Respiratory System Chapter 11 Grade 11

Respiratory System

Group of organs that provides living things with O from outside the body and disposes of waste products such as CO2

Respiration

All of the processes involved in bringing O into the body, making it available to each cell, and eliminating CO2 as waste

Inspiration

The action of drawing O rich air into the lungs
– Diaphragm contracts (flattens out), pulls downward.

– External intercostal muscles contract (ribs rise).

– Chest volume ↑ – Air pressure inside the chest ↓ -draws air in!

Gas exchange

Transfer of O from inhaled air into the blood, and of CO2 from the blood into the lungs; it is the primary function of the lungs

Ventilation

The process of drawing, or pumping, and O containing medium over a respiratory system

Why do we breathe?

For cellular respiration —> ATP

Diffusion Gradient

Describes the relationship in which a dissolved substance moves from a region of high concentration to a region of low concentration

Why does is there diffusion gradient

Because blood and water flow in opposite directions, the diffusion gradient of the O is kept high

Respiratory Surface

increase the surface area for gas exchange allowing for larger bodies

Why does gas exchange have to be large enough for O2 and CO2

to exchange to occur fast enough ot meet the organisms needs

What type of cells cover the respiratory surfaces

thin moist epithelial cells that allow O2 and CO2 to exchange (these gases can only cross cell membranes when they are dissolved in water or an aqueous solution, thus respiratory surfaces must be moist).

Instead of using lungs, some animals do what

exchange gases through their outer bodt surface such as gills or trachea

All organisms do what in terms of the resp sys

use a ventilation process of pumping O over a respiratory surface (gills, trachea, lungs)

Countercurrent flow

when oxygen diffuses along a diffusion gradient (moves from and area of high concentration to an area of low concentration).

How does the gills work

As water flows over the gills, dissolved oxygen diffuses into blood. It flows through blood vessels and capillaries in gill tissue.

Diaphragm

A sheet of muscle that separates the thoracic cavity from the abdominal cavity, contracts and relaxes in response to nervous stimuli

• Changes the volume of the thoracic cavity.

• Respiratory and nervous system work together.

• Diaphragm and intercostal muscles work together to move air into and out of the lungs with signals from the brain.

Respiratory System Principles

1. Movement of air (contains O2) so it contacts a moist membrane overlying blood vessels.

2. Diffusion of oxygen from the air into the blood.

3. Transport of oxygen to the tissues and cells of the body.

4. Diffusion of oxygen from the blood into cells.

5. Carbon dioxide follows a reverse path.

4 Stages of Human Respiration

1) Breathing: inhaling and exhaling.

• Inhalation: muscle contracts lifting ribcage up and out. Diaphragm contracts and moves down which allows air to move in.

• Exhalation: muscles relax ribcage moves back down and in diaphragm moves up and air moves out.

2) External respiration: exchange of oxygen and carbon dioxide between the lungs and blood (gas exchange).

3) Internal respiration: exchange of oxygen and carbon dioxide between blood and body tissue cells.

4) Cellular respiration: Use of oxygen by mitochondria for energy production within cells.

External respiration

Exchange of oxygen and carbon dioxide between the lungs and blood (gas exchange).

3) Internal respiration

exchange of oxygen and carbon dioxide between blood and body tissue cells.

Cellular respiration

Use of oxygen by mitochondria for energy production within cells.

What is a Spirograph

a graph representing the amount (volume) and speed (rate of flow) of all that is inhaled and exhaled, as measured by spirometer

Tidal volume

volume of air that is inhaled and exhaled in a normal breathing movement when the body is at rest (~10 percent of total lung capacity)

Inspiratory reserve volume

the additional volume of air that can be taken into the lungs beyond a regular or tidal, inhalation

Expiratory reserve volume

the additional volume of air that can be forced out of the lungs beyond a regular, or tidal, exhalation

Vital capacity

Total lung volume capacity, the total volume of gas that can be moved into and out of the lungs during a single breath

