respiration in humans Flashcards
what does the respiratory system do?
they work closely with the circulatory system to ensure that all body cells receive the oxygen they require, as well as remove the co2 produced
what is the structure and function of the nasal cavity?
s: lined with mucous membrane, filled with tiny hairs
f: allows air to enter the body, warms and moistens inhaled air, nose hairs filter inhaled air by trapping dust and small particles
what is the structure and function of the larynx?
s: cartilaginous, contains the vocal cords
f: allows air to pass from the throat and enter the trachea
what is the structure and function of the trachea, bronchus, bronchiole?
s: cartilaginous c-shaped rings
f: keeps the airway open as air passes between the nose and lungs
s: contains mucus-producing cells
f: mucus traps dust and small particles (may include pathogens) in inhaled air, mucus also warms and moistens air
s: lined with ciliated epithelial cells
f: sweeping motion of cilia pushes mucus away from the lungs, towards the throat for mucus to be swallowed or expelled
what do alveolis do?
ensure that bloodstream remains well-supplied with oxygen and prevents build-up of co2
what are the structures and functions of the alveoli?
s: numerous in lungs
f: increases the surface area to volume ratio of lungs to increase the rate of diffusion
s: elastic & one-cell thick epithelium
f: helps alveoli inflate and deflate easily, decreases diffusion distance for more efficient diffusion
s: thin film of moisture on alveolar wall
f: allows for oxygen to dissolve into an aqueous state making diffusion more efficient, prevents alveoli from collapsing
s: surrounding capillary network
f: increases the amount of blood that comes into contact with the alveolar surface to occur more efficiently, maintains steep concentration gradient of o2 and co2 in the air between alveoli and bloodstream
explain aerobic respiration
all living cells undergo aerobic respiration
it takes place in the mitochondria
formula: glucose+oxygen=h2o, co2, energy
in the presence of oxygen, glucose is broken down to release energy, with co2 and h2o as the by-products
explain anaerobic respiration
when humans engage in vigorous physical activities that require rapid muscular contractions, the huge increase in energy demands becomes way more than the maximum amount of energy the body can supply. hence, the muscles undergo anaerobic respiration to supplement the energy production.
formula: glucose=lactic acid+energy
anaerobic respiration takes place in the muscle cells. the lactic acid in high concentrations can be very toxic, hence it must be broken down and removed immediately. however, in the case that the lactic acid is not removed as quickly enough, it will accumulate, and can cause us to have fatigue, cramps and burning sensations.
explain lactic acid and oxygen debt
during exercise, the oxygen consumption levels increase to meet the increasing rate of aerobic respiration
when energy demands increases above the supply of aerobic respiration, muscle cells start to undergo anaerobic respiration to supplement the total energy production
at maximum energy consumption, the body is at its physical limit and cannot take in oxygen any faster, and cells reach their maximum rate of respiration
when the person is done exercising, breathing rate does not drop back to resting levels due to the development of oxygen debt
the oxygen debt describes the amount of oxygen is required on top of the resting oxygen requirement to break down the lactic acid produced during anaerobic respiration
the lactic acid is transported into the bloodstream to the liver to break down the lactic to be broken down into less harmful substances to be expelled or excreted
explain nicotine
nicotine is an addictive chemical in tabacco. it stimulates the nervous system and increases blood pressure and heart rate. small blood vessels under the skin constrict more easily and nicotine causes wrinkles to form prematurely.
explain tar
tar is highly carcinogenic and is a sticky substance that deposits on the airway walls which paralyse cilia and irritate the epithelium. this causes for the epithelium to produce more mucus which get trapped in the airways, because the paralysed cilia is not functioning.
tar also coats the inner walls of the alveoli, decreasing the surface area for gaseous exchange. this decreases the amount of oxygen the rbc absorb, and the amount of co2 removed
explain carbon monoxide
carbon monoxide binds more readily and strongly with haemoglobin compared to oxygen
this decreases the amount of oxygen in every volume of blood that gets transported
plaque forms more readily in the blood with more CO which narrows it, increasing the risk of atherosclerosis
narrowed blood vessels face increased blood pressure and vessel walls lose their elasticity
explain bronchitis
cells in the bronchi are irritated by cigarette smoke and become inflamed. this causes the epithelium to swell, narrowing the airways
in response to the irritation, more mucus is produced which further narrows the airways
there is no cure for bronchitis but medication can be prescribed to alleviate the inflammatory response and decrease the swelling which reduces the discomfort, allowing the patient to recover in less pain
explain ephysema
prolonged exposure to irritants in the airways triggers violent coughing as one tries to expel the irritants
the persistent violent coughing weakens the alveolar walls which lose their elasticity and eventually breakdown, decreasing the surface area available for gaseous exchange to occur
there is no cure for ephysema, but similar medications as bronchitis may be given to reduce the swelling on the muscles in the airways, as well oxygen therapy which delivers air in high oxygen content in the lungs
what does COPD increase the risk of?
COPD increases the risk of contracting related conditions like pneumonia and acute respiratory distress syndrome, all of which are potentially life-threatening and fatal if not treated immediately
