respiratory anat 2

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Functions of the Respiratory System

Gas exchange, Communication, Olfaction, Protection, Acid-Base, Blood Pressure, Blood and Lymph flow, Blood filtration, Expulsion of abdominal contents

The Upper Respiratory Tract

includes the respiratory organs in the head and neck

The Lower Respiratory Tract

includes the respiratory organs of the thorax

Nares aka nostrils

anterior opening of nose. lined with mucous membranes, containing sebaceous glands and hair follicles prevent the passage of debris through the nasal cavity.

Nasal Cavity

is divided into R and L sides by the nasal septum. Lined with mucous membrane. Here air is cleansed, warmed, and humidified.

Superior, middle, and inferior nasal conchae

Lined with respiratory epithelium (pseudostratified ciliated columnar epithelium) with goblet cells. Mucus helps trap debris. These “bumps” function to make air turbulent.

Olfactory epithelium

used to detect odors is found deep in the nasal cavity.

Paranasal sinuses

air filled spaces in skull bones connected to nasal cavity. Make skull lighter. Moisten and warm incoming air

Pharynx

is a muscular funnel

Nasopharynx

passes only air and is lined by pseudostratified columnar epithelium

Oropharynx

passes air, food, drink and is lined with stratified squamous epithelium

Laryngopharynx

passes air, food, drink and is lined with stratified squamous epithelium

Larynx - cartilaginous chamber

keeps food and drink out of airway; plays a role in sound production

Epiglottis

an elastic cartilage flap covers the trachea during swallowing

Thyroid Cartilage

hyaline cartilage, the “Adam’s apple” is its laryngeal prominence

Cricoid Cartilage

hyaline cartilage, forms a ring

Vestibular folds

fold of mucous membrane, close larynx during swallowing

Vocal folds

inferiorly located, produce sound when air passes between them

Trachea - rigidly open tube

Is held open by $16$ to $20$ stacked, C-shaped pieces of hyaline cartilage that are connected by dense connective tissue. Flexibility is allowed by the trachealis muscle and elastic connective tissue which connect the C-shaped cartilages posteriorly. Lined with pseudostratified, ciliated columnar epithelium with goblet cells. Trachea marks the transition to the lower respiratory tract.

Carina

The trachea bifurcates at the carina into two hyaline cartilage tubes contained in the lungs called bronchi

Bronchi

2 x Primary bronchi (aka main bronchi); R – 3 x Secondary bronchi; L – 2 x 2° bronchi. Continues to bifurcate (split) after this. Hyaline cartilage and lined with respiratory epithelium

bronchioles

continuation of bronchi; have NO hyaline cartilage but instead are surrounded by smooth muscle; function to change resistance and there for amount of air that can get into the lungs by bronchoconstriction and bronchodilation.

alveoli

the “terminal bubble” of the airways. lined by simple squamous epithelium. Surfactant reduces surface tension. surrounded by elastin fibers to allow expansion and contraction. intimately connected with a net of capillaries

Major function of the lungs

is to perform gas exchange, which requires blood from the pulmonary circulation.

Pulmonary artery/arterioles

carry deoxygenated blood between heart and alveoli.

Pulmonary vein/venules

carry oxygenated blood between alveoli and heart

Right lung

Right superior, middle and inferior lobes; Right horizontal fissure; Right oblique fissure

Left lung

Left superior and inferior lobes; Cardiac notch; Left oblique fissure

The pleura

is the serous membrane that surrounds the lung. Visceral pleural covers the lungs. Parietal pleura lines the inner wall of the thoracic cavity. The space between the two membranes is the pleural cavity and filled with serous

The diaphragm

is a skeletal muscle that plays a role in ventilation.

Conducting Division

Allows for air flow. Nostrils through most bronchioles

Respiratory Division

Respiratory bronchioles, alveoli and other gas-exchange regions in distal airway

Pulmonary Ventilation

is the act of breathing, which can also be described as inhalation and exhalation. Flow of air in and out of lung depends on a pressure difference between air within lungs and outside body

Atmospheric pressure

amount of force exerted by gases in the air surrounding any given surface

Intrapulmonary (aka intra-alveolar) pressure

pressure of air within the alveoli, changes during breathing phases

Intrapleural pressure

pressure of the air within the pleural cavity, slightly negative, keeps lungs inflated; is slightly less than intrapulmonary pressure.

Boyle’s Law

states that at a constant temperature the pressure of a given quantity of gas is inversely proportional to its volume.

The Respiratory Cycle

is one complete breath in and out.

Inspiration

Intrapulmonary pressure drops with increased volume; active

Expiration

Intrapulmonary pressure increases with decreased volume; passive

Quiet Breathing = eupnea

Diaphragm and external intercostals contract > size of thoracic cavity enlarges > air moves from high to low pressure into the lungs. Diaphragm and external intercostals relax > size of thoracic cavity decreases > air moves from high to low pressure out of the lungs

Forced breathing = hypernea

Forced inspiration also uses scalenes, sternocleidomastoid, pectoralis minor. Forced expiration also uses external abdominal obliques, rectus abdominis, internal intercostals

Factors affecting resistance in ventilation

Bronchiolar smooth muscle contractions; Lung and thoracic wall compliance; Pulmonary surfactant and alveolar surface tension

Tidal Volume (TV)

amount of air that normally enters the lungs during quiet breathing; ~ $500\,mL$

Expiratory reverse Volume (ERV)

amount f air you can forcefully exhale past a normal tidal expiration; up to $1200\,mL$; ERV = VC – TV – IRV

Inspiratory Reserve Volume (IRV)

produced by deep inhalation (past tidal volume); extra brought in during forced inspiration; up to another $1300\,mL$; IRV = VC – (TV + ERV)

Residual Volume (RV)

air left in lungs if you exhale as much air as possible; ~$1300\,mL$

Total Lung Capacity

is the sum of all lung volumes; amount of air a person can hold after forceful inhalation.; ~ $6000\,mL$ for men and $4200\,mL$ for women.

