exchange surfaces

Question 1

state 4 factors that make an efficient exchange system and why ?

Answer 1

increase surface area - more can happen at once
short diffusion distance- less distance to travel
semipermeable- allow reactants to get through
high blood flow - maintain steep concentration gradient

Question 2

how does SA and vol change as object gets bigger?

Answer 2

volume increases at a unit of x^3 and SA increases just not as quickly as it is a unit of X^2 so vol increases quicker. the SA:vol gets smaller

Question 3

what is the equation to find out the area of a circle?

Answer 3

π r ^2

Question 4

what is the equation to find out the circumference ?

Answer 4

2πr

Question 5

what is the equation to find out the SA of cuboid ?

Answer 5

2(bh + bl + hl)

Question 6

what is the equation to find out the volume of a cuboid?

Answer 6

h b l

Question 7

describe the structure of the trachea?

Answer 7

pipe of cartilage in a C shape, has goblet cells, ring smooth muscle, ciliated cells, elastic fibres

Question 8

what is the function of the trachea?

Answer 8

cartilage holds structure open prevents it from collapsing under pressure

Question 9

describe the structure and function of the bronchus

Answer 9

2 tubes that split of the trachea, same structure and function as trachea just smaller

Question 10

describe the structure of the bronchioles

Answer 10

no cartilage, held open by smooth muscle, lined with epithelial cells

Question 11

what are 7 features of alveoli that allow it to be efficient for gas exchange?

Answer 11

elastic fibres- cause recoil and push air out of alveoli

walls are 1 cell thick - short diffusion pathway

moist lining of walls- allows gases to dissolve then diffuse through quicker
highly folded- high surface area
high ventilation - maintain steep concentration gradient
blood cell flatten against capillary wall to increase rate of diffusion
walls are covered In surfactant to increase surface area and acts as a lubricant

Question 12

what is the function of smooth muscle in trachea?

Answer 12

contracts to constrict airway in response to harmful substances

Question 13

describe the process of inhalation

Answer 13

diaphragm contracts to be flat, external intercostal muscles contract to force ribs out, volume of chest cavity increases, pressure decreases lower than atmospheric pressure so air moves in

Question 14

describe the process of exhalation?

Answer 14

diaphragm relaxes pushed up, internal intercostal muscles contract to bring ribs in, volume of chest cavity decreases, pressure increases above atmospheric so air moves out

Question 15

what are 4 limitations of the bell jar model?

Answer 15

detail of lung structures are missing, air pressure barely changes, inside jar should be fluid, balloons have limited expansion

Question 16

what is residual volume ?

Answer 16

air that is always in the lungs to stop them from collapsing even after exhalation

Question 17

what is tidal volume?

Answer 17

volume of air moved in and out of lungs with each breath at rest

Question 18

what is vital capacity ?

Answer 18

largest volume of air that can be moved in or out in one breath

Question 19

what is inspiratory reserve volume?

Answer 19

how much air can come in, over and above tidal volume

Question 20

what is expiratory reserve volume?

Answer 20

how much air can be exhaled over and above tidal volume

Question 21

what is total lung capacity?

Answer 21

volume in lungs at max inflation ( VC+RV)

Question 22

why does overall volume of gas in the spirometer tank decrease over time?

Answer 22

soda lime absorbs CO2 to avoid harmful effects, when breathing we use up o2 from tank while co2 we breath out is absorbed

Question 23

how to work out breathing rate from spirometer trace ?

Answer 23

how many peaks or troughs there are

Question 24

why don’t fish have lungs ?

Answer 24

fish get oxygen from water where it is dissolved not air so lungs can’t access it

Question 25

describe the process of fish ventilation
11 steps

Answer 25

mouth opens, buccal cavity floor is lowered, increases volume and decreased pressure of buccal cavity compared to outside, therefore water rushed into mouth down pressure gradient. oppurcular cavity expands, buccal cavity floor is raised, pressure inside BC Is higher than OC so water moves from BC over gills to OC. the mouth closes and operculum opens, sides of OC move in to increase pressure, therefore water out through operculum.

Question 25

what is a countercurrent flow?

Answer 25

when water and blood flow in opposite direction along the distance of the lamella, water will flow along the lamella with high levels of O2 then as it goes along lamella it will diffuse into blood

Question 25

why do fish have the countercurrent flow ?

Answer 25

stops it from reaching equilibrium which would stop the flow so it maintains a constant concentration gradient so oxygen continues down the concentration gradient from water to blood

Question 26

describe the process of inhalation for an insect

Answer 26

the spiracle is in contact with the air outside, as the air sac expands vol increases, pressure decreases lower than atmospheric pressure so air flows in through the filter apparatus and valve

Question 26

describe the process of exhalation in an insect

Answer 26

co2 diffuses into trachiole via the fluid from cells, the air sac will recoil to decrease volume and increase pressure above atmospheric pressure so air flows out of trachea, valve and filter apparatus

Question 27

how does the thorax help to ventilate the insect?

Answer 27

as thorax increases in volume, pressure inside drops below atmospheric pressure so air is brought in.
as thorax decreases in volume, pressure inside increases above a.t.p so air is forced out

Question 28

how does the abdomen help to ventilate the insect ?

Answer 28

as abdomen expands spiracles at the front of body open and air enters. as abdomen reduced in volume, spiracles at rear end open and air leaves