Mrs H bio 1 lungs and health studies Flashcards
how do the reactants for aerobic respiration enter the body?
glucose= intestine oxygen=lungs
how do the products of aerobic respiration leave the body?
water= water vapour when breathing carbon dioxide= lungs
where is the human gas exchange surface?
lungs
what are the alveoli?
air sacs- site of gas exchange
what adaptations do the alveoli have to make them effective at their function?
large surface area (as they are highly folded), high concentration gradient (maintained by a rich blood supply), thin diffusion distance (alveoli have a one cell thick epithelium)
how does oxygen move through the lungs to reach the alveoli?
Trachea -> Bronchi -> Bronchioles -> Alveoli
how does oxygen travel from the alveoli to the blood?
diffuses across the alveolar squamos epithelium -> then diffuses through the epithelium of the capillary -> then combines with haemoglobin in the red blood cells to form oxyhaemoglobin
what is the trachea made out of?
rings of cartilage
what is Fick’s law?
rate of diffusion= surface area x difference in concentration / diffusion distance
what is squamous and what does it reduce?
thin squashed cell and these reduce the diffusion distance
what is the process of inhalation?
external intercostal muscles contract causing the ribcage to move upwards and outwards, diaphragm contracts and flattens, thoracic cavity volume increases, pressure in thoracic cavity decreases to less than outside. active process- requires energy
what is the process of exhalation?
external intercostal muscles relax, diaphragm relaxes and domes up, thoracic cavity volume decreases, pressure in thoracic greater than outside, air moves out of lungs down a pressure gradient
what is the difference with forced exhalation?
same but in addition the internal intercostal muscles contract
what happens when blood reaches the alveoli?
oxygen diffuses into the blood through the squamos epithelial membrane and at the same time carbon dioxide moves from the blood to the alveoli
what happens to the blood after it is oxygenated at the alveoli?
it is circulated away from the alveoli by contractions of the heart, that move the blood away from the lungs and back to the heart to be pumped around the body