Unit 1.2 Transport

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Created by 09snjie about 6 years ago


Flashcards on Unit 1.2 Transport, created by 09snjie on 03/23/2015.

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Question Answer
1.2 1.2
What substances do organisms need and why - Oxygen for aerobic respiration - Glucose as energy source - Proteins for growth and repair - Fats as energy source and to make membranes - Minerals to maintain water potential and help enzyme action
How can organisms absorb these substances - From the surrounding environment - Make them inside their cytoplasm as part of cell metabolism
What waste products from their metabolic reactions within the cytoplasm do organisms need to remove - CO2 - O2 - Ammonia or urea (excess nitrogen)
What type of organisms have a large surface area to volume ratio Single-celled or small organisms
What type of SA to V ratio do multi celluar organisms have Small SA to V ratio
Why do larger organisms need special exchange surfaces - Cant exchange gases, nutrients or waste across their outer surfaces - Need larger area to exchange - Nutrients and gases have to travel further distance to center of organism
Features of a good exchange surface Large surface area Thin barrier, small diffusion distance Fresh supply of molecules on one side to keep concentration high Removal of required molecules on other side to keep concentration low
What do all these features maintain A steep diffusion gradient
What mechanism do some exchange surfaces use to increase exchange Active transport
Example of a specialized exchange surface - Walls of alveoli - Small intestine - Liver
What are the lungs A large pair of inflatable structures lying in chest cavity
Describe the path of the airway through the lungs and where gas is exchanged Air- Nose- Lungs- Trachea- Bronchi- Bronchioles- Alveoli- Gas exchanged on surface
How do people ventilate Ribs covering lungs move together with action of diaphragm
Where does all gaseous exchange in the lungs take place Alveoli
How does O2 get exchanged Passes from air in alveoli to blood in capillaries
How does CO2 get exchanged Passes from blood to alveoli
Features of a good exchange surface - Large surface area - Barrier permeable to O2 and CO2 - Thin barrier to reduce diffusion distance - Maintained diffusion gradient (steep)
Why do exchange surface need a large surface area To provide more space to molecules to pass through
Why are the alveoli sufficient despite being very small They are numerous
Why is a steep diffusion gradient necessary For diffusion to be rapid
How is a steep diffusion gradient maintained Fresh supply of molecules on one side (keep concentration high) , removal of some molecules on other side (keep concentration low)
Summary of blood transport system CO2 from tissue- Blood- Lungs - Concentration of CO2 always higher than that in air of alveoli - Carries O2 from lungs Ensures concentration is always lower in blood than in air of alveoli
How does the heart pump blood through to the lungs Via the pulmonary artery
how are the lungs adapted to reduce diffusion distance - Alveolus wall and capillary wall one cell thick - Squamous walls - Capillaries in close contact with alveolus walls - Total barrier only two cells thick
Summary of how breathing movements of the lung ventilate the lungs - Replace used air with fresh hair - Brings more O2 into lungs and ensures concentration of O2 in air of alveolus remains higher than in the blood - Removes air containing CO2 from alveoli, lower concentration in alveolus
Describe inspiration (inhaling) D E V P A -Diaphragm contracts- flattens and pushes digestive organs down - External intercostal muscles contract to raise ribs -Volume of chest cavity increases -Pressure in chest cavity drops (below atmospheric pressure) -Air moves into lungs
Describe expiration (exhaling) D E V P A -Diaphragm relaxes, pushed up by displaced organs underneath -External intercostal muscles relax and ribs fall -Volume of chest cavity decreases -Pressure in chest cavity increases (above atmospheric pressure) -Air moves out of lungs
What do the trachea, bronchi and bronchioles pass air into The lungs
What requirements must the airways meet in order to be effective - Large to allow sufficient air flow without obstruction - Divide into smaller airways to deliver air to all the alveoli - Strong to prevent collapsing when there is low pressure inside - Flexible to allow movement - Able to stretch and recoil
Which two airway structures have similar structures but differ in size Bronchi (narrower) and trachea
Which airway structures have several layers of tissue Bronchi Trachea
Structure and features of trachea - Mainly cartilage walls - Cartilage form incomplete or c-shaped rings - Loose tissue on inner surface of wall, made of glandular and connective tissue, elastic fibres, smooth muscle and blood vessel - Central inner lining of epithelium; cilia epithelium and goblet cells
