2.1 - The effects of CF on the lungs Flashcards
What is cystic fibrosis?
genetic disease of cell membranes caused by recessive allele
Define allele.
diff forms of same gene
What is a recessive allele?
allele that is only expressed if 2 copies are present
What is a dominant allele?
allele that is always expressed
What is a DNA mutation?
change to DNA base sequence
What is meant by genotype?
genes found on chromosomes
What is meant by phenotype?
physical characteristics expressed in a person
Define gene.
sqnce of base on
a DNA molecules
What is the cause of cystic fibrosis?
mutation in a gene where a protein transports sodium & chloride ions across cell membranes -> causes mucus -> build up in the throat & lungs
What is the trachea?
tubular structure that goes from mouth to the lungs
What is the bronchi?
2 tubes that trachea splits into
Where is the diaphragm in the body?
below lungs & heart + above abdomen
Where are the intercostal muscles in the body?
btwn ribs
What are the bronchioles?
smaller tubes tht bronchi splt into
What are the alveoli?
air sacs @ end of bronchioles
What is the thorax?
🫁,♡, 🩻, intrcstl muscles, bronchioles
What is the trachea made up of? How does this mean the trachea is adapted to its function?
rings of crtlge - keeps airway open always
What is the trachealis muscle? Where is it found?
muscle made up of smth mslce & elstc fbrs - inbwtn rings of crtlge
What is the function of the trachealis muscle?
holds lumen opn, allows flxblty drng inhltn & exhltn
What is the function of the respiratory lining?
warm & moisten air & to trap particles in mucus
What is the respiratory lining made up of?
epithelium & basement membrane
What are the walls of the trachea/bronchi lined with?
ciliated epithelial tissue
What does the ciliated epithelial tissue contain?
goblet cells
What do goblet cells make? What is the function of this substance?
mucus - trps pthgnc prtcls for cilia to waft prtlcs out of airways
What are 3 features of the bronchus?
- less crtlge thn trch & does not form a full circle
- epithelium = ciliated
- v few goblet cells
How is the epithelium made up in larger bronchioles? And in smaller bronchioles?
ciliated cells
non cilliated cells
What type of cells aren’t present in the bronchioles? What replaces them?
goblet cells
clara cells
What is the function of the clara cells?
cmpnts of srfctnt (liquid lining of lungs)
What isn’t present in the bronchioles but is present in the trachea?
cartilage
What are alveoli?
air sacs -> hold gases for gas exchange
How are the alveoili adapted?
- thin alveolus walls (1 cell thick)
- spherical shape
- rich blood supply
- moist layer
How does thin alveolus walls mean that the alveoli are adapted for rapid gas exchange?
short dffsn distnce
How does the spherical shape mean that the alveoli are adapted for rapid gas exchange?
large SA for dffsn
How does a rich blood supply mean that the alveoli are adapted for rapid gas exchange?
mntn high conc grdnt
How does a moist layer mean that the alveoli are adapted for rapid gas exchange?
O2 & CO2 can dissolve into
What makes a good microscope drawing?
use a pencil, no shading, clear lines, label on diagram
What does the inner lining of the blood vessels & alveoli consist of?
single layer of squamous endothelial cells
How are SE cells adapted for gas exchange?
thin
What are SE cells also known as?
pavement cells
How is columnar epithelium formed?
epithelial cells extend out from basement mmbrn
How columnar epithelium adapted?
surface facing intestine lumen is covered in micro villi - increase SA
What is the more scientifically accurate name of the ciliated epithelial cells?
pseudostratified columnar epithelial cells
Define mucus.
- thick slimy fluid secreted by cells lining many organs.
- mucus = produced by cells in GE, DS & RS
- apart from water, main cmpnt = protein called mucin
Define cilia.
- tiny hair-like extensions of cell surface membrn
Where are ciliated epithelial cells found, in relation to gas exchange?
line airways of lungs
eg.trachea, bronchi, bronchioles etc.
What is the function of the cilia in the lungs?
when we breathe in, small prtcls of dust in air are trapped in mucus that lines airways
beating action of cilia cntnsly wafts this mucus & trppd particles up into throat where is swllwd
What is the epithelial tissue?
tissue made up from epithelial cells
which forms outer surface of organs & structures in the body
Define tissue.
grp of cells have smlr strctr & tghthr crry out prtclr fnctn
Define basement membrane.
epthll cells sit on mmbrn frmd by prtn fbrs held in jelly - like sbstnc
Define trachea.
tubular strctr air entrs frm mouth & nose
split into 2 bronchi
Define bronchi.
tubular strctr that trachea splits into
Define bronchioles.
one of small airways that goes from bronchi
-> alveoli
Define alveoli.
