Respiratory System Anatomy Physiology Chapter 14 I Overview

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Respiratory System Anatomy & Physiology Chapter 14

Respiratory System Anatomy & Physiology Chapter 14

I. Overview A. Function: u Brings about the exchange of oxygen and carbon dioxide

I. Overview A. Function: u Brings about the exchange of oxygen and carbon dioxide between the blood, the air, and tissues

B. Organs u Nose u Pharynx u Larynx u Trachea u Bronchi u Lungs

B. Organs u Nose u Pharynx u Larynx u Trachea u Bronchi u Lungs – alveoli

C. Respiratory tract u Pathway of air from nose to lungs u Air in

C. Respiratory tract u Pathway of air from nose to lungs u Air in the respiratory tract are: – Cleansed – by hairs, cilia, and mucus – Warmed – by heat from the blood vessels – Moistened – by the wet surfaces in the passageway u Necessary to keep lung tissue healthy

II. Structure A. Upper Respiratory Tract – Nasal cavities, pharynx, glottis, larynx

II. Structure A. Upper Respiratory Tract – Nasal cavities, pharynx, glottis, larynx

1. Nasal Cavity Description: Hollow canals separated by a septum of bone and cartilage

1. Nasal Cavity Description: Hollow canals separated by a septum of bone and cartilage u Function: Filter, warm, and moisten the air u

u Paranasal Sinuses – Cavities within bones surrounding the nasal cavity – Function of

u Paranasal Sinuses – Cavities within bones surrounding the nasal cavity – Function of the sinuses u Lighten the skull u Act as resonance chambers for speech u Produce mucus that drains into the nasal cavity u Mucous membrane lines nasal cavity – Cilia moves mucous and trapped particles to the pharynx

u Contains lateral projections called conchae – Increases surface area – Increases air turbulence

u Contains lateral projections called conchae – Increases surface area – Increases air turbulence within the nasal cavity u The nasal cavity is separated from the oral cavity by the palate – Anterior hard palate (bone) – Posterior soft palate (muscle) Hard Palate Soft Palate

2. Pharynx – Throat u Description: funnel-shaped passageway between the nasal cavity and larynx

2. Pharynx – Throat u Description: funnel-shaped passageway between the nasal cavity and larynx u Function: Connects nasal and oral cavities to the larynx

u Three regions of the pharynx – Nasopharynx – superior region, passageway for air

u Three regions of the pharynx – Nasopharynx – superior region, passageway for air – Oropharynx – where oral cavity joins pharynx, passageway for food and air – Laryngopharynx – inferior region that opens to larynx u Tonsils – located in oropharynx – A lymphatic tissue that protects against inhaled pathogens

3. Epiglottis Description: flap of tissue that sits at the base of the tongue

3. Epiglottis Description: flap of tissue that sits at the base of the tongue u Function: prevents food from entering the trachea, or windpipe, during swallowing u

4. Larynx Description: Also called the voice box, contains the vocal cords u Function:

4. Larynx Description: Also called the voice box, contains the vocal cords u Function: Produces sound u Vocal cords are elastic tissues that vibrate producing sound as air travels through u – The opening or slit in the vocal cords is called the glottis

B. Lower Respiratory Tract – Trachea, bronchioles, lungs, alveoli

B. Lower Respiratory Tract – Trachea, bronchioles, lungs, alveoli

1. Trachea u Description: known as the windpipe, flexible tube that connects larynx to

1. Trachea u Description: known as the windpipe, flexible tube that connects larynx to bronchi u Function: directs air to bronchi

u Held open by C-shaped hyaline cartilage u Trachea is lined with pseudostratified ciliated

u Held open by C-shaped hyaline cartilage u Trachea is lined with pseudostratified ciliated columnar epithelial cells – Cilia sweeps mucus loaded with dust and other debris away from lungs Cilia Goblet cells Pseudostratified epithelial Basement membrane

Review Breakdown the words “pseudostratified ciliated columnar epithelial” to understand the meaning. u “pseudo”

Review Breakdown the words “pseudostratified ciliated columnar epithelial” to understand the meaning. u “pseudo” – fake u “stratified” – layers u “ciliated” – with hair like projections u “columnar” – cells that are taller than wider u

2. Bronchi u Description: Left and right branched tubes of the trachea u Function:

2. Bronchi u Description: Left and right branched tubes of the trachea u Function: passageway of air to lungs

u Bronchi enters the right and left lungs – Bronchi subdivide into smaller and

u Bronchi enters the right and left lungs – Bronchi subdivide into smaller and smaller branches called bronchioles u Right bronchus is wider, shorter, and straighter than left

