Respiratory System

Components:

• Nose• Pharynx (throat)• Larynx• Trachea• Bronchi• Lungs • Alveoli (in lungs)

• All parts distribute the air except the alveoli

• Alveoli exchanges air(puts it in the blood)

Accessory Structures:Oral cavity

Rib cage

diaphragm

Functions of the respiratory system:

• to move oxygen to the lungs so oxygen can enter the blood

• To move carbon dioxide out of the blood cells to the lungs (exhaled out of the body)

• Respiration- the term for the movement of oxygen into the lungs and the release of carbon dioxide from the lungs

blood vessels

Divisions of the respiratory System:

• 1. upper respiratory tract- includes nose, pharynx, larynx

• 2. lower respiratory tract- includes trachea, bronchial tree (primary bronchi, secondary bronchi, tertiary bronchi), lungs

Components of air you breath in:

• 78-79% nitrogen• 21% oxygen• Trace amounts of

carbon dioxide

and other gases

NOSE• Mostly made of cartilage• Includes the nasal cavity

nasal cavity- extends from external opening of nose to the pharynx

The nasal cavity has 2 parts:

1. external nares- nostrils

2. internal nares- openings to the pharynx

Nasal septum- divides nasal cavity in half

-pressure on the nasal septum may cause nose bleeds called

epistaxis. It is rich in blood.

Functions of the nose:

• Mucous and nose

hairs filter the air

• Humidifies the air/moistens air (air is 100% humidified when it passes through the nose

nasal cavity infections:

• If the nasal cavity or nasal sinuses become infected by bacteria and viruses, the passages become blocked by thick mucous and it accumulates in the sinuses causing headaches.

• Treatment: use decongestants to thin the mucous allowing it to drain out and decreasing pressure

Pharynx (throat):• Connects the passage of

air from the nasal cavity to larynx

• Connects the passage of food from the oral cavity to the esophagus

Parts of the pharynx:1. nasopharynx- 1st section of pharynx

-connects to nasal cavity

-in this region, the soft palate will rise to aid in swallowing. It closes off the nasal cavity to keep things from entering it.

2. oropharynx- 2nd segment- joins nasopharynx to

laryngopharynx

-where the oral cavity empties

3. laryngopharynx- 3rd segment-

-joins oropharynx to larynx

Larynx (voice box)

– Connects to the pharynx

– Has rings on the outside made of cartilage. The largest cartilage around the larynx is the thyroid cartilage (Adam’s apple). In females, this is not as large as in males.

– Has structure called epiglottis which is a flap-like piece of cartilage that closes to keep food out of the windpipe (It stays open until swallowing occurs)

Epiglottis:

Larynx functions:

1. Connect pharynx to trachea

2. Voice box produces sound

3. Removes particles using a ciliated mucous

4. Prevents solid and liquids from entering airway

Vocal cords called glottis:• Paired ligaments

that have folds that vibrate releasing sound by moving muscle.

• The length and the tension of the cords changes which changes the voice.

Trachea:• Also called the windpipe

• Function: passes air from larynx to the 2 bronchi

• Has C-shaped cartilage on the outside to protect and prevent the collapse of it if it is hit

• Obstruction of it can cause death (oxygen can’t get to cells)

Lungs:

• Principal organs of respiration

• Cone shaped • Right lung (3 lobes)• Left lung (2 lobes)

Structures in lungs:• Hilum- where bronchi, vessels,

and nerves enter the lungs

• Upon entering the lungs, the bronchi branch to form the secondary bronchi and the branch to form the tertiary bronchi (bronchioles)

• The branched bronchi is called the bronchial tree because it branches like a tree)

• Alveoli-grape-like structures at the tip of the tertiary bronchi

Alveoli:

• Probably the most important respiratory structures

• They are where gas exchange occurs – Where oxygen enters

the blood– Where carbon dioxide

exits the blood

alveoli

Blood

Thoracic cavity:• Rib cage area/chest• Also called the thorax• 3 divisions:

– Right and left pleural (contains right and left lung)

– Mediastinum (houses the esophagus, trachea, large blood vessels, heart

– Parietal layer- lines the entire thoracic cavity

Function of the thoracic cavity:

• Fluctuates in size to bring about inhalation (breathing in) and exhalation (breathing out)

Pulmonary ventilation (breathing)

Has 2 phases:1. inhale2. exhale

How occurs?• Air moves in and out due to a pressure gradient

(pressure differences in and out of lungs)• Normal air pressure is 760 mm Hg (outside lungs)• When the pressure inside lungs is less than outside

lungs, air goes in lungs (breath in/inhale)• When pressure inside lungs is higher than outside lungs,

air goes out (breath out/exhale)

Inspiration/inhalaton:

• Breathing in • How does it occur?

