respiratory system

functions of the respiratory system

provides gas exchange, regulates blood pH, smell receptors, filters air, produces vocal sounds, excretes water and heat

pulmonary ventialtion

moving air into/out of the lungs

NO GAS EXCHANGE

external respiration

exchange of gases at the alveoli

internal respiration

exchange of gases between blood and tissues

structures of the respiratory system

nose and nasal conchae

entry point, hyaline cartilage

conchae, lined with mucous, warms filters air via turbulence

sinuses

cavities within cranial bones

resonate sound

pharynxes

naso: respiratory only

oro and laryngo: respiratory and digestive

larynx

connect laryngopharynx to trachea

voice box

inferior to hypoid bone and epiglottis

trachea

wind pipe

c-shaped cartilage rings give support

anterior to esophagus

carina

internal ridge where trachea divides into primary bronchi

Bronchi

primary, secondary, tertiary, bronchioles, terminal bronchioles

label lungs

hilum

where bronchi, vessels, and nerves enter at here

pleura

visceral adheres to lung

parietal adheres to chest wall

space between is pleural cavity, filled with fluid

diaphragm

separates the thoracic and abdominal cavities

responsible for 75% of air that enters the lungs

internal intercostals helps with

exhalation

external intercostal help with

inhalation

innervation of the diaphragm

phrenic nerve

“C3, 4, 5 keep the diaphragm”

sympathetic nervous system

norepinephrine causes dilation of bronchial smooth muscle

pulmonary plexus

nerves form this in hilum of lung

parasympathetic nervous system

innervation via vagus nerve CN X

acetylcholine released

causes mucous secretion, constriction of bronchial smooth muscle

conduction zone

part of the respiratory system that bring air into or out of the lungs

nose, pharynx, larynx, trachea, bronchi, bronchioles, terminal bronchioles

respiratory zone

part of the system where gas exchange takes place

respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli

upper respiratory tract

nasal cavity, oral cavity, pharynx

lower respiratory tract

trachea, bronchi, lungs, bronchioles, alveoli

larynx

bridge between upper and lower tracts

stratified squamous epithelium

part of larynx and pharynx

protection

respiratory epithelium

pseudostratified columnar or simple columnar

mucous and cilia on the luminal surface

goblet cells

secrete mucus

mucociliary escalator

mucus + cilia

brings particles out of the lungs and into the pharynx to be swallowed

bronchi smooth muscle: sympathetic

dilate

bronchi smooth muscle: parasympathetic

constrict, increase secretions

label alveolus

Type I cells

simple squamous, gas exchange

Type II

simple cuboidal, secrete surfactant

inspiration

inhalation

move air into the lungs

active process, requires muscle action

expiration

exhalation

move air out of the lungs

usually passive

pressure

collisions of molecules within the wall of the container

temperature

speed at which molecules move

Boyle’s law

pressure and volume are inversely related

if volume goes up

pressure goes down

if volume goes down

pressure goes up

“pump handle”

action of sternum

“bucket handle”

action of ribs

inhalation

diaphragm and external intercostal contract

increase volume, decrease pressure

exhalation

diaphragm relaxes, internal intercostal contract

decrease volume, pressure increase

tidal volume

volume of air inspired or expired during normal breathing

inspiratory reserve volume

all of the air that you can breathe in from the top of tidal volume (deep inhalation)

expiratory reserve volume

all of the air you can breathe out from the bottom of tidal volume during a forced exhalation

residual volume

air still present in lung after maximal exhalation

keeps lungs open

“dead space”

inspiratory capacity

tidal volume + inspiratory reserve volume

function residual capacity

residual volume + expiratory reserve volume

vital capacity

inspiratory reserve volume + tidal volume + expiratory reserve volume

total lung capacity

vital capacity + residual volume

Dalton’s law

sum of partial pressures

Henry’s law

the amount of gas dissolved in a liquid is proportional to the pressure of the gas above the liquid

external respiration

refers to the gas exchange that occurs between the alveolus and capillaries

oxygen moves from alveolus to the capillary

CO2 moves from capillary to the alveolus

gases move by diffusion

V with dot above

amount of air entering lungs per minute

Va

amount of air entering alveoli per minute

perfusion (Q with dot)

amount of blood that flows through the lung capillaries each minute

hypoxic conditions

pulmonary blood vessels constrict, forces blood to areas of higher oxygen

ventilation perfusion coupling

matching of pulmonary blood flow to oxygen

if no air enters the lungs, Va/Q zero

blood flows, no gas exchange occurs

air enters lungs, blood does not flow

Va/Q = infinity

pulmonary embolism

internal respiration is a

process that occurs between capillaries and tissues

O2 delivered to tissues

CO2 picked up and carried to lungs for excretion

hemoglobin

picks up oxygen where partial pressure is highest

releases oxygen where partial pressure is lowest

Alveolar highest, tissue lowest

carbon dioxide carried as

bicarbonate ions

tissue has highest

alveolar has lowest

O2- hemoglobin saturation curve “O2 stat”

saturation curve: effect of pH

hemoglobin affinity/stickiness of O2 shifts to right

less oxygen bound at lung

more oxygen delivered at tissue

pH lower

P co2 higher

higher temperature

hemoglobin affinity curve shift to left

more O2 bound at lung

less O2 delivered at tissues

pH higher

P co2 lower

lower temperature

effect of pregnancy

fetal hemoglobin has a higher affinity for oxygen than maternal hemoglobin

carbon dioxide transport

70% carried as bicarbonate ion

23% carried in hemoglobin

7% dissolved in plasma

buffer

acts as a H+ and/or OH– “sponge” so that pH is kept relatively constant

carbonic acid - bicarbonate buffer system

too acidic?

pushes reaction left

more CO2 is made

too alkaline?

pushes reaction to the right

more H+ and HCO3- are produced

inspiratory center/dorsal respiratory group

active in tidal breathing

stimulates phrenic and intercostal nerves

expiratory center/ventral respiratory group

only activated consciously or with exercise

abdominal muscle contract

forced exhalation

pneumotaxic center

part of pons

limits duration of inspiration, prevents lungs from getting too full

apneustic center

part of pons

coordinates transition from inhale to exhale

tachypnea

rapid breathing

hyperventilation

excessive ventilation

low blood CO2, high blood pH, alkalosis

apnea

temporary halt in ventillation

hypoventilation

decreased ventilation, high blood CO2, low blood pH, acidosis

acidosis increases

respiratory rate, “blowing off” CO2

alkalosis decreases

respiratory rate, retain CO2, increase H+

earliest viable premature babies are

about 23 weeks gestation

surfactants

reduce surface tension in water and break hydrogen bonds

secreted by type II alveolar cells

surfactant production appears at about

20 weeks gestation

lungs begin to develop at

fourth week of pregnancy