B4 - Organising Animals and Plants - Complete Flashcards
What does the human circulatory system comprise of?
The blood, the blood vessels, and the heart
What does the blood consist of?
Mostly plasma, with white and red blood cells suspended within it, as well as substances that have dissolved within it
Give 2 examples of substances your blood plasma carries around the body
Waste carbon dioxide, urea from your kidneys
Give 2 adaptations of red blood cells to make them well suited to their job
They are biconcave discs, giving them an increased surface area to volume ratio for diffusion / They are packed with haemoglobin, which binds to oxygen - making oxygen transfer easy / They have no nucleus, so there is more space for haemoglobin
What is the job of red blood cells?
To carry oxygen throughout the body’s tissues
What are 2 types of white blood cells?
Phagocytes, which engulf invading bacteria and viruses, and lymphocytes, that produce antitoxins against the poisons of microorganisms
What are platelets?
Small fragments of cells that have no nucleus and float around in the blood
What is the function of platelets?
To help clot and block up wounds in order to stop infection and protect the new skin that is being built underneath
What chemical process must take place when a cut is clotting and what is it controlled by?
Fibrinogen into fibrin, which is controlled by enzymes
What are the three main types of blood vessel?
Arteries, veins and capillaries
Describe an artery and how it works
An artery carries blood away from the heart and into the body’s tissues - meaning it is often bright red and oxygenated. Arteries expand and contract as blood passes through them and have thick walls containing muscle and elastic fibres. They are highly pressurised, and as a result very dangerous if cut
Describe a vein and how it works
Veins carry blood away from the organs and back to the heart. They do not have a pulse, their blood is deoxygenated and so often more of a deep red or purple, and they have thinner walls than arteries. Veins also have valves to prevent the back flow of blood through its pathways
What are capillaries and what do they do?
Capillaries are a type of blood vessel that are very small have very thin walls. Substances can easily diffuse in and out of them and they cover all of the parts of the body that a large blood vessel such as a vein or an artery could not
Humans have a double circulatory system, what does this mean?
We have one transport system that carries blood to and from the heart and muscles, and one that goes to and from the heart and lungs
Why is it positive that humans have a double circulatory system?
It makes it very efficient
How is the heart itself supplied with oxygen?
The coronary arteries
Why and how is the heart separated? (in terms of pumps)
Into two different parts: for the two different sectors of our circulatory system (one pumps to the lungs and back, the other to the body and back)
Internally, how is the heart separated?
Into atria and ventricles
What are the main blood vessels that bring blood in and out of the heart, and which is which?
The Vena Cava is the main vein that brings deoxygenated blood back to the heart, and the Aorta is the main artery: taking oxygenated blood back out into the muscles and organs of the body
What is the main blood vessel that takes deoxygenated blood to the lungs from the heart?
The pulmonary artery
What are valves and what are their purpose?
Valves prevent the back flow of blood
What happens in coronary heart disease?
The coronary arteries that supply the blood with oxygen get blocked by deposited fats - making them thinner and eventually blocking the oxygen flow to the heart: causing a heart attack
What are two ways of solving the problem of coronary heart disease?
A stent / blood thinners (statins) / a bypass /
What is a stent and how is it put in place?
A stent is a tiny metal mesh that can be used to open up a blocked or thinned coronary artery. It is inserted with a balloon which is inflated: opening up both the artery and stent at the same time, which then holds the artery open, allowing blood to flow freely through
What is a heart bypass and how does it work?
A heart bypass is when a doctor takes an artery from a different part of your body and transfers to the heart, where they use it to ‘bypass’ the blocked artery - allowing blood to flow freely through the diversion, rather than getting blocked up in the original route. This operation can, however, run the risk of death and is very expensive
What are two treatments for problematic heart valves?
Replacements taken from pigs and other animals: these work extremely well and do not require any kinds of drugs to work, or mechanical valves made from things such as titanium and polymers that do not wear out, but do require drugs to stop blood clotting around them
What problems can a faulty natural pacemaker cause?
If the heart beats too slowly, the person can feel winded and out of breath, but if it beats to fast it won’t pump it around properly
What is an artificial pacemaker and how does it work?
An artificial pacemaker replaces the job of your real pacemaker and stimulates the heart with strong electric signals so that it beats regularly and the way it should
What is 1 positive and 1 negative of a pacemaker?
They extended your life and help your heart significantly if you were experiencing problems, but you must have regular check ups with the doctor to make sure it is working right
What are artificial hearts used for?
Artificial hearts are used for patients who have a heart problem and need a replacement, but have to wait for a correct tissue donor. They can keep people alive until then, but are currently not good enough to warrant a full time solution
What problem makes artificial hearts dangerous for full time replacement?
The blood could clot around it: resulting in death
Why do we breathe?
Other than to stay alive and supply us with oxygen, it allows the lungs to ventilate and a steep concentration gradient so that diffusion in and out of our lungs can take place quickly
What two muscle structures regulate the air moving in and out of your lungs?
The diaphragm and the intercostal muscles (the ones between your ribs)
What are alveoli?
Small structures within your lungs that have high concentrations of capillaries: allowing for lots of oxygen and carbon dioxide diffusion to take place
Why is the gas exchange in our lungs or effective?
As the blood coming into the lungs is almost always high in carbon dioxide and low in oxygen, resulting in a high concentration gradient to and from the blood and allowing the diffusion exchange to be rapid
What is the function of epidermal tissues in plants?
They cover the surfaces of the plants and often secrete a waxy substance that waterproofs them
What is the function of the spongy mesophyll layer in plants?
This layer has large surface areas and air pockets for gas exchange to place, as well as a few chloroplasts for photosynthesis (although the gas exchange is its main job)
What is the function of the palisade mesophyll layer in plants?
The palisade mesophyll layer is when the majority of a plant’s photosynthesis takes place, with many chloroplasts
What does xylem transport?
Water and dissolved mineral ions
What does phloem transport?
Dissolved food from the leaves around the plant
What are stomata and what are their function?
Stomata are holes that can open or close to allow for gas exchange to take place, and therefore allowing for the disposal of and taking in of oxygen and carbon dioxide for and from photosynthesis
What are stomata controlled by?
The guard cells around them
Other than oxygen and carbon dioxide, what can be lost when the stomata open?
Water vapour due to diffusion out of the cells surrounding the stomata, in a process called transpiration
What is the transpiration stream and why does it take place?
The transpiration stream is a result of water moving up through a plant to replace that that has been lost through transpiration. However, this is then often lost as a result of transpiration: resulting in a constant stream of water moving throughout the plant
What are 2 factor that effect the rate of transpiration?
Temperature / Humidity / Light intensity / Amount of air movement
Why does any factor that effects photosynthesis effect the rate of transpiration?
As the stomata open and close as a result of the amount of photosynthesis that takes place: i.e. if more photosynthesis takes place = stomata open more = more transpiration
Why does wilting take place?
As a defence mechanism to stop the plant from having lots of surface area and therefore too much more evaporation taking place. It will remain like this until the temperature drops, the sun sets, or it rains
What piece of equipment is most often used to show the rate of transpiration and the effects of different factors on it?
A potometer
