Respiratory System

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Respiratory System

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Introduction

• The CV and Respiratory system cooperate to supply
  O2 and eliminate CO2

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Introduction

• The Resp. Sys. provides for gas exchange

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Introduction

• The CV transports respiratory gases

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Introduction

• Respiration is the exchange of gases between the
  atmosphere, blood, and cells

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Introduction

• Consists of
• Nose
• Pharynx
• Larynx
• Trachea
• Bronchi
• Lungs

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Introduction

• The conducting system consists of a series of
  cavities and tubes nose, pharynx, larynx,
  trachea, bronchi, bronchiole, and terminal
  bronchiole

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Introduction

• The conducting system conducts air into lungs

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Introduction

• The respiratory portion consists of the area
  where gas exchange occurs-respiratory
  bronchioles, alveolar ducts, alveolar sacs, and
  alveoli

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Nose

• The external portion of the nose is made of
  cartilage and skin and is lined with mucous
  membrane.

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Nose

• It is stratified squamous epithelium inside the
  nostrils

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Nose

• It turns into pseudostratified columnar
  epithelium deeper inside

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Nose

• The bony framework of the nose is formed by the
  frontal bone, nasal bones, and maxillae

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Nose

• The internal structures of the nose are
  specialized for
• 1. warming

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Nose

• 2. moistening

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Nose

• 3. Filtering incoming air

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Nose

• 4. Receiving olfactory stimuli

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Nose

• 5. Serving as large, hollow resonating chambers
  to modify speech sounds

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Nose

• The space within the internal nose is called the
  nasal cavity.

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Nose

• It is divided into right and left sides by the
  nasal septum

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Nose

• The anterior portion of the cavity (nostrils) is
  called the vestibule

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Pharynx

• Throat

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Pharynx

• Muscular tube lined by a mucous membrane

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Pharynx

• Anatomic regions
• Nasopharynx
• Oropharynx
• laryngopharynx

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Pharynx

• Nasopharynx functions in respiration

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Pharynx

• The oropharynx and laryngopharynx function in
  digestion and in respiration

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Larynx

• Voice box

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Larynx

• Passageway that connects the pharynx with the
  trachea

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Larynx

• It contains
• 1. Thyroid cartilage (Adams apple)

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Larynx

• 2. Epiglottis (prevents food from entering the
  larynx)

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Larynx

• 3. Cricoid cartilage (connects the larynx and
  trachea)

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Swallowing

• 1. Larynx raises up

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Swallowing

• 2. Epiglottis covers the entry into the glottis

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Swallowing

• 3. The upper esophageal sphincter opens

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Swallowing

• 4. Food is diverted into the esophagus

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Voice Production

• The larynx contains vocal folds (true vocal
  cords) which produces sound

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Voice Production

• The true cords and the space between them make up
  the glottis

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Voice Production

• In males, the true cords are thicker and longer

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Voice Production

• The false cords close when we clear our throat

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Trachea

• Windpipe

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Trachea

• Extends from the larynx to the primary bronchi

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Trachea

• Composed of smooth muscle and C-shaped rings of
  cartilage

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Trachea

• Lined with pseudostratified ciliated columnar
  epithelium

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Trachea

• The cartilage rings keep the airway open

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Trachea

• Cilia sweep debris away from the lungs and back
  to the throat to be swallowed

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Bronchi

• The trachea divides into the right and left
  primary bronchi

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Bronchi

• The bronchiole tree consists of the
• 1. trachea

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Bronchi

• 2. Primary bronchi

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Bronchi

• 3. Secondary bronchi

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Bronchi

• 4. Tertiary bronchi

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Bronchi

• 5. Bronchioles

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Bronchi

• 6. Terminal bronchioles

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Bronchi

• Walls of bronchi contain rings of cartilage,
  which disappears distally

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Bronchi

• Walls of bronchioles contain smooth muscle only,
  without cartilage

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Bronchi

• The epithelium changes from ciliated
  pseudostratified columnar to non-ciliated simple
  cuboidal in the terminal bronchioles

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Bronchi

• Sympathetics release norepinephrine and epi.
  which stimulates beta two receptors causing
  bronchodilation