3. Bronchioles u Description: Smallest branches of the bronchi u Function: Bronchioles lead to

3. Bronchioles u Description: Smallest branches of the bronchi u Function: Bronchioles lead to the alveoli

u Description: 4. Lungs paired, coneshaped organ that occupy the thoracic cavity u Function:

u Description: 4. Lungs paired, coneshaped organ that occupy the thoracic cavity u Function: contains alveolus where gas exchange occurs

u Apex (superior portion) is near the clavicle u Base (inferior portion) rests on

u Apex (superior portion) is near the clavicle u Base (inferior portion) rests on the diaphragm u Each lung is divided into lobes by fissures – Left lung – two lobes – Right lung – three lobes

u Coverings of the lungs – Visceral pleura covers the lung – Parietal pleura

u Coverings of the lungs – Visceral pleura covers the lung – Parietal pleura lines the walls of the thoracic cavity – Pleural fluid fills the area between layers of pleura to allow gliding

5. Alveoli u Description: Structure made up of simple squamous epithelium surrounded by blood

5. Alveoli u Description: Structure made up of simple squamous epithelium surrounded by blood capillaries u Function: Exchange of gas

u Respiratory membrane – extremely thin membrane that aids in the rapid exchange of

u Respiratory membrane – extremely thin membrane that aids in the rapid exchange of gases

u Gas crosses the respiratory membrane by diffusion – Oxygen enters the blood –

u Gas crosses the respiratory membrane by diffusion – Oxygen enters the blood – Carbon dioxide enters the alveoli u Macrophages add protection u Surfactant in alveoli prevents the lung from closing or collapsing

Review u What gases are exchanged in the respiratory membrane? u How are gases

Review u What gases are exchanged in the respiratory membrane? u How are gases moved or transported across the membrane?

Summary u Draw a flow map showing the pathway air travels through the respiratory

Summary u Draw a flow map showing the pathway air travels through the respiratory system starting with the nasal cavity and ending with the alveoli. Underneath each structure (8 total), write down the function. u Ex.

IV. Gas Exchange and Transport u Respiration – process of exchanging gases between the

IV. Gas Exchange and Transport u Respiration – process of exchanging gases between the atmosphere and body cells

A. External Respiration Exchange of gases between air and blood in the lungs u

A. External Respiration Exchange of gases between air and blood in the lungs u Blood entering the lungs is oxygen-poor and carbon dioxide-rich u Oxygen movement into the blood u – The alveoli always has more oxygen than the blood – Oxygen moves by diffusion from an area of high concentration to an area of low concentration

u Carbon dioxide movement out of the blood – Blood returning from tissues has

u Carbon dioxide movement out of the blood – Blood returning from tissues has higher concentrations of carbon dioxide than air in the alveoli – Pulmonary capillary blood gives up carbon dioxide u Blood leaving the lungs is oxygen-rich and carbon dioxidepoor

B. Internal Respiration u Exchange of gases between blood and body cells u An

B. Internal Respiration u Exchange of gases between blood and body cells u An opposite reaction to what occurs in the lungs – Carbon dioxide diffuses out of tissue to blood – Oxygen diffuses from blood into tissue

C. Gas Transport u Oxygen transport in the blood – Inside red blood cells

C. Gas Transport u Oxygen transport in the blood – Inside red blood cells attached to hemoglobin (oxyhemoglobin [Hb. O 2]) – A small amount is dissolved in the plasma u Carbon blood dioxide transport in the – Most is transported in the plasma as bicarbonate ion (HCO 3–) – A small amount is carried inside red blood cells on hemoglobin, but at different binding sites than those of oxygen

III. Mechanism of Breathing u Ventilation – manner in which air enters and exits

III. Mechanism of Breathing u Ventilation – manner in which air enters and exits the lungs u Two phases – Inspiration – flow of air into lung – Expiration – air leaving lung

A. Inspiration u Active phase of ventilation u Diaphragm and intercostal muscles contract u

A. Inspiration u Active phase of ventilation u Diaphragm and intercostal muscles contract u The size of the thoracic cavity increases u External air is pulled into the lungs due to an increase in intrapulmonary volume

B. Expiration u Largely a passive process which depends on natural lung elasticity u

B. Expiration u Largely a passive process which depends on natural lung elasticity u Diaphragm and intercostal muscles relax u As muscles relax, air is pushed out of the lungs u Forced expiration can occur mostly by contracting internal intercostal muscles to depress the rib cage

C. Nonrespiratory Air Movements u Can be caused by reflexes or voluntary actions u

C. Nonrespiratory Air Movements u Can be caused by reflexes or voluntary actions u Examples – Cough and sneeze – clears lungs of debris – Laughing – Crying – Yawn – Hiccup