– The diaphragm contracts which expands the thoracic cavity (rib cage lifts and expands)

– This makes the pressure less in the lungs allowing more air to flow in from the outside

Exhalation/expiration:• Breathing out

• How it occurs?• Muscles of the ribs and the diaphragm relax• Rib cage declines to normal position which decreases

the size of the lungs• The size of the lungs decreases which increases the

pressure in the lungs pushing the air out (exhalation, expiration)

Gases of ventilation:

• Purpose of breathing is to take in oxygen and give off carbon dioxide

• Every 5 seconds, we move 500 ml of air in and out of lungs

• The air that is breathed in is made of 21% oxygen

• The body uses 7% of the oxygen which leaves 14% to breath back out. Also, the Carbon dioxide output increases by 5.6%

• This is why you can do mouth to mouth and still have enough oxygen to give to someone else

Gas Exchange in the lungs:• Gas exchange in the lungs occurs between the air in the

alveoli and the blood flowing thru the capillaries

• Oxygen enters blood blood

• Carbon dioxide leaves

blood

lungs

• Air gets to the alveoli by the following pathNose pharynxlarynx trachea primary bronchi

secondary bronchi tertiary bronchi alveoli

• Air exits the lungs by reversing the above path

Oxygen transport in the blood:

• Once oxygen enters the blood from the lungs, it has to be taken to the cells of the body

• It is transported in 2 ways:

1. some is dissolved in the plasma

2. the rest is carried by red blood cells

(these cells have hemoglobin that attaches to and carries the oxygen)

Red blood cells

Breathing reflexes:

• Cough reflex- stimulated by foreign matter in the trachea or bronchi or accumulation of excess mucous

-The glottis and epiglottis close which holds air in increasing the pressure in lungs

-The epiglottis then opens suddenly resulting in an upward thrust of air that removes the particle

Sneezing reflex:

• Stimulated by contaminates in the nasal cavity such as dust, mucous, other particles

• The same process occurs like a cough except the burst of air goes thru the nose

Hiccup reflex

• Due to spasmatic contraction of the diaphragm

• Cause unknown• The spasms cause

the glottis to close during inspiration which makes the sound

Yawn reflex:

• Unusual widening of the mouth which lets air in to the lungs

• Reason is unknown • Sometimes it is

thought to be a result of boredom (the brain wants more air to wake up)

Respiratory Disorders:

• Rhinitis- due to inflammation of the mucosa

of nasal cavity

-It is due to a virus ex. Common cold-symptoms: excessive dripping of fluid into

the lower respiratory tract or out nostrils

-this may cause sore throat, coughing or upset stomach

-the nasal lining is irritated so it may cause sneezing to clear the nose

Treatment: antihistimines and decongestants

Laryngitis:

• Due to inflammation of the vocal cords and swelling• Voice production becomes inhibited• Caused by infections, toxic fumes like smoking, vocal

abuse, and alcohol ingestion

Pharyngitis• Sore throat• Due to infection of the

pharynx due to a virus or bacteria

• Strep throat – due to infection of the streptococcus bacteria

• Treatment of pharyngitis: lozengers, rest, fluids, antibiotics, pain med.

Deviated septum

• nasal septum is off center

• Impairs proper breathing due to it being off midline

• If it is extreme, it is corrected with surgery

Bronchitis:• Inflammation of the trachea and

bronchial tree • Due to infection such as

bacteria• Excessive fluid/mucous

accumulates in bronchi and the airway seems to narrow

• Results in a lot of coughing to clear the mucous out and difficulty breathing

• Treatment: antibiotics and breathing treatments

Pneumonia:• Inflammation that affects

the airways of the lungs

• Due to infection such as bacteria, viruses, and chemicals

• Alveoli and bronchi become plugged with thick fluid (pus)

• Symptoms: coughing, breathing faster

• Treatment: antibiotics, acetaminophen, breathing treatments

Tuberculosis (TB)• Chronic infection due to

myobacterium tuberculosis

• Highly contagious• Lesions (large open

sores) occur in the lungs causing coughing, fatigue, chest pain, fever, weight loss

• Damage to the lung tissue makes the lung capacity smaller

• If treated, it can be cured

Lung cancer

• Destroys the alveoli of the lungs

• Most common cause is cigarette smoke

• Lobectomy- removal of damaged area of lung

Asthma

• Due to spasms in the

muscle of the walls of

bronchi• It narrows the airways making breathing difficult• Spasms are triggered by stress, exercise,

infection, allergic reactions• Typically inherited• Treatment: inhalers that stop muscle spasms

Emphysema

• Enlarged alveoli due to damaged lung connective tissue

• Alveoli enlarge and rupture

• Alveoli are where gases enter the blood(decreased alveoli decreases oxygen in blood)

• Symptoms: panting even with mild exertion• Due to enzymes damaging alveoli

Heimlech maneuver• Used to free foreign objects from the respiratory tract

(choking)• Places arms around the

person and thrust the fists

up into the diaphragm area• This pushes air out rapidly

which sometimes blows out

the foreign object• Problem: may break some ribs if done to hard and if can

not do it if the patient is unconscious• Use another type if unconscious