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Bronchi

• Parasympathetic release ACh which stimulates
  muscarinic ACh receptors causing
  bronchoconstriction

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Lungs

• Paired organs in the thoracic cavity

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Lungs

• Enclosed and protected by the pleural membrane

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Lungs

• Parietal pleura outer layer which is attached
  to the wall of the thoracic cavity

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Lungs

• Visceral pleura inner layer, covering the lungs

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Lungs

• Pleural cavity (space) A small space between
  the pleurae that contains a lubricating fluid
  secreted by the membranes

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Lungs

• Extend from the diaphragm to just slightly
  superior to the clavicles

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Lungs

• Lie against the ribs anteriorly and posteriorly

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Lungs

• Right lung has three lobes

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Lungs

• The left lung has two lobes

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Lungs

• Tertiary bronchi supply segments of lung tissue
  called bronchopulmonary segments

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Lungs

• Each bronchopulmonary segment consists of many
  small compartments called lobules

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Lungs

• Lobules contain
• 1. lymphatics

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Lungs

• 2. arterioles

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Lungs

• 3. venules

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Lungs

• 4. Terminal bronchioles

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Lungs

• 5. Respiratory bronchioles

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Lungs

• 6. Alveolar ducts

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Lungs

• 7. Alveolar sacs

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Lungs

• 8. alveoli

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Alveoli

• Have a surface area of 70 square meters

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Alveoli

• Consists of
• Type I alveolar cells (simple squamous)
• Type II alveolar cells (septal)
• Alveolar macrophages (dust cells)

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Alveoli

• Type II alveolar cells secrete alveolar fluid
  which keeps the alveolar moist

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Alveoli

• The alveolar fluid contains surfactant which
  prevents the collapse of alveoli with each
  expiration

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Alveoli

• Gas exchange occurs across the alveolar-capillary
  (respiratory) membrane

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Alveoli

• Respiratory membrane consists of the two layers
  of simple squamous cells and their basement
  membranes

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Pulmonary Ventilation

• Breathing

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Pulmonary Ventilation

• Process by which gases are exchanged between the
  atmosphere and lung alveoli.

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Inspiration

• Occurs when alveolar pressure fall below atm.
  pressure.

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Inspiration

• Contraction of the diaphragm and external
  intercostal muscles increases the size of the
  thorax.

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Inspiration

• Thus decreasing the intrathoracic pressure so
  that the lungs expand.

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Inspiration

• Expansion of the lungs decreases alveolar
  pressure to 758 mmHg.

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Inspiration

• Air moves along the pressure gradient from atm.
  760 into the lungs.

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Expiration

• Occurs when alveolar pressure is higher than atm.
  pressure (760).

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Expiration

• Relaxtion of the diaphragm and external
  intercostals results in elastic recoil of the
  chest wall and lungs which..

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Expiration

• 1. Increases intrathoracic pressure

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Expiration

• 2. Decreases lung volume

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Expiration

• 3. Increases alveolar pressure so that air moves
  from the lungs to the atmosphere

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Alveolar Surface Tension

• Causes the alveolar to assume the smallest
  diameter

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Alveolar Surface Tension

• Surface tension must be overcome to expand the
  lungs during each inspiration

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Alveolar Surface Tension

• It is the major component of elastic recoil,
  which acts to decrease the size of the alveoli
  during expiration

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Alveolar Surface Tension

• Surfactant decreases surface tension of the
  alveoli and prevents their collapse following
  expiration

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Lung Volumes and Capacities

• Tidal volume - amount of air inhaled or exhaled
  with each breath under resting conditions (500ml)

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Lung Volumes and Capacities

• Inspiratory reserve volume Amount of air that
  can be forcefully inhaled after a normal tidal
  volume inhalation (3100)

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Lung Volumes and Capacities

• During forced inspiration the muscles
  sternocleidomastoid and pectoralis minor are also
  used

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Lung Volumes and Capacities

• Expiratory reserve volume Amount of air that
  can be forcefully exhaled after a normal tidal
  volume exhalation (1200ml)

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Lung Volumes and Capacities

• Forced expiration employs contraction of the
  internal intercostals and abdominal muscles

