Human Gas Exchange System

Question 1

What is the thorax

Answer 1

The collection of organs and tissues in the chest cavity wher gas exchange occurs

Question 2

Trachea function how is it specialised

Answer 2

The airway that leads from the mouth and nose to the bronchi.
Lined with goblet cells and ciliated cells
Goblet cells produce mucus to trap dust and microorganisms while the cilia sweep them away from the lungs

Question 3

Lungs function how is it specialised

Answer 3

Where gas exchange occurs
Lots of alveoli

Question 4

Bronchi function how is it specialised

Answer 4

Lead to the bronchioles

Question 5

Bronchioles function how is it specialised

Answer 5

Narrow tubes that carry air from the bronchi to the alveoli

Very narrow with no supporting cartilage so can collapse

Question 6

Alveoli function how is it specialised

Answer 6

Main site of gas exchange in lungs
Thin walls
Large SA:V

Question 7

Capillary network function how is it specialised

Answer 7

Surrounds the alveoli
Acts as an exchange surface between the lungs and blood
During gas exchange oxygen diffuses from alveoli to blood and co2 out of blood into alveoli

Question 8

What is cartilage

Answer 8

Strong and flexible tissue found around the body

Question 9

Function of tracheal rings

Answer 9

Cartilage support the trachea ensuring it stays open and can move and flex when we breath

Question 10

What is ciliated epithelium

Answer 10

Specialised tissue found along the trachea down to the bronchi
Each cell has projections of cilia sweeping mucus, dust and bacteria away from the lungs

Question 11

What are goblet cells

Answer 11

Mucus producing cells that secrete thick mucus to trap dust, bacteria and microorganisms

Mucus can be swept up then be swallowed and any mucus and microorganisms are destroyed by the stomach

Question 12

What is squamous epithelium in the alveoli

Answer 12

Allows for gas exchange as it forms the structure of the alveolar wall so is very thin and permeable for easy diffusion of gases

Question 13

Smooth muscle on bronchi and bronchioles function

Answer 13

Regulates the flow of air into the lungs by dilating when more air is needed and constricting when less is needed.

Question 14

Vast network of capillaries

Answer 14

Surrounds each alveolus
Co2 diffuses out blood and into alveolus and o2 the opposute

Question 15

Capillary width function

Answer 15

3-4 um means only one red blood cell can travel through at any time ensuring that there is sufficient time and opportunity for gas exchange to occur.

Question 16

Ethical concerns around dissections

Answer 16

People worry about how the animals for dissections were rasied and killed

Goes against some religious beliefs

Question 17

Method of preparing a slide for a solid specimen

Answer 17

Use scissors to cut a small sample of the tissue
Peel away a very thin layer of cells from the sample
Treat with chemicals to make rigid
Gently place coverslip on top and press down to remove any air bubbles
A stain may be required to make the structures visible

Question 18

how to prepare a slide for a liquid specmin

Answer 18

add a few drops of sample to slide
cover the liquid with a coverslip
press down to remove air bubbles
wear gloves to reduce cross contamination

Question 19

how to prevent the dehydration of a specimen on a slide

Answer 19

thin layers of material can dry up quickly

add a drop of water to the specimen to prevent cells from damage

Question 20

what to do about blurry images

Answer 20

switch to the lower power lens and try using coarse focus for a clearer image

is the specimen thin enough for light to pass through

Question 21

what takes measurements of cells on the lens of a microscope

Answer 21

graticule

Question 22

function of three way taps

Answer 22

repeat readings can be taken easily as there is no need for apparatus to be reassembled every time

Question 23

example of a 3 way tap in a potometer

Answer 23

When used with a water reservoir they allow for the air bubble to be returned to the start of the tube by allowing water to enter the system

Question 24

concentration of gases in the alveoli

Answer 24

high conc of O2 ( maintained as inspiration brings in)

Low CO2 conc (constantly being expired out)

