Lecture 14: Ventilation and Gas exchange in Animals

Question 1

what is gas exchange?

Answer 1

it is the process by which organisms uptake gasses required for physiological processes and release waste gasses as a byproduct of those processes

Question 2

what gasses do animal cells uptake and release?

Answer 2

uptake oxygen and release carbon dioxide

Question 3

what are sources of oxygen and explain properties of both?

Answer 3

air and water.
air: oxygen is plentiful in the air/21% and it is not dense or viscous. it is easy to breathe so does not require much efficiency.
water: oxygen is scarce in water. it is dense and viscous

Question 4

movement of co2 and o2 moves entirely via?

Answer 4

diffusion

Question 5

what is the respiratory surface in leaves?

Answer 5

mesophyll parenchyma cells

Question 6

what is the respiratory surface in humans?

Answer 6

alveoli in the lungs

Question 7

what should respiratory surfaces have to maximize diffusion efficiency?

Answer 7

• large surface area
• thin and one cell thick
• moist

Question 8

what does ventilation mean?

Answer 8

ventilation is the flow of respiratory medium over the respiratory surface
respiratory medium: air or water

Question 9

ventilation and gas exchange occurs in different animals in different ways because?

Answer 9

depending on environment and locomotion

Question 10

if air is the medium, the fresh o2 in the air can reach the respiratory surface in multiple ways including?

Answer 10

1: diffusion: no pressure involved, relying on concentration gradient. Ex: insects
2: positive pressure: o2 is pushed via buildup of pressure Ex: amphibians and birds
3: negative pressure: o2 is pulled via drop in pressure Ex: mammals

Question 11

Porifera gas exchange?

Answer 11

environment: aquatic
respiratory medium: water
respiratory surface: body wall
ventilation: flagella in the collar cells pull water in through pores in the body
locomotion: sessile

Question 12

Cnidaria gas exchange?

Answer 12

environment: aquatic
respiratory medium: water
respiratory surface: body wall and lining of gastrovascular cavity
ventilation: water circulates through the gastrovascular cavity
locomotion: sessile, weak swimmers

Question 13

Platyhelminthes gas exchange?

Answer 13

environment: aquatic or parasitic
respiratory medium: water or host fluids
respiratory surface: body wall and lining of gastrovascular cavity
ventilation: simple diffusion across outer body surface and gastrovascular cavity
locomotion: sessile or slow swimmers

Question 14

insects gas exchange?

Answer 14

environment: terrestrial but some aquatic
respiratory medium: mostly air
respiratory surface: tracheal system, air sacs, and some aquatic insects have gills
ventilation: tracheal system: spiracles where the air enters the body and the trachea branch into thinner tracheoles which deliver gasses to each cell.
SMALL INSECTS: diffusion
LARGE INSECTS: use muscles to contract and expand body to pump air
locomotion: crawling, jumping, flying, fast locomotion requires rapid gas exchange to support high metabolic rate

Question 15

where does gas exchange occur in animals?

Answer 15

specialized structures: gills or lungs

Question 16

gas exchange in vertebrates respiratory organ?

Answer 16

lungs: facilitate gas exchange in the air
gills: facilitate gas exchange in the lungs

Question 17

gas exchange in fish?

Answer 17

environment: aquatic
respiratory medium: water
respiratory organ: gills
respiratory surface: gill filaments
ventilation: water pulled into the mouth over gill filaments in one direction
locomotion: swimming

Question 18

gas exchange in mammals?

Answer 18

environment: terrestrial or aquatic
respiratory medium: air
respiratory organ: lungs
locomotion: walking, running, swimming, flying, hopping
ventilation: ventilation occurs via negative pressure breathing: pulling air into the lungs

Question 19

human respiratory system

Answer 19

nose, nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, alveoli

Question 20

what is the respiratory system in humans?

Answer 20

alveoli: tiny expandible sacs in the lungs that inflate when you inhale and deflate when you exhale

Question 21

capillaries?

Answer 21

branching nets of fine blood vessels that exchange materials with alveoli and all body cells

Question 22

what is the circulatory system?

Answer 22

carries blood from the lungs to the rest of the body

Question 23

red blood cells have a protein called?

Answer 23

hemoglobin transports oxygen throughout the body

Question 24

how is co2 transported to the lungs?

Answer 24

• some co2 dissolved directly into blood plasma
• some co2 binds with hemoglobin
• most react with water to form bicarbonate which is dissolved into the blood plasma

Question 25

breathing control in humans: what happens if co2 levels in the blood rise?

Answer 25

causes the blood ph to fall, sensors in the heart and medulla cause the diaphragm contraction rate to increase and then co2 levels in blood fall and ph rises

Question 26

gas exchange amphibians?

Answer 26

environment: aquatic if immature and terrestrial if mature respiratory medium: water or air respiratory organ for water: gills or skin and respiratory organ for air: skin lining of mouth, lungs

Question 27

how does the ventilation occur in the frog?

Answer 27

ventilation occurs via positive pressure breathing. 1 breath 4 steps: inhalation, expansion, contraction, and exhalation

Question 28

gas exchange in birds?

Answer 28

environment: terrestrial respiratory medium: air locomotion: walking, running, swimming, flying, hopping respiratory organ: lungs respiratory surface: parabronchi birds have 8-9 air sacs located above or below the lungs: they move air through the parabronchi