The Respiratory System!

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  • Created by: Izzy2807
  • Created on: 29-01-20 15:47
What are the 3 main roles of the respiratory system?
To oxygenate blood, eliminate CO2 from the body and regulate/maintain pH balance of extracellular fluid
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What does external/internal respiration consist of?
Internal: muscles and tissues. External: alveoli and capillaries (across alveolar wall, intersitial space and pul.capillaries)
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What is the basic structure of the respiratory tract? (Bronchial tree)
Larynx, trachea, bronchi, bronchi branches, bronchioles, alveoli
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How does the distribution of cartilage change down the respiratory tract?
Cartilage present in trachea to support it and prevent collapse. Not fully circular to allow trachea to slightly collapse (allows flexibilty). The amount reduces down the tract to allow bronchiole patency (openness)
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What is the function/distribution of smooth muscle in the respiratory tract?
Airflow regulation and airway resistance (contracts/relaxes with insp/exp). SM relaxes to dilate bronchi during exercise, contracts to prevent hypervent. at rest. Increases down tree to support (absence of cartilage)
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How do the cells of the mucus membrane differ down the resp.tract?
Ciliated pseudostratified epithelium (infection barrier and mucocil.esc.) to simple cuboidal epithelium (secrete surfactant to lower ST) to simple squamous epithelium (single layer for rapid diff. of O2/CO2). Goblet cells for mucus prod. for mucocil.
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What is the difference between pneumocyte 1 and 2?
Pneumocyte 1 is tall, thin, flattened squamous epithelium. Pneumocyte 2 is surfactant secreting cell
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What are some features of the alveolus?
High surface area and close blood supply for efficient diffusion. Savanger alveolar macrophages (protect from infection). Pores between alveoli to equalise air pressure throughout lungs, but cause rapid infection spread!
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What is Dalton's law?
That gas concentrations (partial pressures) move from high to low!
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What happens to the majority of CO2 that diffuses into the blood?
70% is converted into bicarbonate (H+ ions!). 23% of CO2 joins to Hb. 7% dissolves in the plasma.
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What happens to the majority of O2 that diffuses into the blood?
97-99% binds to Hb. Hb=globular protein, contains iron that attaches to O2 for transportation. Hb saturation tells us how much O2 there is in the blood.
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What are the the trachea and bronchi made of?
Flexible tubes of expandable fibro-elastic tissue. Contain 'c'-shapes cartilage rings for rigidity.
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What are some features of bronchioles?
Made of ciliated columnar epithelium, few gobelt cells. Arranged in folds (high SA). Have a layer of SM, innovated by ANS. Highest total cross-sectional area.
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What effect does the sympathetic and parasympathetic NS have on the bronchioles?
Sympathetic: Noradenaline attaches to bronc. SM, bronchiodilation (higher airflow). Parasympathetic NS: Acetylchol. attaches to bronch.SM, bronchioconstriction (reduced airflow and increased mucus production).
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Where are the respiratory centres located? (control centres)
In the Pons and Medulla of the Brain Stem. Pons: coordinate transition between insp/exp, interacts witj medulla. Medulla: control basic rhythms (mostly inspiration)
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What are the two respiratory nerve groups in the medulla and what do they do?
Ventral Resp. Group: rhythm generating neurones, stimulate inspirations. Dorsal Resp. Group: integrates inputs from PNS and modifies VRG activity.
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How do the VRG control ventilation?
They have an intrinsic excitability and can also inhibit eachother. Fire impulses down phrenic nerves to the diaphragm and intercostal nerves to external intercostal muscles.
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What are the two pleural membranes of the lungs?
Parietal (outer) pleural membrane: attaches to ribs. Visceral (inner) pleural membrane: attached to alveoli. Pleural cavity between the two filled with serous fluid
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Which is higher, interpleural pressure or intrapulmonary pressure?
Intrapulmonary pressure (inside alveoli)
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What is Boyle's Law?
The higher the volume, the lower the pressure. The lower the volume, the higher the pressure.
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Describe the sequence of events during inspiration!