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Lung Volumes and Capacities

• Vital capacity Maximum amount of air that can
  be exhaled after a maximal inspiration (4800ml)

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Lung Volumes and Capacities

• Residual volume Air remaining in the lungs
  after the expiratory reserve volume is exhaled
  (1200)

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Lung Volumes and Capacities

• Minute Volume of Respiration the total volume
  of air taken in during one minute

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Lung Volumes and Capacities

• Minute Volume of Respiration tidal volume x 12
  respirations per minute 6000ml/min

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Daltons law

• Each gas in a mixture of gases exerts its own
  pressure as if all the other gases were not
  present

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Daltons law

• Partial pressure of a gas the pressure exerted
  by that gas in a mixture of gases

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Daltons law

• Partial pressure of a gas of the mixture
  represented by the gas times the total pressure

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Daltons law

• Total Pressure (P) Add all the partial pressures

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External Respiration

• In internal and external respiration, O2 and CO2
  diffuse from areas of their higher partial
  pressures to areas of their lower partial
  pressures

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External Respiration

• Results in the conversion of deoxygenated blood
  coming from the heart to oxygenated blood
  returning to the heart.

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Internal Respiration

• Tissue Respiration

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Internal Respiration

• The exchange of gases between tissue blood
  capillaries and tissue cells.

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Internal Respiration

• Results in the conversion of oxygenated blood
  into deoxygenated blood

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Internal Respiration

• During exercise more O2 enters tissue cells than
  at rest

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Respiratory Center

• Area of the brain from which nerve impulses are
  sent to resp. muscles

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Respiratory Center

• Consists of
• Medullary rhythmicity area
• Pneumotaxic area
• Apneustic area

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Medullary Rhythmicity Area

• Controls the basic rhythm of respiration

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Medullary Rhythmicity Area

• Consists of
• Inspiratory area
• Expiratory area

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Medullary Rhythmicity Area

• The inspiratory area has autorhythmic neurons
  that set the basic rhythm of respiration

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Medullary Rhythmicity Area

• Expiratory area remains inactive during most
  quiet respiration but active during forced
  expiration

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Medullary Rhythmicity Area

• Inspiration last 2 seconds

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Medullary Rhythmicity Area

• Expiration lasts 3 seconds

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Pneumotaxic Area

• Coordinates the transition between inspiration
  and expiration

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Apneustic Area

• Sends impulses to the inspiratory area that
  activate it and prolong inspiration, inhibiting
  expiration

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Cortical Influences

• Allow conscious control of respiration

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Cortical Influences

• Needed to avoid inhaling noxious gasses or water

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Chemoreceptors

• Monitor levels of CO2 and O2 and provide input to
  resp. center

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Central Chemoreceptors

• Located in the medulla oblongota

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Central Chemoreceptors

• Respond to change in H concentration or PCO2 or
  both in cerebrospinal fluid

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Peripheral Chemoreceptors

• Located in the walls of systemic arteries

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Peripheral Chemoreceptors

• Respond to changes in H,PCO2, and PO2

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Hypercapnia

• A slight increase in PCO2 (and H) stimulates
  central chemoreceptors

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Hypercapnia

• The inspiratory area is activated and
  hyperventilation occurs

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Hypocapnia

• PCO2 is lower than 40 mm Hg

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Hypocapnia

• Chemoreceptors are not stimulated

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Hypocapnia

• Inspiratory area sets its own pace until CO2
  accumulates

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Hypoxia

• Oxygen deficiency at the tissue level

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Hypoxix Hypoxia

• Caused by low PO2 in arterial blood

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Hypoxix Hypoxia

• Caused by high altitude, airway obstruction,
  fluid in lungs

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Anemic Hypoxia

• Too little functioning hemoglobin

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Anemic Hypoxia

• Caused by hemorrhage, anemia, carbon monoxide
  poisoning

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Stagnant hypoxia

• The inability of blood to carry oxygen to tissues
  fast enough to sustain their needs

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Stagnant hypoxia

• Caused by heart failure, circulatory shock

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Histotoxic hypoxia

• Blood delivers adequate oxygen to the tissues,
  but the tissues are unable to use it properly

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Histotoxic hypoxia

• Caused by cyanide poisoning