3.3.2 Gas Exchange in Humans

Question 1

label this diagram without looking at the labbles

Answer 1

https://www.savemyexams.com/a-level/biology/aqa/17/revision-notes/3-exchange–transport/3-2-human-gas-exchange/3-2-1-the-human-gas-exchange-system/

Question 2

what is the epiglottis

Answer 2

flap made of cartilage attached to the entrance of the larynx

prevents food from going into the trachea and instead directs it to the oesophagus

Question 3

what is the larynx

Answer 3

production of sound

Question 4

what is a nasal cavity

Answer 4

filters,warms, and moistens air

Question 5

what is the plural membrane

Answer 5

cover the lungs and line the chest cavity

Question 6

what is the lung

Answer 6

organ of gas exchange

Question 7

what is the intercostal muscle

Answer 7

moves ribs during respiration

Question 8

what is a diaphragm

Answer 8

skeletal muscle of respiration

Question 9

what is bronchi

Answer 9

Two divisions from trachea, each leading to one lung.

Secondary bronchi carry air to each lobe.

Similar structure to trachea but amount of cartilage reduced as bronchi get smaller.

Cilia and mucus present

Question 10

what is alveoli

Answer 10

air sacs for gas exchange

Question 11

what is the trachea

Answer 11

Flexible air way

Supported by c shaped rings of cartilage

Prevent trachea collapsing under low pressure when breathing in.

Muscular walls

Question 12

draw a diagram of a goblet cell

Answer 12

https://www.microscopemaster.com/goblet-cells.html

it should have a lot of microvilli , secretory vesicles , golgi apparatus , goblet cells ,cilliated epithial cell, and ofc a nucleus

Question 13

how many lobes does the right lung have and name all of them

Answer 13

3

superior lobe
middle lobe
inferior lobe

Question 14

how many lobes does the left lung have and name all of them

Answer 14

2

superior lobe
inferior lobe

Question 15

goblet cells produce mucus . why is this important :

Answer 15

Mucus made of mucin. Traps micro-organisms and debris, helping to keep the airways clear.

also acts as a lubricant , acts as a filter and traps any pathogens

Question 16

why are ciliated cells present in the trachea

Answer 16

Cilia beat regularly to move micro-organisms and dust particles along with the mucus.
mitochondria provide energy for beating cilia.

Question 17

what are bronchioles

Answer 17

Branched sub division of bronchi - smaller

Walls have no cartilage and are mainly composed of smooth muscle tissue and elastin lined with epithelial cells

Smooth muscle can constrict tubes to control the flow of air into and out of the alveoli

During exercise the bronchioles dilate for greater air flow.

Constriction avoids dust or environmental pollutants.

Question 18

the trachea are surrounded by cartilaginous rings . why is this important?

Answer 18

acts as a support. they are hard but also very flexable allowing it to move when you swallow food

Question 19

what is the function of the epiglottis ?

Answer 19

To cover the larynx (voice box) during swallowing , preventing food or suliva getting into the lungs.

Question 20

what is a alveoli

Answer 20

Minute air sacs at the end of the bronchioles

Collagen and elastic fibres lie between them

Lined with squamous epithelia

Phagocytes inside keep lungs free of infection by attacking pathogens that have entered in inhaled air.

Question 21

what type of cell is aveoli made of and what is the benifit of this

Answer 21

squarmous epithelium cells

thin and flat , allow for easier diffustion and a greater surface area

Question 22

How are alveoli adapted for gas exchange?

Answer 22

Large surface area (80sqm total for one lung)

Flattened epithelial cells with very thin walls ~ 0.1µm (short diffusion distance)

Surrounded by capillaries to maintain concentration gradient

Collagen and elastic fibres allow expansion and recoil

The alveolar membrane = gas exchange surface

blood is slowed near alveoli therefore more time to diffuse and are flattened against the cappilliary cell wall

Question 23

how do alveoli maintain there structure

Answer 23

Decrease in pressure on inspiration leads to a tendency for the lungs to collapse.

Cartilage keeps the trachea and bronchi open, but the alveoli lack this structural support.

Lung surfactant is a phospholipid that coats the surfaces of the lungs.

Without it, the watery lining of the alveoli would create surface tension and cause the surfaces to stick together

Question 24

info card read and recite

Answer 24

babies born prematurely lack surfactant in their lungs. this causes the alveoli to collapse (neonate respiratory distress syndrome) and this is why neonates need to be intubated and given lung surfactant to help maintain lung structure.

Question 25

what is the pleural cavaty and what is its role

Answer 25

Each lung is enclosed in a double membrane known as the pleural membrane. Space between the two membranes is the pleural cavity, filled with a small amount of pleural fluid. Role: to lubricate the lungs and adhere to the outer walls of the lungs to the thoracic (chest) cavity by water cohesion, so that the lungs expand with the chest while breathing.

