B4 Flashcards
What is the composition of blood?
- plasma
- red blood cells
- white blood cells
- platelets
What is plasma?
Liquid part of blood , transport system
What plasma transports?
1) soluble digestion products such as glucose from the small intestine to other organs
2) carbon dioxide produced by aerobic respiration from the organs to the lungs to be breathed out
3) the waste product urea from the liver to the kidneys to be excreted in urine
What are red blood cells?
Transports oxygen from the lungs to body cells
What is haemoglobin?
Oxygen carrying molecule.
How are red blood cells adapted ?
- No nucleus so more space for haemoglobin
- have a dimple in cell called biconcave disc
What does the biconcave disc do?
Gives red blood cells a greater surface area so oxygen diffuses in and out rapidly .
What are white blood cells?
From part of the immune system , for example produce antibodies
Features of white blood cells?
Contain a nucleus which contains dna which encodes the instructions for white blood cells to do its job
What is blood?
A tissue
What are platelets?
Tiny fragments of cells and help blood to clot.
What is the composition of blood?
- plasma
- red blood cells
- white blood cells
- platelets
What is plasma?
Liquid part of blood , transport system
What plasma transports?
1) soluble digestion products such as glucose from the small intestine to other organs
2) carbon dioxide produced by aerobic respiration from the organs to the lungs to be breathed out
3) the waste product urea from the liver to the kidneys to be excreted in urine
What are red blood cells?
Transports oxygen from the lungs to body cells
What is haemoglobin?
Oxygen carrying molecule.
How are red blood cells adapted ?
- No nucleus so more space for haemoglobin
- have a dimple in cell called biconcave disc
What does the biconcave disc do?
Gives red blood cells a greater surface area so oxygen diffuses in and out rapidly .
What are white blood cells?
From part of the immune system , for example produce antibodies
Features of white blood cells?
Contain a nucleus which contains dna which encodes the instructions for white blood cells to do its job
What is blood?
A tissue
What are platelets?
Tiny fragments of cells and help blood to clot.
Why do you need oxygen in the blood ?
To supply your cells for respiration
Where are the lungs in your body ?
Thorax, separated from lower part by the diaphragm
What protects your lungs?
Ribcage
What do the lungs physically look like and what surrounds them?
Big pink sponges and surrounded by pleural membranes
How does oxygen get to the lungs?
Air that is breathed in goes through the trachea . Splits into two tubes called bronchi, each going to a different lung. There is even smaller tubes called bronchiole which are attached to the alveoli where gas exchange takes place.
What are alveoli?
Litter air sacs in the lungs. There a millions surrounded by a network of blood capillaries . This is where gas exchange takes place.
How does gas exchange work?
- blood passing next to alveoli just returned from the rets of the body so it contains lots of carbon dioxide and very little oxygen
- oxygen diffuses out of the alveolus into the blood . Carbon dioxide diffuses out of the blood into the alveoli to be breathed out
What happens when blood reaches body cells ?
Oxygen is released from the red blood cells and diffuses into the body cells . Then at the same time carbon dioxide diffuses back into the blood cell to be carried back to the lungs
What is the circulatory system made up off?
Heart, blood vessels and blood
What type of circulatory system do humans have?
A double circulatory system
How does the double circulatory system work?
- right ventricle pumps deoxygenated blood to lungs , to take in oxygen . The blood then returns to the heart .
- the left ventricle pumps oxygenated blood around all the other organs of the body. The blood gives up its oxygen at body cells and the deoxygenated blood cells return to the heart to be pumped out to the lungs
What is the heart?
Organ that pumps blood around the body in a double circulatory system. Walls are made of muscle tissue
What do heart valves do?
Make sure blood is flowing in the right direction.
What are the four chambers of the heart?
Left and right atrium
Left and right ventricle
How does blood enter the heart?
Flows in from the pulmonary vein and the vena cava
VPAAPV
Vena cava
Pulmonary artery
Aorta
Pulmonary vein
What does the atria do to the blood once it has been pushed in?
Pushes it into the ventricles.
What do the ventricles do once the atria have pushed the blood down?
Ventricles contract , forcing blood into the pulmonary artery and the aorta and out of the heart. The blood then flows to the organs through arteries and returns through veins . The whole cycle begins again
What do coronary arteries do?
Branch off from the aorta to make sure the heart gets its own supply of oxygenated blood
What is the hearts pacemaker?
A group of cells in the right atrium wall that controls your resting heart rate . These cells produce a small electric pulse which spreads to the surrounding muscle cells , causing them to contract
What is an artificial pacemaker?