Structure and features of Bronchi - Mainly cartilage walls - Cartilage less regular - Loose tissue on inner surface of wall, made of glandular and connective tissue, elastic fibres, smooth muscle and blood vessel - Central inner lining of epithelium; cilia epithelium and goblet cells
Structure and features of bronchioles - Much narrower than bronchi - Only larger ones have cartilage - Wall made mostly of smooth muscles and elastic fibres - Smallest ones have clusters of alveoli at their ends
What is the role of the cartilage tissue - Structural role - Supports trachea and bronchi, holding them open - Prevents collapse, when pressure inside is low during inhalation - Allows flexibility in trachea without constricting the airways -
Role of smooth muscle Role of Elasitic fibres - Can contract and restrict airways - Can make lumen of airway narrower - Control flow of air to alveoli (e.g. when harmful substance is present) - Not voluntary - Airways constrict, elastic fibres in loose tissues deform - As smooth muscle relaxes, elastic fibres recoil to original size and shape - Widening (dilating) the airway
Role of Goblet cells and Glandular tissue - Under epithelium - Secrete mucus - Trap tiny particles from air - Trap bacteria so they can be removed and reduce risk of infection
Role of Ciliated epithelium - Consists of ciliated cells - Cilia waft away mucus up airway to back of throat so it can be swallowed and killed by stomach acid
What is breathing Air moving in and out of your lungs as diaphgram and intercostal muscles contract and relax (12 times a minute)
Tidal Volume definition Volume of air moved in and out at rest
Vital capacity Largest volume of air that can be moved into and out of lungs in one breath
Residual Volume Volume of air that always remains in lungs
Dead space Air in the bronchioles, bronchi and trachea (where no exchange occurs with blood)
Inspiratory reserve volume Volume of air that can be inhaled above tidal volume
Expiratory reserve volume Volume of air that can breathed out above amount breathed in tidal volume breath
What does the spirometer trace look like
How is a spirometer used to measure lung volume - Chamber filled with oxygen floats on tank of water - Person breathes through mouthpiece attached to tube connected to O2 chamber. - Breathing in takes O2 from chamber so tank sinks and vice versa
How can the different elements of lung volume be shown using spirometer Person can be asked to breathe in different ways or do some exercises to show different patterns of breathing
What gas can build up when breathing into and out of a spirometer CO2
What type of lime is used to absorb the CO2 Soda lime
What do all animal cells need a supply of in order to survive Oxygen and nutrients
What are the three main factors that affect the need for a transport system 1) Size 2) SA to Volume ratio 3) Level of activity
How does size affect the need for a transport system Animals with lots of layers of cells won't be able to supply cells in central region as the nutrients will be used up by outer layer of cells
How does the SA to Volume ratio affect the need for a transport system In larger animals surface area isn't large enough to supply to internal cells
How does level of activity affect the need for a transport system More active animals need a sufficient supply of energy from respiration which requires O2 (e.g mammals for warmth)
What are the features of a good transport system - Fluid or medium to carry nutrients and O2 around body -Pump to create pressure to push fluid around body (heart) - Exchange surface - Tubes or vessels - Two circuits (one to pick up and one to deliver O2 to tissues
Example of an animal with a single circulatory system Fish
Example of an animal type with a double circulatory system Mammal
How does the fish single circulatory system work Heart - Gills - Body - Heart
How does the mammal double circulatory system work Two separate circuits Heart - Body - Heart - Lungs - Heart
What are the two circuits for the double circulatory system 1) Carries blood to lungs to pick up O2 (Pulmonary circulation) 2) Carries O2 and nutrients around body to tissues (Systemic circulation)
How are S.C.Systems efficient for fish -Fish are less active and don't maintain their own body temperature - Require less energy - Delivers O2 and nutrients quickly enough
How are D.C.Systems efficient for mammals - Active animals, maintain their body temperature - Require energy from food in process of respiration for heat and activity - Need good supply of both nutrients and O2 to release a lot of energy
Conditions in fish S.C.System - Blood pressure is reduced as blood passes through tiny capillaries of the gills. - Blood doesn't flow very quickly to rest of the body - Rate at which O2 and nutrients are delivered to respiring tissues is limited
Conditions in mammal D.C.System - After blood is passed through lungs, heart can increase its pressure so blood flows more quickly to tissues - S circulation can carry blood at a higher pressure - Blood pressure cant be too high in P circulation as it may damage capillaries in lungs
