Chapter 2: Chemistry, Matter, and Life

Transcription

Cohen: Memmler’s The Human Body in Health and Disease
Phases of Respiration
Respiration:
• Process of obtaining oxygen from environment and
delivering it to cells
Phases of Respiration
Chapter 18:
The Respiratory
System
1. Pulmonary ventilation – between air and lungs
2. External gas exchange – between lungs and blood
3. Gas transport in the blood – carries oxygen and CO2
4. Internal gas exchange – between blood and tissue cells
Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins
Figure 18-1 Overview of respiration.
From which side of the heart
does blood leave to travel
to the lungs?
To which side does it return?
Structures of the Respiratory System
The Nasal Cavities – open spaces between roof of
mouth and cranium
Figure 18-2 The respiratory system.
What organ is located in the medial depression of the left lung?
The Pharynx – the throat; carries air to lungs and
food to stomach
• Nostrils (nares) – air enters here
– Nasopharynx - Superior portion near nose
• Nasal septum –partition that divides nostrils
– Oropharynx - Middle portion near mouth
• Conchae – shell-like projections inside cavity
– Laryngeal pharynx - Inferior portion near larynx
• Air is Filtered, Warmed, Moistened by mucus
membranes
1
Figure 18-3 The larynx.
The Larynx
• Cartilage framework between pharynx and trachea;
(Adam’s apple)
– Epiglottis – flap that closes over esophagus
– Vocal cords – used for speech as air flows over them
– Glottis – opening in the vocal cords
The Trachea
The Lungs
• Takes air to lungs; horseshoe-shaped rings of cartilage
to keep shape
Located on either side of mediastinum
The Bronchi
• Two primary branches that enter the lungs from the
trachea
• Right lung – divided into three lobes that match bronchi
• Left lung – divided into two lobes that match bronchi
– Bronchial tree branches of the bronchi into the lungs
– Bronchioles – smaller, narrower branches
– Terminal bronchioles – end of the branches
• Alveoli – air sacs at the end of bronchioles
– Thin walls – one cell thick to allow gases to pass
– Surface area 60 square meters (volleyball court)
The Process of Respiration
The Pleurae
Pulmonary Ventilation
• Diaphragm – muscle that sits below lungs
• Inhalation (inspiration) is active phase in which the
diaphragm and chest muscles contract
• Parietal pleura - connective tissue coverings of the
lungs
– Surfactant – substance to reduce the surface tension
of fluids in lungs; allows lungs to expand
• Exhalation (expiration) is passive phase; muscles relax
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Figure 18-6 Pulmonary ventilation.
Pulmonary Ventilation
• Lung volumes
– Tidal volume – regular relaxed breathing
– Residual volume – volume of air left in lungs
– Inspiratory reserve volume – breathing in beyond
normal breath
– Expiratory reserve volume – breathing out beyond
normal breath
– Vital capacity– volume breathed out after deep
breath
What muscles are located
between the ribs?
Figure 18-8 A spirogram.
– Functional residual capacity- volume left after normal
breath
– Total capacity- total volume of air in lungs
Gas Exchange
• External exchange— between alveoli and capillaries
– Oxygen leaves alveoli and enters capillaries
– Carbon dioxide leaves capillaries and enters alveoli
• Internal exchange— between body tissue and capillaries
– Oxygen leaves capillaries and enters tissue
– Carbon dioxide leaves tissue and enters capillaries
What lung volume cannot be measured with a spirometer?
Which lung capacities cannot be measured with a spirometer?
Figure 18-9 Gas exchange.
Process of Respiration
Transport of Oxygen
• Most oxygen is transported in blood by hemoglobin.
Transport of Carbon Dioxide
• 10% is dissolved in plasma and fluid in red blood cells
• 15% is combined with protein of hemoglobin and
plasma proteins
• 75% dissolves in blood fluids and is converted to
bicarbonate ion
3
Figure 18-10 Regulation
of respiration.
Nervous Control –
your brain is in control
Regulation of Respiration
Chemical Control
• Central chemoreceptors
• Control center is
located in medulla and
pons of brain stem
– Located near medulla
• Fibers extend from the
spinal cord, through
phrenic nerve to
diaphragm and chest
muscles
• Peripheral chemoreceptors
– Respond to raised CO2 level (hypercapnia)
– Located in neck and aortic arch
– Respond to oxygen level considerably below normal
• Other factors such as pain or emotional responses can
affect breathing patterns
Abnormal Ventilation
Breathing Patterns
• Hyperventilation
Measured in breaths per minute
– High oxygen level and low CO2 level (hypocapnia)
• Adults: 12 to 20 bpm
– Increases blood pH
• Children: 20 to 40
• Hypoventilation
• Infants: more than 40
– Insufficient air in alveoli
– Decreases blood pH
Some Terms for Altered Breathing
Results of Inadequate Breathing
• Hyperpnea- increase in depth and rate
• Cyanosis – bluish color due to insufficient O2
• Hypopnea- decrease in depth and rate
• Hypoxia – lower than normal oxygen in tissues
• Tachypnea- excessive rate, as in exercise
• Hypoxemia – lower than normal oxygen in blood
• Apnea – temporary cessation for short periods
• Suffocation- cessation of breathing due to some
blockage
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Chapter 2: Chemistry, Matter, and Life

Transcription

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