human anatomy&physiology respiratory s

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Human Anatomy and Physiology The Respiratory System Basic functions of the respiratory system: Gas exchange – supply oxygen to aerobic tissues in the body and remove carbon dioxide as a waste product. -Pulmonary ventilation - the physics of getting air in- to and out- of the lungs (ventilation). -External respiration - gas exchange between the lungs and blood (oxygen loading and CO 2 unloading). -Transport of respiratory gases - movement of blood (thus gases) from the lungs to the cell and tissues. -Internal respiration – gas exchange between the capillaries and the tissues (oxygen unloading and CO 2 loading).

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Page 1: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyThe Respiratory System

Basic functions of the respiratory system:

Gas exchange – supply oxygen to aerobic tissues in the body and remove carbon dioxide

as a waste product.

-Pulmonary ventilation - the physics of getting air in- to and out- of the lungs (ventilation).

-External respiration - gas exchange between the lungs and blood (oxygen loading and

CO2 unloading).-Transport of respiratory gases - movement of

blood (thus gases) from the lungs to the cell and tissues.

-Internal respiration – gas exchange between the capillaries and the tissues (oxygen unloading and CO2 loading).

Page 2: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyThe Respiratory System

Functional anatomy of the respiratory system:Conducting Zone

Rigid conduits for air to reach site of gas exchange

-nose-nasal cavity-pharynx-larynx-trachea-bronchi

-Respiratory Zonesite of gas exchange

-respiratory bronchioles

-alveolar ducts

Page 3: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyThe conducting zone

Conducting Zone:

Nose-airway-moistens and warms air-filters inspired air-resonating chamber for

speech-olfaction

-paranasal sinuses-frontal, sphenoid,ethmoid and maxillarybones-warm and moisten air

Page 4: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyThe conducting zone

Conducting Zone:

Pharynx-connects the nasal cavity and mouth to thelarynx and esophagus

-common pathway for food and air (throat)

-nasopharynx-oropharynx-laryngopharynx

Page 5: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyThe conducting zone

Conducting Zone:

Laryngopharynx – common passage way for food and airLarynx – voice box

Page 6: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyThe conducting zone

Conducting Zone:

Trachea-windpipe-larynx at division forming

two primary bronchi at midthorax

-mucosa – pseudostratified epithelium (goblet cells)

-submucosa – connective tissueseromucous glands – mucous

-advantitia – CT hyaline cartilage

Page 7: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyThe conducting zone

Conducting Zone:

BronchiBronchial tree

-left and right primary bronchi-formed by divisions of the trachea

-secondary bronchi (lobar)-inside the lungs-3 on the right-2 on the left

-tertiary bronchi (segmental)-fourth-order-fifth-order-23 orders of branching air ways-bronchioles (under 1 mm in diameter

Page 8: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyThe conducting zone

Conducting Zone:

Bronchioles-bronchioles (under 1 mm in diameter)-terminal bronchioiles (less than 0.5 mm)

Page 9: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyThe conducting zone

Conducting Zone:

Cartilage:-rings -irregular plates-no cartilage in bronchioles -replaced by elastic fibers

Epithelium:-pseudostratified (ciliated)-columnar (ciliated)-cuboidal in terminal bronchioles (no cilia)

Smooth Muscle:-increases as tubes get smaller

Page 10: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyThe respiratory zone

Respiratory Zone:Respiratory bronchioilesAlveoli (300 million)Alveolar ductsAlveolar sacs

Gas Exchange:respiratory membrane

Page 11: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyThe respiratory zone

Respiratory Zone:Respiratory membrane (air-blood barrier) or (Alveolar-capillary membrane) is composed of:-simple squamous epithelial cells (Type I cells)-cobweb of pulmonary capillaries

Primary function is gas exchange

-Type II cells (cuboidal)surfactant

-elastic fibers-alveolar pores allow forpressure equalizationbetween alveoli

-alveolar macrophages(dust cells)

Page 12: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyLungs and Pleural Coverings

Pleural Coverings:-double layered serosa-parietal pleura lines the thoracic wall-pulmonary or visceral pleura which covers thelung surface-pleural cavity is the space between the two layers-pleural fluid fills the cavity

Page 13: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyBlood Supply and Innervation of the Lungs

Blood supply:-Pulmonary circulation-Bronchial circulation

Pulmonary arteries from the right side of the heart supply blood to the lungs.-pulmonary arteries branch profusely along with the bronchi-pulmonary capillary networks surrounding alveoli

-pulmonary veins form post alveoli to carry oxygenated blood back tothe heart

Bronchial arteries come from the aorta and enter the lung at the hilus-the bronchial arteries run along the branching bronchi and supplylung tissue except the alveoli

-bronchial veins drain the bronchi but most moves into the pulmonarycirculation

Page 14: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyBlood Supply and Innervation of the Lungs

Innervation:-parasympathetic motor fibers (some sympathetic fibers)-visceral sensory fibers

Enter the lung through the pulmonary plexus on the lung root

parasympathetic fibers – constrict the air tubessympathetic fibers – dilate air tubes

Page 15: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyRespiratory Mechanics

Breathing:

Simply pressure changes driven by diaphragm and external intercostal muscle contractions

Page 16: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyRespiratory Mechanics

Breathing:

yellow is the increase in volume during inspiration-

Lungs

Volume duringInspiration

VolumeAt rest

Page 17: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyRespiratory Mechanics

Breathing:

Increased volume causes a drop in pressure if the system is closed.Where is the system closed to the outside?

Boyle’s law – P1V1 = P2V2

Lungs

Page 18: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyRespiratory Mechanics

Breathing:

Increased volume causes a drop in pressure if the system is closed.Where is the system closed to the outside? The pleural cavity!The pleural cavity!

Lungs

The decrease in intrapleural cavity pressure is translated to the lungs via the inner visceral pleural membrane because it is attached to the outer surface of the lungThus, an increase in volume causes a decrease in intrapleural pressure because it is a closed system.

Page 19: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyRespiratory Mechanics

Breathing:

The lungs are an open system via the trachea and as such as intrapleural pressure drops lung volume increases and lung pressure also decreases. However, because the lungs are open to the outside, air rushes into the lungs to equalize the pressure. Thus, the drop in pulmonary pressure is transient.

Pulmonary pressure returns to zero as air moves into the lungs to take up the volume change (drop in pressure).

Lungs trachea

Page 20: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyRespiratory Mechanics

Page 21: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyRespiratory Mechanics

Breathing:

Airway Resistance-

-friction or drag along the respiratory passageway

PFlow =

R

-maximum resistance in medium size bronchi then drops as cross sectional area increases

-bronchiole smooth muscle verysensitive to parasym stimulation

Page 22: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyRespiratory Mechanics

Lung volumesdead space – -volume of air filling the conducting zone and never

contributes to gas exchange (anatomical dead space 150 ml).-if some of the alveoli collapse or are obstructed (alveolar dead space). Total dead space = AnaDS + AlvDS

Page 23: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyRespiratory Mechanics

Breathing:-

Page 24: Human Anatomy&Physiology Respiratory S

Human Anatomy and PhysiologyGas Exchange

Gas exchange:-

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