respiratory system
DESCRIPTION
Respiratory System. Respiratory System – Fig. 14-1. Includes the passages that transport air to and from the lungs, and the air sacs in which gas exchange occurs. Respiration is the entire process by which gases are exchanged between the atmosphere and the body cells. - PowerPoint PPT PresentationTRANSCRIPT
Respiratory System
Respiratory System – Fig. 14-1 Includes the passages that transport
air to and from the lungs, and the air sacs in which gas exchange occurs. Respiration is the entire process by which gases are exchanged between the atmosphere and the body cells.
http://www.youtube.com/watch?v=o2OcGgJbiUk&feature=related (Overview of respiratory system)
(Don’t get confused with cellular respiration which is the breakdown of food to produce chemical energy.)
Organs or the Respiratory System
Upper respiratory (outside thorax) – nose, larynx, & pharynx
Lower respiratory (within thorax) – trachea, bronchial tree, and lungs
Nose Supported by bone & cartilage Nostrils provide entrances for air
Organs or the Respiratory System
Nasal Cavity (space behind the nose) – Fig. 14-4 Divided medially by the nasal septum Nasal conchae divide the cavity into
passageways & help increase the surface area of the mucous membrane
Mucous membrane (Fig. 14-2) – filters, warms & moistens incoming air; particles trapped in the mucus are carried to the pharynx by ciliary action & are swallowed
Organs or the Respiratory System
Organs or the Respiratory System
Cilia
Submucosa
Pseudostratifiedepithelium
Mucous gland
Organs or the Respiratory System
Sinuses – Fig. 14-3 Spaces in the bones of the skull that
open into the nasal cavity Lined with mucous membrane that is
continuous with the lining of the nasal cavity
Function mainly to reduce weight of skull, they also serve as resonant chambers that affect the quality of the voice
Organs or the Respiratory System
Organs or the Respiratory System
Pharynx (throat) Located behind the mouth and between
the nasal cavity and the larynx Functions as a common passage for air
and food Aids in creating vocal sounds
Organs or the Respiratory System
Organs or the Respiratory System
Larynx – Fig. 14-5 Enlargement at the top of the trachea Serves as passageway for air & helps
prevent foreign objects from entering the trachea
Composed o muscles & cartilage Contains the vocal cords which produce
sounds by vibrating as air passes over them Pitch of sound is related to the tension of
cords Intensity is related to the force of the air
passing over the cords Glottis (space between vocal cords) &
epiglottis help prevent food & liquid from entering the trachea
Organs or the Respiratory System
1- vocal cords; 2 – vestibular fold; 3 – epiglottis; 4 – glottis; 5 – cartilage; 6 – sinus piriformis; 7 – base of the tongue
Organs or the Respiratory System
Larynx – Fig. 14-5 http://www.youtube.com/watch?v=aj
bcJiYhFKY (vocal cords)
Organs or the Respiratory System
Trachea – Fig. 14-6 Extends into the thoracic cavity in front
of the esophagus Divides into the right and left bronchi Mucous lining continues to filter
incoming air Wall is supported by incomplete (C
shaped) cartilaginous rings; keeps trachea from collapsing
Organs or the Respiratory System
Organs or the Respiratory System
Bronchial tree – Consists of branched air passages that
lead from the trachea to the air sacs Primary bronchi secondary bronchi
bronchioles alveolar ducts alveolar sacs alveoli
****Respiratory surface is alveoli – exchange of carbon dioxide and oxygen between alveoli & capillaries of circulatory system****
Organs or the Respiratory System
Bronchial tree (con’t) Structure of the respiratory tubes
As tubes branch the amount of cartilage in the wall decreases and the muscular layer becomes more prominent
Elastic fibers in the walls aid the breathing mechanism
Epithelial lining changes from pseudostratified & ciliated to cuboidal & simple squamous as tubes decrease in size
Organs or the Respiratory System
Organs or the Respiratory System
Organs or the Respiratory System
Lungs Left and right lungs are separated by the
mediastinum and are enclosed by the diaphragm & the thoracic cage
Visceral pleura is attached to the surface of the lungs; parietal lines the thoracic cavity
R. lung – 3 lobes; L. lung – 2 lobes Lobes contain – alveoli, nerves, blood
vessel, and lymphatic & connective tissue (no muscle tissue)
Organs or the Respiratory System
Organs or the Respiratory System
Breathing/Pulmonary Ventiliation – Fig. 14-11 – movement of air into & out of lungs Inspiration – air moves into lungs (atm.
