B4 organising animals and plants Flashcards
what are four parts of the blood
red blood cells
plasma
white blood cells
platelets
plasma percentage of blood is
55%
red blood cells percentage of blood is
45%
white blood cells percentage of blood is
<1%
platelets percentage of blood is
<1%
what is the structure of plasma
- Straw yellow liquid
- Made up of water and dissolved substances.
what are the functions of plasma
- Plasma transports many dissolved substances around the body. -Examples include digested foods (e.g. glucose), gases (e.g. carbon dioxide), wastes (e.g. urea) and hormones (e.g. insulin), antibodies, anti-toxins.
- Plasma also transports heat around the body.
what are the structures of the red blood cells
- Very small in size. This provides a large surface area to volume ratio.
- They contain Haemoglobin - this is a red pigment that binds oxygen oxyhaemoglobin)
- They are shaped like discs (biconcave) but are thicker at the edges
- They have NO nucleus (so there is more space for haemoglobin)
what are the functions of red blood cells
- To transport oxygen to all the body cells for respiration.
- Haemoglobin binds oxygen molecules forming oxyhaemoglobin.
what are the structures of white blood cells
- Much bigger than red blood cells.
- Much fewer in number than red blood cells.
- They HAVE a nucleus.
- They have no definite shape
what are the functions of white blood cells
-They help protect the body againstdisease.
Phagocytes englf ea pahogens Lymphocytes create antibodies which destroy pathogens
what are the structures of platelets
- These are tiny fragments of cells
- They have NO nucleus
- They cause blood to clot
what are the functions of platelets
Their function is to help form blood clots. This helps seal wounds (and prevent blood loss) when we cut ourselves.
What is meant by humans having a double circulatory system
The heart is an organ that pumps blood around the body in a double circulatory system. The right ventricle pumps blood to the lungs where gas exchange takes place. The left ventricle pumps blood around the rest of the body.
state three blood vessels
arteries
veins
capillaries
what is the function of an artery
Function of artery: transport (usually) oxygenated blood under high pressure away from the heart (except the pulmonary artery which transports deoxygenated blood to the lungs).
what is the function of a vein
Function of vein: transport (usually) deoxygenated blood to the heart (except the pulmonary vein which transport oxygenated blood into the left atrium).
what is the function of a capillary
Function of capillary: allow fast exchange/diffusion of substances e.g. glucose, oxygen - out of the blood into the body cells/tissues.
what is the pathway of blood flow through the heart
(RHS) Vena cava to right atrium to right ventricle to pulmonary artery (pumps blood to the lungs) to (LHS) Pulmonary vein to left atrium to left ventricle to aorta (pumps blood all around the body).
What are the coronary arteries
these are the arteries that supply the heart muscle with oxygen and glucose for respiration.
How can blocked coronary arteries lead to heart disease?
In coronary heart disease layers of fatty material build up inside the coronary arteries, narrowing them. This reduces the flow of blood through the coronary arteries, resulting in a lack of oxygen for the heart muscle.
name 6 treatments for cardiovascular diseases
stent statins artificial valve transplant artificial pacemaker artificial heart
what is a stent
a stent is a wire mesh balloon which is inserted into a (blocked) coronary artery to widen the artery and allow more blood to flow.
what are a stents advantages
- Minor operation (doesn’t need general anaesthetic)
- lower risk of heart attack.
what are a stents disadvantages
-Risk of infection from the surgery.
what is a statin
statins are drugs taken to reduce blood cholesterol levels, which slows down the rate of fatty deposit build up in the coronary arteries.
what are a statins advantages
- Does not require surgery
- Reduces the risk of arteries narrowing.
- reduces the risk of strokes and coronary heart disease.
what are a statins disadvantages
- May increase risk of developing type 2 diabetes
- Need to be taken long term daily. People might forget.
what is an artificial valve
- Valves in the heart prevent backflow of blood. -If the valve becomes faulty this could prevent the valve from opening fully, or the heart valve might develop a leak.
- Faulty heart valves can be replaced using biological or mechanical valves.
what are an artificial valves advantages
High success rate
what are an artificial valves disadvantages
- Risk of infection
- Need to take blood thinners as blood clots may form.
- Major surgery is involved.
what is a heart transplant
Replacement of a faulty / diseased heart with that of one donated by another person.
what are heart transplants advantages
Can treat several heart conditions Increase life expectancy
what are heart transplants disadvantages
Risk of rejection
3 year waiting list for compatible donor
what is an artificial pacemaker
The natural resting heart rate is controlled by a group of cells located in the right atrium that act as a pacemaker. Artificial pacemakers are electrical devices used to correct irregularities in the heart rate.
what is an artificial pacemakers advantages
Long lasting devices
what is an artificial pacemakers disadvantages
Doesn’t treat heart disease
Patient needs to avoid magnetic and electromagnetic fields of energy.
what is an artificial heart
If donor organs are not available doctors may insert an artificial heart.-
- It is a mechanical device that can pump blood for a person who has a failed heart.
- They are used as a temporary fix to keep someone alive until they can have a heart transplant.
what are an artificial hearts advantages
-Less likely to be rejected than a donor heart.
what are an artificial hearts disadvantages
- Major surgery is involved which carries high risk of bleeding and infection.
- Artificial hearts could malfunction.
What are the adaptations of the alveoli in the lungs for efficient gas exchange? You must always mention the structure and function in your answer.
Structure: alveoli have a very large surface area
Function: this provides maximum diffusion of gases
Structure: each alveolus is surrounded by a network of capillaries near the surface
Function: to maintain a steep concentration gradient, this means a faster rate of diffusion.
Structure: the alveoli have thin moist walls
Function: this provides a short (& quicker) diffusion pathway for gases
How does light intensity affect the rate of transpiration?
The brighter the light, the greater the transpiration rate. Stomata begin to close as it gets darker. Photosynthesis can’t happen in the dark, so hey don’t need to be open to let in CO2 in. When the stomata are closed, very little water can escape.
How does temperature affect the rate of transpiration?
The warmer it is, the faster transpiration happens. When it’s warm the water particles have more energy to evaporate and diffuse out of the stomata.
How does air flow affect rate of transpiration
the better the air flow around a leaf (e.g. stronger wind), the greater the transpiration rate. If air flow around a leaf is poor, the water vapour just surrounds the leaf and doesn’t move away. This means there’s a high concentration of water particles outside of the leaf as well as inside it, so diffusion doesn’t happen as quickly. If there’s good air flow, the water vapour is swept away, maintaining a low concentration of water in the air outside the leaf. Diffusion then happens quickly, from an area of higher concentration to an area of lower concentration.
How does the humidity affect the rate of transpiration?
the drier the air around the leaf, the faster transpiration happens. This is like what happens with air flow. If the air is humid. There’s a lot of water in it already, so there’s not much of a difference between the inside and the outside of the leaf. Diffusion happens fastest if there’s a really high concentration in one place, and a really low concentration in the other.
