Anatomy II Presentation

8/2/2019 Anatomy II Presentation

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Discuss Hyperpnea of exercise

Describe the process and effects of

acclimatization to high altitude.


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Respiratory adjustments are geared to both the intensity and

duration of exercise

During vigorous exercise:

Muscles consume large amounts of O2 and produce large amounts of CO2

Ventilation can increase to 20 fold

Increase in ventilation in response to metabolic needs is called Hyperpnea

Exercise-enhanced ventilation is not prompted by rising PCO2 or

declining PO2 or pH in the blood.


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1. As exercise starts:

Ventilation increases abruptly, followed by gradual increase, and then a steady state

of ventilation is reached.

When exercise stops: Abrupt decline in ventilation, followed by gradual decline to the pre-exercise value.

2. Atrial PCO2 and PO2 levels remain surprisingly constant during

exercise.


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Increase in ventilation during exercise isdue to 3 neural factors: Psychological stimuli .

Cortical motor activation of skeletal muscles andrespiratory centers.

Excitatory impulses from proprioceptors in muscles,tendons, and joints.


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Gradual increase/decrease and plateauing ofrespiration reflect the rate of CO2 delivery to the lungs.

Abrupt decrease in ventilation after exercise reflects theshutting off of the 3 neural factors.

Gradual decline to baseline ventilation reflects adecline in CO2 flow as the oxygen deficit is beingrepaired. O2 deficit due to cardiac output limitations or inability of

skeletal muscles to increase their oxygen consumption.

Thus, practice of inhaling pure O2 by mask is uselessdue to oxygen deficit being in the muscles not thelungs.


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Most people live between sea level and an altitude of2400m (8000ft.). In this range, differences in atmospheric pressure are not great

enough to cause healthy people any problems when they spend

brief periods in the higher altitude areas. The body responds to quick movement to elevations

above 8000ft with acute mountain sickness. Symptoms such as headaches, shortness of breath, nausea and

dizziness. Common is travelers in ski resorts.

In severe cases of AMS, lethal pulmonary and cerebral edemamay occur.


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Acclimatization: respiratory and hematopoieticadjustments to altitude by: Chemoreceptors become more responsive to increases in PCO2 due to decrease in atrial PO2

substantial decrease in PO2, directly stimulates peripheralchemoreceptors.

Results in increase in ventilation

Due to brain attempting to restore gas exchange to previous levels.

Minute ventilation stabilizes at level of 2-3L/min higher than the

sea level rate.


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High-altitude conditions result in lower-than normalhemoglobin saturation levels due to: Less O2 being available to be loaded

Hemoglobins affinity to O2 is reduced due to increases in BPG

concentration

When blood O2 levels decline, kidneys accelerateproduction of erythropoietin Stimulates bone marrow production of red blood cells

This phase of acclimatization occurs slowly, providing long-term compensation for living at high altitudes.


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Compare the causes and consequences ofchronic bronchitis, emphysema, asthma,tuberculosis, and lung cancer.


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COPD, exemplified best by Emphysema and Chronicbronchitis.

Major cause of death and disability in North America.

Key physiological feature is an irreversible decrease in the

ability to force air out of the lungs. Patients share common features such as:

More than 80% of patients have a history of smoking

Dyspnea, labored breathing often referred as air hunger,occurs and progressively more severe.

Coughing and frequent pulmonary infections are common

Develop respiratory failure manifested as Hypoventilation,respiratory acidosis, and hypoxemia.


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Permanent enlargement of the alveoli, destruction of the alveolarwalls.

Lungs lose their elasticity

This has 3 important consequences

Accessory muscles must be enlisted to breathe Damage to the pulmonary capillaries as the alveolar walls disintegrate

Bronchioles open during inspiration but collapse during expiration

Traps high volumes of air in the alveoli.

This hyperventilation leads to permanently expended barrel

chest, flattening the diaphragm and reducing ventilationefficiency.


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Alveolar Changes in Emphysema


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Inhaled irritants lead to chronic excessivemucus production by the mucosa in the lowerrespiratory passageway and to inflammation

and fibrosis of that mucosa. These responses obstruct the airways and

severely impair lung ventilation and gasexchange

Pulmonary infections are frequent becausebacteria thrive in the stagnant pools of mucus.


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Categorized by: Dyspnea, wheezing, and chest tightness

Initially thought to be due to a consequence of bronchospasmtriggered by cold air, exercise, or allergens.

However, active inflammation of the airways was found to

precede bronchospasms. Air inflammation, is an immune response under the control of Th 2

cells, that secrete interleukins & stimulate the production of IgEand recruit inflammatory cells to the site.

Inflammation makes the airways hypersensitive to any irritant

Once airways thickened with inflammatory exudates, the effect ofbronchospasm is magnified.

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Infectious disease caused by the bacteriumMycobacterium tuberculosis

Spread by coughing, inhaled air

Treatment entails a 12-month course ofantibiotics

Potential concern are deadly strains of drug-resistantTB, when treatment incomplete or inadequate


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Leading cause of death, causing more deathsthan breast, prostate, and colorectal cancercombined.

Largely preventable Nearly 90% are a result of smoking

Cure rate is notoriously low, most victims die within1 year or diagnosis

Overall 5 year survival rate is about 17%


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Three most common types of cancer:

Squamous cell carcinoma (25-30% of cases) arises inthe epithelium of the bronchi

Adenocarcinoma (40% of cases) originates inperipheral lung areas

Small cell cacinoma (20% of cases) containslymphocyte like cells that originate in the main

bronchi and grow aggressively.


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Embryos develop in a head to tail direction Upper respiratory structures appear first

Olfactory placodes invaginate into olfactory

pits, which form the nasal cavity by the 4th

week.

Laryngotracheal buds are present by the 5thweek

Mucosae of the bronchi and lung alveoli arepresent by the 8th week.

By the 28th week, a baby born prematurely canbreathe on its own.


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During fetal life, the lungs are filled with fluidand all respiratory exchanges are made by theplacenta.

Vascular shunts cause blood to bypass thelungs

At birth, the fluid-filled pathway empties andthe respiratory passageways fill with air.

As PCO2rises in the babys blood, respiratorycenters are excited and the alveoli inflate, beginfunctioning in gas exchange.


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Respiratory rate is highest in newborns andslows until adulthood

Meanwhile, the lungs continue to mature and

more alveoli are formed until youngadulthood.

Respiratory efficiency decreases in old age dueto ciliary activity of the mucosa decreasing andthe macrophages in the lungs become sluggish.


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The chronic obstructive pulmonary disease isexemplified best by?

A) Asthma

B) Emphysema C) Tuberculosis

D) Lung Cancer

Anatomy II Presentation

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