Lecture_4_the_respiratory_system.ppt

The Anatomy and
Physiology of the
Respiratory System
Kamera
Daeyang College of Nursing
4th October 2020

introduction
 Human body depends on the external
environment for survival
 We can survive without food and water for
some days, but we cannot do without
oxygen for even a little moment.
 Our body cell require a continuous supply
of oxygen to carry out their vital functions.
 The respiratory system provide the means
for gas exchange necessary to maintain
life.

Learning outcomes
 Describe the location and function of
different structures that make up the
respiratory system.
 Describe the function of the respiratory
system.
 Describe protective mechanisms of the
respiratory system.
 Differentiate between conducting and
respiratory zone structure.

Learning outcomes
 Describe the makeup of the respiratory
membrane and relate structure to function.
 Explain the relative roles of the respiratory
muscles and lung elasticity in producing the
volume changes that cause air to flow into
and out of the lungs.
 Explain physical factors that influence
pulmonary ventilation.

Learning outcomes
 Describe how oxygen and carbon dioxide
is transported in the blood.
 Describe the neural control of respiration.
 Describe factors that influence breathing
rate and depth.
 Explain and compare the various lung
volumes and capacities.
 Define dead space

Anatomy of the Respiratory system
 Nose
 Pharynx
 Larynx
 Trachea
 Bronchi
 Lungs –
alveoli

Functions of the Respiratory System
 Exchange of gasses
 Between the blood and the external
environment.
 Exchange of gasses takes place within
the lungs in the alveoli
 Filters, warms, and humidifies air
 Passageways to the lungs purify, warm,
and humidify the incoming air
 Influences speech – speech production
 Allows for sense of smell

Functions of the Respiratory System cont…
 Exchange of gasses – occurs through four
processes collectively respiration
1. Pulmonary ventilation
2. External respiration
3. Transport of respiratory gases
4. Internal respiration
 The respiratory system is responsible only
for the first two processes.

Functions of the Respiratory System cont…
 The respiratory system accomplish its
primary goal of obtaining oxygen and
eliminating carbon dioxide by working
closely with the circulatory system in the
third and fourth process.

cont…
 Structurally, the respiratory system can be
divided into upper and lower respiratory tract
(system)
 Upper respiratory tract (outside thorax)
consists of all the structures from the nose to
the larynx
 Nose
 Nasal Cavity
 Sinuses
 Pharynx
Divisions of the Respiratory System

 Upper
respiratory tract
(outside thorax)
 Nose
 Nasal Cavity
 Sinuses
 Pharynx

cont…
 Lower respiratory tract (within thorax)
consists of the larynx and all of the
structures below it.
 larynx
 Trachea
 Bronchial Tree
 Lungs

 Lower
respiratory tract
(within thorax)
 larynx
 Trachea
 Bronchial
Tree
 Lungs

cont…
 Functionally, the respiratory system can be
divided into two zones
 The conducting zone of the respiratory
system includes the organs and structures not
directly involved in gas exchange – from the
nose to the respiratory bronchioles.
 The respiratory zone – the site of gas
exchange, is composed of the respiratory
bronchioles, alveolar ducts and alveoli, all
microscopic structures.

Structures of upper Respiratory System
The Nose
 The major entrance and exit for the respiratory
system is through the nose.
 divided it into two major sections: the external
nose, and the nasal cavity or internal nose.

Structures of upper respiratory system
The Nose cont…
 The external nose consists of the surface and
skeletal structures that result in the outward
appearance of the nose and contribute to its
numerous functions.
 The root is the region of the nose located
between the eyebrows.
 The bridge is the part of the nose that connects
the root to the rest of the nose.

Structures of Upper Respiratory System
The Nose cont…
 The dorsum nasi is the length of the nose.
 The apex is the tip of the nose.
 On either side of the apex, the nostrils are
formed by the alae (singular = ala). An ala is a
cartilaginous structure that forms the lateral side
of each naris (plural = nares), or nostril
opening.
 The philtrum is the concave surface that
connects the apex of the nose to the upper lip.