Pressure = 760 mm Hg) Phrenic nerve impulses cause diaphragm to
contract As dome shaped diaphragm moves downward
the size of the thoracic cavity increases External intercostal muscles may contract
causing ribs to rise which causes in increase in the size of thoracic cavity
As size of thoracic cavity increases pressure within alveoli DECREASES (758 mm Hg)
Atm. Pressure which is greater on the outside forces air into respiratory tract
Lungs inflate
Breathing/Pulmonary Ventilation – Fig. 14-11 – movement of air into & out of lungs Expiration – air moves out of lungs
Diaphragm & external respiratory muscles relax
Elastic tissue of the lungs, thoracic cage and abdominal organs, which were stretched during inspiration suddenly recoil & surface tension causes alveolar walls to collapse
Pressure within the alveoli INCREASES (761 mm Hg) causing expiration of air out of lungs
Breathing/Pulmonary Ventilation – Fig. 14-11 – movement of air into & out of lungs
http://www.youtube.com/watch?v=q6-oyxnkZC0 (Boyles Law and ventilation)
Breathing/Pulmonary Ventilation – Fig. 14-11 – movement of air into & out of lungs Respiratory or Pulmonary Air
Volumes & Capacities – Fig. 14-13 Tidal volume – amount of air that
normally moves into or out of lungs during quiet breathing (approx. 500 ml)
Inspiratory reserve volume – additional air that can be inhaled (approx. 3000 ml)
Expiratory reserve volume – additional air that can be exhaled (approx. 1100 ml)
Residual volume – amount of air that remains in lungs (approx. 1200 ml)
Breathing/Pulmonary Ventilation – Fig. 14-11 – movement of air into & out of lungs Respiratory or Pulmonary Air
Volumes & Capacities – Fig. 14-13 Vital capacity – maximum amount of air a
person can exhale after taking the deepest breath possible
VC = TV + IRV + ERV Lung Capacity – TLC = VC + RV – varies
with age, sex, body size, athlete vs. non athlete
Residual air mixes with new air, this prevents concentrations of oxygen and carbon dioxide from fluctuating excessively with each new breath
Control of Breathing – normal breathing is rhythimic & involuntary, although the respiratory muscles can be controlled voluntarily Respiratory Center
Located in the brain stem and includes parts of the medulla oblongata & pons
Controls both inspiration & expiration & rates of breathing
Control of Breathing Factors affecting breathing
Breathing is affected by certain chemicals, the stretching of lung tissues & the persons emotional state
Chemosensitive areas are associated with the respiratory center CO2 combines with H2O to form H2CO3 which
in turn dissociates into HCO3- & H+
Chemosensitive areas mainly influenced by [H+], this concentration determines acidity of blood
Stimulation of these areas causes the breathing rate to increase
Control of Breathing Factors affecting breathing
Chemoreceptors in the carotid & aortic bodies Sensitive to low [O2] When [O2] is low increase breathing rate
An inflation reflex is triggered by stretching the lung tissues; this reflex reduces the duration of inspiratory movements & prevents over-inflation of the lungs during forceful breathing
Alveolar Gas Exchange – Internal Respiration
Alveoli Tiny sacs clustered at the distal ends of
the alveolar ducts Some alveoli have openings into adjacent
air sacs that provide alternate pathways for air when passages are obstructed
Respiratory Membrane/Surface Consists of the alveolar & capillary walls Gas exchange occurs here
Diffusion Gasses diffuse from regions of higher
concentration to lower concentration O2 diffuses from alveoli to capillaries; CO2 diffuses from capillaries to lungs
Organs or the Respiratory System
Organs or the Respiratory System
Transport of Gases – blood transports O2 & CO2 – Fig. 14-12
O2 transport Mainly combines with HB (hemoglobin) to
produce oxyhemoglobin O2 + Hb HbO2 HbO relatively unstable & releases O2 in
areas where [O2] pressure is low There is an increase in the release of O2 from
the blood when CO2 levels increase pH becomes more acidic blood temperature increases
Transport of Gases – blood transports O2 & CO2 – Fig. 14-12
CO2 transport Carried in solution either bound to Hb or as
HCO3-
Most CO2 transported as HCO3- (approx.
70%) CO2 + Hb HbNHCOOH (carbamino
hemoglobin) (approx. 23%) Some dissolved in plasma (approx. 7%)
Transport of Gases – blood transports O2 & CO2 – Fig. 14-12
Carbon monoxide – CO Combines with Hb more readily than O2 &
forms a stable compound Toxic because decreases Hb available for
transport of O2
Utilization of O2 – used for cellular respiration
C6H12O6 + 6O2 6CO2 + H2O + ATP