Transcript Human Respiratory System

Human Respiratory System
Hanes Magnet School
7th Grade Science
Mr. Bombick
Human Respiratory Tract Outline
• Anatomy of the Respiratory Tract
(both Upper and Lower Tracts)
• Control of Breathing
• Physiology of Breathing
• Measurements of Human
Breathing
• Homeostatic Mechanisms of the
Respiratory System
• Diseases of the Respiratory Tract
Respiratory Tract-Anatomy
• The respiratory tract can be
divided into two major parts, the
upper and lower respiratory tract
• The upper respiratory tract
consists of the nose and the
pharynx
• The lower respiratory tract
consists of the trachea and the
lungs
Events in the Upper Respiratory Tract
The nose and pharynx make up the upper respiratory
tract. The upper respiratory tract has several
important functions which include the filtering of air,
the warming of the air, and humidifying the air before
the air reaches the lower respiratory tract.
The air finally flows into the region of the larynx.
Upper Respiratory Tract-Anatomy
Lower Respiratory Tract-Larynx
The larynx contains two major parts; the vocal
cords and the epiglottis. The epiglottis is a flap of
cartilage that helps prevent food from going into
the lower respiratory tract. Stimulation of the
larynx by ingested food also initiates a type of
coughing or gag reflex to help prevent food from
getting into the lower respiratory tract. A person
can choke on food if the epiglottis fails to close the
opening of the trachea.
The vocal cords consists of two folds of connective
tissue that becomes stretched and vibrated when
air passes through. The length of the vocal cords
determines the pitch of the sound and the volume
of sound is dependent on the intensity of
expiration. Sound is only produced when air is
passing through the cords. The production of sound
can definitely be under voluntary control.
Lower Respiratory Tract-Continued
• The trachea is the major airway from
the larynx to the two bronchi
• The trachea is surrounded by
cartilaginous rings that help maintain
the tubular shape
• Two bronchi branch off of the trachea
• The bronchi go into the lungs and start
to branch into smaller tubes called
bronchioles
• The terminal parts of the smallest
bronchioles create the alveolar sacs
where gas exchange occurs
Lower Respiratory Tract-Anatomy
Control of Breathing
Breathing is an automatic and rhythmic
action produced by bundles of neurons in
the pons and medulla of the hind brain.
Respiratory Physiology
Homeostasis of Respiration
• Central chemoreceptors of the
central nervous system are sensitive
to pH in the blood (increased CO2 in
the blood means more acidic
conditions and therefore, lower pH)
and adjust breathing rate
accordingly
• Peripheral chemoreceptors detect
variations of the oxygen in the
arterial blood, in addition to
detecting arterial CO2 and pH
(decrease in pH increases breathing
rate)
Homeostasis of Respiration (cont.)
• Mechanoreceptors are located in the airways and
lung lining to control reflex reactions that prevent
over inflation of the lungs. Other upper airway
mechanoreceptors control responses as coughing,
sneezing, closure of the glottis, and hiccups. A
spinal cord reflex is responsible for activation of
respiratory muscles for a gasping response,
hypoventilation, and increases in breathing
frequency and volume.
• In addition, respiration can be affected by
conditions such as emotional state (limbic system)
or temperature (hypothalamus).
• Voluntary control of respiration originates from
the cerebral cortex although chemoreceptors are
capable of overriding conscious control.
Emphysema
Normal Lung
Emphysema
Lung Cancer
Cystic Fibrosis
Respiratory Pathologies
• Cancers of the Respiratory System
(include all structures of the respiratory
system)
• COPD (Chronic Obstructive Pulmonary
Disease) includes chronic bronchitis and
emphysema
• Cystic Fibrosis
• Variety of infections (viral, bacterial,
protists, helminthes, nematodes, fungi,
etc.)
• Asthma