Anatomy and Physiology Review Unit 5- Respiratory

Upper respiratory tract

Includes passageways from the nose to larynx

Lower respiratory tract

includes passageways from trachea to alveoli

Passageway to lungs

purify, humidify, and warm incoming air

Nostrils (nares)

route through which air enters the nose

Nasal cavity

inferior of the nose (olfactory epithelium)

nasal septum

divides the nasal cavity

Respiratory mucosa

Lines the nasal cavity, moistens air, traps incoming foreign particles, destroys bacteria chemically through the action of lysozyme enzymes, and moves contaminated mucus to the posterior of the throat

conchae

projections from the lateral walls which increase surface area, air turbulence within the nasal cavity, and trapping of inhaled particles

The palate

separates the nasal cavity from the oral cavity

Hard palate

anterior and supported by bone

Soft palate

posterior and unsupported

Paranasal sinuses

Cavities within the frontal, sphenoid, ethmoid, and maxillary bones surrounding the nasal cavity

Sinuses

Lighten the skull, act as resonance chambers for speech, and produce mucus

the pharynx (throat)

muscular passageway from nasal cavity to larynx

Nasopharynx

superior region behind nasal cavity

oropharynx

middle region behind mouth, common passageway for air and food

Laryngopharynx

inferior region attached to larynx

the larynx (voice box)

routes air and food into proper channels and plays a role in speech

what is the larynx made of?

Eight rigid hyaline cartilages (thyroid cartilage- adam’s apple is the largest)

Epiglottis

Spoon-shaped flap of elastic cartilage, protects superior opening of larynx, routes food to the posteriorly situated esophagus and routes air toward the trachea, during swallowing it rises and forms a lid over the opening of the larynx

Vocal cords (true vocal cords)

Vibrate with expelled air and allow us to speak

Glottis

the opening between the vocal cords

trachea (windpipe)

4-inch long tube that connects to the larynx, walls are reinforced with C-shaped rings of hyaline cartilage (patent airway, trachealis muscle), lined with ciliated mucosa (cilia beat in superior direction, goblet cells produce mucus)

the main bronchi

formed by division of the trachea, right bronchus is wider, shorter, and straighter than left, bronchi subdivide into smaller and smaller branches

Lungs

Occupy the entire thoracic cavity except for the central mediastinum, apex of each lung is near the clavicle (superior portion), base rests on the diaphragm, each lung is divided into lobes by fissue

left lung

two lobes

right lung

three lobes

serosa

covers the surface of the lungs

pulmonary (visceral) pleura

covers the lung surface

parietal pleura

lines the walls of the thoracic cavity

pleural fluid

fills the area between the layers of the lungs, allows the lungs to glide over the thorax, and decreases friction during breathing

The bronchial (respiratory) tree

network of branching passageways, conduits to and from the respiratory zone, main bronchi subdivide into smaller branches and eventually into bronchioles, all but the smallest passageways have reinforcing cartilage in the walls

terminal bronchioles

lead into respiratory zone structures and terminate in alveoli

Respiratory zone

only site of gas exchange

respiratory zone structures

respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli (air sacs)

alveoli

Simple squamous epithelial, alveolar pores connect neighboring air sacs

pulmonary capillaries cover the external surfaces of what?

alveoli

stroma of lung

elastic connective tissue

Respiratory membrane (air-blood barrier)

On one side of the membrane is air, and on the other side is blood flowing past, formed by alveolar and capillary walls

diffusion

the process of gas crossing the respiratory membrane, oxygen enters the blood, and carbon dioxide enters the alveoli

Functions of the respiratory system

Supply the body with oxygen and dispose of carbon dioxide

the four events of respiration

pulmonary ventilation, external respiration, respiratory gas transport, and internal respiration

pulmonary ventilation

moving air into and out of the lungs (commonly called breathing)

external respiration

gas exchange between pulmonary blood and alveoli, oxygen is loaded into the blood and carbon dioxide is unloaded from the blood

respiratory gas transport

transport of oxygen and carbon dioxide via the bloodstream

internal respiration

gas exchange between blood and tissue cells in systemic capillaries

Inspiration

flow of air into lungs, diaphragm and external intercostal muscles contract, lung volume increases, gas pressure decreases, and air flows into the lungs until intrapulmonary pressure equals

Expiration (exhalation)

diaphragm and intercostals relax, lung volume decreases, gas pressure increases, and gases passively flow out to equalize the pressure

Intrapleural pressure

The pressure within the pleural space is always negative (lower than pressure inside lungs), major factor preventing lung collapse, if intrapleural pressure equals atmospheric pressure, the lungs recoil and collapse

Factors that affect respiratory capacity

size, sex, age, and physical condition

tidal volume (TV)

normal quiet breathing, 500ml of air is moved in/out of lungs with each breath

Inspiratory reserve volume (IRV)

amount of air that can be taken in forcibly above the tidal volume, usually around 3,100 ml

Expiratory reserve volume (ERV)

