Breathing / Gaseous Exchange Flashcards
Breathing
the physical process of taking air into the lungs and releasing air from the lungs
respiration
the controlled release of energy from all living cells
word equation for respiration
glucose + oxygen -> carbon dioxide + water + energy
chemical equation for respiration
C6H12O6 + 6O2 -> 6CO2 + 6H2O + ATP
in humans where does gaseous exchange happen?
in the lungs
oxygen diffuses…
into the blood
carbon dioxide diffuses…
out of the blood
carbon dioxide and water are…
excreted out of the lungs
in leaves gaseous exchange occurs by diffusion in…
the stomata and in lenticels in stems
4 ways the lungs are adapted for gaseous exchange
- large surface area (alveoli)
- rich blood supply
- thin walls, permeable by gases (alveoli)
- moist absorbing surface (gases diffused more rapidly if dissolved in water
where are the lungs
in the thoracic cavity
2 examples of tissue in the lungs
epithelial and connective
what type of cavity is the thoracic cavity?
an airtight cavity
what protects the lungs from being punctured?
the ribcage
what protects the lungs
pleural membranes
what’s in the pleural membranes?
pleural fluid
2 functions of the pleural membrane
- Friction free movement of the lungs during breathing
2. Stick the lungs tight to the ribcage and also the diaphragm, so when it moves the lungs move
6 parts from nose to lungs
nasal passages/oral cavity, pharynx, trachea, bronchi, bronchioles and alveoli
what are cilia?
tiny hairs that trap dust and microbes
what do cilia produce?
produce mucus that help trap dust and microbes
what do the cilia do with the dust and microbes
transport them, back to the pharynx where they are swallowed
4 places cilia are found in the respiratory system
nasal passages
trachea
bronchi
bronchioles
4 things the nasal cavity does
air is warmed, filtered, moistened and smelled
warm, moist air
diffuses into bloodstream more easily
where is the pharynx?
at the back of the mouth and nasal cavity, top of trachea
where is the epiglottis?
in the pharynx
what is the epiglottis?
flap of tissue
what does the epiglottis do?
shuts off the trachea during swallowing
function of the epiglottis
prevent food getting into the trachea
what is the larynx called
voice box
what is the larynx made of
cartilage
where is the larynx
sits on top of the trachea
what does the larynx contain
vocal chords
what does the larynx do?
produce sound as they vibrate as air passes over them
what is the trachea called?
the windpipe
what does the trachea do?
carries air from the pharynx (throat) to the two bronchi
what strengthens the trachea?
c-shaped rings of cartilage
what do the c-shaped rings of cartilage do?
prevent the tube from collapsing when air pressure drops during breathing
do the bronchi have c-shaped rings of cartilage?
yes
do the bronchioles have c-shaped rings of cartilage?
no
alveoli
tiny air sacs at the end of the bronchioles where gaseous exchange occurs
how many alveoli in each lung?
700 million
what are lungs composed of?
spongy elastic tissue
what does the lung tissue do?
expands easily during inhalation and recoils rapidly during exhalation
how many pairs of ribs do we have?
12 pairs of ribs
2 muscles of the respiratory system
intercostal muscles
diaphragm
where are intercostal muscle?
located between each rib
what do the intercostal muscles do?
contract causing the ribcage to move upwards and outwards, drawing air into the lungs
what is the diaphragm?
sheet of muscle separating the thorax from the abdomen
what does the diaphragm?
becomes flatten in contraction and helps to bring about inspiration.
shape of diaphragm when relaxed
dome-shaped
4 adaptions of alveoli for gaseous exchange
- thin walls, permeable to gases
- very numerous, large surface area
- large supply of blood capillaries, only short distance to exchange
- well ventilated, air moves in and out quickly
what vessel brings deoxygenated blood to the lungs from the heart?
pulmonary artery
what vessel brings oxygenated blood back to the heart?
pulmonary vein
diffusion
the movement of substances from an area of high concentration to an area of low concentration
diffusion takes places
along a concentration gradient
is energy required for diffusion, why?
no
it’s a passive process
why does oxygen diffuse from the alveoli into the blood?
air in the alveoli has a higher concentration of oxygen than the blood in the capillaries
why does carbon dioxide diffuse from the blood into the alveoli?
the blood in the capillaries has a higher concentration of carbon dioxide than the air in the alveoli
inhaled air oxygen
21%
exhaled air oxygen
16%
inhaled air carbon dioxide
0.03%
exhaled air carbon dioxide
4%
inhaled air nitrogen
78%
exhaled air nitrogen
78%
inhaled air water vapour
varies
exhaled air water vapour
higher than inhaled
exhaled air is…
warmer
air moves from
from an area of high pressure to an area of low pressure
if you increase the volume in the thoracic cavity
you lower the pressure
the process of inhalation
- intercostal muscles contract, ribcage moves upwards and outwards
- diaphragm contracts and flattens
- volume increases pressure decreases
- air is sucked in
the process of exhalation
- intercostals relax, ribcage downwards and inwards
- diaphragm relaxes (dome shape)
- decrease volume, increase pressure, air flows out
why is breathing a passive process?!
muscles only have to relax
the rate of breathing is controlled by?
the level of carbon dioxide in the blood
normal breathing movements
16-18 breaths per minute
where is the unconscious control of breathing?
in the medulla oblongata of the brain
cells in the respiratory centre are very sensitive to…
the level of carbon dioxide in the blood
acidic gas
carbon dioxide
carbon dioxide dissolved in water
carbonic acid
what does carbonic acid do?
causes the pH of the blood to fall
what does the respiratory centre of the medulla do with the fall in the pH of the blood?
sends impulses to the intercostal muscles and diaphragm which causes inspiration to occur
what is the most powerful stimulant for the an increase in the rate of breathing?
carbon dioxide dissolved in the blood
2 breathing disorders
asthma and bronchitis
asthma
narrowing of the bronchioles of the lungs, making breathing difficult and wheezy
a possible cause of asthma
immune reaction to an external allergen e.g..pollen or dust
a preventative measure of asthma
avoid the allergen by avoiding areas where the allergen is present in high quantities
eg. frequent cleaning to avoid house dust
a treatment of asthma
inhaler that has drugs that stimulates the airways to widen and dilate
