Unit 6 - Mine

The Respiratory System - function

Major function-respiration

-Supply body with O2 for cellular respiration; dispose of CO2, a waste product of cellular respiration

-Its four processes involve both respiratory and circulatory systems

Also functions in olfaction and speech

Processes of Respiration

Respiratory system and ciruclatory system

Respiratory system

Pulmonary ventilation (breathing)-movement of air into and out of lungs

External respiration-O2 and CO2 exchange between lungs and blood

Pulmonary ventilation (breathing)

movement of air into and out of lungs

External respiration

O2 and CO2 exchange between lungs and blood

Circulatory system

Transport-O2 and CO2 in blood

Internal respiration-O2 and CO2 exchange between systemic blood vessels and tissues

Internal respiration

O2 and CO2 exchange between systemic blood vessels and tissues

Respiratory System: major organs

Nose, nasal cavity, and paranasal sinuses

Pharynx

Larynx

Trachea

Bronchi and their branches

Lungs and alveoli

Functional Anatomy

Respiratory zone-site of gas exchange

Microscopic structures-respiratory bronchioles, alveolar ducts, and alveoli

Conducting zone-transit area to gas exchange sites: throat, trachea etc

Includes all other respiratory structures; cleanses, warms, humidifies air

Diaphragm and other respiratory muscles promote ventilation

Respiratory zone

site of gas exchange

Microscopic structures-respiratory bronchioles, alveolar ducts, and alveoli

Conducting zone

transit area to gas exchange sites: throat, trachea etc

Includes all other respiratory structures; cleanses, warms, humidifies air

Diaphragm and other respiratory muscles promote

ventilation

Nose functions

Provides an airway for respiration

Moistens and warms entering air

Filters and cleans inspired air

Serves as resonating chamber for speech

Houses olfactory receptors

Two regions of nose

external nose and nasal cavity

External nose

root, bridge, dorsum nasi, and apex

-Philtrum-shallow vertical groove inferior to apex

-Nostrils (nares)-bounded laterally by alae

Philtrum

shallow vertical groove inferior to apex

Nostrils (nares)

bounded laterally by alae

Nasal cavity

within and posterior to external nose

Divided by midline nasal septum

Roof-ethmoid and sphenoid bones

Floor-hard (bone) and soft palates (muscle)

nasal cavity roof

ethmoid and sphenoid bones

nasal cavity floor

hard (bone) and soft palates (muscle)

Nasal vestibule

nasal cavity superior to nostrils

Vibrissae (hairs) filter coarse particles from inspired air

Vibrissae (hairs)

filter coarse particles from inspired air

Rest of nasal cavity lined with mucous membranes

olfactory and respiratory

Olfactory mucosa contains

olfactory epithelium

Respiratory mucosa

Pseudostratified ciliated columnar epithelium

Mucous and serous secretions contain lysozyme and defensins

Cilia move contaminated mucus posteriorly to throat

Inspired air warmed by plexuses of capillaries and veins

Sensory nerve endings trigger sneezing

Nasal conchae

superior, middle, and inferior

During inhalation, conchae and nasal mucosa

Filter, heat, and moisten air

During exhalation these structures

Reclaim heat and moisture

During inhalation, conchae and nasal mucosa

Filter, heat, and moisten air

During exhalation, conchae and nasal mucosa

Reclaim heat and moisture

Rhinitis

Inflammation of nasal mucosa

Nasal mucosa continuous with mucosa of respiratory tract → spreads from nose → throat → chest

Spreads to tear ducts and paranasal sinuses causing

Blocked sinus passageways → air absorbed → vacuum → sinus headache

Pharynx

Muscular tube from base of skull to C6

-Connects nasal cavity and mouth to larynx and esophagus

-Composed of skeletal muscle

Three regions

-Nasopharynx

-Oropharynx

-Laryngopharynx

Three regions of pharynx

Nasopharynx

Oropharynx

Laryngopharynx

Nasopharynx

Air passageway posterior to nasal cavity

Soft palate and uvula close nasopharynx during swallowing

Pharyngeal tonsil (adenoids) on posterior wall

Pharyngotympanic (auditory) tubes drain and equalize pressure in middle ear; open into lateral walls

Oropharynx

Passageway for food and air from level of soft palate to epiglottis

Laryngopharynx

Passageway for food and air

Posterior to upright epiglottis

Larynx

Attaches to hyoid bone; opens into laryngopharynx; continuous with trachea

Functions

-Provides patent airway

-Routes air and food into proper channels

-Voice production

--Houses vocal folds

Nine cartilages of larynx

-All hyaline cartilage except epiglottis

-Thyroid cartilage with laryngeal prominence (Adam's apple)

