3.3.2 Gas Exchange in Humans Flashcards
3.3.2 Gas Exchange in Humans
label this diagram without looking at the labbles
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/
what is the epiglottis
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
what is the larynx
production of sound
what is a nasal cavity
filters,warms, and moistens air
what is the plural membrane
cover the lungs and line the chest cavity
what is the lung
organ of gas exchange
what is the intercostal muscle
moves ribs during respiration
what is a diaphragm
skeletal muscle of respiration
what is bronchi
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
what is alveoli
air sacs for gas exchange
what is the trachea
Flexible air way
Supported by c shaped rings of cartilage
Prevent trachea collapsing under low pressure when breathing in.
Muscular walls
draw a diagram of a goblet cell
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
how many lobes does the right lung have and name all of them
3
superior lobe
middle lobe
inferior lobe
how many lobes does the left lung have and name all of them
2
superior lobe
inferior lobe
goblet cells produce mucus . why is this important :
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
why are ciliated cells present in the trachea
Cilia beat regularly to move micro-organisms and dust particles along with the mucus.
mitochondria provide energy for beating cilia.
what are bronchioles
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.
the trachea are surrounded by cartilaginous rings . why is this important?
acts as a support. they are hard but also very flexable allowing it to move when you swallow food
what is the function of the epiglottis ?
To cover the larynx (voice box) during swallowing , preventing food or suliva getting into the lungs.
what is a alveoli
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.
what type of cell is aveoli made of and what is the benifit of this
squarmous epithelium cells
thin and flat , allow for easier diffustion and a greater surface area
How are alveoli adapted for gas exchange?
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
how do alveoli maintain there structure
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
info card read and recite
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.
what is the pleural cavaty and what is its role
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.
what is the 3 sets of muscles that are responsible for pressure change in the lungs
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)
labbel a diagram of a lung
https://www.pinterest.co.uk/pin/584693964103071381/
how does the ribcage move during inhalation
up and out
how does the ribcage move during exhalation
down and in
what are the steps for inspiration
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
what are the steps for exspiration
Expiration (largely passive)
1)The internal intercostal muscles contract and the external intercostal muscles relax.
- The ribs move downwards and inwards.
- Diaphragm muscles relax and diaphragm moves back up
- This DECREASES the chest volume
5.This INCREASES the chest pressure
6.SO AIR FORCED OUT
y/n does cartilage presents :
trachea
bronchi
large bronchiole
smaller bronchiole
smallest bronchiol
alveoli
trachea :yes
bronchi:yes
large bronchiole:yes
smaller bronchiole:no
smallest bronchiol:no
alveoli :no
y/n does smooth muscle presents :
trachea
bronchi
large bronchiole
smaller bronchiole
smallest bronchiol
alveoli
trachea :yes
bronchi:yes
large bronchiole:yes
smaller bronchiole:yes
smallest bronchiol:yes
alveoli :no
y/n does elastic fiber presents :
trachea
bronchi
large bronchiole
smaller bronchiole
smallest bronchiol
alveoli
trachea :yes
bronchi:yes
large bronchiole:yes
smaller bronchiole:yes
smallest bronchiol:yes
alveoli :yes
y/n does goblet cells presents :
trachea
bronchi
large bronchiole
smaller bronchiole
smallest bronchiol
alveoli
trachea :yes
bronchi:no
large bronchiole:no
smaller bronchiole:no
smallest bronchiol:no
alveoli :no
y/n does epithelium cells presents :
trachea
bronchi
large bronchiole
smaller bronchiole
smallest bronchiol
alveoli
trachea :yes
bronchi:yes
large bronchiole:yes
smaller bronchiole:yes
smallest bronchiol:yes
alveoli : yes
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
the elastic tissue is streached and put under pressure this then pushes back pushing air out and going back to its resting position
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 ?
shortness of breath , tierdness as not enough oxygen is beiing brought to the red blood cells and therefore less oxygen for respiration
comment on the gas composition before and after exhilation
IN:
oxygen : 21 %
CO2: 0.04 %
nitrogen : 78%
OUT :
oxygen :16%
CO2: 4%
nitrogen : 78%
what is :
Tidal volume
Tidal volume: The volume of air breathed in and out without conscious effort (usually, 0.4 – 0.5 dm3 for adults)
what is :
Ventilation rate
Ventilation rate: The number of breaths per minute (healthy person at rest around 15 breaths)
what is :
Inspiratory reserve volume
Inspiratory reserve volume: The additional volume of air that can be inhaled with max effort after a normal inspiration.
what is :
Expiratory reserve volume
Expiratory reserve volume: the additional volume of air that can be forcibly exhaled after a normal exhalation.
what is :
Vital Capacity
Vital Capacity: The total volume of air that can be exhaled after a max inhalation = TV+IRV+ERV
what is :Residual Volume
Residual Volume: The volume of air remaining in the lungs after max exhalation (the lungs can never be completely emptied)
what is ;
Total Lung Capacity
Total Lung Capacity: VC + RV
how do you calculate pulmonary ventilation rate :
tidal volume x breathing rate
what is the use of spirometry
also info card
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.
can you explain why the following is required when taking a spirometry reading :
counterpoise (counter balance)
pushes the thing down to allow it to come back down
can you explain why the following is required when taking a spirometry reading :
carbon dioxide absorber
so that all changes to the lid level are from oxygen
can you explain why the following is required when taking a spirometry reading :
nose clip
so all ventilation comes through the mouth
