Slide set 6- Respiration Flashcards
How does the body know when to breath?
When CO2 goes up, primary trigger in terms of chemoreceptors.
- Sensory output : the pneumotaxic center and apneustic center in the brain receives signals from the chemo receptors
- Relays to the medullary rhythmicity area
- The cerebral cortex can override the “automatic” control of the breathing…
=> breathing can be controlled, but mostly not controlled
What are the 4 pulmonary functions and their components?
- External respiration
- Pulmonary ventilation
- Pulmonary gas exchange - Transport of gases by the blood
- Pulmonary circulation
- Systemic circulation - Internal respiration
- Systemic tissue gas
- Cellular respiration - Regulation of respiration
What are the 2 main division of the respiratory system?
Upper respiratory tract
- To protect lower respiratory structures
Lower respiratory tract
- Organs within the thorax (trachea, bronchial tree, lungs)
*accessory structures (oral cavity, rib cage, and diaphragm…)
What are the inspiration and expiration muscles? when are they used?
Inspiration:
- Diaphragme
- External costal
Expiration:
- Intercostals
- Abdominal muscles
Expiration muscles are usually activated when labour breathing, when focusing air out… respiratory pathology like asthma
What are the 3 parts of pharynx (from upper to lower part…)?
Nasopharynx
Oropharynx
Laryngopharynx
What muscle does 75% of the work in the inspiration?
diaphragm
Pulmonary ________ bring blood from the heart to be _______, and pulmonary _____ brings blood back to the heart to be be _________.
Pulmonary ARTERIOLES bring blood from the heart to be OXYGENATED and pulmonary VEINS brings blood back to the heart to be be DISTRIBUTED through the rest of the body.
What is cleft palate?
- Fail to unite completely palatine bones from hard palate
- Only partial separation of the nose and mouth
- Produces difficulty breathing and swallowing
- Caused by a genetic or mutant gene
- Teratogenic ( chemical that affect fetus- Corticosteroids, benzodiazepines, anticonvulsants)
- DEvelopmental defect resulting from decreased migration of neural crest cells
- If there is a gap in the gum, a bone graft may be sued to fill it
- 48% reduction in cleft palate by taking multivitamin with folic acid
What are the function of the nose?
- Hairs lining the nose cavity => serve as filter
- Turbinates provide a large mucus covered surface over which the air must travel => MOISTENS THE AIR
- Mucus also act as a trap
- when you have stuffy nose => swelling of the turbinates
Go look at pictures from slide 34-36, look at different parts
go
Describe the pharynx
- Connects upper and lower airways
- Tube like from base of skull to esophagus
- Divided in 3 parts: Oropharynx, Nasopharynx, Laryngopharynx
- Pathway for both digestive and respiratory tract
- Pharynx is also involved in speech as it changes shape to produce certain vowel and sounds
What are the accessory organs of the respiratory system?
- Oral cavity
- Rib cage
- Diaphragm
What are the organs included in the lower respiratory system?
- Trachea
- Bronchial tree
- Lungs
Describe the trachea
- Connects larynx to bronchi
- Is part of open airway to the lung (part of the outside body…)
- Smooth muscle in which are embedded cartilage C rings
- Made of hyalin cartilage
What do ciliated epithelium of the trachea do?
- Also produce mucus
- Their job is to push mucus
- Push up the larynx
What are the 3 layers of the bronchial walls?
- Epithelial
- Smooth muscle
- Connective tissue (hyalin cartilage)
Go see picture of slide 44, notice the goblet cells and and ciliated cells of the epithelium
Go
Go see picture slide 45, notice the pores of Kohn., and the capillary bed.
Go
Where is the capillary bed in respiratory system? What does it do?
surrounds alveoli/alveolar sacs. Facilitates gas exchanges with RBCs
What is the respiratory membrane, and what is it made of?
It is the barrier between which gases are exchanged by alveolar air and blood
Composed of:
- Alveolar epithelium
- Capillary endothelium
- Both epithelium joined by basement membrane
The surface of respiratory membrane inside each alveolus is coated with a fluid called________. What is the primary function of it?
Surfactant (produced by type II cells)
- Reduces surface tension
Inspiration is the _______ phase of the respiration cycle, since there is muscle ____________.
Active phase, because of muscle contraction
Describe inspiration vs expiration
INSPIRATION:
- taking air into the lung
- Active phase
- Diaphragm contracts and moves down
- DECREASE INTRA-ALVEOLAR PRESSURE, so that air flows into lung
EPIRATION:
- Exhalation
- Letting air out of the lung
- Relaxation of the diaphragm and elastic recoil of tissue decreases the thoracic volume and INCREASES INTRA-ALVEOLAR PRESSURE
Air will move from a region with ____ pressure to ____ pressure
High to low
Pretty logical..
