GenPhysio Lec: Respiratory System

Processes included in Respiration

1. Ventilation, or breathing, which is the movement of air into and out of the lungs

2. The exchange of oxygen (O₂) and carbon dioxide (CO₂) between the air in the lungs and the blood

3. The transport of O₂ and CO, in the blood

4. The exchange of O₂ and CO₂ between the blood and the tissues.

Enumerate the functions of Respiratory System

1. Respiration

2. Regulation of blood pH

3. Voice Production

4. Olfaction

5. Innate Immunity

Enumerate the Parts of Upper Respiratory Tract

1. External nose

2. Nasal cavity

3. Pharynx

Enumerate the Parts of the Nose

1. External Nose

2. Nasal Cavity

3. Choana

4. Paranasal Sinuses

5. Conchae

6. Nasolacrimal Duct

What is the main composition of the External Nose?

Hyaline Cartilage

What is the extent of the Nasal Cavity?

It extends from nares (nostrils) to choane

What do you call the openings to pharynx?

Choana

What is the roof of choana?

Hard Palate

• air filled spaces within bone

• open into nasal cavity

• lined with mucous

Paranasal Sinuses

• on each side of nasal cavity

• increase surface area of nasal cavity

• help in cleaning, humidifying, warming of air

Chonchae

• carry tears from eyes

• open into nasal cavity

Nasolacrimal Ducts

Enumerate the Functions of the Nose

1. Filters

2. Airway for respiration

3. Involved in speech

4. Olfactory receptors

5. Warms air

6. Sneezing dislodges materials from nose

Enumerate the Parts of the Pharynx

1. Uvula

2. Pharyngeal Tonsil

• "little grape"

• extension of soft palate

Uvula

• aids in defending against infections

Pharyngeal tonsil

Enumerate the Parts of the Lower Respiratory Tract

1. Larynx

2. Trachea

3. Bronchi

4. Lungs

1. What is the location of the Larynx?

2. What is the extent of the Larynx?

1. anterior throat

2. extends from the base of the tongue to the trachea

1. What is the main composition of Larynx?

2. What is it’s other name of its composition?

1. Thyroid Cartilage - largest piece of cartilage

2. Adam's apple

1. What is the flap that prevents swallowed materials from entering larynx?

2. What is it made up of?

1. Epiglottis

2. piece of cartilage

• source of voice production

• air moves past them, they vibrate, and sound is produced

• force of air determine loudness

• tension determines pitch

Vocal Folds/Cords

Enumerate the important terms in Larynx

1. Thyroid Cartilage

2. Epiglottis

3. Vocal Folds/Cords

4. Laryngitis

• inflammation of vocal folds

• caused by overuse, dry air, infection

Laryngitis

1. What is the other term for Trachea?

2. How many C-shaped cartilage pieces does Trachea have?

3. What is the Trachea’s type of tissue

4. What activity kills the cilia?

5. What activity dislodges materials from trachea?

6. Trachea divides which part of the lower respiratory tract?

1. Windpipe

2. 16 to 20

3. Cilia Pseudostratified Columnar Epithelial

4. Smoking

5. Coughing

6. Divides into right and left primary bronchi (lungs)

• Divide from trachea

• Connect to lungs

• Lined with cilia

• Contain C-shaped pieces of cartilage

Bronchi

1. What is the Primary Organ of Respiration?

2. What is the shape of the Lungs?

3. Where does the base of the Lungs rests?

4. Where does the apex of the lungs extends?

5. How many lobes does the lungs have?

1. Lungs

2. Cone shaped

3. Diaphragm

4. above the clavicle

5. Right = 3 lobes

   Left = 2 lobes

Lung Airway Passages

1. Primary Bronchi

2. Secondary Bronchi (Lobar)

3. Tertiary Bronchi (Segmental)

4. Bronchioles

5. Terminal Bronchioles

6. Respiratory Bronchioles

7. Alveolar Ducts

8. Alveoli

   Structures become smaller and more

   numerous from primary bronchi to alveoli

• small air sacs

• where gas exchange occurs

• surrounded by capillaries

• 300 million in lungs

Alveoli

• contraction of terminal bronchioles leads to reduced air flow

Asthma attack

• In lungs where gas exchange between air and blood occurs

• Formed by walls of alveoli and capillaries

• Alveolar ducts and respiratory bronchioles also contribute

• Very thin for diffusion of gases

Respiratory Membrane

Enumerate the Layers of Respiratory Membrane

1. Alveolar Fluid Layer (thin)

2. Alveolar Epithelium (simple squamous)

3. Basement Membrane of Alveolar Epithelium

4. Interstitial space (thin)

5. Basement membrane of Capillary Endothelium

6. Capillary endothelium (simple squamous)

Pleural Membranes and Cavities

1. double-layered membrane around lungs

2. membrane that lines thoracic cavity

3. membrane that covers lung's surface

4. space around each lung

1. Pleura

2. Parietal Pleura

3. Visceral Pleura

4. Pleural Cavity

• a process of moving air in and out of the lungs

• uses the diaphragm, which is a skeletal muscle that separates the thoracic and abdominal cavities

Ventilation (breathing)

Phases of Ventilation

1. Inspiration

2. Expiration

3. Forceful Expiration

1. breathe in

   uses the diaphragm and the external intercostal muscles

2. breathe out

   uses the diaphragm

3. uses internal intercostal muscles

Pressure Changes and Air Flow

• ↑ thoracic cavity volume ↓ pressure

• ↓ thoracic cavity volume ↑ pressure

  Air flows from areas of high to low pressure

What happens to diaphragm, rib cage, thoracic cavity volume, and pressure during Inspiration?

