Chapter 4: Organising animals and plants Flashcards
1
Q
The blood
A
- The blood, blood vessels and heart make up the human circulatory system which transports substances to and from the body cells
- Plasma has blood cells suspended in it and transports proteins and other chemicals around the body
- Haemoglobin is the red pigment that carries oxygen around the body in the red blood cells
- Your red blood cells contain haemoglobin that binds to oxygen to transport it from the lungs to the tissues
- White blood cells help to protect the body against infection
- Platelets are cell fragments that start the clotting process at wound sites
2
Q
The blood vessels
A
- Blood flows around the body in the blood vessels. The main types of blood vessels are arteries, veins and capillaries
- Substances diffuse in and out of the blood in the capillaries
- The valves prevent back flow, ensuring that blood flows in the right direction
- Human beings have a double circulatory system
- Arteries have thick walls, a small lumen and a thick layer of muscle and elastic fibres
- Veins have relatively thick walls, a large lumen and often have valves to prevent backflow
- Capillaries have one cell thick walls, they are a tiny vessel with a narrow lumen
See picture in documents
3
Q
The heart
A
- The heart is an organ that pumps blood round the body
- Heart valves keep the blood flowing in the right direction
- Stents can be used to keep narrowed or blocked arteries open
- Statins reduce cholesterol levels in the blood and this slows down the rate at which fatty material is deposited in the coronary arteries, reducing the chance of coronary heart disease
See picture in documents
4
Q
Helping the heart
A
- Damaged heart valves can be replaced using biological or mechanical valves
- The resting heart rate is controlled by a group of cells in the right atrium that form a natural pacemaker
- Artificial pacemakers are electrical devices used to correct irregularities in heart rhythm
- Artificial hearts are occasionally used to keep patients alive while they wait for a transplant, or for their heart to rest as an aid to recovery
5
Q
Breathing and gas exchange
A
- The lungs are in your chest cavity, protected by your ribcage and separated from your abdomen by the diaphragm
- The alveoli provide a very large surface area and rich supply of blood capillaries. This means gases can diffuse into and out of the blood as efficiently as possible
See picture in documents
6
Q
Tissues and organs in plants
A
- Plant tissues are collections of cells specialised to carry out specific functions
- The structure of the issue in plant organs is related to their functions
- To roots, stem, and leaves form a plant organ system for the transport of substances around the plant
- Xylem carry water and mineral ions from the roots up to the leaves
- Phloem carry dissolved food from the leaves around the plant
See picture in documents
7
Q
Transport Systems in plants
A
- Plants have separate transport systems
- Xylem tissue transport water and mineral ions from the roots to the stems and leaves
- Phloem tissue transport dissolved sugars from the leaves to the rest of the plant, including the growing regions and storage organs
8
Q
Evaporation and transpiration
A
- The loss of water vapor off the surface of plant leaves is transpiration
- Water is lost through the stomata, which open to let in carbon dioxide for photosynthesis
- The stomata and guard cells control gas exchange and water loss
9
Q
Factors affecting transpiration
A
- Factors that increase the rate of photosynthesis or increase stomatal opening will increase the rate of transpiration
- These factors include temperature, humidity, air flow and light intensity
- Transpiration is more rapid in hot, dry, windy, or bright conditions
- Light intensity affects the transpiration stream because it increases photosynthesis (as it increases) meaning the stomata will open more to let in carbon dioxide and let out oxygen, so more water vapour will be lost. Therefore, as light intensity increases the rate of transpiration increases