How is vital capacity calculated

Tidal volume + Inspiratory reserve volume + expiratory reserve volume

Residual Volume

Volume of air that remains in lungs after a complete exhalation:

amount of gas that remains in the lungs and passageways of the resp sys even after a full exhalation. This gas never leaves the resp sys, if it did, the lungs and resp passageways would collapse. the volume has little value for gas exchange because it is not exchanged with air from the outside body

Pharynx

The passageway just behind the mouth that connects the mouth and nasal cavity to the larynx and esophagus

Trachea

the tube that carries air from the nasal passages or mouth to the bronchi and then to the lungs; also konwn as the windpipe

Glottis

The opening of the trachea through which air enterns the larynx

Larynx location and what does it contain

the structure between the glottis and the trachea that contains the vocal cords

Bronchus

the passageway that branches from the trachea to the lungs

Bronchiole

The passageway that branches from each bronchus inside the lung into increasingly smaller, thin-walled tubes

Alveolus

A tiny sac, with a wall that is one cell thick, found at the end of a bronchiole; respiratory gases are exchanged in this sac

hemoglobin

an iron containing protein found in red blood cells, which binds to and transports oxygen from the lungs to the rest of the body

Brain role with diaphragm

• coordinates breathing movements and regulates breathing rate.

• monitors the volume of air in lungs and gas levels in the blood.

Hiccups

muscle spasms of the diaphragm that allows air into the lungs

Expiration

– Diaphragm relaxes (becomes dome shaped)

– External intercostal muscles relax (ribs fall)

– Chest volume ↓

– Air pressure inside the chest cavity ↑

– Air pressure is now greater than atmospheric pressure, forcing air out of the lungs.

– Internal intercostal muscles are only used when expiration is forced (i.e. during exercise or blowing out a candle.) These muscles are not used during normal breathing.

– Regular breathing does not use the full capacity of your lungs.

Intercostal Muscles

• A collection of muscles that run between the bones of the ribcage.

• Contract and relax in response to nervous stimuli.

• Changes the volume of the thoracic cavity.

How do diaphragm and intercostal muscles work together

Using signals from the brain, ___ work together to move air and out of the lungs.

Pleura

• Two layers of tissue separated by a small amount of lubricating fluid. –

  • Prevents friction when lungs expand and recoil.

• Connects lungs to the walls of the thoracic cavity (region of lungs.

• Membrane that creates an air tight seal around each lung.

What defends the body against bacteria and viruses

mucus, cilia, phagocytes

How does the resp sys assist in the control of body pH

acid base imbalances are altered by changes in breathing to expel more CO2 (acidic) which increase the pH to normal.

Site of Gas Exchange

• Each bronchiole ends in several clusters of alveoli.

• Surrounding each alveolus is a network of capillaries.

• Gas exchange occurs between the blood in the capillaries and the air in the alveolus so that blood leaving the lungs is oxygen rich.

The resp pathway

• Air enters the body through the mouth (oral cavity) or nose (nasal cavity).

Nasal Cavity

• Thick hairs lining the nostrils act as filters.

• Lined with cells that produce mucus (goblet cells) to trap foreign material. Expel by coughing or sneezing.

• Nose has many small capillaries filled with warm blood, which help to warm the incoming air to body temperature.

  • Allows better gas exchange.

Oral Cavity:

• When air is inhaled through the oral cavity (mouth), these steps are skipped.

Pharynx

• Common to both digestive and respiratory systems.

• Branches to both the trachea (windpipe) and esophagus.

• Epiglottis swings back and forth between the larynx (at the top of the trachea) and the esophagus.

  • Prevents food from entering larynx

  • Prevents air from entering esophagus

  • Connects the mouth and the nasal cavity

Larynx

• Made of many pieces of small cartilage.

• Contains vocal cords.

  • Two highly elastic folds that vibrate when air passes over them

  • When muscles contract as air passes by from the lungs, the vibrating cords vibrate the air, resulting in sound.

  • Males have a larger larynx because the vocal cords vibrate at lover frequency, thus having a lower voice.

  • Laryngitis is the inflammation of the larynx.

