations of CO2 in the blood (hypercarbia or hypercapnia) also respond to changes in O2 concentration in significant hypoxemia

Question 19

Hypoxemia

Answer 19

Low oxygen concentrations in the blood; ventilation center responds by increasing the ventilation rate

Question 20

Conscious Control of Ventilation

Answer 20

Ventilation can also be controlled consciously though the cerebrum, although the medulla oblongata will override the cerebrum during extended periods of hypo- or hyperventilation

Question 21

Functions of the Respiratory System

Answer 21

1. Gas exchange 2. Lungs lined w capillaries used in thermoregulation 3. Serve an immune function to prevent invaders from gaining access to bloodstream 4. Control blood pH by controlling concentrations

Question 22

The lungs and gas exchange

Answer 22

The lungs perform gas exchange w the blood through simple diffusion across concentration gradients

Question 23

Pulmonary Arteries

Answer 23

Brings deoxygenated with high CO2 concentration to the lungs, where the capillaries which surround alveolus bring deoxygenated blood, originate from left ventricle

Question 24

Pulmonary Veins

Answer 24

Oxygenated blood w a low CO2 concentration leaves the lungs via pulmonary veins to right atrium of heart

Question 25

Respiratory adjustment to higher altitudes

Answer 25

Less O2 available, breathe more rapidly to avoid hypoxia, binding dynamics of hemoglobin would be altered to facilitate O2 unloading at tissue, natural response of hemoglobin to decreased CO2 concentration in environment would actaully be to decrease unloading of O2 to tissues, other mechanisms can counteract and override phenomenon to allow adequate delivery of O2 (ie more red blood cells) in the long term form more blood vessels

Question 26

Vasodilation and Vasoconstriction

Answer 26

The large surface area of interaction between the alveoli and capillaries allows the respiratory sys to assist in thermoregulation through vasodilation and vasoconstriction of capillary beds→ capillaries expand means more blood passes through vessels means more thermal energy can be dissipated. When capillaries contract less blood passes to conserve thermal energy

Question 27

Thermoregulation

Answer 27

Regulation of body temp, highly vascular nature of respiratory sys makes it conducive for this function via vasodilation and vasoconstriction

Question 28

Protection from Pathogens in the Respiratory System:

Answer 28

Multiple mechanisms that help filter the incoming air and trap particulate matter

Question 29

Vibrissae,

Answer 29

In nasal cavity, small hairs which help trap particulate matter and potentially infectious particles

Question 30

mucous membranes, Mucociliary Escalator

Answer 30

Internal airways are lined with mucus to trap particulate matter and larger invaders, underlying cilia propel mucus up respiratory tract to oral cavity where it can be expelled or swallowed

Question 31

Lysozyme

Answer 31

In the nasal cavity and saliva attacks peptidoglycan cell walls of gram-positive bacteria

Question 32

Macrophages

Answer 32

Can engulf and digest pathogens and signal to the rest of the immune system that there is an invader

Question 33

Mucosal Surfaces

Answer 33

Covered w IgA antibodies help protect against pathoges which contact mucus membranes

Question 34

Mast Cells

Answer 34

Have antibodies on their surface that, when triggered, can promote the release of inflammatory chemicals. Mast cells are often involved in allergic reactions as well

Question 35

pH control through bicarbonate buffer system

Answer 35

When blood pH decreases (should be 7.35-7.45), respiration rate increases to compensate by blowing off CO2. This cause a left shift in the buffer equation, reducing hydrogen ion concentration. When blood pH increases, respiration rate decreases to compensate by trapping CO2. This causes a right shift in the buffer equation, increasing hydrogen ion concentration

Question 36

Body pH equation

Answer 36

CO2 (g) + H2O (l) H2CO3 (aq) H+ (aq) + HCO3- (aq)

Question 37

Acidemia

Answer 37

ower body pH than normal (higher H+ concentration)– acid sensing chemoreceptors just outside blood brain barrier send signals to breain to increase resp rate to shift rxn toward more CO2

Question 38

Alkalemia

Answer 38

Blood is too basic respiratory rate is slowed to retain more CO2 which shifts rxn to produce more H+ ions and lower pH