The Nose cont…
 The nares open into the nasal cavity
(internal nose), which is separated into left
and right sections by the nasal septum.
 The nasal septum is formed anteriorly by a
portion of the septal cartilage (the flexible
portion you can touch with your fingers) and
posteriorly by the perpendicular plate of the
ethmoid bone (a cranial bone located just
posterior to the nasal bones) and the thin
vomer bones (whose name refers to its plough
shape).

The Nose cont…
 Each lateral wall of the nasal cavity has three
bony projections, called the superior, middle,
and inferior nasal conchae.
 The inferior conchae are separate bones,
whereas the superior and middle conchae are
portions of the ethmoid bone.
 Conchae serve to increase the surface area of
the nasal cavity and to disrupt the flow of air
as it enters the nose, causing air to bounce
along the epithelium, where it is cleaned and
warmed.

The Nose cont…
 The conchae and meatuses also conserve water
and prevent dehydration of the nasal epithelium
by trapping water during exhalation.
 The floor of the nasal cavity is composed of the
palate. The hard palate at the anterior region of
the nasal cavity is composed of bone.
 The soft palate at the posterior portion of the
nasal cavity consists of muscle tissue. Air exits
the nasal cavities via the internal nares and
moves into the pharynx.

Structures of the Upper Respiratory
Tract
 Nasal cavity
 Olfactory
receptors are
located in the
mucosa on the
superior surface.
 The rest of the
cavity is lined
with respiratory
mucosa.

Structures of the Upper Respiratory
Tract
 Nasal cavity
 warms and
moistens air.
 Traps incoming
foreign particles.
 Palatine bone
separates nasal
cavity from
mouth.

Structures of the Upper Respiratory Tract
 Nasal cavity
 Cleft palate -
Palatine bone
does not form
correctly,
difficulty in
swallowing and
speaking.
 Septum - separates
right and left nostrils

 Nasal cavity cont….
 Paranasal sinuses -
4 air containing
spaces – open or
drain into nose.
 cavities lies within
bones surrounding
the nasal cavity:
Frontal bone;
Sphenoid bone;
Ethmoid bone;
and Maxillary bone

Paranasal sinuses cont…
 Function of the sinuses
Lighten the skull (lowers weight of skull).
Act as resonance chambers for speech
Produce mucus that drains into the nasal
cavity

Pharynx (the throat)
 Muscular passage from nasal cavity to
larynx
 Three regions of the pharynx (Nasopharynx,
Oropharynx, and Laryngopharynx)

Nasopharynx
 posterior to the nasal cavity, inferior to
sphenoid bone and superior to the soft
palate.
 Lies above the point where food enters the
body, therefore serves only as an air
passageway.

Nasopharynx cont….
 High on its posterior wall is pharyngeal
tonsil – traps and destroys pathogens
entering the nasopharynx.

Pharynx (the throat) cont…
Oropharynx
 middle region behind (posterior) mouth
 Extends inferiorly from the level of the soft
palate to the epiglottis – both swallowed
food and inhaled air pass through it.
 The paired palatine tonsils lies embedded
in the lateral walls of the oropharyngeal
mucosa posterior to the oral cavity.

Oropharynx cont…
 The lingual tonsil covers the posterior
surface of the tongue.

Laryngopharynx –
Lies directly posterior to the larynx where
the respiratory and digestive pathways
diverge and extends to the inferior edge
of cricoid cartilage.
It is continuous with the esophagus
posteriorly.
Serves as a passageway for food and air

Laryngopharynx cont…
Lined with a stratified squamous
epithelium.
 NB: The oropharynx and laryngopharynx
are common passageways for air and food

Pharynx cont….
 Changes shape to allow for vowel sounds
= phonation.

