Flashcards in Chapter 19 - respiratory system Deck (123)
Describe the primary functions of the respiratory system
The primary functions of the respiratory system are:
the intake of oxygen
the removal of carbon dioxide
identify the organs of the upper respiratory system and describe their functions
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
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.
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
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.
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
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
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
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
1. Tidal Volume: approx. 500ml moved into or out of lungs during respiratory cycle.
2. Inspiratory Reserve Volume: Approx. 3,000ml inhaled during forced breathing in addition to tidal volume.
3. Expiratory Reserve Volume: Approx. 1,100ml exhaled during forced breathing in addition to tidal volume.
4. Residual Volume: Approx. 1,200ml remaining in lungs even after maximal expiration.
upper respiratory tract includes
lower respiratory tract includes
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.
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.
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.
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.
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
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
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.
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.
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 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.
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
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.