homeostasis- the human breathing system Flashcards
(28 cards)
what is homeostasis
the maintenance of a constant internal environment within the body
homeostasis in animals
body temperature at 37.5
pH of blood approx 7.4
regulating glucose in the body
excreation of urea, salt, water and carbon dioxide
ensuring oxygen levels are sufficient
heart rate and blood pressure
temperature regulation in warm blooded creatures
endothermis
humans, mammals etc
-respiration or metabolism is main source of heat
-maintain a constant internal temperature despite external conditions
temperature regulation in cold blooded creatures
ectothermis
lizards, snakes etc
-must lie on rocks which absorb heat from the sun
-do not have a constant internal temperature and rely on their environment for heat
what is breathing
the process of inhailing air into the lungs and exhailing air out of the lungs
what is respiration
the breakdown of glucose to release energy either with or without oxygen
pathway of air to the lungs
mouth/nose
trachea
bronchus
bronchiole
alveoli
the larynx
our voice box
made of two sheets of muscle that vibrates as air passes between them so we can produce sounds and speech
nose/mouth
warms, filters and moistens the air before it reaches the lungs
mucus and cilia
mucus-the cells that line the nose, trachea and bronchi produces a sticky mucus to trap dust and germs
cilia- tiny hair like projections that ae found in the nose and lining of trachea that waft back and forth to move dust and microorganisms back to the mouth to be swallowed or spit out
become damaged from smoking
epiglottis
a flap of tissue that closes over the trachea reflexively when we swallow to prevent food going into the trachea
-food can only go into the oesophagus
rings of cartilage
-surround the trachea and bronchus, keeps them open as air passes through them
-prevents them from collapsing
gas exchange
-air enters the nose/mouth and travels down the trachea, the bronchus and the bronchioles to the alveoli
-each alveoli is covered in a net of thin walled blood capillaries
-the alveolus is only one cell thick
adaptations of the lungs for gas exchange
-alveoli have a large surface area
-alveoli and blood capillary only one cell thick
-millions of alveoli in lungs
-each alveolus is surrounded by a blood capillary
-walls of alveoli are elastic
composition of inhailed air in the lungs
oxygen 21%
carbon dioxide 0.04%
nitrogen 79%
water vapor varies
composition of exhailed air into the lungs
oxygen 16%
carbo dioxide 4%
nitrogen 79%
water vapor saturated
inhalation
-breathing in
-brain sends signals to intercostal muscles and diaphragm to contract
-ribs are pulled up and out and diaphragm flattens downwards
-volume of chest increases
-air pressure decreases and air is drawn into the lungs and alveoli
exhalation
-breathing out
-brain sends signals to intercostal muscles and diaphragm to relax
-ribs move down and in and diaphragm bounces up
-volume of chest decreases
-air pressure increases and air is pushed out of lungs and alveoli
energy usage
inhalation- active process as it requires energy in the form ATP because muscles are contracting
exhalation- passive process because the intercostal muscles and diaphragm are relaxed
transport of oxygen in the blood
-red blood cells have haemoglobin in them
-red blood cells carry 97% of the oxygen
-the other 3% is carried in the plasma
oxygen + haemoglobin = oxyhaemoglobin
transport of carbon dioxide
-most is carried in the plasma as bicarbonate ions or as dissolved CO2
-a small percentage is carried by the blood cells
role of brain in breathing
-controlled by the medulla oblongata of the brain
what is the controlling factor of gas exchange
carbon dioxide
asthma
the narrowing of bronchioles due to an irritant (dust mite, pollen, cold, virus etc)