Structures of the Lower Respiratory Tract
 Lower
respiratory tract
(within thorax)
 larynx
 Trachea
 Bronchial
Tree
 Lungs

 Larynx - voice box
 Connects pharynx
to trachea.
 Made of nine rigid
hyaline cartilages
and a spoon-
shaped flat of
elastic cartilage
(epiglottis)

 Larynx - voice box
cont…
 2 pairs of folds
 Vestibular - false
vocal cords
 True vocal cords

 Larynx - voice box cont..
 Functions
 Provide a patent
airway.
 Act as switching
mechanism to
routes air and food
into proper
channels.
 Plays a role in
speech (voice
production)

larynx cont…
 Thyroid cartilage -
Adam’s apple –
 The eighth hyaline
cartilage
 largest hyaline
cartilage (larger in
males due to
testosterone.)

larynx cont…
Epiglottis –
 flexible and spoon-
shaped situated
above the glottis
 Extends from
posterior aspect of
tongue to its
anchoring point on
the anterior rim of
the thyroid cartilage

larynx cont…
Epiglottis –
 moves when
swallowing and
speaking.
 closes off trachea
when swallowing
food

 larynx cont…
 epiglottis
 Explain how the epiglottis route food to
the larynx and air towards the trachea.

 larynx cont…
 Vocal cords (vocal folds)
Vibrate with expelled air to create sound
(speech)
 The vocal cords and the medial opening
between vocal cords through which air
passes into the trachea are called the glottis

 larynx cont…
 Inflammation of vocal cords or laryngitis
causes the vocal cords to swell therefore
interfering with their vibration.
 Read with understanding on voice
production and make notes

 Trachea (windpipe)
 Connects Larynx
with bronchi
 Lined with ciliated
mucosa.
 Consists of smooth
cartilage and C
shaped rings of
cartilage.

 Trachea (windpipe)
cont…
 Tracheostomy -
cutting of an
opening in trachea
to allow breathing.

 Bronchi
 Tubes that branch
off trachea and
enter into lungs at
the level of T7.
 Ciliated
 Branches:
Primary enters the
lungs at the hilus
(medial
depression)

 Bronchi cont ….
 right bronchus is
wider, shorter,
and more vertical
than left.
 Therefore , it
more common for
an inhaled foreign
object to get stuck
in the right
bronchus

 Bronchi cont…
 bronchi—secondary
bronchi—tertiary
bronchi—
bronchioles
 Bronchioles branch
into microscopic
alveolar ducts.
Terminate into
alveolar sacs
 Gas exchange with
blood occurs in

Summary of the respiratory tree divisions
 Primary bronchi
 Secondary bronchi
 Tertiary bronchi
 Bronchioli
 Terminal bronchioli

Lungs
 Extend from
diaphragm to
clavicles
 Occupy most of the
thoracic cavity
 Divided into lobes
by fissures. (left
lung – 2 robes; right
lung – 3 robes)

 Lungs cont…
 The right and left lungs differ in size and
shape to accommodate other organs that
encroach on the thoracic region.
 The right lung consists of three lobes and is
shorter than the left lung, due to the position
of the liver underneath it.

 Lungs cont….
 The left lung consist of two lobes and is
longer and narrower than the right lung.
 The left lung has a concave region on the
mediastinal surface called the cardiac notch
that allows space for the heart.

Bronchioles
(Plural – bronchi)

The lungs cont..
Blood supply of the lungs
 Lungs perfused by two circulation:
Pulmonary
bronchial

The lungs cont..
Blood supply of the lungs
 Pulmonary
Systemic venous blood to be oxygenated
in the lungs is delivered by the pulmonary
arteries
Pulmonary veins convey the freshly
oxygenated blood from the respiratory
zone of the lungs to the heart

The lungs cont..
Blood supply off the lungs
 Bronchial
The bronchial arteries which arises from
the aorta provide oxygenated systematic
blood to all lung tissue expect the alveoli.
The tiny bronchial veins drain some
systemic venous blood from the lungs but
most venous blood returns to the heart via
pulmonary veins.