Amount of air that can be forcibly exhaled beyond tidal expiration, approximately 1,200 ml

residual volume

air remaining in the lung after expiration, cannot be voluntarily exhaled, allows gas exchange to go on continuously, even between breaths, and helps keep alveoli open (inflated), about 1,200 ml

Vital capacity

the total amount of exchangeable air, 4,800 ml in men; 3,100 ml in women

vital capacity equation

TV + IRV + ERV = VC

dead space volume

Air that remains in conducting zone and never reaches alveoli, about 150 ml

functional volume

air that actually reaches the respiratory zone, usually about 350 ml

spirometer

measures respiratory capacities

stehtoscope

measures respiratory sounds

bronchial sounds

produced by air rushing through large passageways such as the trachea and bronchi

vesicular breathing sounds

soft sounds of air filling alveoli

what occurs as a result of diffusion

gas exchanges

external respiration in the lungs

exchange of gases occurring between the alveoli and pulmonary blood (pulmonary gas exchange)

the process of oxygen getting loaded into the blood

oxygen diffuses from the oxygen-rich air of the alveoli to the oxygen-poor blood of the pulmonary capillaries

the process of carbon dioxide being unloaded out of the blood

carbon dioxide diffuses from the blood of the pulmonary capillaries to the alveoli

Oxygen transport in the blood

most oxygen travels attached to hemoglobin and forms oxyhemoglobin, a small dissolved amount is carried in the plasma

carbon dioxide transport in the blood

most carbon dioxide is transported in the plasma as bicarbonate ion. a small amount is carried inside red blood cells on hemoglobin, but at different binding sites from those of oxygen

Gas transport in the blood

Bicarbonate diffuses into red blood cells and recombines with H+ from hemoglobin, carbonic acid is converted back into H2O and CO2, CO2 diffuse into the alveolar spaces

internal respiration in tissues

exchange of gases occurring between the blood and tissue cells (systemic capillary gas exchange),

internal respiration in the lungs

carbon dioxide diffuses out of tissue cells to blood (called loading), oxygen diffuses from blood into tissue (called unloading)

Neural regulation

setting the basic rhythm, activity of respiratory muscles is transmitted to and from the brain by phrenic and intercostal nerves, neural centers that control rate and depth are located in the medulla and pons

medulla

sets the basic rhythm of breathing and contains a pacemaker (self-excitement inspiratory center) called the ventral respiratory group (VRG)

pons

smoothes out respiratory rate

normal respiratory rate (eupnea)

12 to 15 respirations per minute

Hyperpnea

increased respiratory rate, often due to extra oxygen needs

non-neural factors influencing respiratory rate and depth

increased body temp, exercise, talking, coughing, volition (conscious control), and emotional factors (fear, anger, excitement)

chemical factors that influence respiratory rate and depth

co2 levels, the body’s need to rid itself of co2 is the most important stimulus for breathing, increased levels of carbon dioxide (thus a decreased or acidic pH) in the blood increase the rate and depth of breathing, changes in co2 act directly on the medulla oblongata

How to oxygen levels influence respiratory rate and depth

changes in o2 concentration in the blood are detected by peripheral chemoreceptors in the aorta and common carotid artery, information is sent to the medulla, oxygen is the stimulus for those whose systems have become accustomed to high levels of carbon dioxide as a result of disease

Hyperventilation

Rising levels of co2 in the blood (acidosis) result in faster, deeper breathing, exhale more co2 to elevate blood pH, may result in apnea and dizziness and lead to alkalosis

Hypoventilation

results when blood becomes alkaline (alkalosis), extremely slow or shallow breathing, allows CO2 to accumulate in the blood

chronic obstructive pulmonary disease (COPD)

exemplified by chronic bronchitis and emphysema, patients always have a history of smoking, labored breathing (dyspnea) becomes progressively worse, coughing and frequent pulmonary infections are common, most patients are hypoxic, retain co2 and have respiratory acidosis, and ultimately develop respiratory failure

Chronic bronchitis

Mucosa of the lower respiratory passages becomes severely inflamed, excessive mucus production impairs ventilation and gas exchange, patients become cyanotic and are sometimes “blue bloaters” as a result of chronic hypoxia and carbon dioxide retention

Emphysema

Alveoli walls are destroyed; remaining alveoli enlarge, chronic inflammation promotes lung fibrosis and lungs lose elasticity. Patients use a large amount of energy to exhale; some air remains in the lungs, sufferers are often called “pink puffers” because oxygen exchange is efficient, overinflation of the lungs leads to a permanently expanded barrel chest, cyanosis appears late in the disease

lung cancer

leading cause of cancer death for men and women, nearly 90% of cases result from smoking, aggressive cancer that metastasizes rapidly

three types of lung cancer

adenocarcinoma, squamous cell carcinoma, small cell carcinoma

Asthma

Chronically inflamed, hypersensitive bronchiole passages, respond to irritants with dyspnea, coughing, and wheezing

Aging affects of the respiratory system

elasticity of lungs decreases, vital capacity decreases, blood oxygen levels decrease, stimulating effects of carbon dioxide decrease, elderly are often hypoxic and exhibit sleep apnea, more risks of respiratory tract infection