THE RESPIRATORY SYSTEM

UEQ: How do we exchange oxygen to and carbon dioxide from the

human body?

What is the respiratory system?

The system that brings oxygen into the body

and expels carbon dioxide out of the body.

ensures that during inspiration, or inhalation, air is brought from the atmosphere to the lungs by a series of cavities, tubes and openings.

ensures that during expiration, or exhalation, air is pushed out of the lungs into the atmosphere using the same structures.

THINK ABOUT IT:

WHAT ORGANS ARE APART OF THE UPPER RESPIRATORY TRACT?

Nasal cavities

Pharynx, or throat

Major Organs Accessory OrgansOral cavity , or mouth

Nose

Paranasal sinuses

The Upper Respiratory Tract

The nose

Bone and cartilage support the nose internally

Two nostrils or nares Air enters and leaves through here

Internal hairs guard nostrils Prevents larger particles carried in air

The nasal cavities

Hollow space behind the nose Divided into narrow canals separated from each other by

cartilage and bone – nasal septum. Nasal conchae

bones and bony processes that divide the cavity into passageways

Support the mucous membrane Increases surface area Pseudostratified ciliated columnar epithelium

Secretes mucous from goblet cells Water evaporates from this lining moistening the air Mucus traps debris coming in with the air

Lined with blood vessels As air enters, heat from blood transfers to air and warms it Adjusts air temp to body temp

Paranasal sinuses Air filled spaces within the frontal,

ethmoid, sphenoid and maxillary bones of the skull and opening into the nasal cavity.

Lined with mucous membranes – continuous with the lining of the nasal cavity

Reduce the weight of the skull Resonance chambers that affect quality

of voice

Pharynx, or Throat Funnel shaped passage way that

connects the nasal and oral cavities to the larynx

Passage way for food moving to esophagus, and air moving to the larynx

Helps to produce sound of speech

Has three parts: 1. Nasopharynx: where the

nasal cavities open above the soft palate

2. Oropharynx: where the oral cavity opens

3. Laryngopharynx: area that opens up into the larynx

Pathway of air through the upper respiratory

system.

REMEMBER!!!! Each time that you take a breath, there are three very important things that happen.

1. The air that you breathe in is cleaned by tiny hairs in your nose, trapping little bits of dirt and dust and germs that come in through your nose.

2. As you breathe, the air is made slightly wet. Your nose having damp passages does this.

3. The next thing that takes place when air enters your nose is that the air is warmed. This happens because the blood flows through the lining of the nose and gives off heat.

Snot and more.. Protecting us from harm Snot:    

"Snot", is just another word for mucus. When bits of stuff get stuck in your nose hairs, it’s the mucus or snot that surrounds the stuff and traps it.

Boogers: Boogers are dried-up snot and dirty nose debris. Encrusted mucus is filled with the junk that’s in

the air you breathe - dust, pollen, germs, sand, fungi, smoke, small particles from outer space.

AND NOW FOR THE MUCUS MODEL…

Achoo…

Mucus model? – How does it compare to the real thing?

Model made up of gelatin (protein) and corn syrup (sugar)

Mucus is made mostly of sugars and protein.

The long, fine strings you could see inside your fake snot when you moved it around are protein strands.

These protein strands make snot sticky and capable of stretching

CHECK IT!Complete the questions for a stamp..

THINK ABOUT IT:

WHAT ORGANS ARE APART OF THE LOWER RESPIRATORY TRACT?

Trachea, or windpipeThe bronchial tree

Diaphragm

Major Organs Accessory Organs

The lungs

Larynx, or voicebox

Glottis

epiglottis

The Lower Respiratory System

Larynx, or voicebox Cartilaginous structure that serves as a

passageway for air between the pharynx and trachea.

A triangular box top of the triangle is located to the front of

the neck (Adam’s apple) Framework of muscles and cartilage

Thyroid cartilage Cricoid cartilage Epiglottic cartilage

Houses the vocal cords Allows for air in and out of the trachea Prevents foreign objects entering into

trachea

Vocal Cords Vocal folds

Composed of muscle tissue and connective tissue Covered with mucous membrane

False vocal cords Upper folds Do not produce sound Muscle fibers help close airway when swallowing

True vocal cords Muscle tissue and elastic fibers Forced air between TVC causes them to vibrate and

produce sound Words = changing shapes of pharynx, oral cavity;

and use of the tongue Pitch= contracting or relaxing muscles that alter

tension

Glottis

Opening between vocal cords Durning normal breathing, relaxed vocal

cords, the glottis opens During swallowing/ eating, muscles

around the false vocal cords contract, the glottis closes.

Epiglottis A flap of soft tissue above the vocal

cords The larnyx will move upward against the

epiglottis when swallowing to prevent food, water and saliva from entering the lungs.

