y3.2: human respiratory system 😤 Flashcards
structures of human respiratory system
nostrils, nasal cavity, larynx, trachea, bronchi (plural, bronchus), bronchioles, alveoli and capillaries surrounding alveoli
features of structures of human respiratory system
nostrils: entrance to respiratory tract
Nasal cavity: cleaning, moistening and warming incoming air
=> Hairs of walls of nostrils filters dust
=> mucus secreting cells produces mucus to trap bacteria or dust
=> blood capillaries are close to the surface of the cavity, warms inhaled air
larynx: contains vocal chords
Trachea: C-shaped rings of cartilage prevent trachea from collapsing during breathing due to change in air pressure
Bronchus (plural: bronchi), bronchioles, alveoli: trachea divides into two bronchi, each bronchus divides into numerous fine tubes, bronchioles. each bronchioles ends in a cluster of alveoli.
role of cilia in breathing
- trachea and bronchi are lined with ciliated cells and gland cells
- gland cells secrete mucus that traps dust particles
- ciliated cells have hair like structures called cilia on their surface which sweep dust trapped mucus up the bronchi and trachea away from the lungs into the pharynx, where they are swallowed or expelled
role of diaphragm, ribs, and intercostal muscles in breathing
inhalation:
1) the diaphragm contracts and flattens
2) external intercostal muscles contracts
3) rib cage moves upwards and outwards
4) lung expands as volume increases, air pressure decreases and air is drawn into lungs (move from higher air pressure to lower pressure in lungs)
exhalation:
1) the diaphragm relaxes and arches upwards to form a dome shape
2) external intercostal muscles relax
33) rib cage moves downwards and inwards
4) lung contracts as volume decreases, air pressure increases and air is expelled from the lungs (move from higher pressure in lungs to lower pressure in air)
role of diaphragm, ribs, and intercostal muscles in breathing
inhalation:
1) the diaphragm contracts and flattens
2) external intercostal muscles contracts
3) rib cage moves upwards and outwards
4) lung expands as volume increases, air pressure decreases
5) air is drawn into lungs as air moves from higher atmospheric pressure to lower air pressure in lungs
exhalation:
1) the diaphragm expands and arches upwards
2) external intercostal muscles relaxes
3) rib cage moves downwards and inwards
4) lung expands as volume increases, air pressure decreases
5) air is expelled from lungs as air moves from higher air pressure in lungs to lower atmospheric pressure
alveolar structural adaptations to function
1) alveolar walls are one cell thick: provides a shorter distance for a faster rate of diffusion of gases into the blood
2) covered with a thin film of moisture: enables gases to dissolve into water, increasing rate of diffusion
3) surrounded by numerous blood capillaries:
- transport diffused oxygen away and carbon dioxide to the lungs
- continuous transport of gases maintains favourable concentration gradient of the gases for faster rate of diffusion
4) alveoli are present in large quantities: large surface area to volume ratio to increase rate of diffusion of gases
oxygen transport from lungs
1) alveolar air contain higher concentration of oxygen than blood
2) oxygen diffuses into the thin film of moisture on the surface of the alveoli
3) oxygen then diffuses through the walls of the alveoli and blood capillaries into blood, and the into red blood cell
4) oxygen bind with haemoglobin in red blood cells to form to form oxyhaemoglobin
- reversible reaction
- dependent on concentration of oxygen in surroundings
5) when blood passes through oxygen-poor tissues, oxyhaemoglobin releases oxygen which will then diffuse through the walls of the capillaries into tissue cells
carbon dioxide transportation from body cells to lungs
body cells:
1) body cells carry out aerobic respiration, producing carbon dioxide
2) carbon dioxide diffuses into blood as blood passes through these tissues, where most carbon dioxide enters the red blood cells, and a small amount is carried in plasma as dissolved carbon dioxide
3) carbon dioxide reacts with water in cytoplasm of red blood cells to form carbonic acid (catalysed by carbonic anhydrase)
4) carbonic acid dissociates to form hydrogen ions and hydrogencarbonate ions
5) hydrogen ions remain in red blood cells, hydrogencarbonate ions diffuse out of red blood cells to be carried in plasma to lungs
carbon dioxide transport from lungs to atmosphere
at lungs:
1) hydrogencarbonate ions diffuse back into the red blood cell, combining with hydrogen to form carbonic acid
2) carbonic anhydrase catalyses the conversion of carbonic acid to carbon dioxide and water
3) carbon dioxide diffuses out of red blood cell, into blood, through the capillaries and alveolar walls to be removed during exhalation
harmful components + effects of smoking
1) carbon monoxide
- binds irreversibly with haemoglobin, reducing the ability of blood to carry oxygen
2) tar
- carcinogenic, paralyses cilia lining airways (chronic bronchitis and emphysema)
3) irritant chemicals
- paralyses cilia
4) nicotine
- makes blood clot easily, increasing risk of coronary heart disease
causes + effects of chronic bronchitis
caused by prolonged exposure to irritants particles (eg. from smoking)
- epithelium lining becomes inflamed
- excessive production of mucus by epithelium
- cilia on the epithelium become paralysed, unable to remove mucus and foreign particles
- airflow becomes blocked, making breathing difficult
- decreases efficiency of gaseous exchange process
- persistent coughing to clear air passages
causes + effects of emphysema
persistent or violent coughing due to bronchitis may lead to emphysema
- walls of the alveoli break down, decreasing surface area for gaseous exchange
- lungs lose elasticity and ability to effectively expel air
- oxygen uptake and carbon dioxide removal is impaired, severe breathlessness is experienced
read experiments at pg 70 onwards!!
im respire-ling out of control
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