3.2 Transport In Animals (and some exchange surfaces and breathing) Flashcards
What substances do organisms need to survive?
Glucose
Oxygen
What substances do organisms need to get rid of?
Lactic acid
Urea
Carbon dioxide
How do small organisms obtain and get rid of substances?
Diffusion, phagocytosis and exocytosis
Why do small organisms not need an exchange system?
The substances reach all cells as they’re all in the external environment
How do large organisms obtain and get rid of substances?
An exchange system
Why do large organisms need an exchange system?
Not all cells are in an external environment as there is a low surface area to volume ratio
What features make a good exchange system?
Moisture
Rich blood supply
Thin membranes
Large surface area
What is inhalation?
Breathing in
What is exhalation?
Breathing out
What happens during human inhalation?
- Rib Cage muscles and diaphragm contract to move down and become flatter/raise displacing digestive organs
- The volume of the thorax increases
- The pressure in the chest cavity drops below atmospheric pressure
- Air is moved into the lungs
What is the thorax?
Thoracic/chest cavity
What happens during exhalation?
- The rib cage muscles and diaphragm relax pushing up the diaphragm from the organs and allowing the ribcage to fall
- The volume of the thorax decreases
- The pressure in the thorax and lungs increases rises above atmospheric pressure
- Air is moved out of the lungs
What is atmospheric pressure?
The pressure in the surrounding air
What is the importance of a large surface area in the lungs?
Provides more space for molecules to pass through. The individual alveoli are also covered with moisture
What is the importance of a barrier permeable to oxygen/CO2 in the lungs?
The plasma membrane readily allows the diffusion of oxygen and carbon dioxide as small and non-polar
What is the importance of a thin barrier in the lungs?
Reduces diffusion distances
How thick are the alveoli?
1 cell
What is the importance of a good blood supply in the lungs?
Maintains a steep concentration as brings/takes substances
What is the importance of ventilation in the lungs?
The air is consistently is being replaced
What is the process of air flow?
Mouth –> Trachea –> Bronchus –> Bronchioles –> Alveoli
How is a rich blood supply maintained in the lungs?
Capillaries run over the surface of alveoli
How is ventilation maintained in the lungs?
Surrounded by diaphragm and intercostal muscles
How is a large surface area in the lungs produced?
Many alveoli
What are the reasons for exchange systems?
- Large multicellular organisms need a breathing system
- Cells in centre of organisms would not receive any oxygen
- Need more energy/high metabolic rate
Describe the structure of the trachea
Supported by a layer of cartilage to hold open and prevent collapse however it is incomplete to allow bending when food is swallowed
Lined with ciliated epithelial cells /goblet cells
Describe the structure of the bronchus?
Extensions of trachea
Split in two (left and right)
Similar to trachea but smaller
Cartilage rings hold pipe open
Describe the structure of the bronchioles
1mm/less in diameter Smaller bronchi Held open by smooth muscles Contracted by smooth muscles Lined with a thin layer of epithelial cells
Describe the structure of the alveoli
Air sacs Where most gas exchange occurs 200-300 NM in diameter Made of thin layer epithelial cells Elastic fibres recoil allowing air to move out of the alveoli
What can the spirometer be used for?
the volume of gas breathed in and out
What happens to the trace on a spirometer when inspiring?
It goes down
What happens to the trace on a spirometer when expiring?
It climbs up
How do you find the volume of a single breath on a spirometer?
The peak of expiration to the low of inspiration
How is carbon dioxide absorbed in a spirometer?
Soda lime
What is the chamber filled with in a spirometer?
Oxygen
How are movements recorded from a spirometer?
The floating chamber lid moves as the person breathes. It is then recorded on a datalogger to produce a trace
What is the tidal volume?
The volume of air inhaled or exhaled in one breath usually measured at a rest
What is the breathing rate?
Number of breaths per minute
What is oxygen uptake?
The volume of oxygen absorbed by the lungs in one minute
What is the vital capacity?
The greatest volume of air that can be expelled from the lungs after taking the deepest possible breath
What is the residual capacity?
The air that remains in the lungs (airways and alveoli) even after forced expiration
How many pairs of gills does a fish have?
5
What does each gill have?
2 rows of filaments attached to a bony arch
What are gill filaments like?
thin and folded into many secondary lamellae (gill plates)
What are gills covered by?
operculum
What is the buccal cavity?