The trachea, or windpipe A tube that connects the larynx to the

primary bronchi Walls consist of connective tissue and

smooth muscle Reinforced by c-shaped cartilaginous rings

Prevents the trachea from collapsing Lies anterior to the esophagus

Soft tissue that completes the c-rings, allow for esophagus to expand as food moves through

The outermost layer of the mucous membrane that lines the trachea is pseudostratified columnar epithelium with goblet cells. Traps particles and moves it upwards to

pharynx to be swallowed

The Bronchial Tree Tubes that allow air to pass through, and are

reinforced with cartilaginous rings, like the trachea. Divided into the left and right primary bronchi, which

lead into the lungs Divison is located in the mediastinum, approximately at the

level of the 5th thoracic vertebrae Branch into the secondary bronchi tertiary bronchi keep dividing until they are about 1 mm in diameter

Bronchi that are 1 mm in diameter are called bronchioles Terminal bronchioles Respiratory bronchioles Alveolar ducts

Alveolar sacs Alveoli

The Lungs Paired, cone-shaped organs

Separated by the mediastinum Diaphragm and rib cage enclose them

Suspended by the bronchus and major blood vessels Visceral pleura surrounds each lung Continues to the parietal pleura which attaches and

surounds the throacic cavity Potential space between the pleura = pleural cavity

Filled with serous fluid Reduces friciton of lungs moving against the thoracic cavity

during breathing Right lung has three lobes, the left lung only two –

due to the heart pointing towards the left Broken even further into lobules, which house

bronchioles serving the alveoli

The Alveoli Lungs have about 300 million alveoli Each alveoli sac is surrounded by blood

capillaries Made up of simple squamous epithelium This is the site where gas exchange

happens

Be sure to complete the following

Your check it questions The diagram at the back of the packet

WARM UP! Why is it important for the capillaries

from the cardiovascular system to be numerous and surround the alveoli?

When finished with the question, take a moment and breathe – notice what happens. Write it down.

Cardio/ Respiratory connection

Oxygen diffuses from alveolar walls and enters the blood.(where it can now go to other cells in the body)

Carbon Dioxide diffuses from the blood through the walls and enters the alveoli. (where it can be exhaled and released)

Alveoli Exchange of Gases: Using the picture below EXPLAIN the gas exchange process:

Why do the blood cells start blue and then turn red?

CHECK IT!

Breathing, or ventilation Has two phases

Inspiration – moving air into the lungs

Expiration –moving air out of the lungs

Inspiration Active phase of ventilation In this phase the diaphragm and muscles of

the ribcage contract – diaphragm moves downward and looks flattened

The volume of the thoracic cavity will increase, so does the lung volume

The pressure within the alveoli is less than the pressure outside in the atmosphere. There is a difference in pressure (or pressure gradient) and air will move into the body naturally.

Pressure and volume have an inverse relationship

Pressure inside the lungs and alveoli decrease, atmospheric pressure will push outside air into airways

During this time the pressure in the alveoli drops 2mmHg below atmospheric pressure

In response, atmospheric pressure forces air into the airways

The external intercostal muscles between ribs are stimulated and move the ribs and sternum upwards

Enlarges thoracic cavity even further Internal pressure is further reduced;

increases amount of air into the lungs

Water within the serous fluid found in between the visceral and parietal pleura creates an attraction between the pleura, and the membranes move upward during inspiration

This expands the lung in all directions. Too much water in the alveolar sacs

creates a surface tension that may collapse the alveoli.

Certain cells within the alveoli secrete a surfactant – lipids and proteins

Fills the alveolar air spaces – reducing the tendency to collaspe, especially when lung volumes are low

Makes it easier to inflate alveoli

Expiration Passive phase of ventilation Come from elastic recoil and surface

tension No effort is required for air to leave

the body Diaphragm and muscles of the

ribcage relax – diaphragm looks cone shaped

Pressure within the alveoli increases to about 1mmHg above atmospheric pressure

Forces the air out of the lungs The volume of the thoracic cavity will

decrease, so does the lung volume

Maximum inspiration and forced expiration

MAXIMUM INSPIRATION FORCED EXPIRATION Involves muscles of

the back, chest, and neck

Thoracic cavity increases more than normal, for maximum lung capacity

Usually during exercise

Contraction of the ribcage muscles forces the ribcage to move downward and inward

Involves the abdominal muscles pushing against the abdominal organs which pushes against the diaphragm, pushing more out of the lungs

Usually during exercise, singing, playing an instrument, or blowing out a candle

CHECK IT!And then the activity.

Volumes of Air in the LungsWarm UP: Are our lungs ever void of air? Why or why not?

