Respiratory System

Conchae

Projection/Lobes

- Increased surface area

- Increased air turbulence

**Note: We want air here to be turbulent to maximize contact with mucous membrane

Respiratory Mucosa

Warms the inhaled air

- Superficial thin-walled veins

- Nosebleeds

Traps Foreign particles (ex. bacteria)

- Lysosome enzymes

Nasal Septum

A wall of cartilage (midline) that divides the nose into two equal sections

Hard Palate

anterior "roof of the mouth" portion, supported by bone

Soft Palate

posterior portion, not supported by bone

Paranasal Sinuses

Openings in bones

- produce mucus

- Resonance chambers for speech

- Frontal, Sphenoid, Ethmoid, and Macillary

Sinuses

cavities in the skull that surround the nasal area

Function =

1. Secretes mucus

2. Humidifies and warms the air

3. Lightens the skull

4. Helps with speech

Ethmoid Sinus

Sphenoid Sinus

Pharynx ("Throat")

About 5 inches long -> The passageway for food and air

Pharyngotympanic tube

connects the middle ear to the nasopharynx

1) Pharyngeal tonsil - 1

- AKA "adenoid"

2) Palatine tonsils - 2

- AKA "tonsils"

3) Lingual tonsils - 2

Types of Tonsils

Larynx ("Voice box")

Properly routes air in/out

Hyoid bone

muscular control of the epiglottis + controls swallowing

Epiglottis

spoon-shaped flap of elastic cartilage

- closes the larynx when swallowing

Hyaline cartilage

Protruding thyroid cartilage

- Produces "Adam's apple"

Glottis

Vocal Cords = mucous membrane folds in the larynx

- Vibrates with expelled air

Trachea ("windpipe")

Air passageway between the larynx to the 5th thoracic vertebra

C rings

Rings of Hyaline cartilage on the trachea

- Keeps the trachea open for air flow despite pressure changes

Trachealis muscle

band of smooth muscle that connects the tracheal and esophagus

ciliated mucosa

Pushes against the flow of air and Traps Pathogens

- ciliated pseudo-stratified columnar epithelium

Main bronchi

Right and left main lung (primary bronchi)

- Right primary bronchus = wider, shorter, and straighter than left (left smaller to make room for heart)

- Bronchi subdivisions (bronchioles) -> Air sacs (alveoli)

Apex

Superior point of lungs near the clavicle

Base

Inferior point of lungs along the diaphram

Left lung = 2 lobes

Right lung = 3 lobes

Lobes of Right and Left lungs

**Note: Lungs surrounded by elastic connective tissue

Pleural cavity

Serous Layer

- Pleural fluid; slippery

- Pulmonary pleura and parietal pleura

Hilum

"root" of lungs where bronchi attach

Alveoli

Air sacs where gas exchange occurs

- Makes up most of the lungs

1. Oral/Nasal cavities

2. Pharynx

3. Larynx

4. Trachea

5. Bronchi

6. Bronchioles

7. Alveoli

Flow of Air

Respiratory membrane

Where gas exchange occurs between the air on the alveolar side and the blood on the capillary side

- the alveolar and capillary walls form the respiratory membrane

- "air-blood barrier"

Alveolar macrophages

Clean up bacteria and other debris

- cuboidal cells that secrete surfactant

Surfactant

- Decreases water surface tension

- Without it -> water molecules stick together and alveolus collapses

External Respiration at alveoli

- Oxygen enters blood

- Carbon dioxide exits blood

Internal respiration at the body's tissues

- Oxygen exits blood

- Carbon dioxide enters blood

External respiration

The exchange of gases between the atmosphere and the blood

- Oxyhemoglobin and bicarbonate ion

Oxyhemoglobin

hemoglobin + oxygen

- some oxygen dissolves in the plasma

Bicarbonate ion - HCO3-

Carbon dioxide transported in the plasma as this

- Some carbon dioxide transported in Red Blood Cells

- HCO3- reduced to carbon dioxide and water -> Then can be released to alveoli

Internal Respiration

- Oxyhemoglobin offloads its oxygen

- Carbon dioxide and water SYNTHESIZE to form bicarbonate ion HCO3-

Inhalation (aka inspiration)

Air flows into the lungs

- Diaphragm contracts (flexes downwards + thoracic cavity expands)

- Intercostal muscles contract (lifts ribs and thrusts sternum forward)

Exhalation (aka expiration)

Air flows out of the lungs

- More passive process

- Relies on elasticity

- Muscles relax

- Affected by asthma, bronchitis, and pneumonia

- May need forced exhalation

Pressure

Air flows from HIGH to LOW pressure

- Inspiration creates a partial vacuum

Intrapleural pressure

Pressure within the pleural space

- always negative pressure to keep lungs inflated

Atelectasis

lung collapse

- when air gets into the pleural space

Respiratory volumes

TV = Tidal volume

normal breathing

IRV = Inspiratory reserve volume

Forced inspiration

ERV = Expiratory reserve volume

forced expiration

RV = Residual volume

cannot be exhaled from the lungs

- allows for continuous gas exchange

- keeps alveoli open

VC = Vital capacity

Total exchangeable air

- TV + IRV + ERV

Characteristic of blood pH

Exercise/holding breath builds up carbon dioxide -> blood pH drops (more acidic)

- chemoreceptors sense blood pH drop

- Increases breathing to exhale carbon dioxide -> Blood pH returns to 7.4

Hyperpnea

Fast breathing

Apnea

Stopped Breathing

Normal respiration rate = eupnea

12-15 breaths per min

Medulla/Pons - controls breathing rhythm

Phrenic and intercostal nerves - trigger muscles

Cerebrospinal Fluid - senses CO2 levels and primary driver for detecting high CO2 as low pH (acidosis)

Aorta chemoreceptors - detect low O2 levels

Other body parts in respiratory system