-Epiglottis-elastic cartilage; covers laryngeal inlet during swallowing; covered in taste bud-containing mucosa

Vocal ligaments-deep to laryngeal mucosa

-Contain elastic fibers

-Folds vibrate to produce sound as air rushes up from lungs

Vestibular folds (false vocal cords)

-Superior to vocal folds

-No part in sound production

-Help to close glottis during swallowing

Larynx functions

Provides patent airway

Routes air and food into proper channels

Voice production

-Houses vocal folds

Nine cartilages of larynx

All hyaline cartilage except epiglottis

Thyroid cartilage with laryngeal prominence (Adam's apple)

Epiglottis-elastic cartilage; covers laryngeal inlet during swallowing; covered in taste bud-containing mucosa

Vocal ligaments

deep to laryngeal mucosa

Contain elastic fibers

Folds vibrate to produce sound as air rushes up from lungs

Vestibular folds (false vocal cords)

Superior to vocal folds

No part in sound production

Help to close glottis during swallowing

Voice Production

Speech-intermittent release of expired air while opening and closing glottis

Pitch determined by length and tension of vocal cords

Loudness depends upon force of air

Chambers of pharynx, oral, nasal, and sinus cavities amplify and enhance sound quality

Sound is "shaped" into language by muscles of pharynx, tongue, soft palate, and lips

Speech

intermittent release of expired air while opening and closing glottis

Larynx - vocal

Vocal folds may act as sphincter to prevent air passage

Example-Valsalva's maneuver

-Glottis closes to prevent exhalation

-Abdominal muscles contract

-Intra-abdominal pressure rises

-Helps to empty rectum or stabilizes trunk during heavy lifting

Trachea

Windpipe-from larynx into mediastinum

Bronchi

Tubes coming off each side of the bottom of the trachea

Conducting Zone Structures

Trachea → right and left main (primary) bronchi

Primary, secondary, tertiary bronchi order or main, lobar, and segmental bronchi (same thing but different names

Each main bronchus enters hilum of one lung

-Right main bronchus wider, shorter, more vertical than left

Each main bronchus branches into lobar (secondary) bronchi (three on right, two on left)

-Each lobar bronchus supplies one lobe

Each lobar bronchus branches into segmental (tertiary) bronchi

-Segmental bronchi divide repeatedly

Branches become smaller and smaller →

-Bronchioles-less than 1 mm in diameter

-Terminal bronchioles-smallest-less than 0.5 mm diameter

From bronchi through bronchioles, structural changes occur

-Epithelium changes from pseudostratified columnar to cuboidal; cilia become sparse

-Relative amount of smooth muscle increases

--Allows constriction

Trachea - Conducting Zone

right and left main (primary) bronchi

Respiratory Zone

Begins as terminal bronchioles → respiratory bronchioles → alveolar ducts → alveolar sacs (where we get gas exchange)

-Alveolar sacs contain clusters of alveoli

--Alveolar sacs are hollow and the holes in the sacs are there for air

--~300 million alveoli make up most of lung volume

--Sites of gas exchange

--Simple squamous epithelium

Alveolar sacs

contain clusters of alveoli

Alveolar sacs are hollow and the holes in the sacs are there for air

~300 million alveoli make up most of lung volume

Sites of gas exchange

Simple squamous epithelium

Alveoli

Surrounded by fine elastic fibers and pulmonary capillaries

Alveolar pores connect adjacent alveoli

-Equalize air pressure throughout lung

Alveolar macrophages keep alveolar surfaces sterile

-2 million dead macrophages/hour carried by cilia → throat → swallowed

Lungs

Occupy all thoracic cavity except mediastinum

Composed primarily of alveoli

Apex-superior tip; deep to clavicle

Base-inferior surface; rests on diaphragm

Hilum-on mediastinal surface; site for entry/exit of blood vessels, bronchi, lymphatic vessels, and nerves

Left lung smaller than right because of the heart

-Cardiac notch-concavity for heart

-Separated into superior and inferior lobes by oblique fissure

Right lung

-Superior, middle, inferior lobes separated by oblique and horizontal fissures

Bronchopulmonary segments (10 right, 8-10 left) separated by connective tissue septa

-If diseased can be individually removed

Lobules-smallest subdivisions visible to naked eye; served by bronchioles and their branches

