Mr Allsop-exchange surfaces Flashcards
what size cell has a larger SA:V ratio
smaller
what are villi
folds in intestine.
what does the root hair cell do
increases the SA of the cell which increases absorbance of nutrients.
what is ficks law
rate of diffusion is inversely proportional to the surface area x concentration difference / thickness of membrane.
what does the trachea do
windpipe.
c shaped cartilage to prevent is collapsing against the trachealis muscle but allows it to expand.
what is the trachea lined with
ciliated pseudostratified columnar epithelium that wafts away mucus and is one layer of long cells.
what is the goblet cells
in-between the ciliated pseudostratified columnar epithelium and releases mucus made in the Golgi apparatus.
how does mucus get destroyed
pathogens, bacteria, dust etc. gets stuck in mucus and the cilia then waft it back up towards the oesophagus where it goes to the stomach and is broken down by the strong PH hydrochloric acid.
what is cystic fibrosis
autosomal recessive disease. ( non-sex chromosome) requires two recessive alleles so people can be carries ( have one dominant allele)
overproduces mucus so can’t be moved.
what does the trachea branch into
the left and right bronchi
what is the hilum
bronchi makes contact with the lung.
what happens to airways in bronchioles
they get narrower and are no longer tissue instead they are elastic tissue.
what do terminal bronchioles divide into
respiratory bronchioles are the start of respiratory zone where airs delivered to alveoli for gas exchange.
what is the epithelium at the start of bronchioles called and its structure.
simple ciliated columnar epithelium and then changes into simple cuboidal epithelium as size decreases.
structure of alveoli
moist lining that gases dissolve in, before moving across membrane by simple diffusion.
surfactant- liquid inside keeping it inflated so has a large surface area.
explain the process from trachea to the alveoli
trachea, bronchi, bronchioles, primary bronchioles, secondary bronchioles, tertiary bronchioles, terminal bronchioles, respiratory bronchioles and alveoli.
what is the squamous epithelium
scaled lining of alveoli.
what is the pleura
surrounds each lung with a pleura sac that contains pleural fluid to allow inner and outer walls to slide over each other during act of breathing with little friction.
what does the phrenic nerve do
autonomous nerve that causes the diaphragm to contract so moves down and out.
what does the external inter costal muscle do.
contracts causing them to elevate bending them open.
what does internal inter costal muscle do.
depresses causing them to open
so it relaxes.
what is a pressure gradient in ventilation
change in pressure from the thoratic cavity to the atmospheric pressure.
explain what happens when we inhale
stimulation from the phrenic nerve contracts the diaphragm moving it in the inferior direction and out. this causes the external intercostal muscle to elevate bending them open by contracting them so the volume increases and therefore decreases the pressure in the thoratic cavity causing a pressure gradient where the atmospheric pressure is higher than in the thoratic cavity causing air to enter by the mouth or nose to reach equilibrium.
where is the larynx
near the voice box.
