B4 Organisation of animals and plants Flashcards
What is an artery
A blood vessel that carries blood away from the heart at relatively high pressures
It has thick muscular walls and a small lumen
What is a capillary
Small thin walled blood vessel that connects arteries to veins
Walls are one cell thick-short diffusion distance
What is a vein
Blood vessel that returns blood to the heart at relatively low pressures
Thin walls
Valves
Large lumen
What happens in our lungs when we breathe
When breathing in air flows in through the trachea
Through the bronchi to each lung, then to the alveoli
The diaphragm and intercostal muscles contract when we breathe in and relax when we breathe out
How are the lungs adapted for efficient gas exchange
Short diffusion pathway
Huge surface area
Good supply of oxygen and blood
What are the heart ventricles
The larger chambers in the heart
The right ventricle pumps blood to the lungs
The left ventricle pumps blood to the rest of the body
What are the atria (atrium)
The smaller chambers in the heart
These fill with blood from the vena cava and pulmonary vein then pump the blood into the ventricles
What is the aorta
The artery leaving the left ventricle
Sends oxygenated blood to the rest of the body
What is the vena cava
The main vein that brings deoxygenated blood back to the heart (The right atrium)
What is the pulmonary artery
The artery that leaves the right ventricle to carry blood to the lungs
What is the pulmonary vein
The vein leading from the lungs back to the heart (left atrium)
What are the 4 components of the blood
Red blood cells
White blood cells
Plasma
Platelets
What is the plasma and what is its function
The liquid part of the blood which all the blood cells are suspended in
It transports: Carbon dioxide from the organs to the lungs, urea from the liver to the kidneys
What are red blood cells and what is there function
Biconcave shaped cells that contain haemoglobin which oxygen can bond to for transportation
Very large surface area for diffusion of gases and can squeeze through capillaries
What are white blood cells and what is there function
Cells in the blood that fight infection caused by pathogens-Form part of the bodies immune system
M
Lymphocytes-Synthesise antibodies
Phagocytes-Engulf and digest pathogens
What are platelets and what is their function
Fragments of cells
Their role is to initiate the process of clotting at a wound, this blocks the wound in the blood vessel and prevents excess blood loss
Where is the hearts natural pacemaker
Right atrium
What are the risk factors of Coronary heart disease
Smoking
Obesity
High blood pressure
How can CHD be treated
Stents can be used to open up the blood vessel
A metal mesh with a tiny balloon inside is inserted into the artery and the balloon is inflated which opens up the blood vessel and allows the blood to flow freely
What happens if your heart valves are damaged
Blood flow is reduced
What is the treatment for leaky or damaged valves
Biological valves-Made from valves taken from pigs of cattle
Mechanical valves-Made from polymers and titanium
What are the pros and cons of biological valves
Pros-
They do not damage red blood cells
Cons-
Can become hardened after several years
May have to be replaced
Risk pf rejection
What are the pros and cons of mechanical valves
Pros-
Strong and durable, wont have to be replaced
Cons-
Damage red blood cells
Require anti clotting drugs for the rest of patients life
Some people say they can hear the valves open and close
What is the epidermal
Type of plant tissue that covers the surface of a plant
What is the palisade mesophyll
The tissue in the leaf where photosynthesis take place
What is the spongy mesophyll
Tissue in the leaf with air spaces between cells-Specialised for gas exchange
What are xylem
Narrow tubes in the roots stems and leaves which transport water and mineral ion for the roots to the shootd
What are the phloem
Tubes that run along side the xylem but transport sugars dissolved in water-Translocation
What are guard cells
Form the stomata on leaves-the holes through which gases are exchanged
They can open and close the stomata as needed
What is transpiration
The process by which plants lose water as vapour from their leaves by the stomata
What factors increase the rate of transpiration
Higher temperature
Lower humidity(drier air) Steeper conc gradient
Higher air flow(windier)Refreshes conc gradients, water vapour is constantly blown away from the plant
Higher light intensity
Why is it useful for guard cells to be able to control the stomata
If the conditions are dry, the guard cells can close the stomata in order to conserve water