Apex

superior tip; deep to clavicle

Base

inferior surface; rests on diaphragm

Hilum

on mediastinal surface; site for entry/exit of blood vessels, bronchi, lymphatic vessels, and nerves

Left lung smaller than right because of

the heart

Cardiac notch-concavity for heart

Separated into superior and inferior lobes by oblique fissure

Right lung

Superior, middle, inferior lobes separated by oblique and horizontal fissures

Bronchopulmonary segments (10 right, 8-10 left)

separated by connective tissue septa

If diseased can be individually removed

Lobules

smallest subdivisions visible to naked eye; served by bronchioles and their branches

Pulmonary circulation

(low pressure, high volume)

Pulmonary arteries deliver systemic venous blood to lungs for oxygenation

-Branch profusely; feed into pulmonary capillary networks

Pulmonary veins carry oxygenated blood from respiratory zones to heart

Lung capillary endothelium contains enzymes that act on substances in blood

-E.g., angiotensin-converting enzyme-activates blood pressure hormone

Bronchial arteries

provide oxygenated blood to lung tissue

Arise from aorta and enter lungs at hilum

Part of systemic circulation (high pressure, low volume)

Supply all lung tissue except alveoli

Bronchial veins anastomose with pulmonary veins

-Pulmonary veins carry most venous blood back to heart

Pulmonary arteries

deliver systemic venous blood to lungs for oxygenation

Branch profusely; feed into pulmonary capillary networks

Pulmonary veins

carry oxygenated blood from respiratory zones to heart

Lung capillary endothelium contains

enzymes that act on substances in blood

E.g., angiotensin-converting enzyme-activates blood pressure hormone

Pulmonary ventilation consists of two phases

Inspiration-gases flow into lungs

Expiration-gases exit lungs

Atelectasis

(lung collapse) due to

Plugged bronchioles → collapse of alveoli

Pneumothorax-air in pleural cavity

-From either wound or rupture of visceral pleura

-Treated by removing air with chest tubes; pleurae heal → lung reinflates

Pulmonary Ventilation

Inspiration and expiration

Mechanical processes that depend on volume changes in thoracic cavity

-Volume changes → pressure changes

-Pressure changes → gases flow to equalize pressure

Inspiration

Active process - You put more energy into doing it

-Inspiratory muscles (diaphragm and external intercostals) contract

-Thoracic volume increases → intrapulmonary pressure drops (to −1 mm Hg)

-Lungs stretched and intrapulmonary volume increases

-Air flows into lungs

***Increase volume-decrease pressure-air goes in lungs

Expiration

Quiet expiration normally passive process

-Inspiratory muscles relax

-Thoracic cavity volume decreases

-Elastic lungs recoil and intrapulmonary volume decreases → pressure increases →

-Air flows out of lungs

Note: forced expiration-active process; uses abdominal (oblique and transverse) and internal intercostal muscles

***decrease volume-increased pressure-air is forced out of the lungs

Respiratory Volumes

Used to assess respiratory status

-Tidal volume (TV) - amount of air inhaled or exhaled with each breath under resting

-Inspiratory reserve volume (IRV) - amount of air that can be forcefully inhaled after a normal tidal volume inspiration

-Expiratory reserve volume (ERV) - amount of air that can be forcefully exhaled after a normal tidal volume inspiration

-Residual volume (RV) - amount of air remaining in the lungs after a forced expiration

Tidal volume (TV)

amount of air inhaled or exhaled with each breath under resting

Inspiratory reserve volume (IRV)

amount of air that can be forcefully inhaled after a normal tidal volume inspiration

Expiratory reserve volume (ERV)

amount of air that can be forcefully exhaled after a normal tidal volume inspiration

Residual volume (RV)

amount of air remaining in the lungs after a forced expiration

Gas Exchanges Between Blood, Lungs, and Tissues

External respiration-diffusion of gases in lungs

Internal respiration-diffusion of gases at body tissues

Both involve

-Physical properties of gases

-Composition of alveolar gas

External respiration

diffusion of gases in lungs

Internal respiration

diffusion of gases at body tissues

O2 and Hemoglobin

Rate of loading and unloading of O2 regulated to ensure adequate oxygen delivery to cells

-Po2

-Temperature

-Blood pH

-Pco2

Hypoxia

Inadequate O2 delivery to tissues → cyanosis (blue tissue)