Question 25

how is the conc grad of o2 maintained between alveoli and blood

Answer 25

within the blood, oxygen is used up in respiration which means low o2 conc in blood and o2 moves by simple diffusion from hiogh to low conc

Question 26

large number of alveoli reason

Answer 26

increases the surface area available for oxygen and co2 to diffsue faster across

Question 27

thin walls in alveoli reason

Answer 27

short diffusion distance so gas exchange is quick and efficient

Question 28

extensive capillary network

Answer 28

walls of cappilaries are 1 cell thick short diffusion distance constant flow of blood through these cappilaries maintaines a concentration gradient

Question 29

what is the order of pathway of air

Answer 29

nose / mouth trachea bronchi bronchioles alveoli

Question 30

what is the function of ventilation

Answer 30

ensures there is always a higher concentration of oxygen in the alveoli than the blood

Question 31

proccess of breathing in

Answer 31

diaphragm contracts and flattens ches volume increases air pressure decreases external intercoastals contract air moves in

Question 32

proccess of breathing out

Answer 32

passive proccess as the lungs have elastic tissue which recoils volume in ches decreases and pressure increases external intercoastals relax diaphragm contracts and becomes dome shaped in excersize the internal intercoastals also must contract to pull the ribs down and back

Question 33

PVR calculation formula

Answer 33

PVR = tidal volume x breathing rate

Question 34

what is PVR

Answer 34

the volume of air breathed in in one minute

Question 35

what is the tidal volume

Answer 35

volume of air inspired in each breath

Question 36

What is the breathing rate

Answer 36

The number of breaths taken per minute

Question 37

How does lung cancer occur

Answer 37

Mutations affect the regulation of mitosis in cells Tumours then develop if mutations occur in oncogenes or tumor suppressors of the epithelial cells in the bronchi Results in a mass of cells in the lumen of the airway

Question 38

What occurs in the lungs with a tumour

Answer 38

Becomes larger as it has no method of apoptosis and survives as it develops its own blood supply It can then squeeze against blood vessels - developing more tumours

Question 39

What are some symptoms of lung cancer

Answer 39

Coughing up blood A persistent cough Back/shoulder pain

Question 40

Symptoms of chronic obstructive pulmonary disease

Answer 40

Shortness of breath Chronic cough Difficulty breath

Question 41

What occurs in chronic obstructive pulmonary disease

Answer 41

Goblet cells become enlarged and produce more mucus Destroys cilia Cannot sweep mucus from lungs Microorganisms stay in lungs Causes phagocytes to be attracted which breaks down alveolar walls Alveoli have reduced elastin so break down and burst

Question 42

What chemicals are in a cigarette and why bad

Answer 42

Tar - carcinogen Nicotine -addictive Carbon monoxide - binds to haemoglobin

Question 43

What does tar do to the air passages

Answer 43

Destroys the cilia causing a buildup of Mucus Potentially leading to bronchitis as there is a buildup of mucus

Question 44

Tar effect on alveoli

Answer 44

Walls of alveoli break down causing them to merge together SA:V ratio decreases allowing less gas exchange Reduces efficiency of gas exchange Tar can also build up and form a layer on top of the alveolar cells which can increase the diffusion distance

Question 45

results of the Doll and Hill study about the effect of cigarettes

Answer 45

smoking increases mortality rate the greater the intensity of smoking, the higher the increased mortality smoking increases cancer risk giving up smoking reduces mortality rate

Question 46

what is a risk factor

Answer 46

any factor that corrolates with an increased chance of suffering from a particular disease

Question 47

what is the incidence of disease

Answer 47

the number of cases of a disease that occur within a particular group of people within a given time

Question 48

why is sample size so important

Answer 48

more reliable results identify and remove anomolous results

Question 49

things to take into consideration when analysing data

Answer 49

sample size individuals in sample levels of exposure control group statistical significance influence of other factors

Question 50

correlation is

Answer 50

an association or relationship between variables

Question 51

causation is

Answer 51

when one variable has an influence or is influenced by another