Trachea (Windpipe)

• A strong tube containing rings of cartilage that prevent it from collapsing. Opening to the trachea is the glottis.

• Connects larynx to lungs.

• The mucosa that lines the airway warms and moistens the air before it reaches the lungs

• The mucosa contains mucus-producing cells and ciliated cells help to protect lungs from dirt and particles.

• Ciliated cells push the mucus/dirt up the trachea to the pharynx, where it is swallowed and digested in the stomach or coughed up.

• is a

  semi-circular loops

  of cartilage.

• Approximately

  10-12 cm in length.

• Runs from throat

  to middle of chest.

Lungs

Paired organs that lie on either side of the heart and fill up the thoracic (chest) cavity

Lobes of Lungs

Each lung is divided into lobes (partitions) by fissures. • Each lobe differs in size and shape: 3 right, 2 left

cardiac notch

Because the heart is slightly larger on the left side, the left lung has an indent called the ___ and is slightly smaller than the right.

Why is each lung surrounded by a pleural membrane

To protect the lungs

Within the lungs, the trachea branches into the left and right bronchus, which does what?

divide into increasingly smaller branches called bronchioles

Acinus

The smallest bronchioles end in a cluster of hollow air sacs, collectively called an ____ The ____ is made of individual air sacs called alveoli. Latin for berry. Collection of cells that resemble a raspberry. The alveolar sac is acinar in form (containing multiple alveoli).

Alveoli

are like small balloons that inflate and deflate with air during respiration.

– Site of gas exchange.

– Each human lung contains approximately 150 million alveoli – a huge surface area!

– The walls of an alveolus are only one cell thick and lie next to capillaries (also one cell thick), allowing quick gas exchange.

Alveoli def

because the concentration of oxygen is greater in atoms, it diffuses into the lungs.

Blood

because the concentration of carbon dioxide is greater in blood it diffuses across the membrane and is exhaled into air where it is less concentrated.

Gas Law

an equal volume of gas is maintained at the same temperature, the pressure exerted by a gas determines the speed of diffusion (diffusion of gas occurs from an area of high pressure to an area of low pressure).

Dalton’s Law of Partial Pressure:

each gas in a mixture exerts its own pressure, which is proportional to the total volume.

• Law states that in a mixture of non-reacting gases, the total pressure exerted is equal to the sum of the partial pressures of the individual gases.

• Partial pressure is very important in understanding the movement of gases. Causes oxygen to enter and carbon dioxide to leave the blood more quickly.

  • Example: Atmospheric pressure at sea level is 101 kPa. If Air is 21% O2, then 21% x 101 kPa =21.21 kPa.

  • If Air is 0.03% CO2, then 0.03% x 101 kPa =0.04 kPa.

Factors that affect Gas Exchange

Surface area, Concentration difference, Diffusion distance

Surface Area

the ↑ the surface area means the ↑ gas exchange.

Concentration

the ↑ the difference between oxygen or carbon dioxide concentrations in the air, lungs and the blood, the more rapidly diffusion will take place.

• As a result of alveolar air contains a greater amount of carbon dioxide and greater oxygen than atmosphere air. Therefore, oxygen enters the lungs and carbon dioxide leave the blood as both gases diffuse from and area of high to low concentration.

Diffusion distance

the ↓ the distance gases must diffuse across, the faster gas exchange will occur.

• surface area available for gas exchange is on average 54.4m2 counting all of the 150 million alveoli.

Partial pressures of O2 and CO2 dissolved in the blood differs greatly depending on

Location in the body

Where is partial pressure greater and less in terms of O2, CO2, veins, arteries and aveoli

Partial pressure of CO2 is greater in tissues and veins and that of O2 is greater in arteries and alveoli.

In the Atmosphere: [O2] is ___, [CO2] is ___.

O2 is the highest, CO2 is the lowest

At the alveoli in the lungs: [O2] is ___ then atmosphere, and [CO2] is ____.