2 2
What is the mammalian heart and how is it divided - Muscular double pump - Divided into two sides
What does the right hand side pump Deoxygenated blood to lungs to be oxygenated
What does the left hand side pump Oxygenated blood to rest of body
How is blood moved along the arteries Heart squeezes the blood putting it under pressure which then forces the blood along
External features of heart - Atria (thin-walled chambers) - Ventricles (main pumping chambers) - Coronary arteries (lie over surface, carry oxygenated blood to heart muscle) - Tubes: veins and arteries
Internal features of heart - Two upper atria - Vena cava (deoxy blood to right atria) - Pulmonary vein (Oxy blood from lungs to left atrium) - AV valves - Tendinous cords (inside ventricles, attach valves to walls and prevent back flow) - Septum (wall of muscle separating ventricles from each other) - Semilunar valves
What happens when the muscle of each chamber contracts Pressure in blood is increased
Why is the muscle of the atria thin Chambers don't need to create much pressure Function is to push blood into ventricles
Which ventricle is thicker and why Left ventricle, have to pump blood around whole body, more pressure
Stages of contraction in cardiac cycle - Filling phase - Atrial contraction - Ventricular contraction
Why is important that the chambers of the heart all contract in a coordinated fashion To avoid inefficient pumping
What is the cardiac cycle A sequence of events involved in one heartbeat (as it is a cycle there is no clear end or beginning)
What happens during the Filling phase and what is it known as - Atria and ventricles are relaxing - Internal volume increases and blood flows into heart from major veins - Blood flows into atria, through AV valves and into ventricles Diastole
What happens during the Atrial contraction and what is it known as - Heart beat starts - Right and left atria contract together - Small increase in pressure by contraction - Helps push blood into ventricles - Walls of ventricles stretched, full of blood - Once full, ventricles contract - Blood fills AV valves causing them to snap shut - Prevents backflow Atrial Systole
What happens during ventricular contraction and what is it known as - All four heart valves are closed for a short period - Walls of ventricles contract Ventricular Systole - Raises pressure in ventricles very quickly contraction starts at apex of heart - blood pushed upwards towards arteries - semilunar valves open - blood pushed out of heart - Contractions last for short time Ventricle walls relax, heart starts filling again
How do valves work - Ensure blood flows in correct direction - Opened and closed by changes in blood pressure in various chambers of the heart
What causes the AV Valves to open When pressure in the ventricles drops below pressure in the atria. (When ventricular walls relax and recoil after contracting)
Where does blood entering the heart flow straight through Through the atria and into the ventricles
What happens to the pressure in the atria and ventricles as they fill Slowly rises
Do the valves remain open or closed while the atria contract Open
As the ventrticles begin to contract does the pressure of blood in the ventricles rise or fall Rise
In what direction does the blood start to move, when the pressure in the ventricles rises above that in the atria Upwards
How does this upwards movement prevent blood flowing back into the atria Fills valve pockets and keeps them closed
When the ventricles start to contract, is the pressure higher in the major arteries or in the ventricles In the major arteries
What effect does this have on SV valves (ventricles contracting) Semilunar valves are closed
Why does the pressure inside the ventricles rise quickly as they contract Blood cannot escape
What leads to the semilunar valves being pushed open Pressure in the ventricles being higher than the pressure in the aorta and pulmonary arteries
In what state of pressure is blood forced out of the ventricles Under very high pressure
What happens to the heart muscle once the ventricle walls have finished contracting Heart muscle starts to relax
Role of elastic tissues in ventricular walls after contraction & as a result what does it cause - Recoils to stretch muscle out again and return ventricles to original size - This causes the pressure in pressure to drop quickly
What happens once the pressure in the ventricles drops below pressure in the major arteries SV valves pushed closed By blood starting to flow back towards the ventricles & collecting in valves pockets
What does the closing of the SV valves prevent Back flow to the ventricles (blood)
What sound does the heart make Lub-dup
What is the first sound 'Lub' a result of AV valves closing as ventricles start to contract
What is the second sound 'Dup' a result of SV vales closing as ventricles start to relax
The shutting of which valve is louder (not due to blood accumulating in their pockets) AV valves
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