Respiratory System Cardiovascular System. The Respiratory System.
6 the Respiratory System
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Transcript of 6 the Respiratory System
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Anatomy of the Larynx
Thyrohyoidmembrane
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Cartilages of the Larynx
Hyaline cartilage:
1 thyroid cartilage 1cricoid cartilage
2 arytenoid cartilage
Fibroelastic cartilage:- the epiglottis
Thyrohyoidmembrane
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The Thyroid Cartilage
Laminae are separated, v-shape notch known as thyroidnotch
Upper part lined with
stratified squamous epithelium,
lower part with
ciliated columnar epitheliumThyrohyoidmembrane
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The Cricoid Cartilage
This lies below thyroid cartilage
Shaped like ring, circling the larynx with a narrow partanteriorly, broad part posteriorly
Broad part articulates with
arytenoid cartilages,
inferior cornu of
thyroid cartilage
lined with ciliatedcolumnar epithelium
Thyrohyoidmembrane
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The arytenoid cartilages:
Two roughly pyramid shaped
situated on top of broad part of cricoid cartilage
give attachment to vocal cords & muscles
lined with ciliated columnar epithelium
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The Epiglottis
Leaf shaped fibroelastic cartilage
Attached to the inner surface of the anterior wall of
thyroid cartilage, below thyroid notch
Covered with stratified squamos epithelium
Larynx is likened to a box and
epiglottis as a lid
So it closes of larynx during
swallowing & protect the lungs
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Interior of the larynx:
Vocal cords are two pale folds of mucousmembrane from the inner side of thyroid cartilage
anteriorly to the arytenoid cartilages posteriorly.
Muscles controlling the vocal cords are
Relaxed Contracted
Vocal cords open
(Abducted)
Vocal cords stretched out
(Adducted)
Pitch of the sound is low Pitch of the sound is high
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The Glottis
Vocal cord
abducted
Vocal cord
adducted
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Functions:
Production of sound:
1. Voice depends upon the length and tightness of vocal cord
2. Volume of the voice depends upon the force with which cords
vibrate
greater the force of expired air
more cords vibrate and the louder sound emitted3. Tone is depending upon the shape of the mouth, position
of tongue, lips, facial muscles and air in Para nasal sinuses
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Speech: This occurs during expiration when the sounds
produced by the vocal cords are manipulated by the
tongue, cheeks and lips
Protection of the lower respiratory tract: During
swallowing, larynx moves upwards, and epiglottis closes
over the larynx.
Passageway of air: between pharynx and trachea
Humidifying, filtering and warming
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What is the structure ofairways outside the lungs?
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Gross Anatomy of the Lungs
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The Lungs Two lungs, cone shaped having an
apex, base, costal surface & medialsurface
The Apex : rounded, rises into the rootof the neck, about 25 mm (1 inch)above the clavicle
structures associated: first rib, blood
vessels & nerves in root of the neck
The Base: concave in shape.
closely associated with the thoracic
(superior) surface of the diaphragm
Position and associated structures:
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The Costal surface: Surface is convex.
closely associated with cartilages, the ribs and
the intercostals muscles
The Medial surface: Surface is concave & has
roughly triangular shaped area called hilum atthe level of 5th, 6th & 7th thoracic vertebrae
Structures which form root of the lung enter &
leave at the hilum, include
primary bronchus,
-pulmonary artery supplying
the lung & two pulmonary veins draining it,
- bronchial artery & veins, and
-the lymphatic and
-nerve supply
Area betn the lungs is the mediastinum occupied by the heart, great vessel, trachea,
right and left bronchi, oesophagus, lymph nodes, lymph vessels and nerves
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The Right Lung:
Has 3 lobes: superior, middle, and inferior
separated by horizontal and oblique fissures
Organization of the Lungs:
The Left Lung: It is smaller as the heart is situated left of the midline
Has 2 lobes:
superior and inferior
are separated by an oblique fissure
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Pleura and Pleural Cavity:
Pleura consists of a closed sac of serous membrane which contain
small amount of serous fluid
Lung is invaginated into this sac so that it forms two layers:
One adheres to the lung and other to the wall of thoracic cage
The Visceral Pleura: adherent to the lung
The Parietal Pleura: adherent to the inside of the chest wall &
the thoracic surface of the diaphragm
The Pleural cavity: Two layers of pleura are separated by only
a thin film of serous fluid,
1.which allows them to glide over each other
2. prevent friction between them during breathing
Serous fluid is secreted by the epithelial cells of the serous membrane
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Interior of the Lung:
composed of the bronchi and smaller air passages, alveoli, connective
tissue, blood vessels, lymph vessels, nerves.
