Respiratory System

Ventilation

air flow in and out of the lungs

Respiration

exchange of gases that occurs during diffusion

Internal respiration

exchange of gases between capilaries and cells (blood and tissues)

External respiration

exchange of gases between alveoli and lung capillaries

Lungs

in thoracic cavity, right has 3 lobes, left has 2 lobes (slightly smaller)

Mediastinum

middle of the chest, trachea divides into two branches (space ebtween the lungs)

Diaphragm

breathing muscle, separates thoracic and abdominal cavity, innervated by phrenic nerve

Hilum

blood vessels, nerves, lymphatic tissue, and bronchial tubes enter and exit this area

Upper respiratory tract

nose and sinuses, pharynx (nasopharynx, oropharynx, laryngopharynx), larynx

Lower respiratory tract

trachea, bronchial tree (bronchi, bronchioles, terminal bronchioles), lungs

respiratory mucosa

specialized membrane, mucus blanket traps inspired irritants, cilia move mucus upward to pharynx for removal

Nose structure

nasal septum separates two cavities, mucous membrane lines nose, sinuses drain into nasal cavity

Sinuses

frontal, maxillary, sphenoidal, ethmoidal

nose functions

warm and moisten inhaled air, nerve endings for smell (olfaction receptors)

pharynx functions

passageway for food, liquids, and air

pharynx structure

nasopharynx: pharyngeal tonsils (adenoids), eustachian tubes
oropharynx: palatine tonsils
laryngopharynx

larynx structure

several pieces of cartilage, thyroid cartilage (largest), epiglottis, mucous lining, vocal cords stretch across interior

larynx function

air distribution (air passes through to and from lungs), voice production

trachea structure

tube from larynx to thoracic cavity, mucous lining, c-shaped rings of cartilage hold it open

trachea function

passaeway for air to move to and from lungs

trachea obstruction

blockage occludes airway, complete blockage cause death in minutes

bronchi structure

trachea branches into right and left bronchi, bifurcation area called carina

bronchioles structure

each bronchus branches into smaller and smaller tubes eventually leading to bronchioles

alveoli structures

bronchioles end in clusters of alveolar sacs, walls are made up of alveoli, made of simple squamous epithelium (1 micron thick) called the respiratory membrane

bronchi and bronchioles function

air distribution, passageway for air to move to and from alveoli

alveoli function

gas exhange, exchange oxygen and CO2 between alveoli and capillaries

alveoli diffusion

millions of alveoli make enormous surface for gas exchange, surfactant (surface of respiratory membrane inside alveoli) helps reduce tension and prevents alveoli collapse during respiration

lungs apex

narrow upper part of each lung under the collarbone

lung base

broad lower part of each lung, rests on diaphragm

Lungs structure/function

apex, base, right lung (3 lobes), left lung (2 lobes and cardiac notch), pleura lines lungs
function: breathing (pulmonary ventilation)

Pleura

moist, smooth, slippery, double-layered membrane, reduces friction during breathing
partial pleural (outer)
visceral pleura (inner)

inspiration

diaphragm contracts and descends, increases intrathoracic space, decreases intrathoracic pressure, air flows in to equalize pressure (active process)

expiration

diaphragm relaxes and ascends, decreases intrathoracic space, increases intrathoracic pressure, air pushed out to equalize pressure along with lung elastic recoil (passive process)

gas exchange in lungs

carbinohemoglobin breaksdown CO2 and hemoglobin
CO2 moves from capillary to alveoli and out of body
O2 moves from alveoli to capillaries
hemoglobin combines with O2 (oxyhemoglobin)

gas exhange in tissues

Oxyhemoglobin breaks down into O2 and hemoglobin
O2 moves out of tissue capillary blood into tissue cells
CO2 moves from tissue cells to capilarry blood
Hemoglobin combines with CO2 (carbaminohemoglobin)

Blood transport of oxygen

1. O2 combines with hemoglobin, forms oxyhemoglobin (HbO2) to be carried to tissues

2. Dissolved O2 in blood plasma

Blood transport of CO2

biproduct of cellular metabolism, transported dissolved in blood plasma (10%), as carbaminohemoglobin (20%), or as bicarbonate ions (HCO3) (70%)

Hemoglobin

contains 4 iron-containing HEME components that can bind one O2 molecule each (4 total)

Spirometer

tool to measure volumme of air exchange in breathing

Tidal Volume

amount of air normally breathed in or out with each breath

Vital capacity

greatest amount of air that one can breath out in one expiration

Expiratory reserve volume

amount of air that can be forcibly exhaled after expiring the tidal volume

Inspiratory reserve volume

amount of air that can be forcibly inhaled after a normal inspiration

Residual volume

air that remains in the lungs after the most foreceful expiration

Regulation of respiration

change in respiration rate as the body needs, controlled in Medulla Oblongata (Respiratory Control centers)
cerebral cortex: limited voluntary control of breathing
chemoreceptors responde to chemical changes
pulmonary stretch receptors prevent overinflation

PONS

pneumotaxic center that limits respiration, apneustic center that promotes inhalation and deep inhalation (limited by stretch receptors) (both antagonists)