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Introduction

THE RESPIRATORY SYSTEM

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The total lung capacity of fully grown healthy lungs is about 5-6 L of air, a person normally inhales and exhales about 0.5 L.

Tidal Volume: amount of air inhaled and exhaled in a normal breath Expiratory Reserve Volume: the amount that can be forcibly exhaled after a normal exhalation Vital Capacity: the maximum amount of air that can be exhaled Inspiratory Reserve Volume - the amount of air that can be forcibly inhaled after a normal inhalation

Lung Capacity

vital capacity = inspiratory reserve volume + expiratory reserve volume + tidal volume

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Food = weeksWater = daysOxygen = minutes

Survival

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Why do we respire?

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Gas ExchangeThe diffusion of gases from an area of higher concentration to an area of lower concentration.• oxygen is highest in the atmosphere and lowest in the veins and tissues• carbon dioxide is highest in the tissues and veins and the lowest in the atmosphere

THINso that gases can

quickly diffuse through them

MOISTso that gases can

dissolve before diffusing

LARGE SURFACE

AREA

GOOD BLOOD SUPPLY 

so that large volumes of gases can be

exchanged

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Simple Gas Exchange• Single celled organisms rely on

diffusion.• To fulfill the moist requirement these

organisms must live in wet, aquatic environments (in the environment or in a host organism)

• Some simple multicellular organisms also exchange gas in this manner (aquatic)

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On Land• Unicellular organisms like

bacteria and fungi need to exchange gas.

• Water in the soil satisfies the moist requirement.

• If the terrestrial organism lives on the surface of the soil then the moisture is derived from the soil below and from the air above.

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all processes involved in the exchange of oxygen and carbon dioxide between cells and the environment

• Breathing: air enters and leaves the lungs• External respiration: exchange of gases (O2 and CO2) between

the air and blood• Internal respiration: exchange of gases (O2 and CO2) between

the blood and tissue fluids• Cellular respiration: production of ATP in body cells

Respiration

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movement of gases between the respiratory membrane of living things and their external environment

• In aquatic organisms oxygen is extracted from surrounding water, land animals extract oxygen from the atmosphere

• The respiratory membrane is the living membrane where diffusion of oxygen and other gases occur

• The bigger the animal the more surface area needed

Breathing

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• Earthworms use their skin as a respiratory membrane

• So the skin must be kept moist all the times

• Skin is lined with capillaries which allow oxygen to enter the circulatory system and carbon dioxide to exit

Skin “Breathing” external

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• Mediate gas exchange in many aquatic animals

• Consists of branched or feathery tissue richly supplied with blood vessels, (increases surface area)

• The gills may be enclosed in cavities, through which the water is often forcibly pumped, or they may project from the body into the water

• The surrounding water keeps the gills wet

Gills external

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• Respiratory membrane is located in the body

• A tracheal system connects cells directly to atmosphere by openings in the exoskeleton called spiracles

• Oxygen enters the body through the spiracles and is then delivered to the cells by the tracheae and blood

Insects internal

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• lungs and can absorb oxygen through the skin• the lungs provide more surface area

The Lung• Characteristic of air-breathing vertebrates • Internal respiratory surface connected to the air by means of internal

passageways• One or two lungs with a moist respiratory surface.• A means of forcibly bringing air into contact with the lung surface• A circulatory system to move the gases around the body

Amphibians both

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• 1) What is respiration? (4 parts) • 2) Cellular respiration forumla (why do we

need oxygen?) • 3) External vs internal example• 4) What is a respiratory membrane and

what four key things it needs to be?

Test Questions

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Activity: Make a Lung

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• nostrils are the opening of nasal passages and are lined with hair and mucus to trap particles which enter with the air

• nasopharynx is the nasal passages that connect the nostrils to the pharynx, they contain a rich supply of blood vessels that help to warm the air as it enters, and they are covered with mucus to trap foreign particles

• oral cavity is a passageway that allows for the transport of large quantities of air (especially useful when the nasal passages are blocked or when more gas exchange is needed to keep up with the body’s demands)

Mammals internal

air enters the respiratory system either through the nostrils or the mouth

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• pharynx is the passageway at the back of the throat (shared by both air and food)

• two openings branch from the pharynx, the trachea (or windpipe) and the esophagus

• glottis is the opening to the trachea (covered by the epiglottis during swallowing to prevent liquids, food and saliva from going into the respiratory tract)

Mammals internal

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• larynx/voice box is the first and upper portion of the trachea

• the larynx contains the vocal cords which are bands of mucus membranes stretched across the larynx

• vibrate as air is forced from the lungs towards the pharynx

• different sounds are produced by a change in tension on the vocal cords

• larynx is protected by a thick band of cartilage commonly known as the Adam’s apple

• following puberty the cartilage and larynx of males increase in size and thickness

Mammals internal

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• trachea/ windpipe is the main (and largest) tube of respiration. It is reinforced and supported by C-shaped cartilage rings. Its inner membrane is lined with mucus covered ciliated cells which trap particles and sweep them up and out of the respiratory tract.

