week 5 Flashcards
- Each lung is surrounded by two layers of serous membrane known as pleurae. These are:
visceral pleura; covers the surface of the lung
parietal pleura; lines the inside of the thoracic wall.
The space in between is called the pleural cavity and it is filled with
pleural fluid
This pleural fluid assists breathing movements by acting as a
lubricant.
On expiration the lungs do not collapse but are held in a semi-expanded state due to the presence of a vacuum in the
pleural space.
- In the bronchial tree air flows from the trachea through the
primary,
secondary, and
tertiary bronchi into smaller bronchiole and
smaller terminal bronchiole before entering
alveoli.
The trachea and bronchi contain
cartilage rings
cartilage rings keeps
the airways open.
- Bronchiole do not contain
cartilage rings
bronchiole do contain
more smooth muscle
This allows for regulation of airflow.
- The pulmonary artery carries blood
which is low in oxygen to the lungs
Pulmonary capillaries exchange
gases with the alveoli
Blood leaves the lungs in the pulmonary veins,
which carry oxygenated blood back to the heart.
- Name the three types of cells in the alveolus:
Type I alveolar cell;;
simple squamous epithelium
Alveolar macrophages; removes debris and microbes
Type II alveolar cell;
secretes surfactant.
The surfactant reduces the surface tension which prevents the alveoli from collapsing.
- Oxygen is transported in the blood:
?% is bound to hemoglobin
?% dissolves in plasma
98%
2%
- When oxygen is loaded onto hemoglobin in the lungs, hemoglobin is called
oxyhemoglobin,
when oxygen is unloaded from the hemoglobin at the tissues it is called
carboxyhemoglobin.
- 70% of Carbon dioxide is transported in blood as
Bicarbonates in plasma
the rest is bound to haemoglobin and dissolved in plasma.
- The muscles involved in inspiration are
Diapragm,
external intercostals
and Sternoclidomastoid
- The muscles involved in expiration are
Internal intercostals,
Rectus abdominus,
external oblique
and other abdominals
- The respiratory control area in the brain are the
the Pneumotaxic center,
the Apneustic center,
and Medullary center.
- The pneumotaxic area of the brain controls the depth of
inspiration.
- The term “bronchoconstriction” refers to constriction of the lumen in which part of the bronchial tree?
Terminal bronchiole
- What is the effect of histamine, produced during an asthmatic attack, on the bronchioles?
bronchoconstriction
- What is the effect of adrenaline on the bronchioles?
bronchodilatation
- What is the effect of acetylcholine on the bronchioles?
bronchoconstriction
- The amount of air you quietly breath in and out, (about 500 mls), is referred to as
Tidal volume
- Cartilage rings maintains
the patency (openness) of the trachea.
- State the effect of sympathetic stimulation on the bronchioles.
bronchodilatation
Which respiratory-associated muscles would contract if you were to blow up a balloon?_
Internal intercostals, Rectus abdominus, external oblique and other abdominals
- A normal adult lung residual capacity is approximately
1200 mls
- The lungs are perfused by two circulations
the pulmonary and the bronchial
The pulmonary circulation is for
oxygenation of blood
The bronchial circulation supplies blood
to the lung structures (tissue).
- The factors responsible for holding the lungs to the thorax wall are
vacuum/negative pressure in the pleural cavity
and capillary/surface tension from pleural fluid.
- Surfactant helps to prevent the alveoli from collapsing by
decreasing the cohesiveness of water molecules, thereby reducing the surface tension of alveolar fluid.
- The most powerful respiratory stimulus for breathing in a healthy person is increase of
pCo2 in blood.
- Intrapulmonary pressure is the pressure within the
alveoli/parenchyma of the lungs.
- The walls of the alveoli are composed of two types of cells, type I and type II.
The function of type II is to
produce surfactant.
- Unlike inspiration, expiration is a
Passive act because no muscular contractions are involved
Expiration, however, depends on two factors, the recoil of
elastic tissue/in lungs and muscles that were stretched during inspiration and the inward pull of surface tension due to the film of surfactant_.
- Particles such as dust fail to reach the lungs because of the
pseudostratified ciliated epithelium lining the nasal, pharyngeal and tracheal passageway
- A baby is born at 28 weeks’ gestation, what major problem will the doctors look for?
Lack of surfactant/Respiratory distress.
- Name the instrument used to measure lung volumes
Spirometer.
