The Respiratory System For a link to the Respiratory System of the Cat, click HERE

What are the functions of the Respiratory System? 1) Gas Exchange 2) Regulation of blood pH pH: 3) Voice production 4) Olfaction 5) Innate immunity

Pathway of air during Inhalation & Exhalation Breathe: Inspire + expire Inspiration Oral cavity/nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, alveoli, blood Expiration Exact reversal of inhalation

Organization of the Respiratory System 2 divisions: Upper respiratory system: above the larynx Lower respiratory system: from the larynx down

Components of the Respiratory System Figure 23–1

Pharynx

The Nose & Nasal Cavity I. Nose II. Nasal Cavity Air enters through nostrils or mouth Nasal hairs: first particle filtration system (innate immunity) II. Nasal Cavity Mucous secretions: clean and moisten the nasal cavity Olfactory region: provides sense of smell

III. The Pharynx A chamber shared by digestive and respiratory systems Extends from internal nares to entrances to larynx and esophagus

The Epiglottis Composed of elastic cartilage Made of ligaments Prevents food and liquids into respiratory tract Back of pharynx

IV. Larynx Made up of cartilage & ligaments (vocal cords) Forms what we call the Adam's apple

Sound Production Sound Variation Air passing: Sound is varied by: vibrates vocal folds produces sound waves Sound Variation Sound is varied by: tension on vocal folds voluntary muscles

V. The Trachea Also called the windpipe branches into right and left pulmonary bronchi Ciliated cells

VI. Bronchi… Smooth muscle Cartilage Cilia/mucous Branch into bronchioles

Alveolar sac Alveoli Figure 23–2

Bronchitis Inflammation of bronchial walls: causes constriction and breathing difficulty

The Respiratory Epithelium For gases to exchange efficiently: alveoli walls must be very thin (< 1 µm) surface area must be very great

VII. Alveolar Organization Respiratory bronchioles are connected to alveoli 300 million alveoli= 40x SA of skin!

The Lungs Left and right lungs: are in left and right pleural cavities Pleura: secrete mucous, decrease friction Rest on top of diaphragm

The Right Lung Has 3 lobes: superior, middle, inferior Wider Above liver

The Left Lung Has 2 lobes: superior and inferior Longer Cardiac notch

Is this the way you want your lungs to look? DON’T SMOKE!!

The Respiratory Defense System Consists of a series of filtration mechanisms Removes particles and pathogens

Components of the Respiratory Defense System Alveolar macrophages engulf small particles that reach lungs

Respiration External Respiration Internal Respiration Exchange of gases with 2 processes: External Respiration All processes in exchanging O2 and CO2 with environment Internal Respiration Also called cellular respiration Involves uptake of O2 and production of CO2 within individual cells

What physical principles govern the movement of air into the lungs?

Gas Pressure and Volume Figure 23–13

Atmospheric Pressure Boyle’s Law Relationship between gas pressure and volume: As volume decreases, pressure increases Balloon popping In a contained gas: Pressure is due to all molecules bumping into each other Claustrophobic at a small party

Mechanisms of Pulmonary Ventilation Inspire = Chest expands —muscles contract (ribs out and up) & diaphragm goes down --Decrease pressure (air in) Figure 23–14

Mechanisms of Pulmonary Ventilation 2. Expire= chest flattens Air forced out until pressures are equal

Pressures are equal –some air remains

Respiratory Performance and Age Figure 23–28

Control of Respiration Involuntary centers of the brain regulate breathing (__________receptors) Sense pH in blood Send message to increase rate and depth Conscious thought tied to strong emotions (rage, fear) stimulate hypothalamus—affect breathing Breathe more when cells work more