Contraction of the external intercostal muscles and diaphragm. Diaphragm flattens and ribcage moves up and out. Increases volume of the thorax, pleural membranes pulled, alveoli expand...decs intrapulm. pressure. Air moves into alveoli down PG
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Describe the sequence of events during expiration!
Relaxation of external intercostal muscles and diaphragm. Ribcage pulled down and in, diaphragm domes. Thorax volume decreases (aided by elastic recoil of alveolar tissue), increase intrapul pressure, air out of alveoli down PG
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How is pulmonary ventilation aided?
Lungs remain partially filled with air at end of exp (to prevent alveolar collapse). Low intrapleural pressure keeps alveolar expanded. Surfactant (P type 2) lining alveoli decrease surface tension to prevent collapse
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What is acidosis, hypoxaemia and hypercapnia?
Acidosis: low blood pH. Hypoxaemia: low PaO2. Hypercapnia: too much PaCO2.
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What are the two groups of chemoreceptors?
Central (chemosensitive area in the medulla, detect pH of extra.cel fluid and cerebrospin.fluid). Peripheral (aortic arch and carotid bodies), detect arterial CO2 and O2.
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What is the homeostatic FB loop when CO2 levels are too high in the blood?
Chemorec. detect increase in H+ and CO2. Send more afferent impules to medulla, VRG/DRG group send more efferent impulses down phrenic nerve to diaphragm and intercostal nerves to IMs. Increases forcibility/contraction...inc. resp rate and depth
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What other factors regulate breathing?
Other receptors (pain/emotional...on hypothalamus). Cerebral cortex (voluntary). Stretch receptors in lungs. Receptors in muscles/joints. Irritant receptors.
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What is tidal volume and total capacity?
Tidal volume: volume inhaled and exhaled during normal breathing. Total capacity: volume filling lungs after maximal inspiration
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What are the inspiritory and expiratory reserve volumes?
IRV: volume inhaled additionally after normal inspiration. ERV: volume exhaled additionally after normal expiration
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What is the functional residual volume and residual volume?
FRV: volume remaining in the lungs after normal expiration. RV: volume remaining in the lungs after maximal expiration
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What is minute volume?
Respiratory rate X tidal volume
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What are the inspiratory ACCESSORY muscles?
External IM, abdominal muscles, sternocleidomastoid, scalenes. Make upper part of chest rise, lung volume increases, more air enters.
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What are the expiratory ACCESSORY muscles?
External IM and abdominal muscles. Contraction decreases volume of thorax, forcing air out.
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Why might patients with CPD have issues in oxygenating blood, exacerbated by bacterial infections?
CPD causes bronchial tubes to become inflamed and narrowed which obstructs bronchioles, reducing O2 diff. Often become clogged with mucus, reducing airflow. Emphysema (alveolar damage) causes reduced O2 diff. Infections increase inflam. & mucus prod.
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What is tachypnonea and bradypnoea?
Tachy: increased respiratory rate. Brady: decreased respiratory rate.
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What is Cheyne-Stokes respiration and dyspnoea?
C-S R: periodic breathing with episodes of apnoea. Dyspnoea: subjective experience of breathing discomfort (breathlessness).
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What is cyanosis and orthopnoea?
Blue colouration of tissues due to low levels of oxygen saturation (hypoxemia). Orthopnoea: difficulty breathing lying flat.
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How is CO2 made, what is O2 needed for and which direction do they diffuse?
CO2 made in respiration. O2 used in respiration to make ATP. O2 moves from blood to tissues, CO2 moves from tissues into blood -- down PP gradients
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Other cards in this set

Card 2

Front

What does external/internal respiration consist of?

Back

Internal: muscles and tissues. External: alveoli and capillaries (across alveolar wall, intersitial space and pul.capillaries)

Card 3

Front

What is the basic structure of the respiratory tract? (Bronchial tree)

Back

Preview of the front of card 3

Card 4

Front

How does the distribution of cartilage change down the respiratory tract?

Back

Preview of the front of card 4

Card 5

Front

What is the function/distribution of smooth muscle in the respiratory tract?

Back

Preview of the front of card 5
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