Chapters 7 & 8 - Exchange and Transport in Animals

Question 1

why can small organisms gains all O2 and CO2 needed be gained by diffusion

Answer 1

• low metabolic activity means low oxygen demands
• They have a short diffusion distance and high surface area to volume ratio

Question 2

why can large organisms not depend on diffusion to supply all gases

Answer 2

• high metabolic demands
• low SA:V ratio and diffusion distance is too large

Question 3

Surface area: volume ratio calculation, how to display?

Answer 3

SA/V
model as: x:1

Question 4

pattern of decreasing SA:V ratio

Answer 4

size of organism and diffusion distance increases

Question 5

how does increased surface area help gas exchange

Answer 5

provides area needed for exchange and overcomes the limitations of low SA:V in large organisms

Question 6

how do short diffusion distances help gas exchange

Answer 6

process of diffusion is faster and more efficient

Question 7

how does a good blood supply help gas exchange

Answer 7

• substances constantly delivered and removed from the exchange surface
• maintains a steep concentration gradient

Question 8

how does ventilation help gas exchange

Answer 8

maintains conc grad for gases

Question 9

mammalian gas exchange system: nasal cavity

Answer 9

• high SA and good blood supply (warms air to body temp)
• hairy lining and goblet cells trap bacteria and dust to prevent irritation
• moist surfaces: increase humidity of air to reduce evaporation from the exchange surface

Question 10

mammalian gas exchange system: trachea

Answer 10

• supported by C-shaped cartilage rings to prevent collapse
• lined with Ciliated epithelium and goblet cells that trap and remove dust to be swallowed and digested

Question 11

mammalian gas exchange system: bronchi

Answer 11

• branch off trachea to each lung
• 2
• similar structure to trachea

Question 12

mammalian gas exchange system: bronchioles

Answer 12

• branch from bronchi
• no cartilage rings
• smooth muscle walls
• muscle contracts/ dilate to change airflow

Question 13

mammalian gas exchange system: alveoli

Answer 13

• 1 cell thick wall
• collagen and elastic fibers allow stretch and recoil
• good blood supply and ventilation
• lung surfactant prevents alveolar collapse

Question 14

inspiration

Answer 14

• diaphragm contracts, flattens and lowers
• external intercostal muscles contract
• ribs move up and out
• thorax volume increases, pressure decreases
• air drawn in

Question 15

expiration

Answer 15

• diaphragm relaxes
• external intercostal muscles relax
• ribs move down and in
• thorax volume decreases, pressure increases
• air forced out

Question 16

forced expiration

Answer 16

• internal intercostal muscles contract to force ribs down quickly

Question 17

vital capacity

Answer 17

volume of air the lungs can breathe in with the strongest exhalation and deepest possible breath intake

Question 18

tidal volume

Answer 18

the volume of air that moves in and out of the lungs with each resting breath

Question 19

breathing rate

Answer 19

the number of breaths taken per minute

Question 20

ventilation rate formula

Answer 20

tidal volume x breathing rate

Question 21

insects: spiracles

Answer 21

openings along the exoskeleton

Question 22

insects: tracheae

Answer 22

carry air into the body line and strengthened with rings of chitin

Question 23

insects: tracheoles

Answer 23

• branch from tracheae no chitin
• air moves along by diffusion to all tissues

Question 24

specialisations of insects

Answer 24

• high SA of tracheoles
• moist walls
• tracheal fluid limits penetration of air

Question 25

Why do multicellular organisms require transport systems

Answer 25

- higher metabolic demands - small sa :v ration and large diffusion distances - molecules needed in different places to where they’re made (hormones)

Question 26

Open circulatory system

Answer 26

Small amounts of vessels that contain transport medium pumped from the heart to the body cavity at low pressure

Question 27

Closed circulatory system

Answer 27

Blood enclosed in vessels doesn’t come into direct contact with cells Pumped around body by heart

Question 28

Single circulatory system

Answer 28

Blood pumped from heart all around the body and back Heart has 2 chambers and passes through 2 sets of capillaries 1 exchanges CO2 and O2, the other exchanges blood to cells

Question 29

Double circulatory system

Answer 29

Heart has 4 chambers 2 separate circulations Blood passes heart twice per circuit Ox and deox blood seperate

Question 30

Elastic fibres

Answer 30

Stretch and recoil Provide vessels with flexibility

Question 31

Smooth muscle

Answer 31

Contract and relax Changes size of the lumen

Question 32

Collagen

Answer 32

Structural support Maintains shape and volume

Question 33

Arteries

Answer 33

Narrow lumen maintains a high blood pressure Thick outer collagen layer prevents rupture under high pressure Inner muscle and elastic layer controls pulse flow

Question 34

Arterioles

Answer 34

Link arteries to capillaries Constrict and dilate to control blood flow at individual organs

Question 35

Capillaries

Answer 35

Narrow diameter Low blood flow 1rbc allowing time for exchange 1 cell thick wall Leaky walls allow plasma and dissolved solutes to leave blood

Question 36

Veins

Answer 36

Wide lumen maximises blood flow back to heart Thin wall mostly collagen carries low pressure blood Valves prevent back flow and pooling Pulse lost at capillaries

Question 37

Venules

Answer 37

Link capillaries and veins

Question 38

Prevention of backflow

Answer 38

Valves Muscle contraction

Question 39

Diastole

Answer 39

Heart relaxes Semilunar valves close (dub) Atria and ventricles fill with blood increasing pressure Av valves open

Question 40

Atrial systole

Answer 40

Atria contract Blood travels from atria to ventricles through AV valve

Question 41

Ventricular systole

Answer 41

Atria relax ventricles contract Av valves close (lub) Blood moves from ventricle to aorta/pulmonary artery through open SL valves