Week 5 (pulmonary system) Flashcards
Define respiration
The process by which oxygen is supplied to tissues and carbon dioxide is removed.
Name the three stages of physiological respiration
Pulmonary ventilation/breathing
External respiration
Internal respiration
Describe pulmonary ventilation
Inhalation and exhalation of air.
Exchange of air between the atmosphere and the pulmonary alveoli of the lungs.
Permits oxygen to enter the lungs and carbon dioxide to leave.
Describe external respiration
Exchange of gases between pulmonary alveoli and blood in pulmonary capillaries.
Meet respiratory demands.
Oxygen moves from alveoli to blood.
Carbon dioxide moves from blood to alveoli.
Describe internal respiration
Exchange of gases between blood in systemic capillaries and cells of tissues.
Cells absorb oxygen.
Cells produce carbon dioixde.
Name the components of the upper respiratory system
Nose
Nasal cavity
Pharynx
Name the components of the lower respiratory system
Larynx
Trachea
Bronchi
Lungs
What are the functions of the respiratory system?
Gas exchange
Regulation of blood pH
Receptors for smell
Filters inspired air
Vocal sounds
Excrete small amounts of water and heat.
Name the two zones of the respiratory system
Conducting zone
Respiratory zone
What is the function of the conducting zone?
Provides a passageway for air to travel into and out of lungs.
Name the components of the conducting zone
Nose
Nasal cavity
Pharynx
Larynx
Trachea
Bronchi
Bronchioles
Terminal bronchioles
What is the function of the respiratory zone?
The site of oxygen and carbon dioxide exchange with the blood.
Name the components of the respiratory zone
Respiratory bronchioles
Alveolar ducts
Alveolar saccules
Pulmonary alveoli
Describe the external nose
Protects the inner nose
Allows entry of air
Filters stiff out
Function of interior structure
- warm, moisten and filter incoming air
- olfactory receptors
- modify speech vibrations
Describe the internal nose (nasal cavity)
Large inferior respiratory region
Smaller superior olfactory region
Describe the respiratory epithelium
Contains ciliated columnar epithelium and goblet cells.
Goblet cells produce mucus which trap the dust particles and the ciliated epithelium moves the mucus out of the body.
Describe the pharynx
Skeletal muscle lined with mucous membrane
Passageway for air and food
Resonating chamber for speech
Tonsils
Describe the larynx
Connects laryngopharynx with the trachea
Describe the trachea (windpipe)
Tubular passageway
Semi-rigid structure to maintain patency.
Is made up of 4 layers; respiratory mucosa, submucosa, hyaline cartilage and adventitia
Which side bronchus is the biggets?
Right
Describe the Clara cells found in the bronchioles
Non-ciliated secretory cells.
Protect against harmful effects of inhaled toxins and carcinogens.
Develop into epithelial cells.
They produce surfactant which traps pathogens to help regulate innate and adaptive immune function.
Describe the lungs
Paired cone-shaped organs in the thoracic cavity.
Separated by the heart and other structures of the mediastinum.
Enclosed and protected by a pleural doubled-layered serous membrane.
How many lobes does the right lung have?
3
How many lobes does the left lung have?
2
What are lobules?
Each lung is divided into lobules which are wrapped in elastic connective tissues which allows for the inflation and deflation of the lungs.
What are pulmonary aleoli?
Alveolar saccule’s outpouchings.
Name and describe the two types of epithelial cells that the alveoli contain
Pneumocyte type I
- simple squamous epithelial cells
- most abundant
- main site of gaseous exchange
Pneumocyte type II
- septal cells
- rounded epithelial cells
- found in type I cells
- microvilli
- secrete pulmonary alveolar fluid which maintains surface tension which helps the alveoli to maintain their structure.
What are macrophages?
A type of phagocyte that remove dust and debris.
Act as protection.
What are fibroblasts?
reticular and elastic fibres that allow flexibility
What is the respiratory membrane?
A membrane that is formed by pulmonary alveolar and capillary walls.
It is the site of gaseous exchange.
Made of 4 layers; alveolar wall, epithelial basement membrane, capillary basement membrane, capillary endothelium
0.5 micrometres thick = rapid diffusion
Describe inhalation
Pulmonary alveoli pressure < atmospheric pressure.