Question 26

what is the 3 sets of muscles that are responsible for pressure change in the lungs

Answer 26

Diaphragm (sheet of muscle separating thorax from abdomen) Internal intercostal muscles (lie between ribs and cause expiration)) External intercostal muscles (lie between ribs and cause inspiration)

Question 27

labbel a diagram of a lung

Answer 27

https://www.pinterest.co.uk/pin/584693964103071381/

Question 28

how does the ribcage move during inhalation

Answer 28

up and out

Question 29

how does the ribcage move during exhalation

Answer 29

down and in

Question 30

what are the steps for inspiration

Answer 30

Inspiration (an active process) 1) External intercostal muscles contract moving ribs up and out 2) Internal intercostal muscles relax# 3) Diaphragm muscles contract causing it to flatten 4)This INCREASES the chest volume 5)This DECREASES the chest pressure 6)Atmospheric pressure is greater than pulmonary pressure and so SO AIR RUSHES IN

Question 31

what are the steps for exspiration

Answer 31

Expiration (largely passive) 1)The internal intercostal muscles contract and the external intercostal muscles relax. 2. The ribs move downwards and inwards. 3. Diaphragm muscles relax and diaphragm moves back up 4. This DECREASES the chest volume 5.This INCREASES the chest pressure 6.SO AIR FORCED OUT

Question 32

y/n does cartilage presents : trachea bronchi large bronchiole smaller bronchiole smallest bronchiol alveoli

Answer 32

trachea :yes bronchi:yes large bronchiole:yes smaller bronchiole:no smallest bronchiol:no alveoli :no

Question 33

y/n does smooth muscle presents : trachea bronchi large bronchiole smaller bronchiole smallest bronchiol alveoli

Answer 33

trachea :yes bronchi:yes large bronchiole:yes smaller bronchiole:yes smallest bronchiol:yes alveoli :no

Question 34

y/n does elastic fiber presents : trachea bronchi large bronchiole smaller bronchiole smallest bronchiol alveoli

Answer 34

trachea :yes bronchi:yes large bronchiole:yes smaller bronchiole:yes smallest bronchiol:yes alveoli :yes

Question 35

y/n does goblet cells presents : trachea bronchi large bronchiole smaller bronchiole smallest bronchiol alveoli

Answer 35

trachea :yes bronchi:no large bronchiole:no smaller bronchiole:no smallest bronchiol:no alveoli :no

Question 36

y/n does epithelium cells presents : trachea bronchi large bronchiole smaller bronchiole smallest bronchiol alveoli

Answer 36

trachea :yes bronchi:yes large bronchiole:yes smaller bronchiole:yes smallest bronchiol:yes alveoli : yes

Question 37

recoil of elastic tissue plays a majour part in expiration (rather like the air being released from a ballon) waht is it meant by recoil

Answer 37

the elastic tissue is streached and put under pressure this then pushes back pushing air out and going back to its resting position

Question 38

only under more under more strenous conditions (exercise) do the various muscles play a part. if elastic tissue are damaged by disease expiration doesn't occur as efficiently and concentration gradients cant be maintained. what effect will this have on an individual ?

Answer 38

shortness of breath , tierdness as not enough oxygen is beiing brought to the red blood cells and therefore less oxygen for respiration

Question 39

comment on the gas composition before and after exhilation

Answer 39

IN: oxygen : 21 % CO2: 0.04 % nitrogen : 78% OUT : oxygen :16% CO2: 4% nitrogen : 78%

Question 40

what is : Tidal volume

Answer 40

Tidal volume: The volume of air breathed in and out without conscious effort (usually, 0.4 – 0.5 dm3 for adults)

Question 41

what is : Ventilation rate

Answer 41

Ventilation rate: The number of breaths per minute (healthy person at rest around 15 breaths)

Question 42

what is : Inspiratory reserve volume

Answer 42

Inspiratory reserve volume: The additional volume of air that can be inhaled with max effort after a normal inspiration.

Question 43

what is : Expiratory reserve volume

Answer 43

Expiratory reserve volume: the additional volume of air that can be forcibly exhaled after a normal exhalation.

Question 44

what is : Vital Capacity

Answer 44

Vital Capacity: The total volume of air that can be exhaled after a max inhalation = TV+IRV+ERV

Question 45

what is :Residual Volume

Answer 45

Residual Volume: The volume of air remaining in the lungs after max exhalation (the lungs can never be completely emptied)

Question 46

what is ; Total Lung Capacity

Answer 46

Total Lung Capacity: VC + RV

Question 47

how do you calculate pulmonary ventilation rate :

Answer 47

tidal volume x breathing rate

Question 48

what is the use of spirometry also info card

Answer 48

a spirometer is used to measure lung function and can be used to diagnose lung diseases. a spirometer is the standard equipment used ti measure the capacity of the human lungs. it consists of a chamber (of capacity appoximatly 6dm^-3) suspended freely over water and counterbalanced so that gases passed in or drawn out makes the chamber rise and fall. you can makea permanent marker record of the movements of the chamber either by attaching a pen to it and allowing it to write on a drum revolving slowly (kynograph) or by attaching a motion sensor which will conver movement into electronic signals that are then interpreted by your datalogging software.

Question 49

can you explain why the following is required when taking a spirometry reading : counterpoise (counter balance)

Answer 49

pushes the thing down to allow it to come back down

Question 50

can you explain why the following is required when taking a spirometry reading : carbon dioxide absorber

Answer 50

so that all changes to the lid level are from oxygen

Question 51

can you explain why the following is required when taking a spirometry reading : nose clip

Answer 51

so all ventilation comes through the mouth