15 -Transport System in Living things summary Flashcards
Summary Revision
Why do complex organisms like humans and animals need a transport system?
Because they are made up of millions of cells, and most of these cells are far away from the outside environment and cannot directly obtain necessary materials or remove waste. A transport system delivers substances like oxygen, digested food, and water to all cells and carries waste away.
What is diffusion?
Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration. It can occur with or without a partially permeable membrane. Examples include ink spreading in water (membrane absent) and oxygen moving from a leaf to the atmosphere (membrane absent). Diffusion also occurs with a membrane present, such as the diffusion of mineral salts from soil to xylem.
What is osmosis?
Osmosis is the net movement of water molecules from a region of higher water potential to a region of lower water potential through a partially permeable membrane. It is a specific type of diffusion that: 1. Only involves water molecules 2. Requires a partially permeable membrane. It occurs from a dilute to a concentrated solution and is seen in the movement of water from soil to xylem.
What are the three main parts of the human circulatory system?
The three main parts are the heart, blood, and blood vessels.
What is the main function of the heart?
The heart is an organ which pumps blood around the body.
Which side of the human heart typically carries blood low in oxygen?
The right side of the heart carries blood low in oxygen.
Which side of the human heart typically carries blood high in oxygen?
The left side of the heart carries blood high in oxygen.
What are the upper and lower chambers of the heart called?
The two upper chambers are the right atrium and left atrium, and the two lower chambers are the right ventricle and left ventricle.
What are the walls of the heart made of? What does this allow the heart to do?
The walls of the heart are made of muscles. These muscles contract and relax, allowing the heart to pump blood around the body.
What is the function of coronary arteries? What can happen if they become blocked?
Coronary arteries are blood vessels that transport oxygen and nutrients to the heart muscles. Blockage due to fatty substances can lead to a heart attack, where heart muscles may get damaged or die.
What are the two main functions of blood?
The two main functions of blood are: 1. To transport materials around the body (including nutrients like glucose and amino acids, oxygen, carbon dioxide, and other waste substances) and 2. To protect us against diseases.
Describe red blood cells and their main function.
Red blood cells have no nucleus and contain haemoglobin, which combines with oxygen and transports it around the body. They are bright red when carrying oxygen. Their biconcave shape increases its surface area to volume ratio, allowing oxygen to diffuse into it at a higher rate.
Describe white blood cells and their main function.
White blood cells contain a nucleus and lack haemoglobin (colourless). They are irregular in shape and larger than red blood cells. There are fewer white blood cells than red blood cells. Their main function is to keep the body healthy by fighting disease.
What is plasma and what does it transport?
Plasma is a pale yellow liquid made up of water (90%) and dissolved substances (10%) e.g., nutrients (glucose, amino acids, fatty acids, mineral salts) and waste substances. Plasma transports water and substances around the body.
What are platelets and what is their function?
Platelets are not true cells but fragments of cytoplasm. They play a part in blood clotting, which prevents excessive blood loss and prevents entry of germs into the blood.
What is the main function of arteries? What is a key characteristic of their structure and why?
Arteries carry blood away from the heart. They have walls which are thick, muscular and elastic to withstand the immense pressure of the blood as it is forced out of the heart. The lumen itself is very narrow to enable the pressure to be high.
What is the main function of veins? What are some key characteristics of their structure?
Veins carry blood to the heart. The walls of the veins need not be as thick and muscular as those of arteries, and they contain less elastic tissue than arteries because the blood pressure in the veins is much lower than the blood pressure in the arteries. Most veins have valves to prevent backflow of blood, especially when going against gravity. The lumen of veins is generally larger than that of arteries.
What is the main function of capillaries? What is a key characteristic of their structure?
Capillaries carry substances to and from cells. Their walls are made up of only a single layer of greatly flattened cells, providing a large surface area for the exchange of substances between blood and body cells. Red blood cells move in single file, slowing blood flow for more time for exchange. They carry blood from the arteries to the veins and also connect the veins back to the heart.
What are the main components of the transport system in plants?
The main components are leaves, stem, and roots, all of which contain xylem and phloem.
What is the function of xylem? What are some key structural features?
Xylem transports water and dissolved mineral salts from the roots to the stem and leaves and also provides mechanical support for the plant. It is made of many dead cells fused together at the ends to form a long hollow tube, and its walls have a woody substance known as lignin deposited to strengthen the hollow structure, preventing collapse. The cells in xylem vessels do not have a cell membrane, cytoplasm, or nucleus.
What is the function of phloem? What is the process called?
Phloem transports manufactured food (sucrose, amino acids) from the leaves to other parts of the plant. This process is called translocation.
What is a drug?
A drug is a substance that can affect body systems.
What is organ transplant?
Organ transplant is a medical procedure that is carried out to replace a damaged organ. The damaged organ is removed from the recipient and replaced with a healthy organ from a donor.
What is the purpose of the Human Organ Transplant Act (HOTA) in Singapore?
HOTA allows for the kidneys, heart, liver and corneas to be removed for the purpose of transplantation, in the event of death from any cause for Singapore Citizens and Permanent Residents 21 years old and above, who are not mentally disordered, unless they have opted out.
What is the difference between single and double circulation in the context of transport systems?
In single circulation (e.g., in fish), a drop of blood will go through the entire cycle and only pass into the heart once. In double circulation (e.g., in humans), blood passes through the heart twice in one complete circuit: once with deoxygenated blood from the body to the heart and then to the lungs, and again with oxygenated blood from the lungs back to the heart and then out to the rest of the body.