- tiny air sacs in lungs where GE takes place
What are the alveoli lined by? How is this adapted to the alveoli’s function?
- lined by a layer of squms epthlm = v thin to ensure effcnt dffsn of O2 into blood & CO2 into alveoli
- has large SA -> ensure effcnt dffsn
Define pathogens.
- term used to describe microorgnsms that cause disease
Name 2 example of pathogenic bacteria.
campylobacter & heliobacter
Other than bacteria, what are 2 types of pathogen?
viruses & fungi
What is the difference in concentration, that allows diffusion to take place, called?
diffusion grdnt
Define gas exchange surface.
layer which O2 & CO2 are exchngd across
Define surface area.
area of surface
When does a concentration gradient occur?
occurs when a sbstnc is at higher conc. in 1 place than another
Define Fick’s law.
rate of diffsn ∝ size of SA x diff in conc./ thcknss of GE surface
What can you use to measure cells under a microscope?
graticule
What do you use to calibrate a scale when measuring cells under a microscope?
stage micrometre
How do you calibrate a scale when measuring cells under a microscope?
- align scales of graticule w stage micrometre
- find another point where scales align
- count the eyepiece graticule & stage micrometre units btwn 2 points
- now calculate conversion factor for eyepiece graticule
What is the equation for one eyepiece graticule unit?
1 EPGU = number of smu / number of EPGU x length of 1 smu in mm
*smu = stage micrometre units
How do you go from mm -> µm?
x1000
What is the equation for magnification?
image size/actual size
Why do lung lobes appear to be spongy? How does this suit the role of the lung lobes in gas exchange?
covered in millions of alveoli - have large SA for effcnt GE
How do you calculate SA? And volume?
SA = area of sides x how many sides there are
V = b x w x h
How are alveoli adapted to high surface area?
spherical shape
How is the small intestine adapted to a high surface area?
covrd in folds = villi, which r covrd in more folds called microvlli
How are root hair cells adapted to have a high surface area?
long finger like extensions of cell membrane & wall
What type of epithelial cells line the trachea and bronchus?
pseudostratified ciliated columnar epithelial cells
What type of epithelial cells line the wall of the alveoli?
squamous
Define diffusion.
net mvmnt of molecules (or ions) from a region of high concentration to a region of their lower concentration
In diffusion, what do the molecules move down?
conc. gradient
In diffusion, what makes the molecules move randomly?
natural KE
As a result of diffusion, what do the molecules eventually reach? What does this mean?
equillibrium - no net movemnt on either side of membrane
How is the cell membrane designed for diffusion?
partially permeable
Define polar.
oppositely charged particles
Define non polar.
equally charged particles
What are the 4 factors which determine the rate of diffusion?
- steepness of cocnentration grdnt
- temperature
- surface area
- type of molecules or ions
How does the steepness of concentration gradient affect the rate of diffusion?
rate of diffusion ∝ diff in conc.
bigger the difference in conc. between two sides of the membrane, the quicker the rate of diffusion
How does temperature affect the rate of diffusion? How?
rate of diffusion ∝ temperature
higher temperatures give molecules or ions more kinetic energy. Molecules move around faster, so diffusion is faster
How does surface area affect the rate of diffusion?
greater the surface area the faster the diffusion can take place. This is because the more molecules or ions can cross the membrane at any one moment
How does the type of molecule or ion affect the rate of diffusion?
large molecules need more energy to get them to move so they tend to diffuse more slowly. Non - polar molecules diffuse more easily than polar molecules because they are soluble in the cell membrane.
According to Fick’s Law, the rate of diffusion is dependent on what 3 factors?
surface area
diff. in conc
thickness of gas exchng surface
How are the lungs adapted for efficient diffusion?
- many alveoli increases surface area of the lungs (alveoli have spherical shape)
- blood flow maintains diff. in conc, the steeper the cocnentration gradient the higher the rate of diffusion .
- the alveoli & capillaries walls = 1 cell thick, bc they r made out of flattened cells so there is a short diffusion distance
