Gas Exchange

SRJC, BIO 2.2, Swinstrom. Everything you need to know about gas exchange

What is SA:V ?

There can be a high SA to low V ratio or low SA to high V ratio. its the part of the object which interacts with the environment. The ration will depend on how efficient exchange of gasses can be.

What type of SA:V ration would you expect a gas exchange surface to have?

High SA to low V ratio. Greater SA leads to a greater gas absorption

What other physical features do all gas exchange surfaces need to have?

All of them need to have a wet surface

How do oxygen and carbon dioxide move across
plasma membranes?

Via simple diffusion

What determines the direction and speed of the
process you named in question 4?

a concentration gradient determines its direction and speed of simple diffusion

How does oxygen travel in your blood?

Oxygen binds to the iorn in hemoglobin of the rbc

Describe the structure of fish gills

gills are outfoldings which create a large SA. Arteries are on the outside of the gill fillaments and veins are on the inside.

How do fish gills use this to absorb oxygen

The water flows perpendicular to the gills, creating a countercurrent exchange. The way gills are designed allows for a concentration gradient to occur, allowing oxygen to always flow inwards.

Two-way air flow

Tidal breathing is found in most vertebrates. Oxygen moving in interacts with the carbondioxide moving out. Not very efficient

Unidirectional air flow

air only moves in one direction, ensuring that inhaled air does not interact with exhaled air

Describe unidirectional airflow

1st inhalation air enters posteiror air sac → 1st exhalation air enters lungs bia contraction of air sac →2nd inhalation air passes through the lungs and enters anterior air sacs → 2nd exhalation air sac contracts pushing air out of the body

Describe bidirectional airflow

Inhalation:

rib muscles contract→ ribcage expands → ribs pushed upward →sternum pushed downward → diaphragm contracts → expands thoracic cavity downward

Exhalation:

muscles relax → air pushed outwards

What are all the organs used for respiration in mammals?

Nasal cavity, pharyns, larynx, trachea, bronchi, bronchioles, alveoli, diaphragm, rib muscles, sternum, hemoglobin

Nasal cavity

humidifies air

pharynx

back of throat that connects to larynx

Larynx

voice box, leads to trachea

Trachea

wind pipe, has cartilage rings to keep it open

bronchi

connects trachea and bronchioles

Bronchiole

connect to alveoli

alveoli

gas exhange surface

diaphragm

muscles that help with contraction

ribs

help with contraction and protects lungs

rib muscles

move ribs ton increase volume in lungs

sternum

help with contractions to increase volume in lungs

Hemoglobin

contains iorn which has a high affinity for oxygen and is used in for its transport

How is breathing controlled

blood pH falls due to rising CO2 levles in tissues → madulla dates a decrease in pH of cerbralspinal fluid → at the same time sensors in major clood vessels also detect a decrease in blood pH → signals from medulla to rib and muscles and diaphragm to increase rate and depth of ventillation →bood CO2 levels fall and pH rises → normal blood pH

What are some adaptations for breath holding?

• increase in myglobin

• fermntation instead of cellular respiration to generate atp

• lower metabolism rate

• mechanisms to remove lactic acid buildup

• more blood per Kg of mass

• restric or shut off blood supply

• use less muscle energy, glide insted of swim