The lungs cont..
Covering of the lungs
 Pulmonary (visceral) pleura covers the lung
surface
 Parietal pleura lines the walls of the thoracic
cavity and the superior face of diaphragm
 Pleural fluid fills the area between layers of
pleura to allow gliding
 Pleurisy = inflammation of the pleural lining

The alveoli
 Structure of alveoli
 Alveolar duct
 Alveolar sac
(alveolar sccules)
 Alveolus
 Gas exchange

Respiratory Membrane (Air-Blood Barrier)
 The wall of the alveoli are composed
primarily of a single layer of squamous
epithelial cells surrounded by a flimsy
basement membrane.
 The external surface of the alveoli is covered
with a “cobweb” of pulmonary
 Together, the capillary and the alveolar wall
and their fused basement membrane form
the respiratory membrane.

The respiratory Membrane (Air-Blood
Barrier)

Gas exchange
 Gas crosses the respiratory membrane by
simple diffusion
Oxygen enters the blood
Carbon dioxide enters the alveoli
 Macrophages add protection (Marieb p 841)
 Surfactant coats gas-exposed alveolar
surfaces to reduce the surface tension of the
alveolar fluid. (refer Marieb p 847)

Events of respiration
 Pulmonary ventilation (PV) – moving air in
and out of the lungs (commonly called
breathing)
 i.e. it consist of inspiration and
expiration.
 External respiration – gas exchange between
pulmonary blood and alveoli

Events of respiration cont…
 Respiratory gas transport – transport of
oxygen and carbon dioxide via the
bloodstream
 Internal respiration – gas exchange between
blood and tissue cells in systemic capillaries

Respiratory physiology
Pressure relationship in the thoracic cavity
 Respiratory pressures are always described
relative to atmospheric pressure.
 Intrapulmonary pressure.
 Intrapleural pressure
 Transpulmonary pressure

Respiratory physiology
Pulmonary Ventilation (breathing)
 Completely mechanical process
 Depends on volume changes in the thoracic
cavity
 Volume changes lead to pressure changes, which
lead to the flow of gases to equalize pressure
 Two phases
inspiration
Expiration

Respiratory Physiology
Pulmonary Ventilation
(breathing)
 Mechanism
 Movement of gases
through a pressure
gradient - hi to low.
 When atmospheric
pressure (760
mmHg) is greater
than lung pressure -
--- air flows in =
inspiration.

Pulmonary Ventilation
(breathing) cont….
 When lung pressure
is greater than
atmospheric
pressure ---- air
flows out =
expiration.

 Pressure gradients are established by
changes in thoracic cavity.
 increase size in thorax = a decrease in
pressure --- air moves in.
 Decrease size in thorax = increase in pressure
--- air moves out.

http://people.eku.edu/ritchisong/301notes6.htm

Inspiration
-contraction of diaphragm and intercostal
muscles

Inspiration cont…
 Inspiratory muscles contract (diaphragm and
descends; the rib cage rises).
 The size of the thoracic cavity increases
 The lungs are stretched; intrapulmonary
volume increases.
 Intrapulmonary pressure drops (to -1mm Hg)
 External air is pulled into the lungs due to an
increase in intrapulmonary volume and down
its pressure gradient until intrapulmonary
pressure is 0 (equal to atmospheric pressure).

Expiration
 relaxation of diaphragm and intercostal
muscles

Expiration cont…
 Largely a passive process which depends on
natural lung elasticity
 As muscles relax, air is pushed out of the
lungs
 Forced expiration can occur mostly by
contracting internal intercostal muscles to
depress the rib cage

Expiration cont…
 Inspiratory muscles relax (diaphragm rises:
rib cage descends due to recoil of costal
cartilage)
 Thorax cavity volume decreases
 Elastic lungs recoil passively;
intrapulmonary volume decreases.
 Intrapulmonary pressure rises to + 1
mmHg)
 Air (gases) flows out of thee lungs down its
gradient until intrapulmonary pressure is 0

Volumes of Air Exchange
 Tidal volume - amount of air inhaled or
exhaled with each breath under resting
conditions. Normal - about 500 ml
 Expiratory Reserve volume - additional
amount of air forcibly expired after tidal
expiration (1000 - 1200 ml).
 Inspiratory Reserve volume - (deep
breath) amount of air that can be forcibly
inhaled over and above normal.
 Residual volume - amount of air that stays
trapped in the alveoli and blood (about 1.2
liters).