D. Ventilation Control u Normal breathing rate is 12 -20 ventilation per minute u

D. Ventilation Control u Normal breathing rate is 12 -20 ventilation per minute u Controlled by the respiratory center in the medulla oblongata (brain) u Factors that influence ventilation – Nervous input – Chemical input

u 1. Nervous input – Intercostal and phrenic nerves stimulate muscles to contract for

u 1. Nervous input – Intercostal and phrenic nerves stimulate muscles to contract for inspiration – Lack of stimulation results in expiration

u 2. Chemical input – Level of carbon dioxide in the blood is the

u 2. Chemical input – Level of carbon dioxide in the blood is the main regulatory chemical for respiration – Increased carbon dioxide increases respiration

E. Respiratory Volumes u Normal breathing moves about 500 ml of air with each

E. Respiratory Volumes u Normal breathing moves about 500 ml of air with each breath (Tidal Volume [TV]) u Respiratory capacities are measured with a spirometer u Many factors that affect respiratory capacity – A person’s size – Sex – Age – Physical condition

u Inspiratory reserve volume (IRV) – Amount of air that can be taken in

u Inspiratory reserve volume (IRV) – Amount of air that can be taken in forcibly over the tidal volume – Usually between 2100 and 3200 ml u Expiratory reserve volume (ERV) – Amount of air that can be forcibly exhaled – Approximately 1200 ml

u Residual volume – Air remaining in lung after expiration – About 1200 ml

u Residual volume – Air remaining in lung after expiration – About 1200 ml u Vital capacity – The total amount of exchangeable air – Vital capacity = TV + IRV + ERV u Dead space volume – Air that remains in conducting zone and never reaches alveoli – About 150 ml

u Functional volume – Air that actually reaches the respiratory zone – Usually about

u Functional volume – Air that actually reaches the respiratory zone – Usually about 350 ml

V. Respiratory Disorders u A. Tonsillitis – occurs when tonsils become inflamed and enlarged

V. Respiratory Disorders u A. Tonsillitis – occurs when tonsils become inflamed and enlarged – Can make breathing difficult – Tonsils are the first line of defense against pathogens that enter the pharynx u B. Laryngitis – infection of larynx – Lead to inability to talk audibly – Disappears with treatment

u C. Chronic Obstructive Pulmonary Disease (COPD) – Term used to describe several progressive

u C. Chronic Obstructive Pulmonary Disease (COPD) – Term used to describe several progressive lung diseases – Third leading cause of death in the U. S. – Example: chronic bronchitis, emphysema, asthma

u 1. Chronic Bronchitis – Airway becomes inflamed and fills with mucus – Loss

u 1. Chronic Bronchitis – Airway becomes inflamed and fills with mucus – Loss of cilia and normal cleansing action – Caused by smoking cigars, cigarettes, and some pollutants

u 2. Emphysema – Chronic and incurable disorder where the alveoli bursts and fuse

u 2. Emphysema – Chronic and incurable disorder where the alveoli bursts and fuse into larger air spaces – Reduces surface area for gas exchange – Caused by prolong cigarette smoking

u 3. Asthma – Disease of the bronchi and bronchioles marked by wheezing and

u 3. Asthma – Disease of the bronchi and bronchioles marked by wheezing and breathlessness – Airways are sensitive to irritants (pollen, animal dander, dust, etc) – Causes muscle in the bronchioles to spasm and may even cause them to become inflamed – Treated with inhalers that stop the spasms or reduce the inflammation

D. Pneumonia u u u Inflammatory lung condition affecting the alveoli Can be bacterial

D. Pneumonia u u u Inflammatory lung condition affecting the alveoli Can be bacterial or viral – Bacterial often causes high fevers – Viral causes more flu-like symptoms Symptoms include cough, fever, chills, shortness of breath Diagnosed with chest X-ray Can be fatal, especially to the terminally ill, elderly and those suffering from other conditions, including COPD

E. Lung Cancer u Cancer of the lungs caused by smoking & second hand

E. Lung Cancer u Cancer of the lungs caused by smoking & second hand smoke – Begins with the thickening and callusing of the bronchi – Epithelium and cilia are destroyed – Atypical cells appear in tissue – Tumor forms – Cells break loose and spread to other organs (metastasis)

u Tumor can grow until it blocks bronchi, cutting off air supply u Lung

u Tumor can grow until it blocks bronchi, cutting off air supply u Lung collapses u Treatments: – Pneumonectomy – remove a lobe or a whole lung – Chemotherapy – Radiation