Respiratory System - Exam 3

Functions of Respiratory System

• provides surface area between air and circulates blood

• regulation of blood pH

• voice production

• olfaction

• protection (cilia in trachea)

• Lungs produce ACE

• Breathe due to CO2 (medulla oblongata)

Pleurae

• two serous membranes that cover lungs

• inner layer: visceral pluera = covers the surface of lung

• outer layer: parietal pleura = covers thoracic wall & diaphragm

Pleural cavity

the space in between and contains lubricating fluid for decreased resistance during lung expansion

Structures of the Respiratory System

Upper and lower respiratory system

Functional components of Respiratory System

• Conducting zone = tubes to bring air in

• Respiratory zone = get gas exchange here

  • Primary gas exchange is in the alveoli

Upper respiratory system

nose, larynx, and pharynx

Lower respiratory system

trachea, bronchi, and lungs

Nose

made of paired nasal bones & hyaline cartilage

Nose functions

protection due to sneezing and nose hairs; warm and humidify air

Nasal conchae

• bony structures along the lateral wall of the nasal cavity

• lined w/ pseudostratified ciliated columnar epithelium

• serves to increase surface area

  • increases the chance that air will come in contact with/ warm & most surfacd epithelium

Nasal Meatus

passageway in the nasal cavity

Paranasal Sinuses

• Paired air spaces w/ drainage ducts to nasal cavity

• Function: warming air, sound resonance, & decreasing the weight of skull

Nasopharynx

• psuedostratified ciliated columnar epithelium for warming, humidifying, and filtering inspired air

• posterior portion of nasal cavity to rip of soft palate

Oropharynx

• protective against mechanical stress as this cavity is a passageway for both air and food/drink

• tip of soft palate to hyoid

Laryngopharynx

• also common passageway for air and food

• hyoid to start of esophagus

Larynx

a passageway that connects the pharynx and trachea

Epiglottis

• elastic cartilage

• during swallowing = pharynx & larynx rise → elevation of pharynx widens to receive food or drink → elevation of larynx causes epiglottis to move down and form lid over the glottis = routes food and liquid to esophagus

Sound loudness

determined by the force of the airstream = greater force of expiration/exhalation = louder sound

Speech requires

• muscles of pharynx, soft palate, plus tongue & lips

• air movement over vocal cords only produce buzzing sounds

Vocal folds

true cords are used in sound production

Vestibular folds

support vocal cords

Trachea

• contains 16-20 C-shaped hyaline cartilage rings that aid in keeping airway open

• splits into primary bronchi (carina is the ring at this junction)

• smooth muscle

Terminal bronchioles

the end of the conduction zone

Bronchiole structure

• have no cartilage

• dominated by smooth muscle

Bronchodilation

increasing diameter by relaxing smooth muscle cells

• caused by sympathetic ANS activation = NE

Bronchoconstriction

decreasing diameter by contracting smooth muscle cells

• caused by parasympathetic ANS activation

• Histamine release

Alveoli and blood flow

• blood (deoxygenated) enters lungs via pulmonary arteries and bronchial arteries = supplies lungs w/ O2 & nutrient

• blood (oxygenated) exits the lungs via pulmonary veins and bronchial veins = removes waste

Lungs have a high compliance

easily expand due to surfactant

Lungs have elasticity

can recoil easily

Respiratory zone

• begins after the terminal bronchioles

• terminates at the alveoli

Alveolar Epithelium

• simple squamous epithelium

• pneumocyte type I = gas exchange

• patrolled by alveolar macrophages (dust cells)

• pneumocyte type II = produce surfactant

Why do we need surfactant?

• gases have to dissolve before the diffuse on earth

• fluid in alveoli is under tension due to hydrogen bonds

• this reduces surface tension of water

  • makes it easier to inflate the lungs

  • increases compliance

What can’t human babies before 24-28 weeks make?

Surfactant

Inspiration/Inhalation

increasing volume in our lungs = decreases the pressure in lungs as air rushes in

• air pressure within lungs is lower than atmospheric pressure

• external intercostals are used

Expiration/Exhalation

the volume in our lungs decreases and air exits

• air pressure within lungs is greater than atmospheric pressurw

Why did Elizabeth faint due to wearing a corset?

She could not increase her lung volume = lack of CO2

When there is more volume in the lungs

there is less pressure

Quiet breathing

at rest use diaphragm & external intercostals = inhalation is always active

Exhalation at rest

passive due to elastic recoil at lungs

Active exhalation

use internal intercostals and abdominal muscles

Rhythmicity area

in the medulla oblongata

Inspiratory center

within the medulla oblongata

• Phrenic and intercostal nerves = functions in every respiratory cycle

• Forced expiratory portion = Vagus CN X = sends info about lung inflation

  • nerve also helps to prevent over inflation of lungs

Pontine respiratory center

pons

• pneumotaxic center: responsible for adjusting the rhythm of respiration

• Apneustic center: controls the depth of inspiration (deep breathing)

Central chemoreceptors

in the medulla oblongata. senses CO2

How do we breathe?

Due to levels of CO2. If you hold your breath & pass out, you start breathing due to CO2 livels going back up

Peripheral chemoreceptors

• Aortic bodies: in the aortic arch

• Carotid bodies: located at the junction of internal and external carotid arteries. O2 changes, CO2, H+

High altitude

• Less O2 per breath → hyperventilating → blow off too much CO2 → alkalosis (more basic)

• Kidneys try to help fix the alkalosis & you end up needing to pee more

• Don’t really sleep at night

Did Manuela pee while doing the Inka Trail at night?

no because of the spiders

PFT

determines the amount of air that lungs can hold, how quickly air moves in and out of lungs, and how well lungs add oxygen to blood and remove CO2 from blood

Tidal Volume (TV)

volume inspired/expired; normal quiet ventilation

Inspiratory reserve volume (IRV)

volume forcibly inspired after a normal TC inspiration

Expiratory reserve volume (ERV)

volume forcibly expired after a normal tidal expiration

Residual volume (RV)

air remaining in lungs after forceful expiration

Vital capacity (VC)

how much air is available for gas exchange

TV + IRV + ERV

Inspiratory capacity

TV + IRV

Total lung capacity

IRV + TV + ERV + RV

Functional residual volume

ERV + RV

Pulmonary edema

when there is less O2, blood vessels constrict in lungs

• fluid backs up and compromises gas exchange

Why did Taryn fall down the mountain

due to pulmonary edema

What happens in other tissues when O2 levels decrease

blood vessels dilate

Pneumonia

acute infection/inflammation of the alveoli = causes fluid to leak into alveoli and will compromise respiration

Emphysema

destruction of the walls of the alveoli = due to loss of elastic fibers (smoking, pollution, dust) = creates less surface area for gas exchange

Pulmonary edema

fluid accumulation in interstitial spaces and alveoli = could be due to high capillary pressures = high blood pressure or increased fluid loss of capillaries

SIDS

sudden infant death syndrome = more common in infants of drug abuse, smokers, premature babies, etc. Rhythmicity center stops working

Chronic bronchitis

excessive secretion of bronchial mucous = leading cause is smoking = destroys cilia

Asthma

• airways become inflamed and mucosal linings are irritated

• airways become restricted = trouble breathing.

• Can get better (not completely in some), either by itself or with treatment