Pulmonary blood supply: pulmonary artery divides into two, one
branch conveying deoxygenated blood to each lung
Within the lungs,
Walls of the alveoli and capillaries each consist of only one layer offlattened epithelial cells
Exchange of gases between air in the alveoli and blood in the
capillaries takes place across this two very fine membranes
The Pulmonary capillaries join up and become two pulmonary veins
in each lung,
Which leave the lungs at hilum and convey oxygenated blood to the
left atrium of the heart
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Relationship between Lungs and Heart
Figure 238
i i
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Refers to 2 integrated processes:
external respiration
internal respiration
External Respiration
Includes all processes involved in exchanging O2 and CO2 with
the environment
Internal Respiration
Also called cellular respiration
Involves the uptake of O2 and production of CO2 within individual
cells
Respiration
Inflation and deflation of the lungs with each breath ensures that
regular exchange of gases
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Muscles of respiration:
In normal breathing,
Intercostal muscles and diaphragm
During difficult or deep breathing,
They are assisted by the muscles of neck, shoulders and abdomen
Intercostal muscles:11 pairs of muscles that occupy the spaces between the 12 pairs of ribs
Arranged in two layers,External And Internal Intercostal Muscle
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The first rib is fixed, therefore, when intercostal muscles contract
they pull all the ribs towards first rib
Bcoz of the shape they move outward, when pulled upward
In this way thoracic cavity enlarged anteriorly, posteriorly and
laterally
Intercostal muscles are stimulated to contract by intercostal nerves
Diaphragm
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Diaphragm
Dome shaped structure separating the thoracic and abdominal cavities
forms the floor of the thoracic cavity and roof of the abdominal cavity
It consist of central tendon from which muscle fibres radiate to be attached tothe lower ribs and sternum
It is supplied by the Phrenic nerves
When the muscle of diaphragm,
Relaxed Contracts
central tendon is at the level
8th thoracic vertebra 9th thoracic vertebra
(muscle fibre shortens, central
tendon pulled downwards)
Enlar in the thoracic cavit
decreases pressure in the thoracic cavity
and increases it in the abdominal and
pelvic cavities
Intercostal muscles & diaphragm
contract simultaneously ensure
enlargement from all side
Cycle of respiration:
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Cycle of respiration:
This occur 12 to 15 times per minute and consists of three phases:
Inspiration Expiration Pause
I i i i f h i i i d
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Inspiration: capacity of thoracic cavity increased
by simultaneous contraction of both muscles
Parietal pleura moves with the walls of thoraxand the diaphragm
Reduces pressure in the pleural cavity than atmospheric pressure
Visceral pleura follows parietal pleura &
pulling lung with it
Stretches the lungs & the pressure within alveoli fall down
in order to equalize atm. & alveolar pressure
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Expiration: Relaxation of the both muscles results in
Downward and inward movement of rib cage &
elastic recoil of lungs
Pressure inside the lungs exceeds that in the
atmosphere
And therefore air is expelled
Inspiration Expiration
active process passive process
Requires expenditure of energy not require
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Blood flow
to alveolus
Blood flow
from alveolus
PO2 100 mm Hg
PCO2 40 mmHg
Atmospheric Air
PO2 40 mm Hg
PCO2 44 mmHg
PO2 100 mm Hg
PCO2 40 mmHg
Blood Capillary
Pulmonary
Artery
Pulmonary
Vein
Fig. External Respiration : Exchange of gases between alveolar air
and capillary blood
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CO2
O2
Diffusion of Co2
Blood Flow
Diffusion of O2
Cells
Tissue fluid
Venous end of
capillary
Fig. Internal respiration : exchange of gases betn capillary and tissues
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Transport of gases in the blood stream:
Transport of blood oxygen and Carbon dioxide necessary for
internal respiration
Oxygen: present with heamoglobin 98.5%
present in plasma water 1.5 %
Dissociates from these
Factors of dissociation: increased CO2 level in tissue fluid,
raised temp., 2,3- diphosphoglycerate present in RBC
In active tissues increased production of CO2 and heat
leads to increase release of oxygen
Carbon dioxide: waste product of metabollism
1. In the form of bicarbonate ions in the plasma 70 %
2. In the plasma 7%, 23 % heamoglobin
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Control of respiration
The respiratory center
Chemoreceptors
Peripheral receptors
Heiring-Breur reflex
Other factors: singing, speeking,
laughing, crying, sneezing and other
environmental factors