MCAT Biology Ch8: Respiration Kap

Question 1

lungs

Answer 1

• where gas exchange occurs

- primary function - movement of gas in the lungs

Question 2

air pathway

Answer 2

enters resp tract through external nares of nose (mouth and nose warm and humid air before into lungs)–> nasal cavity, filtered through mucous membranes and nasal hairs, cilia (so don’t breathe in lungs) –> pharnyx –> larnyx –> cartilaginous trachea –> mainstream bronchi –> bronchioles –> alveoli

Question 3

external nares

Answer 3

air enters resp tract here first

Question 4

larynx

Answer 4

• only for air

- opening of it (glottis) is covered by epiglottis during swallowing

Question 5

pharnyx

Answer 5

between mouth and esphoagus where food travels

Question 6

epiglottis

Answer 6

covers glottis during swallowing

Question 7

trachea

Answer 7

-air passes here from larynx, then into bronchi

–ciliated epithelial cells to catch material that pasted nose

Question 8

bronchi

Answer 8

• one per side
• air comes from trachea
• divided into bronchioles, where air goes
• ciliated epithelial cells to catch material that pasted nose

Question 9

bronchioles

Answer 9

• smaller structures divided from bronchi, which air comes from
• air goes to alveoli

Question 10

alveoli

Answer 10

• tiny structures in which gas exchange occurs
• air comes from bronchioles
• each alveolus coats w/ surfactant –> lowers surface tension and prevents alveolus from collapse
• network of caps surrounds each to carry O2 and CO2
• branching and min. size –> large SA for gas exchange (100 m2)

Question 11

surfactant

Answer 11

detergent that lowers SA and prevents alveolus from collapse

Question 12

thoracic cavity

Answer 12

• lung are in here
• also contains heart
• separated from organs of digestion by muscle known as diaphragm

Question 13

diaphragm

Answer 13

• muscle separates thoracic cavity from organs of digestion
• necessary for inspiration
• composed of skeletal muscle –> somatic control
• chest wall forms one side

Question 14

inspiration

Answer 14

diaphragm is necessary for this

Question 15

pleurae (sing. pleura)

Answer 15

• membrane surrounds each lung

- closed sac against which lung grows

Question 16

visceral

Answer 16

• surface against lung

- inner

Question 17

parietal

Answer 17

• all other parts of sac (pleura)

- outer, assoc w/ chest wall

Question 18

intrapleural space

Answer 18

• space w/in space (between visceral and parietal)
• contains thin layer of fluid
• helps lubricate two pleural surfaces
• pressure differential between it with lungs –> for proper respiration

Question 19

stages of ventilation

Answer 19

• pressure –> work
• pressure differentials between lungs and intrapleural space to drive air into lungs
• inhalation and exhalation

Question 20

inhalation

Answer 20

• active process
• use diaphragm and external intercostal muscles to expand thoracic cavity
• cavity enlarges –> diaphragm flattens down –> chest wall moves out –> intrapleural vol increase (dec pressure) –> lungs (atm) sucks in higher pressure (outside air) –> expand

Question 21

external intercostal muscles

Answer 21

• used during inhalation to expand thoracic cavity

- layers of muscles between ribs

Question 22

negative-pressure breathing

Answer 22

• during inhalation

- driving force is lower (relatively neg) pressure in intrapleural space compared w/ lungs (alveoli)

Question 23

exhalation

Answer 23

• doesn’t have to be active process
• diaphragm and external intercostals relax –> chest cavity dec in size (vol) –> intrapleural space pressure down vol (inc. pressure) –> air pushed out –> exhalation
• surfactant prevents complete collapse of alveoli during exhalation by reducing surface tension at alveolar surface

Question 24

internal intercostal muscles

Answer 24

-highly active tasks –> speed process using this which opposes externals and pull rib cage down –> actively dec vol of thoracic cavity

Question 25

control of ventilation

Answer 25

- breathing requires input from nervous control center - primarily regulated by neurons; primarily sensitive to carbon dioxide conc; CO2 rise --> resp. rate will inc. to counter -limited extent to control our breathing through cerebrum -hypoventilation - inc. CO2 levels and override by medulla -hyperventilation - blow too much CO2 and inhibit ventilation (low level O2 --> hypoxia drive ventilatory response)

Question 26

ventilation centers

Answer 26

ventilation primarily regulated by neurons in the medulla oblongata, rhythmically fire to cause regular contraction of respiratory muscles

Question 27

chemoreceptors

Answer 27

- how CO2 conc are measured | - neurons' surfaces monitor changes in blood's pH

Question 28

total lung capacity (TLC)

Answer 28

--healthy = 6 to 7 liters -breathe in --> total amount of air in lings at this point

Question 29

spirometer

Answer 29

- instrument to assess lung capacities - measure amount of air normally present in lungs and rate which ventilation occurs. - normal respiration - 12 breaths/min - higher elevation --> ventilation may inc.

Question 30

vital capacity (VC)

Answer 30

-breathe out until we cannot breathe out --> total amount forced out

Question 31

residual volume (RV)

Answer 31

-left over air in lung (expelling all --> lung collapse)

Question 32

TLC

Answer 32

VC + RV

Question 33

tidal volume (TV)

Answer 33

air naturally comes out w/ exhalation

Question 34

expiratory reserve volume (ERV)

Answer 34

-resp. muscles to push air out, the bit of air that exits

Question 35

inspiratory reserve volume (IRV)

Answer 35

-extra air take in

Question 36

VC

Answer 36

TV + ERV + IRV

Question 37

gas exchange

Answer 37

-pulmonary cap. surrounds each alveolus (single-celled layer) --> bring deoxygenated blood from pulmonary arteries

Question 38

left lung

Answer 38

has small identation => smaller lung, due to position of heart in the cavity

Question 39

digestive system

Answer 39

also has villi and microvilli

Question 40

pneumothorax

Answer 40

air in intrapleural space => inc. the pressure => lung collapse => needle to withdraw air

Question 41

boyle laws

Answer 41

applies neg- pressure breathing

Question 42

emphysema

Answer 42

destruction of alveolar walls => reduced elastic recoil of lungs

Question 43

inhalation and exhalation

Answer 43

muscle contraction => neg. pressure in thoracic cavity => forces air in during inspiration => expiration => elastic recoil of lungs and musculature => during more active states => muscle used to force air out => speed ventilation