Bio Final Exam Iii

Front 1

define ventilation

Back 1

- movement of gases in and out of the lungs
- performed by respiratory muscles
- inspiration and exhalation

Front 2

define respiration

Back 2

- exchange of gases (to cells=cellular respiration) i.e. taking in oxygen and expelling carbon dioxide

Front 3

Define cellular respiration

Back 3

- using O2 to make ATP
- obtaining energy by oxidizing food molecules
glucose + 6O2 + 6H2O --> 6CO2 + 12H2O + ATP(energy)

Front 4

Describe energy at rest and with exercise

Back 4

- energy at rest=basal
- increases sharply with exercise (15 to 20 times more)

Front 5

Describe relationship between brain and oxygen

Back 5

- very sensitive to oxygen levels
- low anaerobic metabolism capacity
- lack of oxygen for more the 4 minutes=brain damage

Front 6

How many divisions of branching air passages are there?

Back 6

23 divisions

Front 7

What is the mucociliary escalator?

Back 7

- cilia and mucus work together to get rid of unwanted particles by moving them upward

Front 8

What protects the lungs from foreign material? (3 things)

Back 8

- Branching of air passages
- Mucociliary escalator
- Aveolar macrophages (White Blood Cells of the immune system)

Front 9

Define inspiration

Back 9

- inhaling
- an active process (requires ATP)
- contraction of the two muscles (diaphragm and the rib muscles/intercostals)
- diaphragm shortens
- movement of air into the lungs due to a drop in the air pressure created when the thoracic cavity is enlarged.

Front 10

Expiration

Back 10

- exhaling
- passive process (no ATP)
- diaphragm and intercostals relax (diaphragm lengthens)
- elastin recoils and muscles lengthen creating the mechanical forces that push air out of the lungs.

Front 11

What mechanisms prevent the lungs from collapsing?

Back 11

Surfactant and Pleura

Front 12

Surfactant

Back 12

- lipoprotein found on inner surface of the lung
- stretched thin during inspiration
- thickens during exhalation which resists the recoiling of the lung and keeps it open.

Front 13

Pleura

Back 13

- membrane (CT) that surrounds the lungs and attaches them to the ribcage

Front 14

Describe the active process of breathing

Back 14

- inhalation
- outward forces produced by muscles
- creates vacuum in lungs (decreases partial pressure)

Front 15

Describe the passive process of breathing

Back 15

- exhalation
- inward forces due to elastin and released diaphragm increase the mechanical force that expels the air.

Front 16

What is the pathway of air?

Back 16

Nasal cavity >> pharynx >> larynx >> trachea >> bronchus >>bronchiole >> alveoli

Front 17

nasal cavity

Back 17

warms air and adds moisture

Front 18

pharynx

Back 18

pathway to the trachea and the esophagus

Front 19

larynx

Back 19

- voice box
- membranes vibrate when expelling air and makes sound

Front 20

trachea

Back 20

- the wind pipe
- pathway to bronchi with cartilaginous rings

Front 21

function of the cartilaginous rings

Back 21

- provides protection
- prevents trachea from collapsing

Front 22

Bronchi

Back 22

The two large and major branches off the trachea

Front 23

bronchioles

Back 23

- pathway from the bronchi
- have alveoli (air sacs)

Front 24

Alveoli

Back 24

- air sacs
- site of gas exchange
- there are about 3 million air sacs in the human lung >> increased surface area

Front 25

Concentration gradient of oxygen exchange

Back 25

O2 concentration (ppO2)
Lungs >> blood >> tissue
160 >> 100 >> 0-40 mm Hg
- blood is depleted of O2 by tissues

Front 26

Where will O2 be released according to the concentration gradient?

Back 26

- the more a tissue is depleted (low ppO2), the greater the release of O2 there
- insures that the tissues that need O2, get O2
O2 --> H2O + ATP
↑O2 --> ↑H2O + ↓O2

Front 27

Describe the binding of O2 to hemoglobin according to O2 concentration

Back 27

- Decreased binding of O2 to hemoglobin in blood when O2 concentration in tissue is low

Front 28

What is the average PO2 of deoxygenated blood returning to the heart?

Back 28

40 mm Hg

Front 29

How much of the O2 in arterial blood is released to the tissues during rest or light exercise?

Back 29

25%

Front 30

How much oxygen is held in reserve by hemoglobin and when is it released?

Back 30

- 75%
- can be released to the tissues with a low ppO2

Front 31

define hemoglobin

Back 31

- RBC protein that greatly facilitates O2 transport

Front 32

Hemoglobin structure

Back 32

- 4 peptide chains containing a heme
- Heme contains Fe which binds to O2
- Can carry 4 O2 molecules

Front 33

myoglobin

Back 33

- found in muscles
- high binding affinity (ex. 60 % bound at 5PO2)
- can still deliver O2 even when tissue has low oxygen

Front 34

Describe the binding affinity of Hemoglobin if you live at a high altitude

Back 34

- air pressure is low
- in order to bind O2, needs a high binding affinity

Front 35

Describe human hemoglobin

Back 35

- human DNA allows us to make different hemoglobin for various needs (fetus and maternal)

Front 36

Concentration gradient of CO2

Back 36

Tissues >> blood >> lungs
(greater than 45) >45 >> 45 >> 0.3 mm Hg

Front 37

What are the 3 ways CO2 is transported?

Back 37

- hemoglobin
- transported in plasma as CO2
- transported as bicarbonate (HCO3) >>> majority (70%)

Front 38

How does CO2 become bicarbonate? Where does this happen?

Back 38

- carbonic anhydrase (found in RBC) converts CO2 to H2CO3 (catalyzes this reaction)
CO2 + H2O --> H2CO3 --> 2H+ + HCO3-
- reaction occurs slowly in the plasma and sped up in the RBC
- ENZYME CAN GO BOTH WAYS
Blood >> Air sacs >> exhaled
CO2 + H2O <--> 2H+ + HCO3-

Front 39

How does the conversion of HCO3- help with the transportation of CO2?

Back 39

The conversion of HCO3- maintains the concentration gradient needed to move CO2 out of the tissues and into the lungs.

Front 40

How is respiration controlled?

Back 40

- the autonomic nervous system
pons
medulla
(brainstem)
major blood vessels

Front 41

Role of the pons in respiration.

Back 41

Controls medulla inspiration center.

Front 42

Role of the medulla in respiration.

Back 42

Controls rhythmic inspiration and expiration.
(efferent neuron to diaphragm)

Front 43

Role of the brainstem in respiration.

Back 43

Chemoreceptors in the brainstem sense the H+ concentration.

(CO2 + H20 --> H2CO3 --> H+ + HCO3-)

Front 44

How does the blood level of O2 or CO2 gases assist in controlling respiration?

Back 44

Blood levels of gases provide feedback information to the breathing rhythm generator in the medulla.

Front 45

What is the control center for breathing?

Back 45

The medulla is the control center.
Medulla can function without pons.

Front 46

What is the role of the neurons in the pons?

Back 46

Neurons excite breathing neurons in the medulla.

Front 47

how is efficient exchange achieved in the alveoli

Back 47

- must be a very thin epithelium lining the alveolar sacs
- sacs are closely positioned next to the blood capillary
- two-cell membrane thick layer to exchange gases: (alveolar cell and the epithelial cell of the blood capillary)

Front 48

how is exchange made in the alveoli?

Back 48

- Exchange is made by pressure-dependent (concentration-dependent) diffusion.
- from a region of high O2 concentration to lower one
- (Air in lung is high in oxygen, diffuses into capillaries which contains blood low in oxygen).