MCAT Biology - Respiratory System

Chapter 6

Thoracic Cavity

structure specifically designed to perform breathing

Where does air enter

the external nares of nose and pass through nasal cavity

Where is air filtered when it enters respiratory tract

The muscous membranes and the nasal hairs

Pharynx

common pathway for both air destined for lungs and food destined for esophagous, resides behind nasal cavity and back of the mouth

Larynx

Lies below pharynx and is only a pathway for air

What keeps food out of respiratory tract

epiglottis

Ciliated pseudostratified columnar epithelial cells

catch and remove particulate that have made it past the mucous membranes in the nose and mouth

alveoli

tiny balloon like structures in which gas exchange occurs

Surfactant

detergent that lowers surface tension and prevents alveolus from collapsing on itself

Visceral pleura

surface adjacent to the lungs

Parietal pleura

outer part of pleura

diaphragm

thin, muscular structure that divides the chest cavity from the abdominal cavity

Intrapleural space

space within visceral and parietal pleura which contains thin layer of fluid

Is inhalation an active or passive process

active

How does diaphragm and thoracic cavity react to inhalation

Diaphragm and external intercostal muscles to expand thoracic cavity

Intrathoracic volume

volume of chest cavity

Negative pressure breathing

lungs expand into intrapleural space and pressure in the lungs drop driving force is lower pressure in intrapleural space computed with the lungs.

Exhalation occurs, what happens to diaphragm and cavity

Diaphragm relaxes, the chest cavity decreases in volume, pressure in intrapleural space is higher than in the lungs

Spirometer

Instrument asses lung capactities and volumes

Total Lung Capacity TLC

Maximum volume of air in the lungs when one inhales completely, usually around 6 to 7 liters

Residual Volume RV

Volume of remaining air in the lungs when one exhales completely

Vital Capacity VC

Difference between minimum and maximum volume of air in the lungs

Tidal Volume

The volume of air inhaled or exhaled in a normal breath

Expiratory Reserve volume

Volume of additional air that can be forcibly exhaled after a normal exhalation

Inspiratory reserve volume

The volume of additional air that can be forcibly inhaled after a normal inhalation

Ventilation Center

collection of neurons in medulla oblangata that fire rhythmically to cause regular contraction of respiratory muscles, regulates ventilation

What are Chemoreceptors sensitive to

Primary sensitive to carbon dioxide concentration

Hypercarbia

pressure of CO2 in blood rises

Hypoxemia

low oxygen concentration in the blood

What is purpose of amount of surface area when alveoli and capillaries interact

Maximize gas exchange

Thermoregulation

regulation of body temp

How is heat of body surfaces regulated

vasodilation and vasoconstriction

How does nasal cavity prevent infection

small hairs help trap particulate matter and potentially infectous particles

Lysozome

Enzyme that attack peptidoglycen walls of gram positive bacteria

Muscoiliary escalotor

matter trapped in mucus then cilia propel mucus up the respirtory tract to the oral cavity, where it can be expelled or swallowed

Macrophages

engulf and digest pathogen and signal to the rest of the immune system that there is an invador

Mast cells

antiobodies on surfaces, when substances attach to antibody, release inflammatory chemicals into the surrounding area to promote an immune response

what pH Body maintain

7.35-7.45

How does increase H concentration affect the buffer

Shift bicarbonate buffer generating additional CO2