Respiratory System

Front 1

RESPIRATORY SYSTEM
FUNCTIONS

Back 1

Gas exchange
Vocalization
Sense of smell
Helps regulate blood pH
Other
— Sneezing
— Coughing
— Abdominal compressions

Front 2

PARANASAL SINUSES

Back 2

— Frontal, sphenoid, ethmoid and maxillary bones
— Open into nasal cavity
— Lined by same mucosa as nasal cavity and perform same functions
— Also lighten the skull
— Can get infected: sinusitis

Front 3

NASAL CAVITY Functions

Back 3

Prepares air
— Warms
— Filters
— Moistens
Olfactory senses
Resonance chamber
for speech

Front 4

PHARYNX

Back 4

= “throat”
Common passageway for food and air
3 parts
— Nasopharynx
— Oropharynx
— Laryngopharynx
— LARYNX

Front 5

EPIGLOTTIS

Back 5

Elastic cartilage covered by mucosa
Attaches to back of tongue
During swallowing, keeps food out of lower respiratory tract

Front 6

VOCAL CORDS

Back 6

Sound is produced by vibrating vocal folds as air passes over them
Pitch = tension on vocal folds
Loudness = amount of air

Front 7

TRACHEA

Back 7

= “windpipe”
12.5 cm long, 2.5 cm wide
15–20 C- shaped hyaline cartilage rings hold it open
Lined with pseudostratified ciliated epithelium
TRACHEOTOMY

Front 8

BRONCHIAL TREE

Back 8

Trachea
— Right and left primary bronchi
— Secondary bronchi
— Tertiary bronchi
— Intralobular bronchioles
— Tertiary bronchioles
— Respiratory bronchioles
— Alveolar ducts
— Alveolar sacs
— Alveoli

Front 9

The walls of primary, secondary, and tertiary bronchi

Back 9

— Contain progressively less cartilage and more smooth muscle
— Cells also change
— Larger tubes - pseudostratified ciliated columnar with goblet cells
— Respiratory bronchioles – cuboidal
— Alveoli – simple squamous

Front 10

ALVEOLI

Back 10

= “air sacs”
Microscopic
surface area of half a tennis court (300 million sacs)
Where gas exchange occurs
3 cell types:
— Type I cells
— = simple squamous epithelium
— Type II cells
— = septal cells
— secrete surfactant, reduces surface tension
— Alveolar macrophages

Front 11

LUNGS

Back 11

Soft and spongy
Located in pleural cavities within larger thoracic cavity
L lung is smaller due to cardiac notch (heart)

Front 12

Pleural cavity

Back 12

Consists of 2 layers:
— Parietal pleura = lines thoracic cavity wall
— Visceral pleura = membrane adhered to surface of lung
— Pleural cavity
— Contains serous fluid
— Reduces friction
— Protection

Front 13

LUNGS

Back 13

RESPIRATORY ZONE
End-point of respiratory tree
Structures that contain air-exchange chambers are called alveoli
Respiratory bronchioles lead into alveolar ducts: walls consist of alveoli
Ducts lead into terminal clusters called alveolar sacs – are microscopic chambers
There are 3 million alveoli!

Front 14

ATMOSPHERIC GASES

Back 14

The air in the atmosphere that surrounds the earth is a mixture of gases:
Nitrogen – 78%
Oxygen – 21%
CO2
Water vapor (H2O)
Inert gases (Ar, Ne, Ze, Kr)
Air flows from areas of high pressure to areas of lower pressure

Front 15

RESPIRATION INCLUDES

Back 15

Pulmonary ventilation
— Air moves in and out of lungs
— Continuous replacement of gases in alveoli (air sacs)

Front 16

External respiration

Back 16

— Gas exchange between blood and air at alveoli
— O2 (oxygen) in air diffuses into blood
— CO2 (carbon dioxide) in blood diffuses into air

Front 17

Transport of respiratory gases

Back 17

— Between the lungs and the cells of the body
— Performed by the cardiovascular system
— Blood is the transporting fluid

Front 18

Internal respiration

Back 18

— Gas exchange in capillaries between blood and tissue cells
— O2 in blood diffuses into tissues
— CO2 waste in tissues diffuses into blood

Front 19

RESPIRATORY MUSCLES

Back 19

Diaphragm:
Contraction draws air into lungs
75% of normal air movement
External intercostals muscles:
Assist inhalation
25% of normal air movement
Accessory muscles assist in elevating ribs:
Sternocleidomastoid
Serratus anterior
Pectoralis minor

Front 20

RESPIRATORY MUSCLES
BOYLE’s LAW
INHALATION
Active process

Back 20

Gases move from an area of high pressure to low pressure
— Diaphragm contracts downward and lungs expand
— Lung volume increases, pressure decreases
— Lung pressure is lower than outside pressure, so air moves in (equilibrium)

Front 21

EXHALATION
Passive process

Back 21

Gases move from an area of high pressure to low pressure
— Diaphragm and muscles relax
— Volume in lungs decreases, pressure increases
— Lung pressure is higher inside than outside, so air moves in (equilibrium)
— GAS EXCHANGE

Front 22

GAS EXCHANGE

Back 22

Gases are exchanged between alveolar
air and capillary blood because of
differences in partial pressure

Front 23

GAS TRANSPORT

Back 23

Carbon dioxide
— 70% as bicarbonate ion (HCO3-) dissolved in plasma
— 23% bound to hemoglobin
— 7% as CO2 dissolved in plasma
Oxygen
— 99% bound to hemoglobin
— Oxyhemoglobin
— 1% as O2 dissolved in plasma

Front 24

RESPIRATORY VOLUMES AND CAPACITIES

Back 24

Measured with a spirometer
Values are used to help with
— Diagnosis of respiratory diseases/disorders
— Asthma
— Lung cancer
— Emphysema
— Evaluating treatments/medications
— Athletic training

Front 25

RESPIRATORY REGULATION

Back 25

The most important factor affecting the rhythmicity center is CO2
Neurons in the medulla oblongata forms the rhythmicity center:
— Controls automatic breathing
Brain stem respiratory centers:
— Medulla
— Pons
­ in arterial CO2 causes ­ in acidity of CSF
­ in CSF acidity is detected by pH sensors in medulla
medulla ­ rate and depth of breathing (stimulates muscles)

Front 26

BLOOD BUFFER SYSTEM

Back 26

CO2 + HOH <===> H2CO3 <===> H+ + HCO3-
RESPIRATORY ACIDOSIS
RESPIRATORY ALKALOSIS

Front 27

RESPIRATORY ACIDOSIS

Back 27

Acidosis = pH below 7.35
Reduced CO2 elimination
Causes:
— Lung disease such as emphysema, chronic bronchitis, severe pneumonia, pulmonary edema, and asthma)
— Sleep-disordered breathing
— Slowed breathing due to over sedation (narcotics) or strong drugs that induce sleep (sedatives)
Symptoms:
— Nausea
— Headache and Drowsiness
— Stupor and coma
— Death

Front 28

— RESPIRATORY ALKALOSIS

Back 28

Increased CO2 elimination
pH exceeds 7.45
Caused by:
— Hyperventilation due to anxiety, pain, shock
— Drugs (aspirin)
— Pneumonia, pulmonary (lung) congestion, or embolism
— Exercise, fever
Symptoms:
— May cause irritability
— Muscle twitching
— Muscle cramps
— If severe and prolonged, tetany and spasms of muscles can develop