Anemic hypoxia-too few RBCs; abnormal or too little Hb

Ischemic hypoxia-impaired/blocked circulation

Histotoxic hypoxia-cells unable to use O2, as in metabolic poisons

Hypoxemic hypoxia-abnormal ventilation; pulmonary disease

Carbon monoxide poisoning-especially from fire; 200X greater affinity for Hb than oxygen

Anemic hypoxia

too few RBCs; abnormal or too little Hb

Ischemic hypoxia

impaired/blocked circulation

Histotoxic hypoxia

cells unable to use O2, as in metabolic poisons

Hypoxemic hypoxia

abnormal ventilation; pulmonary disease

Carbon monoxide poisoning

especially from fire; 200X greater affinity for Hb than oxygen

Hyperventilation

increased depth and rate of breathing that exceeds body's need to remove CO2

→ decreased blood CO2 levels (hypocapnia) → cerebral vasoconstriction and cerebral ischemia → dizziness, fainting

Apnea

breathing cessation from abnormally low Pco2

Respiratory Adjustments: High Altitude

Quick travel to altitudes above 2400 meters (8000 feet) may → symptoms of acute mountain sickness (AMS)

-Atmospheric pressure and Po2 levels lower

-Headaches, shortness of breath, nausea, and dizziness

-In severe cases, lethal cerebral and pulmonary edema

Acute mountain sickness (AMS)

Atmospheric pressure and Po2 levels lower

Headaches, shortness of breath, nausea, and dizziness

In severe cases, lethal cerebral and pulmonary edema

Acclimatization to High Altitude

Acclimatization-respiratory and hematopoietic adjustments to long-term move to high altitude

Always lower-than-normal Hb saturation levels

-Less O2 available

Decline in blood O2 stimulates kidneys to accelerate production of EPO

RBC numbers increase slowly to provide long-term compensation

Acclimatization

respiratory and hematopoietic adjustments to long-term move to high altitude

Chronic obstructive pulmonary disease (COPD)

Exemplified by chronic bronchitis and emphysema

Irreversible decrease in ability to force air out of lungs

Other common features

-History of smoking in 80% of patients

-labored breathing ("air hunger")

-Coughing and frequent pulmonary infections

-Most develop respiratory failure (hypoventilation) accompanied by respiratory acidosis, hypoxemia

COPD treatment

Treated with bronchodilators, corticosteroids, oxygen, sometimes surgery

Emphysema

Permanent enlargement of alveoli; destruction of alveolar walls; decreased lung elasticity →

-Accessory muscles necessary for breathing

--→ exhaustion from energy usage

-Hyperinflation → flattened diaphragm (biggest warning side) → reduced ventilation efficiency

-Damaged pulmonary capillaries → enlarged right ventricle

Chronic bronchitis

Inhaled irritants → chronic excessive mucus → Inflamed and fibrosed lower respiratory passageways → Obstructed airways → Impaired lung ventilation and gas exchange → Frequent pulmonary infections

Asthma-reversible COPD

Characterized by coughing, labored breathing, wheezing, and chest tightness

Active inflammation of airways precedes bronchospasms

Airway inflammation is immune response

Inhalers - inflates bronchial tubes

Inhalers

inflates bronchial tubes

Tuberculosis (TB)

Infectious disease caused by bacterium Mycobacterium tuberculosis

Symptoms-fever, night sweats, weight loss, racking cough, coughing up blood

Treatment- 12-month course of antibiotics

-Are antibiotic resistant strains

Cystic fibrosis

Most common lethal genetic disease in North America

Abnormal, viscous mucus clogs passageways → bacterial infections

-Affects lungs, pancreatic ducts, reproductive ducts

Cause-abnormal gene for Cl- membrane channel

Treatments for cystic fibrosis

Mucus-dissolving drugs; manipulation to loosen mucus; antibiotics

Digestive System

Two groups of organs

1. Alimentary canal (gastrointestinal or GI tract)= food moves through these organs.

-Mouth to anus

-Digests food and absorbs fragments

-Mouth, pharynx, esophagus, stomach, small intestine, and large intestine

2. Accessory digestive organs = food doesn't move through these, they are "helpers to the process"

-Teeth, tongue, gallbladder

-Digestive glands

--Salivary glands

--Liver

--Pancreas

1. Alimentary canal

(gastrointestinal or GI tract)= food moves through these organs.

-Mouth to anus

-Digests food and absorbs fragments

-Mouth, pharynx, esophagus, stomach, small intestine, and large intestine

2. Accessory digestive organs

food doesn't move through these, they are "helpers to the process"

-Teeth, tongue, gallbladder

-Digestive glands

--Salivary glands

--Liver

--Pancreas