a&p - respiratory system

Primary role of respiratory system

Supply the blood with oxygen and remove carbon dioxide from the body

The five steps of respiration

1. Breathing

2. Alveolar gas exchange

3. Gas transport

4. Systemic gas exchange

5. Aerobic respiration

Breathing

Movement of air into and out of lungs

Gas transport of respiration

Transport of O2 and CO2 between the lungs and tissue with the help of cardiovascular system

Systemic gas exchange of respiration

Exchange of O2 and CO2 between blood in systemic capillaries and tissue cells

Aerobic respiration

The use of O2 and production of CO2 during ATP production

External respiration

• breathing and alveolar gas exchange

• Involves respiratory system structures

Internal respiration

Systemic gas exchange and aerobic respiration

Along with gas exchange the respiratory system is responsible for:

• detecting odor

• Producing sound

• Regulating blood pH - should be between 7.35 to 7.45. Also called acid base balance

• Trapping and defending the body from airborne pathogen

• Assisting in movement of venous blood and lymph

Which structures compose the upper respiratory tract?

Nose and pharynx

Which structures compose the lower respiratory tract?

Larynx, trachea, bronchi, and lungs

Respiratory mucosa

• mucous membranes containing pseudostratified ciliated columnar epithelium

• Lines rest of nasal cavity, larynx, trachea, and bronchi

• Goblet cells

• Air is warmed by blood vessels in mucosae

• Cilia move trapped particles to pharynx where they can be swapped

• Digested by gastric juice

Goblet cells

In epithelium produce mucus - moisten incoming air and trap particles

Larynx

• cartilaginous and box life structure

• Passageway for air between pharynx and trachea

• Thyroid cartilage Adam’s Apple

• Cricoid cartilage connects to trachea

• Epiglottis - flap to keep solids and liquids out

• Supported by ligaments that extend from hyoid bone

• Vocal folds

• Vestibular folds

Vocal folds - larynx

• 2 bands of elastic connective tissue covered by respiratory mucosa

• Relaxed during resting breathing

• Vibrate when contracted to produce sound

• Pitch is determined by vibration frequency

• Loudness is determined by vibration amplitude

Vestibular folds - larynx

• lie above vocal folds

• Keep solids and liquids from entering glottis

• No role in sound production

Glottis

Vocal folds and space between them

Changes in larynx during swallowing

• goal is to keep stuff out and direct to esophagus

1. Muscles lift this up

2. Epiglottis folds over to cover glottis

3. Food is directed into esophagus

Trachea

Airway that extends from larynx into thoracic cavity

• branches form right and left main bronchi

• tracheal cartilages support it

• Inner wall lined by respiratory mucosa

Tracheal cartilage

Holds airway open during breathing. Open portion allows esophagus to expand slightly during swallowing

The exchange of oxygen and carbon dioxide between alveoli and blood is called:

alveolar gas exchange

The use of oxygen and production of carbon dioxide during ATP production is called:

aerobic respiration

Bronchi

2 main bronchi of trachea → three lobar bronchi in right lung and two in left → segmental bronchi

Walls have cartilaginous rings

Are pathogens and disease in upper or lower respiratory tract more dangerous?

Lower because they do not have mucous to get rid of particles

Bronchioles

• very small tubes lacking cartilage that branch from bronchi

• Smooth muscle for air flow - bronchoconstriction and dilation

• Lined with mucous membrane containing simple cuboids epithelium. Can’t remove particles

what do the main bronchi branch branch into?

lobar bronchi

what do lobar bronchi branch into?

segmental bronchi - one for each segments within each lung

Alveolar ducts

Branches from smallest bronchioles that terminate in pulmonary alveoli

Pulmonary alveoli

• Filled with watery fluid to aid in diffusion

• need to fill with air for oxygen and carbon dioxide to exchange

• Surrounded with capillary network both arterial and veinular

• Site of alveolar gas exchange - bronchial tree and bronchioles have no role

• Surfactant prevents collapse during exhalation - reduces attraction between water molecules

where does alveolar gas exchange occur?

across the respiratory membrane with pulmonary alveoli

lungs consist of:

• pulmonary alveoli

• air passageway

• blood and lympathic vessels

• nerves

• connective tissue

how many lobes does the left lung have?

2

how many lobes does the right lung have?

3

lung lobes

separated by the mediastinum. each lobe is supplied by a lobar bronchus, blood vessels, lymphatic vessels, and nerves

pleurae

two layers of serous membrane that surround each lung

• viseral pleura

• parietal pleura

• pleural cavity

pleural cavity

space in lungs filled with pleural fluid which:

• reduces friction between pleurae

• helps hold the pleural together

when one pleura expands the other must also to expand the lungs

breathing

the process of exchanging air between atmosphere and pulmonary alveoli

• air moves along an air pressure gradient (high to low)

the three pressures important to breathing

atmospheric, intra-alveolar, and intrapleura

intrapleural pressure

pressure within the pleural cavity

•Keeps lungs pressed against inner walls of thoracic cage

•Keeps lungs expanded even during exhale

→ If it equaled atmosphere pressure, lungs would collapse

for inspiration what must happen to intra-alveolar pressure?

it must be reduced to less than atmospheric air pressure

diaphragm in resting inspiration

Moves downward and flattens with contraction

external intercostals

Elevate and protract ribs and push sternum forward with contraction

process of resting inspiration

•Thoracic cavity size increases

•Lungs are pulled along when the thoracic cage expands

•Increases lung volume and decreases intra-alveolar pressure to -1 centimeter H_2 O

•Higher atmospheric pressure pushes air towards the lower intra-alveolar pressure in lungs

Air inflow continues until both pressures are equal

forceful inspiration requires what additional muscles?

