Chapter 11 Respiration

Question 1

What are various organs for gas exchange?

Answer 1

o Gills
o Lungs
o Gas bladders
o Swim bladders
o Skin and other membranes

Question 2

What is a partial pressure and how does it drive gas exchange?

Answer 2

o Measure of the composition of the mixture of gases, percentage of it will be considered a partial pressure
o Each percentage gives partial pressure
o Mixture of air shown on previous slide
o Size of container a factor; bigger the container, lower the pressure (and vice versa)
o At a constant temperature in a compressible container, the pressure of a gas is inversely related to its volume

Question 3

How does surface area of a respiratory surface influence gas exchange?

Answer 3

Partial pressure gradient:
▪ Moves from high partial pressure to low partial pressure, across respiratory membrane
▪ - If particles can move through respiratory membrane, considered semipermeable
▪ Larger surface area of the respiratory membrane = more diffusion

Question 4

Gas exchange

Answer 4

Respiratory medium (water, air) into contact with respiratory surface = gas exchange

Question 5

Unidirectional ventilation

Answer 5

o Water through mouth, water through muscles, water flows across gills and then gas exchange takes place
o Seen In fish
o One way path

Question 6

Bidirectional ventilation

Answer 6

breathing process in which air flows into and out of the lungs through the same pathways during inhalation and exhalation, typical of most mammals

o Goes in and then back out the way it came, two way path
o oxygenated air comes in, mix with some deoxygenated air that leaves
o - Steady oxygen in lungs to always keep inflated

Question 7

Name the three general mechanisms for ventilation

Answer 7

Water and Air(Buccal and Aspiration)

Question 8

Water ventilation

Answer 8

Cilia: Tiny hair-like structures that beat in coordinated waves to move water over respiratory surfaces, facilitating gas exchange.

Dual Pump: A mechanism in fish where a buccal (mouth) cavity and an opercular (gill cover) cavity work together to create a continuous flow of water over the gills.

Question 9

Air: Buccal Pump

Answer 9

• positve pressure
  Two-Stroke Type: Involves two phases where air is drawn into the buccal cavity and then pushed into the lungs.

Four-Stroke Type: Involves four phases where air is drawn into the buccal cavity, compressed, pushed into the lungs, and then expelled.

Question 10

Air: Aspiration Pump

Answer 10

• negative pressure
  Ventilation: Air is drawn into the lungs by creating a negative pressure in the thoracic cavity, primarily through the contraction of the diaphragm and intercostal muscles.

Elastic Recoil: Refers to the natural tendency of the lungs to return to their original size after being stretched during inhalation, causing exhalation by pushing air out.

Question 11

Primary Lamellae

Answer 11

• structure on fish gill
  These are the large, finger-like projections extending from the gill arches, providing the main surface for gas exchange.

Question 12

Secondary lamellae

Answer 12

• fish gill structure
• These are the smaller, perpendicular structures on the primary lamellae that greatly increase the surface area for efficient gas exchange.

Question 13

Afferent filament vessel

Answer 13

• fish gill structure
• This vessel carries deoxygenated blood from the heart to the gill filaments for oxygenation

Question 14

Efferent Filament vessel

Answer 14

• fish gill structure
• This vessel carries oxygenated blood away from the gill filaments to the rest of the body

Question 15

Why do lampreys sometimes use tidal ventilation?

Answer 15

o Because the adult lamprey’s mouth often is attached to prey, water must alternatively enter as well as exit via pharyngeal slits
o Gill ventilation in the lamprey, unlike most fishes, is tidal
o Cannot breathe unidirectionally while attached to prey/fish
o Use muscles of pharynx to pump water in and out on gills, this is tidal ventilation (done while feeding only usually)

Question 16

What is the function of the velum in hagfishes?

Answer 16

o Scrolling and unscrolling of the velum, one on each side, together with synchronized contractions and relaxations of the branchial pouches, produces a current of water
o Water brought in through nostrils
o Pulled in by current created by structure of roof of pharynx, velum
o Velum unfold, generates current to draw water in
o Brachial pouches

Question 17

Septal Gill Structures

Answer 17

Respiratory unit includes branchial and parabranchial pouch

o Surrounding unit:
▪ Primary and secondary lamellae
▪ Gill aterties by brachial pouch
▪ Flap valve near parabrachial pouch
▪ Gill ray down the middle

Question 18

Shark ram ventilation (gills)

Answer 18

o Ram ventilation: swim with mouth open, constantly ventilates lungs
o - Sharks usually have to keep moving to breathe/ventilate gills

Question 19

Shark gill ventilation : buccal pumping

Answer 19

o Flap valves close during inhalation and that relative pressures are always lower in the parabranchial chamber than in the pharynx
o Buccal pump adjacent/positive pressure adjacent
o Open mouth and spiracle, draws water into mouth
o Outside gills: flaps close
o Water moves unidirectionally across the gills in a pulsing but continuous flow