Chapter 19 - respiratory system Flashcards
Describe the primary functions of the respiratory system
learner Objective
The primary functions of the respiratory system are:
the intake of oxygen
and
the removal of carbon dioxide
identify the organs of the upper respiratory system and describe their functions
(learner Objective)
The upper respiratory system consist of the
A. Nose: allows air to enter and leave via the nostrils.
B. Nasal cavity: helps to warm and moisten air, using mucus to trap particles.
C. Paranasal sinuses: reduce the skulls weight and effect the quality of the voice.
D. Pharynx: carries food from the oral cavity to the oesophagus and allows air to pass from the nasal cavity to the larynx; helps produce the sounds of speech.
describe the structure of the airway outside the lungs
learner Objective
outside of the lungs, the trachea or windpipe splits into the right and left bronchi.
branched airways leading from the trachea to the alveoli make up the bronchial tree.
these branches begin with the right and left primary bronchi, with each dividing into a secondary bronchus, then into tertiary bronchi, and even finer tubes.
bronchioles are the smaller tubes that continue to divide.
describe the functional anatomy of the alveoli.
learner Objective
The alveoli are microscopic air sacks inside capillary networks of the lungs.
they provide a large surface of epithelial cells that allow easy exchange of gases.
oxygen defuses from the alveoli into the capillaries, and carbon dioxide defuses from the blood into the alveoli.
define and compare the processes of internal and external respiration
(learner Objective)
external respiration is defined as gas exchange between air in the lungs and blood.
Internal respiration is defined as gas exchange between blood and cells.
Describe the major steps involved in external respiration.
learner Objective
External respiration consists of ventilation, which is the movement of air from outside of the body into and out of the bronchial tree and alveoli.
During normal inspiration, when inside pressure decreases, atmospheric pressure pushes outside air into the airways.
Phrenic nerve impulses stimulate the diaphragm to contract, moving downward. The thoracic cavity enlarges, internal pressure falls, and atmospheric pressure forces air into the airways. As the diaphragm contracts, the external intercostal muscles contract. The ribs raise and the sternum elevates. The lungs expand in response, and the thoracic wall moves upward and outward. There is an opposing effect in the alveoli.
explain the important structures of the respiratory membrane
learner Objective
The respiratory membrane is located in the alveoli.
The inner lining is made up of simple squamous epithelium.
Dense networks of capillaries are found nearby.
At least two thicknesses of epithelial cells and a fused basement membrane layer separate the air in an alveolus form the blood in a capillary.
These layers make up the respiratory membrane; it is here where blood and alveolar air exchange gases.
Describe how oxygen is picked up, transported and released in the blood
(learner Objective)
As oxygen from the lungs enters the blood, it dissolves in the plasma along with carbon dioxide from the cells or combines with blood components.
About 98% of the oxygen transported by the blood binds the iron containing protein haemoglobin in red blood cells. The remainder dissolves in the plasma.
In the lungs, oxygen dissolves in blood and combines rapidly with the iron atoms of haemoglobin to form oxyhemoglobin.
As the partial pressure of oxygen decreases, oxyhemoglobin molecules release oxygen, diffusing into nearby cells that have depleted their oxygen supplies in cellular respiration. When carbon dioxide increases in the blood, more oxygen is released.
Describe the factors that influence the respiration rate
learner Objective
Respiration rate is controlled by the respiratory areas of the brain, in the the brainstem: the pons and the medulla oblongata.
The medullar respiratory centre consists of the dorsal and ventral respiratory groups and the respiratory group of the pons.
The dorsal group is important in stimulating the muscles of inspiration.
Increased impulses result in more forceful muscle contractions and deeper breathing.
Decreased impulses result in passive expiration.
The ventral group controls mostly the intercostal and abdominal muscles to increase inspiratory efforts.
Certain chemicals also affect breathing rate and depth, as do emotional states, lung stretching capability, and physical activity.
Identify the four distinct respiratory volumes
learner Objective
- Tidal Volume: approx. 500ml moved into or out of lungs during respiratory cycle.
- Inspiratory Reserve Volume: Approx. 3,000ml inhaled during forced breathing in addition to tidal volume.
- Expiratory Reserve Volume: Approx. 1,100ml exhaled during forced breathing in addition to tidal volume.
