Module 10 - Respiratory system

Question 1

Respiratory organs in fish?

Answer 1

gills

Question 2

Gills are made of … ?

Answer 2

dense capillary beds

Question 3

Where are gills located?

Answer 3

internally - associated with pharyngeal slits & pouches

externally - arise in branchial regions as filamentous capillary beds

Question 4

How does respiration occur in internal gills?

Answer 4

via muscular pump of buccal cavity -> actively drives water across internal gills

Question 5

How does respiration occur in external gills?

Answer 5

water currents flow across projecting surfaces (moving water currents)
specialised muscles sweep external gills back & forth to ventilate them

Question 6

A bit on gas bladders

Answer 6

elongated sac filled with gas from:
- air via pneumatic duct connected to digestive tract
- secreted directly into bladder from blood
aids in buoyancy control (swim bladder) & resp. (lungs)

Question 7

How does the swim bladder differ from the lungs? 3 ways…

Answer 7

1. situated dorsal to digestive tract (lungs - ventral)
2. single (lungs - paired)
3. returning blood drains to general systemic circulation (separate venous return from lungs)

Question 8

Similarities between swim bladder & lungs…?

Answer 8

• both have outpocketings from gut or pharynx

- have roughly equivalent nerve & muscle supply

Question 9

Compare different lung anatomy of mammals, birds, amphibians, and reptiles…?

Answer 9

mammals - alveoli for gas exchange as do birds
amphibians - range from simple sacs + few blood vessels to pouches divided into many large compartments with dense vascularisation
reptiles - rely on bellows-like pumping of posterior sacs facilitating air flow

Question 10

Hilus of each lung located …?

Answer 10

near middle of medial side

Question 11

What is the hilus?

Answer 11

Area where structures that form root of lung enter & leave viscus such as bronchus, pulmonary artery & nerves enter, pulmonary vein & lymphatic vessels leave

Question 12

Describe the structures from trachea to gas exchange in alveoli…

Answer 12

slide 13

Question 13

How is naming of lobes of the lungs based?

Answer 13

depending on subdivision of bronchi - NOT external subdivisions of lungs

Question 14

How do cow, sheep, and pig lungs differ from horse lungs?

Answer 14

C. S. P. (and all other domestic animals) have cranial, middle, caudal & accessory/intermediate lobe of right lung.
Horse - no lobes except accessory/intermediate lobe of right lung

Question 15

Describe the gas exchange process of marine mammals on land or water surface

Answer 15

O2 from air -> -> -> skeletal muscle via cardiopulmonary sys
Also, O2 & energy stores in tissue of each major anatomical compartment…
(Practice describing to someone)

Question 16

What happens during a dive…?

Answer 16

ambient O2 not available -> lungs collapse with increased hydrostatic pressure -> bradycardia -> decreased CO -> change blood distribution -> change in O2 transport to skeletal muscle

Question 17

What is different about sea otters & dugongs’ lung volumes?

Answer 17

They have larger than expected volume capacities

Question 18

What changes occur to respiratory tract structures at depth?

Answer 18

Lungs, trachea, bronchi, and alveoli collapse

Question 19

Which structure determines depth of diving in marine mammals?

Answer 19

rigidity of trachea - partial calcification of tracheal rings prohibits deep diving (eg. river otter)

Question 20

Which animals have lesser calcification of the trachea, enabling deep diving?

Answer 20

harp seals & walrus

Question 21

How are lungs protected during a dive?

Answer 21

Airways are reinforced by muscle or cartilage to ensure patency during lung compression at depth -> allows progressive collapse of lung structures during increased hydrostatic pressure from alveoli -> small -> large airways
(Works in reverse when ascending)

Question 22

How are the lungs of seals & whales protected?

Answer 22

seals - large SM’s surround non-cartilaginous portion of bronchiole connecting to resp. bronchiole & finally alveoli
whales - cartilaginous reinforced airways leading directly to alveoli

Question 23

Explain why marine mammals can stay submerged whilst highly active for long periods

Answer 23

Contain exceptionally large stores of O2 in LUNGS, BLOOD & MUSCLE -> aerobic activity

Question 24

Total O2 stores in marine mammals relative to terrestrial mammals?

Answer 24

2-3 times > than terrestrial spp.

Question 25

Dolphins O2 distributions?

Answer 25

22-24% stored in lungs, rest in blood & skeletal muscle

Question 26

Deep divers (Weddell seals) O2 distributions?

Answer 26

> 87% in blood & skeletal muscle

Question 27

How do ‘elite divers’ overcome blood nitrogen tensions at depth?

Answer 27

collapsible lungs -> air into upper airways away from blood

Question 28

Up to slide 28…

Answer 28

avian respiration