The mouth
What are fish filaments/primary lamellae?
slender branches of tissue that make up the gill
What are secondary lamellae?
folds of the filament to increase the surface area
What is the operculum?
a bony flap that covers the gills
What is countercurrent flow?
Blood flows along one gill arch and out along the ligaments to the secondary lamellae.
Blood flows through capillaries in opposite directions of water flow over lamellae so that the maximum amount of oxygen can be absorbed
What is a spiracle?
External opening and closing pore that allows air in and out of the trachea. It is found in insects.
Why can insects not be big?
The trachea system could not supply enough oxygen
What is the tracheal system?
A series of tubes that supply the muscles with oxygen directly
How do insects ventilate the body?
Pump their abdomen
Why do spiracles open and close?
To minimise water loss
How does oxygen move in trachea system?
By diffusion
What is the function of trachioles?
Store trachiole fluid
What are the 3 main components of an insect’s ventilation system?
Spiracles
Trachea
Tracheoles
What kind of circulatory system do insects have?
Single and open
What kind of circulatory system do mammals have?
Closed and double
What kind of circulatory system do fish have?
Closed and single
What factors affect the need for circulatory systems?
Surface area to volume ratio
Size
Level of activity
Metabolic rate
What is an open circulatory system?
Blood is not held within the vessels
What is a closed circulatory system?
Blood is not held in vessels. It is continuous tubes in a complete circle directly into tissues.
What is a double circulatory system?
A higher pressure system where blood passes through the pump twice
What are the three stages of the cardiac cycle?
Diastole
Atrial systole
Ventricular systole
What happens during diastole?
Blood flows in
Low pressure
What happens during atrial systole?
Semi-lunar valves close
Atrioventricular valves open
Atria muscles contract
Pressure increases in atrium decreases in ventricles
What happens during ventricular systole?
Atrioventricular valves close
Semi-lunar valves open
Ventricular muscles contract
Pressure decreases in the atria and increases in the ventricles
What are the two types of heart muscles?
Smooth tissue
Myocardial tissue
What are the purpose of valves?
Prevent backflow
Maintain pressure
What happens if there is pressure in front of the valve?
It closes
What happens if there is pressure behind the valve?
It opens
What machine is used to measure lung capacity?
Spirometer
What valves open and close during ventricular systole?
Semilunar open
Atrio ventricular close
Describe why the oxygen dissociation curve is not a straight line
S shape cure rather than straight line
The oxygen diffuses out of the red blood cell into the tissues
At a low oxygen tension there isn’t much oxygen available - hard to find the haem group
Once binds causes conformational change making it easier for oxygen 1 and 2 to bind
It is harder for oxygen 4 to bind to the last haem group as it is harder to find the one that isn’t taken up
What is conformational change?
A slight change in the haemoglobin molecule when the first oxygen binds making it easier for oxygen 1 and 2 to bind
Why is fetal haemoglobin have a line further to the left in oxygen diassociation?
It has to go through the placenta and already has been used around the body
Low oxygen concentration
Has to have a higher affinity - stronger pull
What does affinity mean?
Stronger pull/attraction
What is the innermost layer of the blood vessels called?
Endothelium
Which way does the graph shift during carbon dioxide transport?
Right
Why does the graph shift right during carbon dioxide transport?
Hydrogen joins haemoglobin pushes oxygen out by changing the tertiary strucure
Who is the bohr effect useful for?
Active mammals - more oxygen delivered to muscles
Describe the bohr effect
- CO2 enters the red blood cells forming carbonic acid which dissociates to release hydrogen ions
- Hydrogen ions affect pH of cytoplasm - making it more acidic
- Changes in pH cause the tertiary structure of the haemoglobin to change reducing the affinity for oxygen
- Unable to hold as much oxygen and it released into tissues
How do Hydrogen ions affect the pH of the cytoplasm?
Make it more acidic
How are the hydrogen ions formed during the transportation of carbon dioxide?
It dissociates from carbonic acid
Where does CO2 diffuse from when going into the red blood cells?
The body
What do enzymes in red blood cells combine?
CO2 and H2O
Where is oxygen released into from the red blood cells?
Plasma of the blood
Why does oxyhaemoglobin dissociate?
Low pO2 and under the influence of hydrogen ions
What are the three different types of CO2 transport?
5% dissolved in the plasma
10-20% combine with amino groups of haemoglobin to carbaminohemoglobin
75-80% converted to hydrogen carbonate ions in the cytoplasm of red blood cells