Volumes of air within the lungs during ventilation

Why do we need to know this? Knowing the amounts of air in the lungs

and how it flows through the respiratory system helps to diagnose respiratory issues

Respiratory Air Volumes and Capacities

Spirometry is the test that measures air volumes in or out of the lungs. Three distinct repiratory volumes can be

measured: Resting Tidal volume Inspiratory reserve volume Expiratory reserve volume

One inspiration + one expiration = respiratory cycle. Air that enters of leaves during a respiratory

cycle is the tidal volume

Respiratory cycle: One inspiration plus one expiriation. (Breathe in- breathe out)

1. Resting Tidal volume- the normal amount of air that enters the lungs and leaves the lungs during a respiratory cycle.

The average is about 500 milliliters of air per breath in and the same amount out.

During Tidal volume you do not use the total amount of space in your lungs! They only use about 75-80%

2. Inspiratory Reserve Volume: When you take a deep breath in to hold more air than a usual breath. “Forced inhalation”.

3. Expiratory Reserve Volume: Forced expiration. Expelling air beyond the tidal volume. Even after the most forceful exhale however you still have air left in your lungs.

This left over air is called the Residual Volume.

2.

3.

4.

5. 1.

6.

4. Vital Capacity: Combining the tidal volume with both the inspiratory reserve volume and the expiratory reserve volume.

5. Total Lung Capacity: The vital capacity plus the residual volume. All the possible air that can come into or out of the lungs, including the air that never leaves the lungs.

Fill in the following table with the appropriate terms:

Respiratory centers and control of breathing…

Medullary respiratory center- controls both inspiration and expiration Found within the pons and

medulla oblongata Medulla oblongata has two

groups Ventral respiratory group –

controls basic rhythm Dorsal respiratory group-

controls the diaphragm

Factors that Affect breathingflow charts.. CHECK IT!

PP. 456- 458Create flow charts for the following factors

that affect breathing CO2 levels O2 levels Depth of breathing Emotional upset Holding your breath Hyperventilation

HOW AND WHY GAS EXCHANGE HAPPENS:

Location: The alveoliMethod: Diffusion

Partial pressure: In a mixture of gases such as air or blood, each gas accounts for a portion of the total pressure the mixture produces. The amount of pressure each gas contributes is the partial pressure.

Diffusion of Gases:

When blood reaches the alveolus / lungs the blood is oxygen poor- it has depleted its oxygen source to the rest of the body and needs to “pick up more”.

Diffusion of Gases: Due to the pressure gradient,

oxygen will move from the alveoli to the blood stream.

In other words, there is more oxygen in the alveoli than the bloodstream, so oxygen will naturally move into the bloodstream.

Carbon dioxide will be orin the bloodstream.

So what about Carbon Dioxide?

Carbon dioxide will or

the bloodstream into the alveoli where it will be expelled out of the body.

higher lower

move into out of

Color and label the diagram

GAS TRANSPORT

Factors affecting release of O2

Increase in CO2 concentration= increase in O2 release If blood

Becomes acidic Temperate increases

More O2 is released to skeletal muscle during physical activity; less O2 released to non active cells

HYPOXIA – deficiency of O2 reaching tissues

GAS TRANSPORT - OXYGENHEMOGLOBIN OXYHEMOGLOBIN

98% of oxygen in blood binds to hemoglobin

a protein in red blood cells that carries oxygen

PO2is high – oxygen dissolves in blood and combines with hemoglobin to form oxyhemoglobin

Unstable bonding As PO2 decreases in the

body, O2 is released from oxyhemoglobin

O2 diffues across the membrane of cells to be used in cellular respiration

CO2 Transport

Capillary blood gains CO2, as tissues have increased levels of PCO2

Transported in three ways to the lungs: Dissolved in plasma Bound to hemoglobin Bicarbonate ions

Amount of CO2 dissolved in plasma dependent on its partial pressure Increased PCO2 = more CO2 in solution Only 7% of CO2 transports in this form

GAS TRANSPORTCarbaminohemoglobin Bicarbonate Ions

CO2 loosely bonds with hemoglobin = carbaminohemoglobin

Decomposes readily in regions of low PCO2 – releasing CO2

Only about 23% of the CO2 carried in the blood is formed in molecule, as this reaction happens slowly

Most important CO2 transport mechanism

CO2+ H2O => H2CO3 (carbonic acid)

Occurs slowly in plasma Carbonic anhydrase

speeds up reaction, releasing H+ and HCO3- (bicarbonate ions)

Bicarbonate ions diffuse into the plasma – 70% of all CO2 in blood is transported this way

CO2 Transport Continued

Plasma release CO2 Dissolved CO2 diffuses into the alveoli (alveoli

PCO2 is low

Bicarbonate Ions Release CO2 As blood passes through the capillaries of the

lungs At same time H+ and HCO3- combine to make

H2CO3 under influence of carbonic anhydrase H2CO3 breaks down quickly to form CO2 and

H2O CO2 then diffuses into the alveolus

Carbaminohemoglobin release of CO2 As blood passes through the

capillaries of the lungs Release of CO2 happens Will continue until PCO2 of blood and

alveolar air are at equilibrium

CO2 Transport Continued