Bio 102 Unit 4 Chapter 35

Front 1

Respiration

Back 1

the sequence of events that results in gas exchange between to body’s cell and the environment.

In terrestrial vertebrates, respiration includes these steps.

• Ventilation
• External respiration
• Internal respiration

Gas exchange takes place by the physical process of diffusion.
For external respiration to be effective, the gas-exchange region must be
1. Moist
2. Thin
3. Large in relation to the size of the body

Almost every animal needs oxygen. Oxygen enters the mitochondria where cellular respiration takes place.
However, in 2010, a team of Italian and Danish deep-sea divers discovered a new species of jelly-fish like animals (named loriciferans) that live in the sediment 10, 000 feet below the surface of the Mediterranean. This far down, there is almost no oxygen! First multicellular organism that does not appear to need oxygen!

Front 2

Overview of Gas-Exchange

Back 2

• There is more oxygen in air (per volume) than in water, so easier for animals to breath air.
• Water is more dense , so more energy spent in order to get oxygen out of water

Front 3

Cell membrane

Back 3

Cnidarians, like Hydra, body surface is large in relation to volume, so simple diffusion occurs along the body of the Hydra.
o Water goes in and out of gastrovascular cavity; CO2 and O2 diffuse in and out of body tissues across the cell membranes.

Front 4

Skin

Back 4

Some organisms use their skin as a respiratory organ. It has a large surface area compared to volume.
o Earthworms are an example of this. Skin of earthworms is kept moist with mucus.

Front 5

Gills

Back 5

Aquatic invertebrates and vertebrates use Gills, which are finely divided, vascularized outgrowths of the body surface of the pharynx.
o Water is pumped across

Front 6

Trachea

Back 6

Insects have a system of air tubes called tracheae. Oxygen is delivered directly to the cells without entering the blood.
o Air sacs located near the wings, legs and abdomen act as bellows to help move the air into the tubes through

Front 7

Lungs

Back 7

Terrestrial vertebrates usually have Lungs. Lungs are vascularized outgrowths from the lower pharyngeal region.

Front 8

Pharynx

Back 8

In vertebrates, the common passageway for both food intake and air movement: Located between the mouth and the esophagus. (In us, the upper neck region).
• The hard and soft palates separate the nasal cavities form the mouth, but the air and food passages cross in the pharynx. This can cause a problem!
• Disadvantage: choking hazard!!
• Advantage: can breathe through mouth as well as nose. Also, can take in bigger amount of air through the mouth during heavy exercise.

Front 9

Glottis

Back 9

Opening for airflow into the larynx. The larynx is the “voice box” that is positioned above the trachea and contains the vocal cords.

Front 10

Epiglottis

Back 10

Structure (flap of tissue) that covers the glottis, the air-tract opening, during the process of swallowing.

Front 11

Trachea

Back 11

The trachea (windpipe). This is the air tube that runs between the larynx and the Bronchi. The trachea is held open by a series of C shaped, cartilaginous ring that do not completely meet in the rear.

Front 12

Swallowing

Back 12

when food is swallowed, the larynx rises, and the glottis is covered by the epiglottis. Also, the backward movement of the soft palate covers the entrance of the nasal passages in to the pharynx and food will then enter the esophagus which lies behind the larynx.

Front 13

Bronchi

Back 13

The trachea divides into two main branches called the Bronchi, (sing. Bronchus), which enter the lungs. Left bronchus enters the left lung and the right bronchi enter the right lung.

Front 14

Bronchioles

Back 14

smaller tubes that branch off of the bronchi and carry air into the lungs and terminate at the alveoli (air sacs).

Front 15

Lungs

Back 15

Internal respiratory organs containing moist surfaces for gas exchange.

Front 16

Alveoli (alveolus)

Back 16

terminal, microscopic, grapelike air sac found in lungs.

Front 17

Negative Pressure Breathing System

Back 17

During breathing, the lungs are ventilated. Oxygen moves into the blood and carbon dioxide moves out of the blood into the lungs. Blood transports oxygen to the body’s cells and carbon from the cells to the lungs.

Front 18

Breathing (ventilate their lungs by moving air into and out of the respiratory tract)

Back 18

• Amphibians use positive pressure to force air into the respiratory tract. Floor of mouth pushes air into the lungs.
• Reptiles, birds and mammals use negative pressure to move air into the lungs and positive pressure to move air out.

• Inspiration (inhalation) is the act of moving air into the lungs.

• Expiration (exhalation) is the act of moving air out of the lungs.

• Reptiles have jointed ribs that can be raised to expand the lungs

• Mammals have both a rib cage and a diaphragm.

o The diaphragm is a horizontal muscle that divides the thoracic cavity (above) from the abdominal cavity (below).
o During inspiration in the mammals, the rib cage moves up and out, and the diaphragm contract and moves down. This is known as the active phase of breathing
o As the thoracic (chest) cavity expands and the lung volume increases, air flows into the lungs due to the decreased air pressure in the thoracic cavity and lungs (air is sucked into lungs due to negative pressure!!)

o During expiration, in mammals, the rib cage moves down, and the diaphragm relaxes and moves back up into its prior position. No muscle contraction is required, thus expiration is the passive phase of breathing in reptiles and mammals.

o External and Internal Intercostal muscles;

 External Intercostal muscles raise the ribs, expanding the rib cage during inspiration.
 Internal intercostal muscles are used for FORCED exhalation

Front 19

Inspiration (inhalation)

Back 19

the act of moving air into the lungs.

Front 20

Expiration (exhalation)

Back 20

the act of moving air out of the lungs.

Front 21

Gas Exchange and Transport

Back 21

Respiration includes the exchange of gases in out lungs, called external respiration as well as
the exchange of gases in the tissues, called internal respiration .

The principles of diffusion largely govern the movement of gases into and the out of blood vessels
in the lungs and in the tissue.

Gases exert pressure. The amount of pressure each gas exerts is called the partial pressure.
Symbols are PO2 and PCO2. IF the partial pressure of oxygen differs across a membrane,
oxygen will diffuse from the higher to the lower pressure.
Same thing will occur with Carbon dioxide.

Ventilation causes the alveoli of the lungs to have a higher PO2 and a lower PCO2 than the blood in the pulmonary capillaries and this accounts for the exchange of gases in the lungs.

When Blood reaches the tissues, cellular respiration in the cells causes the tissue fluid to have a lower PO2 and a higher PCO2 than the blood in the systemic capillaries and this accounts for the exchange of gases in the tissues.

Front 22

Hemoglobin

Back 22

a respiratory pigment. Each hemoglobin molecule consists of four polypeptide chains, each chain is folded around an iron containing group called a heme. This gives hemoglobin its red color when it binds to oxygen and is found in red blood cells (RBCs). Also, when hemoglobin binds to oxygen, its becomes oxyhemoglobin.

The iron forms loose associations with oxygen atoms and thus, hemoglobin is able to transport oxygen to the cells, and release it. However, a shift in pH is required to cause hemoglobin to release oxygen. Heme groups release oxygen more readily when the immediate pH around the tissues is acidic.

Front 23

Bohr Effect

Back 23

An effect by which an increase of carbon dioxide in the blood and a decrease in pH results in a reduction of the affinity of hemoglobin for oxygen.

Front 24

Bohr shift

Back 24

A shift to the right of the oxygen hemoglobin dissociation curve due to an increase in carbon dioxide or acid in the blood.