BIOS 1310 lab quiz 6

Respiration

aka breathing

the process by which the body exchanges gases w/ the environment

oxygen in

CO2 out

essential for maintaining body’s supply of oxygen while eliminating waste gases produced by cellular activity

Inhalation

Breathing IN

diaphragm contracts and moves downward

increases volume with chest cavity —→ allows lungs to expand

Inhalation pathway

air drawn into body through nose/mouth

air travels down windpipe (trachea) and into branching airways of the lungs

Once inside lungs air reaches alveoli

passes through alveolar walls and enters blood within capillaries

• CO2 moves from the capillaries into the alveoli

Alveoli

tiny air sacs surrounded by capillaries

walls are very thin

• allows gases to move easiy between them

Exhalation

diaphragm and muscles between ribs relax

reduces volume of the chest cavity and causes the lungs to deflate

as lungs contract, CO2 that moved into alveoli is pushed out through the trachea and exits through nose or mouth

Why is respiration necessary?

cells of the body require oxygen to produce energy needed for normal function and survival

How is CO2 produced?

as cells generate energy, CO2 is produced as a waste product

• makes the blood acidic

Upper respiratory tract

nasal cavity

paranasal sinuses

pharynx

larynx

lie outside the thoracic cavity

conduct and condition incoming air

Nasal cavity

main entry point for air

contains hair follicles and mucous membranes

• trap dust and other particulate matter

contains:

• nasal conchae

• olfactory receptors

Nasal conchae

curved bony structures

increase surface area

warm and humidify air as it moves through passages

Olfactory receptors

in the posterosuperior aspect of the nasal cavity

detect odorant molecules and transmits signals to brain

• allows for sense of smell

Pharynx

funnel-shaped muscular tube

pathway for both air and food

divided into 3 regions

• nasopharynx

• oropharynx

• laryngopharynx

Nasopharynx

functions only as an airway

Oropharynx

allows passage of both food and air

Laryngopharynx

where the repiratory and digestive systems separate

Larynx

voicebox

contains vocal cords

• produce sound

includes the epiglottis

Epiglottis

closes over airway during swallowing to prevent food or liquid from entering the lower respiratory tract

known as aspiration

Lower repiratory tract

trachea

bronchi

bronchioles

lungs

Trachea

windpipe

rigid tube supported by C shaped rings of cartilage

• keep the airway open as air travels from the larynx toward lungs

Where and how does the trachea divide?

the level of the sternal angle

two main bronchi

• one to each lung

Carina

landmark junction where trachea splits

one of the most sensitive regions for triggering a cough

Right main bronchus

wider

short

more vertically oriented than the left

• more susceptible to foreign body obstruction

Inside the lungs…

the main bronchi continue branching into lobar and segmental bronchi

eventually into bronchioles

• even smaller airways

eventually end in alveoli

Bronchial tree

formed from the branching of bronchi in the lungs

Alveoli

clusters of microscopic air sacs

surrounded by capillaries

primary site of gas exchange

Gas exchange in alveoli

O2 from inhaled air diffuses across thin alveolar walls into blood within capillaries

CO2 moves from the blood into alveoli to be exhaled

Lungs

spongy

cone shaped

located in throacic cavity

each is surrounded by pleura

Right lung

3 lobes

Left lung

2 lobes

to accommodate space occupied by the heart

pleura

double layered membrane

reduces friction

allows lungs to move smoothly during breathing

Diaphragm

dome-shaped sheet of muscle located beneath lungs

primary muscle for breathing

When the diaphragm contracts…

flattens and increases volume of the throacic cavity

• draws air into lungs

Intercostal muscles

located between ribs

assist by expanding and contracting the rib cage during inhalation and exhalation

2 zones of respiratory system

conducting zone

respiratory zone

conducting zone

nose

pharynx

larynx

trachea

bronchi

terminal bronchioles

primarily:

transport

filter

warm

humidify incoming air

Respiratory zone

respiratory bronchioles

alveoli

where gas exchange takes place

Lung volumes and capacities

measurements used to describe the amount of air contained in the lungs during different stages of the breathing cycle

provide important info about respiratory mechanics and overall lung function

Lung volumes

individual amounts of air present during specific phases of respiration

Lung capacities

combinations of two or more lung volumes

derived by combining two or more of these volumes

represent the functional limits of lung expansion and contraction

Tidal volume

amount of air inhaled or exhaled during a normal breathing cycle

typically ranges from 300-500 mL or 6-8 mL per kilogram of body weight

reflects:

• activity of respiratory centers

• strength of the respiratory muscles

• mechanical properties of lungs and chest wall

can increase due to deep breathing or exercise

Inspiratory reserve volume (IRV)

the additional amount of air that can be forcibly inhaled after normal inhalation

becomes important for deep breathing or physcial exertion

usually not used during quiet breathing

normal range from 1900-3300 mL

Expiratory Reserve Volume (ERV)

extra amount of air that can be forcefully exhaled after normal exhalation

normal value typically 700-1200 mL

certain conditions such as:

• obesity

• abdominal pressure

• recent abdominal surgery

can reduce ERV

Residual Volume (RV)

amount of air that remains in the lungs after maximal exhalation

this air cannot be voluntarily expelled

helps prevent lung collapse by keeping the alveoli partially inflated

average is 1200 mL

cannot be measured directly by spirometry

estimated using other lung measurments

In obstructive lung diseases….

such as emphysema

RV may increase due to air trapping and incomplete emptying of lungs

Inspiratory Capacity (IC)

maximum amount of air that can be inhaled following a normal exhalation

calculated as IC=TV +IRV

Vital capacity

represents the total volume of air that can be exhaled after a maximal inhalation

VC = TV + IRV + ERV

averages around 3100-4800 mL

varies depending on body size, age, and sex

reflects the ability to take deep breaths and produce an effective cough (important for clearing secretions from respiratory tract)

Functional Residual Capacity (FRC)

the volume of air remaining in the lungs at the end of a normal exhalation

FRC = RV + ERV

represents the resting position of the lungs where the inward elastic recoil of the lungs is balanced by the outward recoil of the chest wall

Total lung capacity (TLC)

maximum volume of air the lungs can contain after a maximal inhalation

sum of all four primary lung volumes ( TLC = TV+IRV+ERV+RV)

averages 4-6 L

Changes in TLC

may indicate certain pulmonary disorders

may increase in obstructive diseases such as emphysema

may decrease in restrictive conditions such as pulmonary fibrosis or ches wall abnormalities

Lung sounds

aka respiratory sounds

produced by air moving through the repiratory tract

can provide important info about lung health

Vesicular sound

soft, low pitched rustling noise heard over most of the lung fields

Bronchovesicular sounds

medium pitched

heard near major airways

Bronchial sounds

louder, high pitched

heard over trachea

adventitious breath sounds

abnormal sounds

may indicate underlying respiratory problems

Wheezes

high-pitched, musical sounds

caused by narrowed airways

commonly associated w conditions such as asthma or COPD

Crackles (rales)

bubbling or clicking sounds

produced when fluid is present in alveoli

may occur w pneumonia or heart failure

Rhonchi

low-pitched snoring like sound heard during inspiration

caused by mucus or obstruction within the larger airways

Stridor

harsh, high pitched sound heard during inspiration

often signals a seruous upper airway obstruction

Pleural friction rub

grating or creaking noise

compared to walking on fresh snow

caused by inflamed pleural surfaces rubbing together during breathing

Spirometry

measurments of lung volumes and capacities

noninvasive pulmonary function test

measures both the volume and speed of air moving in and out of lungs

helps evaluate lung function and diagnose respiratory conditions

2 Key measurments during spirometry

Forced Vital Capacity (FVC)

Forced expiratory volume in one second (FEV₁)

help distinguish between obstructive diseases and restrivtive diseases

Forced Vital capacity (FVC)

total amount of air that can be forcefully exhaled after a deep inhalation

Forced Expiratory volume in 1 second (FEV₁)

measures how much air can be expelled during the first second of exhalation

Obstructive disease

airway narrowing and reduced airflow

Restrictive disease

limit lung expansion

Largest amount of CO2 is…

hydrated and carried in the form of bicarbonate in the blood plasma

In red blood cell, CO2…

reacts w water to form carbonic acid in a reaction catalyzed by carbonic anhydrase

dissociates into

• H+

  • binds to hemoglobin—→ forms deoxydemoglobin

• bicarbonate

  • exchanged for chloride and pumped out of the red blood cell into plasma

  • also found in blood plasma from CO2 diffusing into bloodstream

    • This occurs slowly due to no carbonic anhydrase in blood plasma

CO2 can be…

bound to hemoglobin in RBCs

CO2 enters red blood and attaches to hemoglobin —→forms carbaminohemoglobin (HbCO2)

• second most common way CO2 is carried in blood

CO2 can also enter the blood as…

dissolved gas similar to carbonated beverages

the more dissolved CO2 present in blood, the more H+ will be released into plasma and the lower the pH will be

least common way CO2 is carried from tissues to lungs

Arterial blood gas (ABG)

arterial blood test

usually drawn from radial artery

used to assess CO2, O2, pH levels

measures the amount of gas pressure in an artery

PaCO2

partial pressure of CO2 in an artery

normal range is 35-45 mmHg

PaO2

partial pressure of oxygen in an artery

normal range is 80-110 mmHg

SaO2

oxygen saturation level

percent of hemoglobin molecules saturated w oxygen

Normal is 95-100%

Ethmoid cells

External naris

Frontal sinus

hard palate

maxillary sinus

nasal cavity

nasal septum

sphenoidal sinus

Uvula

Epiglottis

Ethmoid cells

inferior nasal concha

Hard palate

laryngopharynx

larynx

Middle nasal concha

middle nasal meatus

nasopharynx

oropharynx

soft palate

superior nasal concha

uvula

vocal fold

Carina

Horizontal fissure R lung

L lung

L main bronchus