• at its base, it branches into the left and right bronchi, each contains cartilage and smooth muscle for support and each extends into their own lung

Mammals internal

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• bronchioles are the the small branches of the lungs that conduct air towards and away from the respiratory surface

• they not contain cartilage (smooth muscles in the walls can decrease their diameter)

Mammals internal

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Mammals internal• air moves from the bronchioles into tiny sacs

called alveoli• small pouches that cluster together to make

one alveolar sac, each alveolus contains a cavity of alveolar air and a wall comprised of a single layer of epithelial cells (wall expands and contracts with inhalation and exhalation)

• each alveolus is surround by pulmonary capillaries

• composed of a single layer of cells (rapid gas exchange)

• in the alveoli, gases diffuse between the air and blood according to concentration gradients

• Pulmonary arteriole and pulmonary venule

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Mammals internal

• Carbon dioxide• Oxygenated blood• Deoxygenated

blood• Oxygen

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• the outer surface of the lungs is surrounded by a thin membrane called the pleural membrane, which also lines the wall of the chest cavity

• the space between the pleural membranes is filled with fluid that reduce the friction between the lungs and the chest cavity during inhalation

Mammals internal

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• ribs form the ribcage which provides physical protection to the heart and lungs

• intercostal muscles are located between the ribs and they lift the ribcage when the muscles contract and lower the ribcage when the muscles relax

Mammals internal

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• diaphragm large band of muscle that separates the organs of the thoracic (chest) cavity from the organs of the abdominal cavity• located directly below

the lungs and it is the main muscle of respiration

Mammals internal

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about pressure differences!inspiration (inhalation) occurs when pressure inside the lungs is less than that of the atmosphere expiration (exhalation) occurs when pressure inside the lungs is greater than that of these atmosphere

Breathing Movements

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• diaphragm regulates the pressure in the chest cavity • inspiration: diaphragm muscle contracts (shortens) pulling

downwards this increases chest volume, pressure therefore decreases in the lungs

• the atmosphere pressure is now greater than the pressure in the chest cavity and air moves into the lungs

• expiration: diaphragm relaxes, returning to its dome shape due to the force exerted by the organs in the abdomen, volume decreased and the pressure increases

• now the chest cavity is greater than atmospheric pressure and air move out of the lungs

Breathing Movements

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Breathing Movementsinspiration1) diaphragm contracts2) increases chest volume3) pressure decreases (lung) 4) atm. pressure > chest cavity= air moves into the lungs

expiration1) diaphragm relaxes2) decreases chest volume3) pressure increases (lung) 4) atm. pressure < chest cavity= air moves out the lungs

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diaphragm is assisted through the action of the intercostal muscles• the ribs are hinged to the vertebral column allowing them

to move up and down• external intercostal muscles: a nerve stimulus causes

contraction, pulling the ribs up and out increasing the volume of the chest cavity, lowering the pressure and causing air moves into the lungs

• when not stimulated the muscle relaxes and the rib cage falls

• internal intercostal muscles: pulls the rib cage downwards, increasing pressure, during times of extreme exercise or forced exhalation (not employed during normal breathing)

Breathing Movements

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• They don’t truly “breathe” • The umbilical cord provides the baby

with oxygen until first breath• The mother breathes for the fetus,

and the oxygen in her blood is transferred to the fetuses blood

• Lungs are filled with ammoniac fluid • Practice breaths

How do fetuses breathe?

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• 1) What muscles are involved in breathing?

• 2) Name two breathing muscles and their function.

• 3) Anatomy• 4) How do we breathe?

Test Questions

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1) Air enters through nose or the mouth 2) Moves to the pharynx, trachea, bronchi and then bronchioles and alveoli in both lungs3) In the alveoli (respiratory membrane) gases diffuse between air and blood following concentration gradients4) During inspiration (inhalation) diaphragm flattens and pulls down, intercostal muscles contract, and chest volume increases, pressure decreases and air moves in5) During expiration (exhalation) diaphragm relaxes, intercostal muscles relax, and chest volume decreases, pressure in lungs increases and air moves out

How do we breathe?

