2-10-12 Friday

PHYS
Chapter 16: Respiratory

Phases-process of obtaining O2 from environment
-pulmonary ventilation
-external exchange of gases-lungs
-internal exchange of gases-tissue

75% o2 saturation of blood entering Right atrium
95-99% o2 sat leaving left ventricle

Respiratory system
into lungs:
nasal cavities
pharynx
larynx
trachea (windpipe)
bronchi

Nasal cavity:
nostrils (nares)
mucous membrane (epithilial stratified squamous)
-filters foreign bodies
-warms tissue
-moistens air (humidifies)
conchae
nasal septum
sinuses

Pharynx: carries air to respiratory tract and food digest system
-nasopharynx
superior portion
-odopharynx
middle portion
-laryngeal pharynx
inferior portion

Larynx: voice box, b/w pharynx and trachea
-cartilage framework
thyroid cartilage (adam's apple)
-vocal folds (vocal cords)
used for speech
-glottis
-epiglottis

Trachea: windpipe; air b/w larynx and lungs
framework
horseshoe shape
open at back for expansion during swallowing

Bronchi:
trachea divide into 2 primary bronchi enter:
lungs
hilum
epithelial tissue lining
-pseudostratified
-cilia
right lung more likely to get foreign body due to bigger bronchi
-anatomical dead space

Lungs
-mediastinum: space between
-lobes
bronchial tree
bronchioles
alveoli
-diaphragm
-pleura: covering of lungs
parietal pleura: body cavity
visceral pleura: on organ
pleural space: between the two

Process of respiration
ventilation of lungs
exchange gases
transport of gases in blood
creates a vacuum
pressure gradient

Pulmonary vent.
inhalation is active phase
compliance
exhalation is passive phase
lung capacity

Gas exchange
diffusion of mvmt of molecules higher to lower concentration
external exchange
-gases move between alveoli and capillary blood
internal exchange
-gases move between blood and tissue

Transport of o2
-most o2 in capillary blood binds to hemoglobin
-o2 must separate from hemoglobin to enter cells

Transport of co2
10% dissolved in plasma and fluid in rbc
15% is combined with protein of hemoglobin and plasma protein
75% dissolves in blood fluids and is converted to bicarbonate ion (baking soda)
-first combines with water to form carbonic acid
-carbonic acid ionized (separates) into hydrogen and bicarb
-carbonic anhydrase enzyme spend conversion?
-buffers blood to keep pH steady

Regulation of respiration
fundamental resp. pattern
controlled by CNS centers
partly in medulla (main control centers), partly in ....

Nervous Control
medulla and pons
motor nerves fibers extend into spinal cord
**fibers extend through PHRENIC NERVE to diaphragm

Chemical control
-central chemoreceptors
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-peripheral chemoreceptors