Respiratory System

upper respiratory tracts contains…

nose, nasal cavity, pharynx

lower respiratory tracts contains…

larynx, trachea, bronchi, bronchioles, alveolar ducts, alveoli

respiratory zone;

gas exchange

bronchioles, alveolar ducts, alveoli

conducting zone;

brings filtered air to respiratory zone, voice, secretes mucus (for filtering)

all other structures

goblet cells are…

musous and serous glands; in epithelial lining

what does the mucin protein do?

increases mucus viscosity to help filter

what is sputum?

when mucus is mixed with saliva and other substances, and is coughed out

respiratory muscles…

diaphram, internal intercostal muscles, external intercostal muscles

functions of the nose…

secretes mucus that contains lysozyme and defensins to destroy bacteria, and ciliated mucosal cells to remove contaminated mucus, resonating chamber for speech

pharynx regions;

nasopharynx, oropharynx, laryngopharynx

nasopharynx helps with…

preventing food from entering the nasal cavity

oropharynx helps with…

being the passageway for food and air

laryngopharynx helps with…

dividing the pharynx into the larynx and esophagus

what are the paranasal sinuses lined by?

pseudostratified ciliated columnar epithelium

functions of larynx…

provide an airway, switching mechanism of the food vs air route, voice production

how does the pharynx help with vocal production?

speech, pitch, loudness, and sound

what are the 3 leayers of the trachea?

mucosa, submucosa, adventitia

what are the respiratory airways made from?

trachea and larger bronchi; cartilage to prevent collapse

how many alveoli doe the lungs have?

about 300 million

what does the respiratory zone help with?

helps with gas exchange, gives a large surface space for it

how do the alveolar walls do gas exchange?

simple diffusion

what does type I alveolar cells do?

secrete ACE

what does type II alveolar cells do?

secrete pulmonary surfactant

how do the alveolar stay clean?

macrophages keeps them sterile

how many ribs do humans have?

12 pairs of ribs (24 total)

what is the pleural say?

closed sac; parietal pleura lines the thoracic walls; visceral pleura covers the lungs

what does the intrapleural fluid do?

lubricates pleural surfaces

what is the diaphragm?

sepreates thoracic cavity from abdominal cavity, skeletal muscle; helps inhale

3 different pressures…

ATMp

intrapulmonary pressure, IPp

intrapleural pressure

is intrapleural pressure less than IPp and ATMp?

yes, it’s always less than

forces that promote lung collapse;

elasticity of lungs and surface tension

what is pulmonary ventilation?

mechanical process that depends on the volume changes in thoracic cavity, which leads to pressure changes

what muscles help exhale?

internal intercostal and abdominal muscles

what is lung compliance?

how much effort is required to stretch or distend the lungs?

what is elastic recoil?

elastic connective tissue in the lungs, alveolar surface tension (tries to make the alveoli as small as possible)

what helps reduce tensions on the alveoli?

surfactants help reduce surface tension and keep it from collapsing; type II cells

law of Laplace

T = pressure is directly proportional to surface tension

r = pressure is inversely proportional to radius of alveolus

types of dead space;

anatomical dead space, alveolar dead space, total dead space

anatomical dead space is…

colume of respiratory passages (~150 mL)

alveolar dead space is…

alveoli that dont act in has exchange due to collapse or obstruction

total dead space is…

alveolar + anatomical dead space

partial pressure is…

pressure of individual gases

what is ventilation?

the amount of gas reaching the alveoli

what is perfusion?

the blood flow reaching the alveoli

when is Po2 in lower levels?

when in tissue, it’s always lower than systemic arterial blood

what determines hemoglobin saturation?

Po2 determines the % of hemoglobin

how does hemoglobin help with oxygen in the lungs?

it unloads O2 into the tissue of the lungs

what else can factor hemoglobin saturation?

temperature, H+, and Pco2

Bohr effect

the O2 binding with hemoglobin is inversley related to acidity and CO2 concentration

when does more O2 unload?

when pH is lower

what is methemoglobin?

oxidation of iron from Fe2+ (ferrous) into Fe3+ (ferric)

does methemoglobin bind to oxygen?

no, it doesnt bind

what reduces iron back to its ferrous state?

normal RBC

what can cause methemoglobinemia?

drugs like lidocaine, nitrates, and nitrites

how does carbon dioxide transport?

disolved in plasma (7-10%), bound to hemoglobin (20-30%), and bicarbonate in in plasma (60-70%)

what are breathing muscles controled by?

motor neurons

voluntary breathing is controlled by…?

the cerebral cortex

involuntary breathing is controlled by…?

the medulla oblongata and pons

control of rate and depth of respiration….

arterial PO2, arterial PCO2, and arterial pH

arterial PO2 is…

PO2 is low (hypoxia)

arterial PCO2 is…

most important regulator of ventilation

arterial pH is…

as hydrogen increasesm alveolar ventilation increases

nervous control mechanism is located…

in the medulla and pons; dorsal respiratory group, ventral respiratory group, apneustic center, pneumotaxic center

dorsal respiratory group…

inspiratory area, contraction of diaphram and external intercostals; stimulates basic inspiration for about 2 sec and then basic expiration for 3 sec

ventral respiratory group…

expiratory area, activated by inspiratory area; causes contraction of internal intercostals and abdominal muscles

apneustic area….

stimulates inspiratory area of medulla in prolonged inhalation; recieves inhibitory impules from sensory vagal fibers and inhibitory impulses from pneomotaxic center

pneomotaxic area…

breathing is more rapid when pneumotaxic area is active

Hering-Breuer inflation reflex…

stretch receptors signals through vagus nerver in DRG, switches off inspiratory signals; reflex seems to be a protective mechanism to prevent excess lung inflation

peripheral chemoreceptors…

mainly in the carotid and aortic bodies, send impulses to rhythmicity centers, sensitive to changes in arterial PO2; fall of PO2, rise of PCO2, and fall of pH stimulaes chemoreceptors to increase ventilation

central chemoreceptors…

located in ventrolateral surface of medulla oblongata, CO2 can freely cross the BBB

chemoreceptors in medulla…

carbon dioxide doesnt really stimulate neurons, however it has a potent indirect effect; hydrogen ions have a potent direct stimulatory effect on respiration

during vigorous exercise…

ventilation increases 20 fold, PCO2, PO2, and pH remail constant