Volumes of Air Exchange cont…
 Vital capacity - the largest volume of air
an individual can move in and out of the
lungs.
 Vital capacity = sum of IRV+TV+ERV
 Depends on many factors
 size of thoracic cavity
 posture
 volume of blood in lungs 
congestive heart failure, emphysema,
disease, etc…

Volumes of Air Exchange cont…
 Functional residual volume (FRC)
Volume of air remaining in the lungs after
a normal tidal volume expiration.
Usually about 2200-2400 ml
FRC = ERV +RV
 Respiratory capacities are measured with a
spirometer

Volumes of Air Exchange
 Eupnea - normal quiet breathing, 12-15
breaths per minute.
 Hyperpnea - increase in breathing to meet
an increased demand by body for oxygen.
 Hyperventilation - increase in pulmonary
ventilation in excess of the need for
oxygen.
 Someone hysterical Breathe into
 exertion paper bag.
 Hypoventilation - decrease in pulmonary
ventilation.
 Apnea - temporary cessation of breathing
at the end of normal expiration.

respiratory sounds
 Sounds are monitored with a stethoscope
 Bronchial sounds – produced by air rushing
through trachea and bronchi
 Vesicular breathing sounds – soft sounds of
air filling alveoli

External respiration
 Oxygen movement into the blood
The alveoli always has more oxygen than
the blood
Oxygen moves by diffusion towards the
area of lower concentration
Pulmonary capillary blood gains oxygen

External respiration cont…
 Carbon dioxide movement out of the blood
Blood returning from tissues has higher
concentrations of carbon dioxide than air
in the alveoli
Pulmonary capillary blood gives up
carbon dioxide
 Blood leaving the lungs is oxygen-rich and
carbon dioxide-poor

gas transport in the blood
 Oxygen transport in the blood
Inside red blood cells attached to
hemoglobin (oxyhemoglobin [HbO2])
A small amount is dissolved in the plasma
Oxygen is poorly soluble in water so only
about 1.5% of oxygen transported is
carried in dissolved form.

gas transport in the blood cont..
 Carbon dioxide transport in the blood
Most of carbon dioxide is transported in
the plasma as bicarbonate ion (HCO3
–)
A small amount is carried inside red blood
cells on hemoglobin, but at different
binding sites than those of oxygen

internal respiration
 Exchange of gases between blood and body
cells
 An opposite reaction to what occurs in the
lungs
 Carbon dioxide diffuses out of tissue to
blood
 Oxygen diffuses from blood into tissue

 External
Respiration, Gas
Transport, and
Internal Respiration
Summary

Neural Regulation of Respiration

Neural Regulation of Respiration cont..

Factors Influencing Respiratory Rate and
Depth
 Physical factors
Increased body temperature
Exercise
Talking
Coughing
 Volition (conscious control)
 Emotional factors

Depth cont…
 Chemical factors
Carbon dioxide levels
 Level of carbon dioxide in the blood is
the main regulatory chemical for
respiration
 Increased carbon dioxide increases
respiration
 Changes in carbon dioxide act directly
on the medulla oblongata

Depth cont…
 Chemical factors cont….
Oxygen levels
Changes in oxygen concentration in the
blood are detected by chemoreceptors in
the aorta and carotid artery
Information is sent to the medulla
oblongata

references
 Merieb, E.N. and Hoehn, K. (2016). Human
Anatomy and Physiology (10th ed.) Pearson
Education Limited.
 McKinley, M.P., O’Loughlin, V.D and Bidle,
T.S. (2013) Anatomy and Physiology: an
intergrative approach. (1st ed.) McGraw Hill
Co.

Lecture_4_the_respiratory_system.ppt

Recommended

Recommended

More Related Content

Similar to Lecture_4_the_respiratory_system.ppt

Similar to Lecture_4_the_respiratory_system.ppt (20)

More from Alick12

More from Alick12 (20)

Recently uploaded

Recently uploaded (20)

Lecture_4_the_respiratory_system.ppt