1. Diaphragm descends and rib cage expands

2. Thoracic cavity volume increases, pressure decreases

3. Atmospheric pressure is greater than (high) alveolar pressure (low)

4. Air moves in to alveoli (lungs)

What happens to diaphragm, rib cage, thoracic cavity volume, and pressure during Expiration?

1. Diaphragm relaxes and rib cage recoils

2. Thoracic cavity volume decreases, pressure increases

3. Alveolar pressure is greater than (high) atmospheric pressure (low)

4. Air moves out of lungs

• is the tendency for an expanded lung to decrease in size

• occurs during quiet expiration

• is due to elastic fibers and thin film of fluid lining alveoli

Lung Recoil

• is a single fluid layer on the surface of thin fluid lining alveoli

  reduces surface tension

• keeps lungs from collapsing

Surfactant

1. What is the mixture of Surfactants?

2. Which produces Surfactants?

1. Lipoprotein

2. secretory cells of the alveoli

• pressure in the pleural cavity

• less than alveolar pressure

• keep the alveoli from collapsing

Pleural Pressure

Enumerate the Factors that Influence Pulmonary Ventilation

1. Lung Elasticity

2. Lung Compliance

3. Respiratory Passageway Resistance

Factors that Influence Pulmonary Ventilation

1. lungs need to recoil between ventilations

   decreased by emphysema

2. expansion of thoracic cavity

   affected if rib cage is damaged

3. occurs during an asthma attack, infection, tumor

1. Lung Elasticity

2. Lung Compliance

3. Respiratory Passageway Resistance

Enumerate the Pulmonary Volumes

1. Spirometer

2. Tidal Volume

3. Inspiratory Reserve Volume

4. Expiratory Reserve Volume

5. Residual Volume

6. Vital Capacity

7. Total Lung Capacity

Pulmonary Volumes

1. device that measures pulmonary volumes

2. volume of air inspired and expired during quiet breathing

3. volume of air that can be inspired forcefully after a normal inspiration

4. volume of air that can be expired forcefully after a normal expiration

5. volume of air remaining in lungs after a maximal expiration (can't be measured with spirometer)

6. max. amount of air a person can expire after a max. inspiration

   VC = IRV + ERV + TV

7. TLC = VC + RV

1. Spirometer

2. Tidal Volume

3. Inspiratory Reserve Volume

4. Expiratory Reserve Volume

5. Residual Volume

6. Vital Capacity

7. Total Lung Capacity

Enumerate the Factors that Influence Pulmonary Volumes

1. Gender

2. Age

3. Height

4. Weight

• where gas exchange between blood and air occurs

  primarily alveoli

  some in respiratory bronchioles and alveolar ducts

• does NOT occur in bronchioles, bronchi, trachea

  influenced by thickness of membrane, total area of membrane, partial pressure of gases

Gas Exchange: Respiratory Membrane

Respiratory Membrane Thickness

• Increased thickness decreases rate of diffusion

  Pulmonary edema decreases diffusion

  Rate of gas exchange is decreased

  O, exchange is affected before CO₂ because CO₂ diffuse more easily than O₂

Respiratory Membrane Surface Area

• Total surface area is 70 square meters (basketball court)

  Decreased due to removal of lung tissue, destruction from cancer, emphysema

• the pressure exerted by a specific gas in a mixture of gases

  the total atmospheric pressure of all gases at sea level is 760 mm Hg

  the atmosphere is 21% 02

  the partial pressure for O, is 160 mm Hg

  the upper case letter P represents partial pressure of a certain gas (Po₂)

Partial Pressure

• Cells in body use O, and produce CO₂

  Blood returning from tissues and entering lungs has a decreased Po₂ and increased Pco₂

  O₂ diffuses from alveoli into pulmonary capillaries (blood)

  CO, diffuses from capillaries into alveoli

Diffusion of Gases in Lungs

• Blood flow from lungs through left side of heart to tissue capillaries

  Oxygen diffuses from capillaries into interstitial fluid because Po, in interstitial fluid is lower than capillary

  Oxygen diffuses from interstitial fluid into cells (Po₂) is less

Diffusion of Gases in Tissues

• CO, diffuses from cells into capillaries

  CO₂ enters blood and is transported in plasma, combined with blood proteins, bicarbonate ions

  CO, reacts with water to form carbonic acid

  CO₂ + H₂O = H₂CO₃

  bicarbonate ions dissociate into a hydrogen ion and a bicarbonate ion

  H₂CO₃ = H+ + HCO₃-

• Carbonic anhydrase (RBC) increases rate of CO, reacting with water

  CO₂ levels increase blood pH decreases

Carbon Dioxide Transport and Blood pH

• Normal respiratory rate is 12 to 20 respirations per minute (adults).

  In children, the rates are higher and may vary from 20 to 40 per minute.

  The rhythm is controlled by neurons in the medulla oblongata.

  Rate is determined by the number of times respiratory muscles are stimulated.

Rhythmic Ventilation

Enumerate the Respiratory Areas in the Brainstem

1. Medullary Respiratory Center

2. Pontine (pneumotaxic) Respiratory Group

The respiratory center is located in the medulla oblongata and pons, in the brainstem. The respiratory center is made up of three major respiratory groups of neurons, two in the medulla and one in the pons.

Respiratory Structures in the Brainstem

• Higher brain centers allow voluntary breathing

  Emotions and speech affect breathing

  Hering-Breuer Reflex:

  inhibits respiratory center when lungs are stretched during inspiration

Nervous Control of Breathing

• Chemoreceptors in medulla oblongata respond to changes in blood pH

• Blood pH are produced by changes in blood CO₂ levels

• An increase in CO₂ causes decreased pH, result is increased breathing

• Low blood levels of O₂ stimulate chemoreceptors in carotid and aortic bodies, increased breathing

Chemical Control of Breathing