- Residual Volume: Approx. 1,200ml remaining in lungs even after maximal expiration.
upper respiratory tract includes
Nose
Nasal Cavity
Paranasal Sinuses
Pharynx
lower respiratory tract includes
Larynx
Trachea
Lungs
thyroid cartilage
The thyroid cartilage is a hyaline cartilage structure that sits in front of the larynx and above the thyroid gland. The cartilage is composed of two halves, which meet in the middle at a peak called the laryngeal prominence, also called the Adam’s apple.
cricoid cartilage
is the only complete ring of cartilage around the trachea. It forms the back part of the voice box and functions as an attachment site for muscles, cartilages, and ligaments involved in opening and closing the airway and in producing speech.
arytenoid cartilages
The arytenoid cartilages are a pair of small three-sided pyramids which form part of the larynx, to which the vocal folds are attached. These allow and aid in the vocal cords’ movement.
vocal ligaments
The vocal ligaments are two bands enclosed within the vocal folds. They consist of elastic tissue. Anteriorly the vocal ligament is connected to the posterior side of the thyroid cartilage, and posteriorly the vocal ligament is connected to the arytenoid cartilage.
inferior nasal concha
The inferior nasal concha is one of the three paired nasal conchae in the nose. It extends horizontally along the lateral wall of the nasal cavity and consists of a lamina of spongy bone, curled upon itself like a scroll,. The inferior nasal conchae are considered a pair of facial bones. As the air passes through the turbinates, the air is churned against these mucosa-lined bones in order to receive warmth, moisture and cleansing. Superior to inferior nasal concha are the middle nasal concha and superior nasal concha which arise from the cranial portion of the skull. Hence, these two are considered as a part of the cranial bones.
Tracheal cartilages
In the trachea, or windpipe, there are tracheal rings, also known as tracheal cartilages. Cartilage is strong but flexible tissue. The tracheal cartilages help support the trachea while still allowing it to move and flex during breathing. There are generally sixteen to twenty individual cartilages in the trachea
soft palate
The soft palate is, in mammals, the soft tissue constituting the back of the roof of the mouth. The soft palate is part of the palate of the mouth; the other part is the hard palate. The soft palate is distinguished from the hard palate at the front of the mouth in that it does not contain bone.
the c-shaped rings of the trachea
made of cartilage
allow the oesophagus to expand slightly into the tracheal space.
keep the trachea open for passage of air
total lung capacity of an adult
approx. 6 litres
location of pnuemotaxic and apnuestic centres
Pons
How is the basic rhythm of quiet respiration set?
by pacemaker cells in the diaphragm; by the pneumotaxic area of the pons; by the apneustic area of the pons; by the inspiratory area of the medulla oblongata; by the expiratory area of the medulla oblongata;
nasal cavity is divided by
The nasal septum divides the cavity into two fossae.
Each fossa is the continuation of one of the two nostrils.
hilum
a depression or pit at the part of an organ where vessels and nerves enter.
Each lungs mediastinal surface has an indentation known as the Hilum.
Pulmonary and systemic blood vessels and bronchi, lymphatic vessels, and nerves enter and leave the loan at this point.
Lingual tonsils.
The lingual tonsils are two small mounds of lymphatic tissue located at the back of the base of the tongue, one on either side. They are composed of lymphatic tissue that functions to assist the immune system in the production of antibodies in response to invading pathogenic bacteria or viruses
Surfactant
surfactant is produced by the alveolar cells in the lungs and line mainly the alveoli and small bronchioles, and prevents the alveoli from collapsing. Lung surfactant makes it easier for oxygen to penetrate the lung surface lining and move into the blood.
Glottis
the space between one of the true vocal cords and the arytenoid cartilage on one side of the larynx and those of the other side
epiglottis
The epiglottis is a leaf-shaped flap of cartilage located behind the tongue, at the top of the larynx, or voice box. The main function of the epiglottis is to seal off the windpipe during eating, so that food is not accidentally inhaled. The epiglottis also helps with some aspects of sound production in certain languages.
The cough center location
The cough center of the brain is a region of the brain which controls coughing, located in the medulla oblongata area of the brain.
how many pieces of hyaline cartilage in trachea
20 c shaped pieces
carina
a cartilage structure called the carina projects posteriorly from the final tracheal cartilage.
This is the point where the trachea branches into the two primary bronchi.
bronchial tree
branched airways leading from the trachea to the alveoli make up the bronchial tree.
right and left primary bronchi. near the level of the fifth thoracic vertebrae.
each primary bronchus divides into secondary bronchus
then tertiary bronchi
and even finer tubes
The right bronchi aka bronchus dexter is wider, shorter and more vertical then the left bronchus aka bronchus sinister.
The right Bronchus AKA
bronchus dexter
is wider, shorter and more vertical
branches off to the upper lobe of the right lung. This branch is called the eparterial branch.
it then divides into two branches for the middle and lower lobes.
divides into secondary or lobar bronchi, with three on the right. each supplying a single lobe.
then divide into tertiary bronchi or segmental bronchi.