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What is a hiccup?

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In unidirectional ventilation, the medium (air or water) moves across tissues in one direction. This method is efficient because the medium is always fresh. Fish and birds have unidirectional respiration.

Unidirectional and BidirectionalIn bidirectional respiration the medium enters and exits through the same channel. In this case, the medium (air) contains more waste and is not as efficient.

Cutaneous respiration is also possible and occurs via the skin. Cutaneous respiration is unique in that it can occur in air or water. Amphibians utilize this form.

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Bidirectional

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Bidirectional

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UnidirectionalInhalation 1: Air moves down trachea, through the lungs, into back airs sacsExhalation 1: Abdomen contracts, air from sacs move into lungs (gas exchange)Inhalation 2: Air driven from lungs, into front air sacsExhalation 2: Front air sacs contract, air driven up trachea and out of nostrils

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Unidirectional and Bidirectional

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• At sea level there is a pressure equivalent to 10 metres of water pressing down on all of us all the time (weight of the air above us in the atmosphere)

• When you travel up a mountain, there is less air above you in the atmosphere

• This decrease in pressure means that in given volume of air, there are fewer molecules present, including oxygen.

Altitude and Oxygen

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• The major cause of altitude illnesses is going too high too fast• Given time, your body can adapt to the decrease in oxygen molecules at a

specific altitude (generally takes 1-3 days at that altitude) • A number of changes take place in the body to allow it to operate with

decreased oxygen.• The depth of respiration increases.• Pressure in pulmonary arteries is increased• The body produces more red blood cells to carry oxygen• The body produces more of a particular enzyme that facilitates the

release of oxygen from hemoglobin to the body tissues.

Acclimatization

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FreedivingSurface - 30 Feet• Heart rate soles down by about 10%

(mammalian diving reflex) • At 33 feet the water pressure on your body

doubles, lungs shrink to half their normal size

• The urge to take a breath is triggered by rising carbon dioxide levels (not low oxygen)

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Freediving40 Feet• Body stops being buoyant and you sink• Mammalian diving reflex works to keep

vital organs warm and working (capillaries in arms and legs constrict, sending blood back to brain and heart)

• Spleen contracts to add extra oxygenated blood cells into system

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Freediving100 Feet• Pressure three times what it is at

surface• Slow heart beat• Reported rates as low as 14 beats

per minute (60-70)

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Freediving300 Feet• Pressure should cause lungs to

collapse • BUT mammalian diving reflex makes

the lungs counteract the pressure by engorging it with about 2 L of blood

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Drowning• laryngospasm (luh-RING-go-spaz-um) is a

spasm of the vocal cords that temporarily makes it difficult to speak or breathe (occurs when water comes into contact with the larynx)

• after an initial gasp, there is a period of voluntary breath holding

• followed by spasm of the larynx and the development of hypoxemia (decreased levels of oxygen in the bloodstream)

• lack of oxygen causes aerobic metabolism to stop• as body function declines, aspiration may occur

as the larynx relaxes allowing water to enter the lungs

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Pepper Spray• main active ingredient is oleoresin capsicum

(OC) — oil extracted from a genus of peppers known as capsicum

• skin: pain, burning and even blistering of the skin

• eyes: burning pain in the eyes, inflammation and involuntary closing of the eyelids

• respiratory system: burning throat, wheezing, gagging, and difficulty breathing (extreme cases it can cause laryngospasm)

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Nerve Gas• Poisoning by a nerve agent leads to contraction

of pupils, profuse salivation, convulsions, involuntary urination and defecation, and death by asphyxiation

• Respiratory arrest is caused by apnea (cessation of breathing) due to failure of the lungs to function effectively

• Acts directly on the diaphragm to paralyze it and it also inhibits the firing rate of neurons in an area of the brainstem that controls breathing

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Carbon Monoxide Poisoning • Binds to oxygen

receptors (hemoglobin) 200 times more tightly then oxygen does

• Symptoms similar to hypoxia

• Toxic in low levels

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The cold vs the flu?• Both respiratory illnesses • The common cold is a

viral infection caused by then adenovirus or coronavirus

• Runny nose, congestion, sore throat

• The flu is a viral infection caused by the influenza virus (vaccination)

• Fever, headache, lungs, joints, pneumonia

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Research and Model• Bronchitis• Asthma • Emphysema• Pneumothorax

(Collapsed Lung)

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• 1) Disorders: name x and explain x• 2) Unidirectional, bidirectional, cutaneous

Test Questions