Exam 2

respiratory system

passageways that filter incoming air and ultimately transport it into the microscopic air sacs where gases are exchanged

respiration

process of exchanging gases between the atmosphere and body cells

5 parts of respiration

ventilation

external respiration

transport of respiratory gases

internal respiration

cellular respiration

ventilation

breathing

external respiration

air into lungs gas exchange out

transport of respiratory gases

gases in blood transported from lungs to body cells and back to lungs

internal respiration

exchange of gases at body capillaries

cellular respiration

use of oxygen by cells to produce energy

upper respiratory organs are lined with

mucous membranes

upper respiratory organs

epithelium over connective tissue

mucus functions to

trap debris

warm and moisten incoming air

nose

bone and cartilage with internal hair

traps large particles

nasal cavity

bone and cartilage lined with mucous membranes

warms and moistens incoming air

olfactory reception

resonating chambers for speech

paranasal sinuses

within four skull bones

drain into nasal cavity

lined with mucous membranes

reduce weight of skull

resonating chambers for speech

pharynx/throat

wall of skeletal muscle lines with mucous membrane

passageway for air and food

larynx

passageway for air only

epiglottis

closes off the airway during swallowing

voice production

mucous membranes form two pairs of folds

false vocal cords

upper ventricular folds

true vocal cords

lower vocal folds

sound originates from

vibration of the vocal folds

trachea

windpipe

c-rings

incomplete rings of hyaline cartilage

c-rings are completed by

trachealis muscle and elastic CT facing esophagus

trachea lined by

mucous membranes with cilia that beat the debris to the pharynx to be swallowed and destroyed by digestive enzymes

carina

point where trachea divides into right and left primary bronchi

function of trachea

support against collapse and continue to warm, moisten, and filter air

lobules

little lobes

bronchial tree

primary bronchus

secondary bronchi

tertiary bronchi

intralobular bronchioles

terminal bronchioles

primary bronchus

leads into each lung and the branches into secondary bronchi

secondary bronchi

branch to each lobe and then branch into tertiary bronchi

tertiary bronchi

each serve one of 10 lobules that divide into intralobular bronchioles

intralobular bronchioles

branch several times into tubes called terminal bronchioles

terminal bronchioles

subdivides into microscopic branches called respiratory bronchioles

respiratory bronchioles

lined by simple squamous epithelium that subdivide into several alveolar ducts

alveolar ducts

terminate into numerous air sacs

epithelium

decreases in thickness; deeper it gets thinner it is

mucus production

deeper it gets less mucus

cartilage branching

decreases

smooth muscle

increases

parasympathetic and histamine

constrict bronchioles

sympathetic and epinephrine

dilate bronchioles

alveoli

microscopic air sacs where gas exchange occurs

alveoli wall consists of

two types of epithelial cells and macrophages

type I alveolar cells

simple squamous lining of alveolar wall

type II alveolar cells

interrupt simple squamous lining and secrete surfactant

surfactant

lowers surface tension and prevents alveolar collapse

alveolar macrophages

remove dust particles and other debris from alveolar spaces

alveolar-capillary membrane

epithelium over epithelium

simple squamous epithelium of alveolus

simple squamous endothelium of the lung capillary

basement membrane of lung cap

structure of alveolar-capillary membrane

thin

function of alveolar-capillary membrane

rapid diffusion of gas

high to low pressure

blood supply to lungs

two fold

pulmonary circuit brings

deoxygenated blood to lungs

oxygenated blood is delivered

through bronchial arteries

location of lungs

thoracic cavity

lungs covered by

pleural membranes

visceral pleura

covers organ

parietal pleura

folds back on itself

pleural fluid has

very high surface tension; two membranes act as one

each lung is divided into

lobes

right lung has

3 lobes

left lung has

2 lobes

each lobe

receives a secondary bronchus

divided into lobules

each lobule

wrapped in elastic CT

ventilation involves two actions

inspiration and expiration

inspiration

breathing air in

force necessary for inspiration

atmospheric pressure

diaphragm is at rest

curved upward

air pressure outside of the lungs is

equal to the air pressure inside the lungs

during inspiration the diaphragm

muscle pushes downward

size of thoracic cavity increases

pressure in the thoracic cavity decrease to 758 mm Hg

at 758 mg Hg

intra-alveolar pressure is less than atmospheric pressure and air rushes into lungs to equalize the pressure gradient

contraction of the external intercostal muscles

aid inspiration

compliance

the ease at which lungs can expand

expiration

breathing out

expiration depends on

elastic recoil of tissues

inward pull of surface tension due to the alveolar fluid

atelectasis

collapsed lungs

end of an expiration

alveoli tend to recoil inward and collapse on themselves

surfactant produced by type II alveolar cells

decreases the surface tension in the lungs and prevents complete collapse of the alveoli

respiratory distree syndrome

premature newborns collapsed lungs; lack of surfactant in the alveoli

respiratory volumes and capacities are measured by

spirometer

respiratory cycle

one inspiration following an expiration

tidal volume

amount of air that enters the lungs during normal inspiration and leaves the lungs during normal expiration

inspiratory reserve volume

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

expiratory reserve volume

amount of air that can be forcibly exhaled after a normal tidal expiration

residual volume

amount of air that always remains in lungs

vital capacity

maximum amount of air that can be exhaled after a maximum inhalation

vital capacity equals

tidal volume + inspiratory reserve volume + expiratory reserve volume

total lung capacity

vital capacity + residual volume

minute ventilation equals

tidal volume x respiratory rate

minute ventilation

amount of air that enters and exits respiratory system in one minute

anatomic dead space

air space in respiratory passageways not involved in gas exhange

alveolar ventilation

actual amount of air involved in gas exchange

alveolar ventilation equals

(tidal volume - anatomic dead space) x respiratory rate

normal breathing

rhythmic and involuntary

respiratory center

nervous control

location of respiratory ceneter

located in pons and medulla of brain stem

peripheral chemoreceptors

in carotid and aortic bodies

peripheral chemoreceptors are sensitive to

low levels of oxygen

high levels of CO2

central chemoreceptors

breathing rate and depth increases