[O2] is lower and [CO2] is increased

In the Tissues: [O2] drops ______ and [CO2] _____

O2 even lower CO2 increases further

In atmosphere what is the % of O2 and CO2

21 % O2, 0.04% CO2

O2 diffuses from the alveoli into the

blood and plasma

Oxygen Transport

• Hemoglobin (respiratory pigment in RBCs) ↑ O2 carrying capacity.

• A small amount of O2 dissolves in the water of the blood plasma (1%).

• The majority of the O2 diffuses in the RBCs (99% O2 carried by hemoglobin).

When O2 Dissolves in Hemoglobin: O2 + Hb = ? and what happens

oxyhemoglobin (weak bond)

• O2 comes off the Hb when it passes through tissues that have a lower O2 concentration than the RBCs and freely diffuses into the cell’s mitochondria for cellular respiration

• With Hb, blood can carry 20 mL of O2 /100 mL of blood. 70% more than it could without it. •

• ~ 0.3 mL of O2 dissolves in blood plasma(1%), not very soluble.

The amount of O2 that combines with Hb

depends on what?

the partial pressure of O2.

• Ex: At the lungs (where partial pressure of O2 is high), blood is saturated with O2!

• Ex: At the capillaries (where the partial pressure of O2 drops), causes the dissociation or separation of O2 from hemoglobin so that O2 will diffuse into the tissues.

CO2 is how many times more soluble than O2.

20 times

CO2 is transported three ways

1) as dissolved gas in water molecules of blood plasma (9%).

2) combines with hemoglobin (23%) of the RBCs (27%)

3) reacts with water to produce carbonic acid which immediately dissociates into bicarbonate ions (HCO3-) and H+ ions in the RBCs & the plasma.

In plasma: CO2 + H2O =

HCO3- (very slow reaction)

in RBCs, with the help of an enzyme, CO2 + H2O =

HCO3- (very fast!!!). The enzyme is called Carbonic Anhydrase (found in RBC’s) » Speeds the conversion of carbon dioxide and water to form carbonic acid.

conversion of carbon dioxide and water to form carbonic acid does what

reduces the concentration of CO2 in the plasma and ensures CO2 to diffuse into blood

In RBC’s, with carbonic anhydrase, CO2 combines with water to form carbonic acid (HCO3-), which then dissociated into H+ and HCO3- ions. Because?

acids can lower pH of blood to dangerous levels, they must be buffered.

This rapid conversion of free CO2→H2CO3, ↓ the concentration of CO2 in the plasma, thus maintains

a low partial pressure of CO2 in the blood ensuring that CO2 continues to diffuse into the blood.

The formation of acids (HCO3-) can change the pH of blood (this can be very dangerous!) therefore, they must be ___

Buffered

What acts in our blood as a buffer and why?

Hemoglobin acts as a buffer in our blood b/c of the unstable carbonic acid which dissociates to bicarbonate ions (HCO3-) and hydrogen ions (H+).

Buffer

helps maintain a specific pH in the body. Therefore achieving homeostasis.

Body tissue to blood capillary CO2 Transport

• CO2 diffuses from body tissues into blood plasma and RBC’s where it binds to hemoglobin.

• Reacts with water to produce carbonic acid which then dissociates into H+ and HCO3- ions.

Blood capillary to lung CO2 Transport

• Once the venous blood reaches the lungs the high concentration of CO2 diffuses from blood into alveoli and is eliminated during exhalation.

Pneumonia

Alveoli fill with thick fluid, making gas exchange difficult

Bronchitis

Airways are inflamed due to infection (acute) or due to an irritant (chronic). Coughing brings up mucus.

Asthma

Airways are inflamed due to irritation, and bronchioles constrict due to muscle spasms

Emphysema

Alveoli burst and fuse into enlarged air spaces. Surface area for gas exchange is reduced.

Disorders of lower resp tract

Pneumonia, Bronchitis, Bronchitis, Asthma, Emphysema

Bronchodilators

Puffers, used to dilate and open up pathway to lungs

acute bronchitis

severe inflammation that occurs short term. often caused a viral infection or bacterial infection that settles in lungs

chronic bronchitis

COPD (Chronic Obstructive Pulmonary Disease) is bronchitis that doesn’t go away