The left bronchus AKA
bronchus sinister
has no eparterial branch because there is no third lobe in the left lung
divides into secondary or lobar bronchi, with two on the left. each supplying a single lobe.
then divide into tertiary bronchi or segmental bronchi.
Bronchioles
smaller tubes that continue to divide and include terminal bronchioles, respiratory bronchioles and thin alveolar ducts.
The ducts lead to outpouchings called alveolar sacs, which lead to microscopic alveoli inside capillary networks.
The term bronchioles refers to bronchial passages that are smaller than 1 mm in diameter. The smallest are called terminal bronchioles, which are less than 0.5 mm in diameter.
cartilage and muscle of airways
bronchi have less cartilage then the trachea
bronchioles have no cartilage.
smaller and smaller respiratory tubes have smooth muscle instead of cartilage.
Alveoli
The alveoli provide a large surface of epithelial cells that allow easy exchange of gases.
Oxygen diffuses from the alveoli into the capillaries.
Carbon dioxide diffuses from the blood into the alveoli.
The alveoli are not the same as the alveolar sacs. The alveoli are the actual sides of gas exchange.
There are approximately 300 million alveoli in the lungs, all of them filled with gas. They make up most of the body’s long volume, creating a huge surface area for gas exchange.
conducting zone structures
include all respiratory passageways except those that make up the respiratory zone.
The conducting zone structures are relatively bridges and the organs with in function to clean, humidify and warm the incoming air.
Therefore, when this air reaches the lungs, it contains less dust, bacteria, and other irritants then when it entered the nose and has become warm and damp.
trachea splits to primary bronchi, found at T7 when a person is standing. They move downward into the hilum, or medial depression, of the lungs.
Respiratory zone structures
The respiratory zone is where actual gas exchange occurs.
It’s made up of microscopic structures: respiratory bronchioles, alveoli ducts, and alveoli.
The respiratory zone starts at the point of the terminal bronchioles feeding into the respiratory bronchioles inside the lungs.
Scattered alveoli protrude from the respiratory bronchioles which also lead into twisting and turning alveolar ducts.
The walls of the alveolar ducts are completely made up of diffuse rings of connective-tissue fibres, alveoli and smooth muscle cells.
The ducts lead to alveolar sacs or alveolar saccules, which are terminal clusters of alveoli.
alveolar sacs
The alveolar sacs resemble bunches of grapes.
with the alveoli being the individual grape-like structures.
alveolus
In each alveolus the walls are mostly made up of one layer of squamous epithelium cells, also called type one alveolar cells.
These are surrounded by a thin respiratory basement membrane. There are also scattered, cuboidal Type II alveolar cells. These secrete surfactant, which case the alveoli surfaces that are exposed to gas. The Type II cells also secrete many antimicrobial proteins comma needed for innate immunity.
lung apex
Just below the clavicle bone on each side is the lungs narrow superior tip or apex
base of lung
The base of the lung is the concave inferior surface that rests on the diaphragm muscle
elastic rebound
The action of the diaphragm and rib cage returning to their normal positions is called elastic rebound.
Most of the lungs contain airspaces, with the remainder, called the stroma, which is primarily an elastic connective tissue.
This makes the lungs very soft, spongy and light.
They collectively weigh slightly more than 1 kg.
two types of lung circulation
upto pg 452 - delete this bracketed note
pulmonary and bronchial.
pulmonary: the pulmonary arteries deliver systemic venous blood that is deoxygenated, these arteries are located anterior to the main Bronchi. highly branched eventually bringing blood to the pulmonary capillary networks that surround the alveoli. Freshly oxygenated blood from the respiratory zone is brought by the pulmonary veins from the lungs to the heart. These veins flow to the hilum with corresponding bronchi as well as in the connective-tissue septa between the bronchopulmonary structures.
When a pulmonary arteries blocked by any type of embolus, including clots, air bubbles, or fat masses, a pulmonary embolism occurs. This can cause alveolar collapse, researchers failure, congestive heart failure and death.
what innervates the lungs
sympathetic and parasympathetic motor fibres along with visceral sensory fibres.
the visceral sensory fibres enter the lungs through the pulmonary plexus, which is located at the root of each lung, and runs along the bronchial tubes and lung blood vessels.
parasympathetic motor fibres effect on lungs
the parasympathetic motor fibres constrict the air tubes, known as broncho-constriction
excessive parasympathetic stimulation, which occurs in asthma, may also totally prevent airflow along terminal bronchioles.
sympathetic motor fibres effect on lungs
the sympathetic motor fibres dilate air tubes, know as broncho-dilation