Vital Capacity (VC)

is the amount of air a person can move into or out of his or her lungs in one breath; is the sum of all except RV; ~$4$-$5000\,mL$

Anatomical dead space

air is present in the airway but never reaches the alveoli or participates in gas exchange.

Alveolar/physiologic dead space

air found within alveoli that are unable to function, such as those affected by disease or abnormal blood flow.; should be zero in health individuals

Total dead space

anatomical dead space and alveolar dead space together, represents all the air in the respiratory system not being used in the gas exchange process.

Restrictive Disease

airway is less complaint (elastic) and they are stiff or fibrotic. Patient has reduced lung volume. Ex. Respiratory distress syndrome, pulmonary fibrosis

Obstructive Disease

Compliance is increased, loss of elastic fibers. Aire is trapped in lungs at end of exhale. Ex. Emphysema, asthma, pulmonary edema

Dalton’s Law

states that in a mixture of non-reacting gases, the total pressure is equal to the partial pressure of individual gasses. It considers that in this mixture, each specific gas exerts a force independent of the other gases.

Henry’s Law

states that the concentration of gas in a liquid is directly proportional to the solubility and partial pressure of that gas. This means that the greater the partial pressure of the gas, the greater the number of gas molecules that will dissolve in the liquid. And, this law also considers that the solubility is different for each gas present.

External Respiration

exchange at the alveoli between the external environment and the capillaries.

Internal Respiration

exchange of gases in the tissues between the internal environment and the capillaries.

Cellular Respiration

O2 > ATP > CO2

Oxygen Transport in Blood

1.5% is dissolved in the plasma; 98.5% of oxygen in the blood is in the RBCs, bound to hemoglobin; $O_2 + Hb \rightarrow HbO_2$

Deoxyhemoglobin

has no oxygens bound

Oxyhemoglobin

has at least 1 oxygen bound

Bohr effect

means $H^+$ ions weaken the bond between hemoglobin and oxygen. Lactic acid is a byproduct of cellular metabolism. Greater amounts of $CO_2$ will lower blood pH.

Carbon Dioxide Transport in Blood

Dissolved gas ~$7$-$10\%$; Carbaminohemoglobin ~$20\%$; Bicarbonate ~$70\%$

Medulla Oblongata

Dorsal Respiratory Group – maintains rhythm; impulses cause contraction of external intercostals and diaphragm. Ventral Respiratory Group – generates forced breathing

Pons

Apneustic center – controls depth of inspiration. Pneumotaxic center – cuts off inspiration; control overall volume and rate

Central chemoreceptor

located in brainstem; respond to hypercapnia ($P_{CO_2}$)

Peripheral chemoreceptors

located in the carotid arteries and aortic arch; respond to hypoxemia ($P_{O_2}$)

Chemical stimuli for ventilation

pH - $75\%$ input from central chemoreceptors in the medulla, $25\%$ from peripheral chemoreceptors; CO2 - most carbon dioxide influence is indirectly through pH; O2 - Only significantly affects respiration if it drops below $60\,mmHg$ and here will excite peripheral chemoreceptors

Hyperventilation

ventilation in excess of metabolic demand; lowers the blood $CO_2$ and raises blood pH

Hypoventilation

reduced pulmonary ventilation; increased blood $CO_2$ and decreases blood pH

Apnea

cessation of breathing

lobes

The respiratory system contains a total of five __________.

Dalton's

Which law states that the total pressure of a gas mixture is equal to the sum of the partial pressures of its individual gases?

inspiratory reserve volume

The amount of air in excess of tidal volume that can be inhaled with maximum effort is the __________.

carbonate

Carbon dioxide is transported by all the following means except _________.

Assists in thesynthesis of vasodilators

Which of the following is not a function of the respiratory system?

Anticipation ofthe needs of exercising muscle

During exercise, which of the following directly increases respiratory rate?

An increase inmembrane thickness

Which of the following would slow down gas exchange between the blood and alveolar air?

4

Each hemoglobin molecule can transport up to __________ oxygen molecules.

Carbonicanhydrase

Which of the following enzymes in an RBC breaks H ₂CO ₃ down to water and carbon dioxide?

larynx

The upper respiratory tract extends from the nose through the _________.

goblet cells

Mucus plays an important role in cleansing inhaled air. It is produced by __________ of the respiratory tract.

bicarbonate ions

The blood transports more CO ₂ in the form of ___________ than in any other form.

VRG

Which center bears the primary responsibility for generating the respiratory rhythm, but is influenced by several other centers?

Central chemoreceptors

The pH of the cerebrospinal fluid is monitored by which of these brainstem centers?

Nares → Vestibule → Nasal Cavity → Nasopharynx → Oropharynx → Laryngopharynx → Larynx → Trachea → Primary Bronchus → Secondary Bronchus → Tertiary Bronchus → Bronchiole → Terminal Bronchiole → Respiratory Bronchiole → Alveolar Duct → Alveolar Sac → Alveolus

If one inspires through their nose, which of the following answers has the correct order of structures the air would move through?

pulmonary artery

Each alveolus is surrounded by a web of blood capillaries supplied by the _________.

Left mainbronchus

Which bronchus is about 5cm long and slightly narrower and more horizontal than the one on the opposite side?