Increases the size of the lungs
Active process
Describe the process of inhalation during quiet breathing
Diaphragm contracts, flattens and domes, which increases the vertical diameter of the thoracic cavity.
External intercostals contract and elevate the ribs which increases anteroposterior and lateral dimeters of the chest cavity.
Describe the process of inhalation during forced breathing
Sternocleidomastoid muscles elevate the sternum.
Scalene muscles elevate the first two ribs.
Pectoralis minor muscles elevate ribs 3-5.
Describe exhalation
Passive process (no muscular contractions)
Lung air pressure > atmospheric air pressure.
Begins when inspiratory muscles relax.
Recoil of elastic fibres stretched during inhalation. Inward pull of surface tension of film of intrapleural fluid.
Describe the process of exhalation during quiet breathing
Diaphragm relaxes and moves up.
Extern intercostals relax and the ribs depress.
The diameter of the thoracic cavity and lung volume decreases.
Alveolar pressure increases and air flows out of the lungs.
Describe the process of exhalation during forceful breathing
Abdominal and internal intercostal muscles contract which increases the pressure in the abdominal region and thorax.
The contraction of the abdominals moves the inferior rib downward, compresses the abdominal viscera and forces the diaphragm up.
The contraction of internal intercostals which pulls the ribs inferiorly.
What factors affect pulmonary ventilation?
Surface tension of alveolar fluid.
Lung compliance
Airway resistance
What is lung compliance?
The effort required to stretch the lungs and chest wall.
Name the two main mechanisms that control respiration
Central pattern (autonomic)
Voluntary
Describe the central pattern control of respiration
Inspiratory and expiratory muscles contract and relax.
The muscles are controlled by medulla neurons and fine tuned by pons.
Describe the voluntary control of respiration
Origin in the cerebral cortex
Additional influences
What controls respiration?
Respiratory centre: medulla respiratory centre on medulla oblongata and the pontine respiratory group in the pons.
Medulla: coordinates quiet and forced breathing, controls frequency of ventilation.
Pons: controls volume and depth of ventilation
Name the two groups in the medulla respiratory centre
Dorsal respiratory group (DRG)
Ventral respiratory group (VRG)
Describe the dorsal respiratory group
- controls diaphragm and external intercostal muscles
- inspiration and expiration in quite breathing
Describe the ventral respiratory group
- controls accessory inspiration and expiratory muscles
- inspiration and expiration during forced breathing
Describe the pontine respiratory group
Transmits nerve impulses to medulla DRG.
Modifies basic rhythm of breathing generated by VRG.
Exercising, speaking or sleeping.
Describe the cortical influences that regulate the respiratory centre
Voluntarily alter our breathing pattern.
Protective mechanism.
Increased carbon dioxide and hydrogen stimulates the DRG neurons.
Breathing resumes.
Describe chemoreceptor regulation
Monitors carbon dioxide, oxygen and hydrogen levels.
Central chemoreceptors are found in the medulla oblongata.
Peripheral chemoreceptors are found in the aortic and carotid bodies.
List the order of homeostasis maintenance
- controlled condition
- monitor
- control centre
- effect a change
- monitor
Describe the stretch receptors
Baroreceptors in the bronchi and bronchiole walls are stretched during the overinflation of the lungs (forced breathing).
Nerve impulses are transported down the Vagus nerve to the DRG.
DRG is inhibited and the diaphragm and intercostals relax.
Exhalation begins
What happens when the baroreceptors detect an increase in blood pressure?
Ventilation is decreased
What happens when the baroreceptors detect a decrease in blood pressure?
Ventilation is increased
What happens during gaseous exchange?
Diffusion of oxygen in the air in the pulmonary alveoli to blood in pulmonary capillaries.
Diffusion of carbon dioxide in the opposite direction.
Describe the direction of gas exchange during external repsiration
From higher partial pressure to lower partial pressure
Which sides of the heart does deoxygenated and oxygenated blood travel to?
Deoxygenated blood moves from the right side of the heart.
Oxygenated blood is retuned to the left side of the heart.
Describe the process of gaseous exchange during internal respiration
Exchange of oxygen and carbon dioxide between systemic capillaries and tissue cells.
What does the rate of gas exchange depend on?
Partial pressure difference of the gases.
Surface area available for gas exchange.
Diffusion distance.
Molecular weight and solubility of gases.
