respiration Flashcards
Cardiovascular and respiratory systems
- Work together in an integrated manner
- Together ensure access to oxygen for every cell
- Also allow disposal of waste product, CO2
What are the changes that happen during exercise an example of
How the systems act as an integrated whole
What do the cardiovascular and respiratory systems do during exercise and why
- working muscle requires more oxygen
- redirects blood
- Increasing cardiac output, respiratory rate and tidal volume
External respiration
movement of gasses between environment and the body’s cells
External respiration
- 3 exchanges
- Atmosphere to lung (ventilation)
- Lung to blood
- Blood to cells
Cellular respiration
Intercellular reaction of O2 with various molecules to produce CO2, water and energy (ATP)
Respiratory system
- Main functions
- Exchange of gasses
- Involved in regulation of PH in organism
- Protective function - prevent pathogens and other irritants getting into the rest of the system
- Allows you to speak - air passing through vocal chords
Respiratory system
- Main parts
- Nose
- Pharynx
- Epiglottis
- Larynx
- Trachea
- Bronchus
- Lung
Nose
Air enters body through nose, where cilia and mucus trap particles and warm and moisten the air
Pharynx
From nose air moves down to pharynx or throat, which is shared with the digestive system
Epiglottis
Small flap of tissue folds of trachea and prevents food entering it when you swallow
Larynx
- Voice box
contain vocal chords, which vibrate to produce sound
Trachea
From pharynx air moves down towards the lungs through the trachea
- Made up of stiff rings of cartilage that support and protect it
Bronchus
Air moves from the trachea into the right and left bronchi which lead inside the lungs
Lung
- Main organs of respiration
- soft, spongy texture - due to many thousands of tiny hollow sacs that compose them
Airways
- Trachea branches in to two bronchi - one to each lung
- Each bronchus branches 22 more times
- Finally terminating in a cluster of alveoli
- As size of branches reduces the number of the increases
Cilia
Propels mucus up the throat through the momentum of them moving
Alveoli
- The larger the area of reaction the more oxygen can be absorbed and CO2 expelled
Alveoli to red blood cell
- Premature babies are born without type II cells - why they sometimes die due to respiration problems
- Type I cells allow gas exchange
- Type II cells secrete a liquid called surfactant with protein and phosphor lipids
Alveolar structure
Composed of type I cells for gas exchange and type II cells that synthesize surfactant
- Alveolar macrophages ingest foreign material that reaches the alveoli
Atmospheric air pressure
760mmHg (sea level, dry)
What makes up the air
- nitrogen
- oxygen
- CO2
- Water vapor
Dalton’s law
total pressure of a mixture of gases is the sum of pressures of the individual gases
What is the pressure of a single gas referred to as
Partial pressure (P)
Which way do individual diffuse
from higher to lower partial pressure
Partial pressure gradient
Partial pressure gradient is the primary driving force of the lung-blood and blood-cells gas exchanges
Area of gas exchange
- Airways connect lungs to the environment via about 20-30 branched generations
- Alveolar surface area for gas exchange is about half the area of a tennis court
- Capillary surface area for gas exchange in periphery exceeds that for alveoli
Pulmonary circulation
high flow, low-pressure system
Breathing
- Occurs because the thoracic cavity changes volume
- Breathing rate is 10-20 breaths/minute at rest, and 40-45 at maximal in adults
Inspiration
- Inspiration uses external intercostals and diaphragm to enable us to breath
Expiration
- Passive at rest
- uses internal intercostals and abdominals during severe respiratory load
Diaphragm
- responsible for 60-70% of change in thoracic volume
- Edges are attached to rib cage
- Only moves 1-2cm
- Diaphragm relaxes when we exhale
- Moisture inside and moisture outside
Intercostals
- Pump handle motion increases anterior - posterior dimensions of rib cage
- Bucket handle motion increases lateral dimensions of rib cage
Lung volumes
- Dead space in the average young male is 150ml
- When we are relaxed 0.5 litres of air comes out with each cycle (tidal volume)
- we can exhale more when requires (known as expiratory reserve volume) - 1ishL
- We can inhale more if required (known as inspiratory reserve volume)
- 4-5L for vital capacity (when you add tidal volume, expiratory reserve volume and inspiratory reserve volume together) - more in athletes
- 1-2L of residual air
Use of the reserve volumes
- tidal volume increases
- breath more frequently
Effects of dead space
Due to rate that alveolar rate is renewed, rate of alveolar ventilation is low due to the effect of dead space
Alveolar ventilation
one of the major determinants of the concentration of oxygen and carbon dioxide in the alveoli
Slow replacement of alveolar air
To replace half the gas in the alveoli it takes approx. 17s
- Is important because prevents sudden fluctuation of gas concentration in the blood
Pressure changes
- Changes in volume, means changes in pressure, allowing air to move from high pressure to low pressure
- Pressure changes proportionally
- when inhaling chest cavity increases - so pressure decreases - allowing air to flow into lungs
- When exhaling chest cavity decreases - so pressure increases, so is higher atmospheric pressure around - so air can flow out of lungs
Summary of steps involved in respiration
- ventilation
- gas exchanges between alveolar air and lung capillaries
- bulk transport via the circulation
- gas exchange between capillaries and tissue cells and cellular utilization of O2 and production of CO2
Ventilation during exercise
- Ventilation increases when we start to exercise
- source of info - we have receptors in muscle
Regulation of breathing
-
Regulation of breathing
- Respiratory muscles are under neutral control in the medulla oblongata and pons, in the brain stem and voluntary control
Central chemoreceptors
- Located in brain
- Monitor CO2 - triggers inspiratory centre when levels get too high
Peripheral chemoreceptors
Located in aortic arch and carotid artery (O2, CO2, PH)
Stretch receptors
Located in air passages, stimulate the expiratory centre to prevent lung over-inflation