What are the 3 pressures important in pulmonary ventilation?
Atmospheric pressure (PB): - Air pressure of the atmosphere outside the the body airways
Alveolar pressure (PA):
- Intrapulmonary pressure
- Pressure at the far end of the internal airways
Intrapleural pressure (PIP):
- Created by 2 membranes that surround the lungs
- It is the fluid pressure of the pleural fluid between the PARIETAL (more outside), and VISCERAL (more inside) pleura
- Go see picture slide 54
What does pulmonary ventilation imply?
Pulmonary ventilation mechanism must establish 2 gas pressure gradients :
- Pressure in alveoli of lungs is lower than atmospheric pressure, to allow inspiration
- Pressure in alveoli is higher than atmospheric pressure, allow expiration
Pressure gradients are established by change in size of the thoracic cavity , produced by contraction and relaxation of muscles
Expansion of the thorax and downward movement of the diaphragm results in ________ intrapleural pressure, leading to ______ in alveolar pressure
Decrease, decrease
What is compliance?
Ability of pulmonary tissue to stretch, making inspiration possible.
When you have a low compliance, you than have a low _____ and ______ capacity
volume and lung capacity
What is compliance affected?
- Disease
- Smokers
- Fibrosis
…
Describe briefly the how surfactant is produce, and its role.
- It is a lipoprotein formed from protein and phospholipid secretions by type II cells in the wall of the alveolus
- Acts to reduce surface tension and prevents alveolar collapse during exhalation
How does surfactant reduce surface tension?
It is a film that insert itself between water molecules
- Water molecules want to shrink together because H2O molecules are attracted to each other => this would decrease the size of the alveolus
- Surfactant acts to decrease attraction between ware molecules
So.. surfactant are interspersed between water molecules, and in doing so promote expansion of the lungs, and act against tendency to recoil
What do alveolar macrophage do?
Primary phagocytes of innate immune system (innate system= non specific immune system)
- They go around and pick up stuff
- Clearing the air space of infectious, toxic, allergic particles
- Secretion of lysozyme, antimicrobial peptide and proteases
- Through process of phagocytosis
- Can eliminate small inocula of typical microbes that are aspired daily in the host…
Surfactant is often missing in _________
Premature babies
Name 3 factors that affect amount of oxygen that diffuses in the blood.
- Total functional surface area of respiratory membrane
- can be affected by smoking - The respiration volume
- Alveolar ventilation
What are structural factors that facilitate oxygen diffusion from alveolar air to blood?
- Capillary bed
- Walls of alveoli and capillaries form only a very a thin barrier for gas to cross (single cell layer)
- Alveolar and capillary surfaces are large
- Blood is distributed through the capillaries through a thin layer, so each RBC comes closer to alveoli
Describe the negative feedback control that operates to increase respiration rate in response to thigh plasma CO2 (go see picture slide 64)
- increase cellular respiration in exercise cause rise of PCO2 - detected by central chemoreceptors in carotid and aorta
2, Feedback information is relayed to integrators in teh brainstem that response respond to increase PCO2
- Nervous signal is send to effector muscles (respiratory muscles)
- Effector muscles increase their alternate contraction/relaxation, thus increasing respiration rate
- As respiration rate increase, rate of CO2 loss from the body increases and PCO2 decreases back to its point value
Hoe does PCO2 influence breathing?
PCO2 acts on central chemoreceptors in medulla
- If PCO2 increase=> faster breathing
- If decrease=> slower breathing
How does pH influence breathing?
A decrease in pH (more CO2) stimulates peripheral chemoreceptors in the carotid and aortic bodies, and even more => central chemoreceptors (because they are surrounded by unbuffered fluid to slow breathing)
How does arterial blood PO2 influence breathing?
Presumably little influence if it stays above a certain level
What are the symptoms of Bronchitis? (go see slide 66)
- Enlarged submucosal gland
- Inflammation of epithelium
- Mucus accumulation
- Hyperinflation of alveoli
Air tubes narrow as a result of swollen tissues and excessive mucus production
What are the symptoms of asthma? (go see slide 67)
Excessive mucus production and and edema of respiratory mucosa cause obstruction of airways.
- Mucus
- Hyperinflation of alveoli
- Smooth muscle constriction
- Mucus plug
What is emphysema? What are the symptoms?
Walls of alveoli are torn and cannot be repaired. Alveoli fuse into large air space.
- Enlargement and destruction of alveolar walls