• sternocleidomastoid, serratus anterior, pectoralis minor

  • contraction further elevates and protracts ribs which requires more of an increase in thoracic cavity volume

what must happen to intra-alveolar pressure for expiration?

it must be elevated above atmospheric pressure

resting expiration

• Diaphragm and external intercostals relax

• Thoracic cavity and lungs to return to original size

• Aided by abundant elastic tissue in lungs and thoracic wall

process of resting expiration

•The decrease in lung volume increases intra-alveolar pressure to +1 centimeter H_2 O

•High intra-alveolar pressure pushes air out of lungs

•Air outflow continues until both pressures are equal

forceful expiration requires what additional muscles?

• internal intercostal muscles

  • depress and retract the ribs

• contraction of abdominal muscles

  • force abdominal viscera and diaphragm up

muscle role in forceful expiration

Muscle contraction further decreases volume of lungs

• Causes a greater increase in intra-alveolar pressure, causing more air to flow out

tidal volume - in spirogram

•Volume of air exchanged during a resting breathing cycle

•Approximately 500mililiters

inspiratory reserve volume

•Maximum volume of air that can be forcefully inhaled after a tidal inspiration

•Approximately 3,000mL

Expiratory reserve volume - spirogram

•Maximum volume of air forcefully exhaled after a tidal expiration

•Approximately 1,100mL

residual volume - spirogram

•Volume of air remaining in lungs after expelling ERV

•Approximately 1,200mL

•Exists because of intrapleural pressure and surfactant

Vital capacity - spirogram

•Maximum amount of air that an be forcefully exchanged

•TV + IRV + ERV

Approximately 4,600mL

total lung capacity - spirogram

• VC + RV

• Approximately 5,800 mL

what controls involuntary breathing?

centers in the medulla oblongata and pons

• ventral respiratory group

• dorsal respiratory group

• pontine respiratory group

what controls voluntary breathing?

primary motor area of the cerebral cortex

ventral respiratory group

• in medulla oblongata

• Responsible for normal rhythmic cycle of breathing

• Neurons rhythmically send action potentials to diaphragm and external intercostals

  • Action potentials cause muscles to contract

  • When action potentials stop, muscles relax

dorsal respiratory group

•Center for receiving and integrating input from sensory sources

•Sends action potentials to VRG to alter breathing as the needs of the body change

•Deeper or shallower, faster or slower

pontine respiratory group

• Located in pons

• Receives input from higher brain centers

• Sends action potentials to DRG and VRG to modify breathing pattern

• Has neurons that stimulate or inhibit the VRG and DRG

  • Alters the rate and depth of breathing

• Adapts breathing to speaking, singing, exercise, sleep, and emotional responses (crying, gasping)

chemical factors affecting respiration

• csf most important

• co2

• h+

  • by product of co2 transport therefore an increase in co2 will increase this concentration

• o2

chemoreceptors

• in medulla oblongata detect changes in H^+  and CO_2 in CSF

• in carotid and aortic bodies detect changes in H^+, CO_2, and O_2 in blood

what happens if co2 and h+ increase in blood or csf?

DRG stimulates the VRG to increase rate and depth of breathing

→ Causes loss of CO_2 and H^+, which lowers levels to homeostasis

what happens if co2 and h+ decreases in blood or csf?

breathing will be shallow and slow

→ Provides time for concentrations to increase back to homeostasis

what parts are sensitive to decline in o2 concentration?

carotid and aortic bodies

• •Increases the sensitivity of chemoreceptors in respiratory area to changes in CO_2 concentrations

• it does not alter rate or depth of breathing unless very low

Action potentials voluntarily generated by cerebral cortex involved in breathing

• Created when a person chooses to alter the pattern of resting breathing

• Voluntary control is limited

Involuntary action potentials from cerebral cortex and hypothalamus involved in breathing

• •Created during emotional experiences that activate the autonomic division

  • Fear, anxiety, and excitement can lead to an increase in breathing rate

  • Sudden emotional experience, sharp pain, or sudden cold stimulus can cause apnea

respiratory disorders are grouped as:

inflammatory and noninflammatory disorders

chronic obstructive pulmonary disease

• inflammatory

• long term obstruction that reduces airflow to and from the lungs

  • chronic bronchitis

  • emphysema

emphysema

• inflammatory disorder caused from long term exposure to airborne irritants

• exhaling requires voluntary effort

• Uncommon except in long term smokers or people with long term exposure to second hand smoke

• No cure but can be prevented and progressive deterioration can be stopped by removing the irritant

Effects:

• Large spaces form when pulmonary alveoli rupture

• Air trapped in pulmonary alveoli due to excess mucus production in bronchioles

• Reduces respiratory surface area and impairs gas exchange

inflammatory disorders include:

asthma, influenza, and pneumonia

lung cancer

• Second most common cancer, leading cause of cancer death in Americans

• Develops due to long-term exposure to irritants, such as cigarette smoke

• Metastasizes rapidly and spreads quickly to other body areas

• Treatments include surgery and chemotherapy