Ch. 42 - Respiration

Question 1

what is partial pressure?

Answer 1

the amount of gas present in an air or fluid

Question 2

how does oxygen move from the alveoli to the blood?

Answer 2

PO2 in alveoli = 160mmHg
PO2 in blood = 40mmHg
oxygen diffuses down its concentration gradient from lungs to blood

Question 3

what is respiratory media?

Answer 3

the substance from which O2 must diffuse to enter the organism

Question 4

why is respiratory media an important factor in breathing?

Answer 4

1. water has less dissolved oxygen than air
2. it’s easier to move air through vessels than it is to move water

Question 5

what conditions do a respiratory surface need to meet?

Answer 5

a respiratory surface must be moist and have a large surface area

Question 6

what is countercurrent exchange? in what animal does it occur in?

Answer 6

-occurs in fishes
-to maximize O2 diffusion, water moves in one direction while blood moves in the other to get the most out of the concentration gradient in the gills

Question 6

what are the 5 main structures of the mammalian respiratory system?

Answer 6

the nose, pharynx, larynx, bronchioles, and alveoli

Question 7

what is the function of the nose?

Answer 7

to filter / “cleanse” incoming air by trapping particles in mucus

Question 8

what is the function of the pharynx?

Answer 8

swallowing

Question 9

what is the function of the larynx?

Answer 9

vocalization and protecting the trachea - epiglottis folds down to block incoming food

Question 10

what structures compose the respiratory tree?

Answer 10

-trachea and bronchi, which are composed of cartilaginous rings
-bronchioles, which have smooth muscle to regulate the amount of incoming air

Question 11

what is the structure of alveoli?

Answer 11

-thin respiratory membrane which collectively give a large surface area
-1 capillary bed per alveoli

Question 12

what is the function of surfactant?

Answer 12

to oppose surface tension and keep alveoli from collapsing in on themselves

Question 13

what is the function of alveoli?

Answer 13

to exchange O2 and CO2 between the blood

Question 14

what is positive pressure breathing and what animal does it occur in?

Answer 14

-occurs in frogs
-air is brought into mouth -> nose and mouth close -> mouth floor rises and pushes air into lungs

Question 15

what occurs in mammals during diaphragm contraction?

Answer 15

-pressure in lungs decreases, volume increases, leading to oxygen entering lungs

Question 16

what occurs in mammals during diaphragm relaxation?

Answer 16

diaphragm relaxes, pressure increases, volume decreases, leading to air leaving lungs

Question 17

how is respiration in birds different from mammals?

Answer 17

-birds have 1 flow of air direction so old/new air are not mixed
-air sacs bring air in, parabronchi allow one way flow
-one complete cycle = 2 sets of inhalation and exhalation

Question 18

what variable in the human body regulates respiratory rate?

Answer 18

blood pH: if pH goes down, breathing increases, and vice versa

Question 19

what equation regulates blood pH in humans?

Answer 19

CO2 + H2O <-> H2CO3 <-> HCO3- + H+
-when there is more CO2, equation shifts right, making blood more acidic

Question 20

what is a dissociation curve?

Answer 20

a curve showing how much O2 is carried by Hemoglobin and how its saturation changes as it unloads oxygen to the body