Often used to control the heart beat if the natural pacemaker cells do not work properly. It is a little device implanted under the skin and has a wire going to the hear . It produces an electric current to keep heart beating regularly
What are the three blood vessels?
Arteries
Capillaries
Veins
What are arteries?
Carry blood away from the heart
What are capillaries ?
Involved in the exchange of materials at the tissues
What are veins?
These carry blood to the heart
How are arteries structured?
- artery walls are strong and elastic as the heart pumps blood out at a high pressure
- walls are thick compared to size of the hole so the lumen is small
- contain thick layers of muscle to make strong and elastic fibres to allow them to stretch and spring back
How are capillaries structured?
- branch of from arteries
- capillaries are very small
- carry blood closely to cells so they can exchange substances
- permeable walls so substances can diffuse easily
- supply food and oxygen and take away waste like c02
- walls are usually one cell thick, this increases the rate of diffusion by decreasing the distance over which it occurs
How are veins structured?
- capillaries eventually join up to form veins. The blood is at a lower pressure in the veins so the walls dont need to be as thick as the artery walls
- have bigger lumen than arteries to help blood flow despite lower pressure
- have valves to help keep blood flowing on the right directipm
Example of plant organs?
Stems
Roots
Leaves
What are examples of plant tissues?
- epidermal tissue
- palisade mesophyll tissue
- spongy mesophyll tissue
- xylem
- phloem
- meristem
What is the epidermal tissue ?
Covers the leaf
What is the palisade mesophyll tissue?
Part of the leaf where most photosynthesis takes place
What is the spongy mesophyll tissue?
Found in leaf contains big air spaces to allow gases to diffuse in and out of the cell
What is the xylem and phloem tissue?
Transport system of food and water and mineral ions
What is the meristem tissue ?
Found at growing tips of roots and shoots and is able to differentiate .
How is the epidermal tissue structured?
- covered with a waxy cuticle which helps reduce water loss by evaporation
How is the upper epidermis tissue structured?
Transparent so that light can pass through it to the palisade layer
How is the palisade layer structured?
Has lots of chloroplasts so near the top of the leaf to get most light
How are the xylem and phloem structured?
Form a network of vascular bundles , which deliver water and other nutrients tot he entire leaf and take away glucose produced by photosyntheis . They also support the structure.
How are tissue in the leaves adapted for gas exchange?
Lower epidermis is full of little holes called stomata which let co2 diffuse directly into the leaf. The opening and closing of the stomata is controlled by guard cells in response to environmental conditions. Air spaces in the spongy mesophyll tissue increase rate of diffusion
What does the phloem transport?
- Made of columns of elongated living cells with pores in the end of the cell walls to allow cell sap
- transport substances (mainly dissolved sugars) made in the leaves to the rest of the plants for immediate use or for storage
- transport goes in both directions
- this process is called translocation
What does the xylem tissue do?
- made of dead cells joined end to end with no end walls between them and a hole down the middle . They’re strengthened with a material called lignin
- they carry water and mineral ions from the roots to the stem and leaves
- the movement of water from the roots, through the xylem and out of leaves is called transpiration stream.
What is transpiration?
1) Caused by evaporation and diffusion of water from a plants surface . Most transpiration happens at the leaves
2) evaporation creates a shortage of water in the leaf , and so much water is drawn up from the rest of the plant through the xylem vessels to replace it.
3) this in turn means more water is drawn up from the roots and theres a constant transpiration stream of water through the plant
What is transpiration to photosyntheis?
A side effect . They have stomata in them so gases can be exchanged easily . Because theres more water inside the plant than in the air outside the water escapes through the leaves by diffusion
How light intensity effects the transpiration rate ?
Brighter the light, the greater the transpiration rate. Stomata begins to close as it gets darker . When stomata closes very little water escapes
How temperature effects the transpiration rate?
The warmer , the faster the transpiration rate . Water particle have more energy to evaporate and diffuse out of the stomata
How air flow effects the rate of transpiration?
Better the air flow the greater the transpiration. Water vapour surrounds leaf if airflow is poor. Greater conc. of particle outside leaf so slows down diffusion . Good airflow means water is swept away maintaining quick diffusion
How humidity effects the transpiration rate?
The drier the air around the leaf the faster the transpiration rate.
How to estimate the rate of transpiration?
Measure plants uptake of water and control the variables
What are guard cells ?
Control the stomata
How are guard cells adapted?
- kidney shape which opens and closes the stomata in a leaf.
- when it has lots of water in the guard cells it goes turgid. This makes the stomata open so gases can be exchanged for photosynthesis
- thin outer walls and thickened inner walls make the opening and closing work
- close at night to save water without losing it on photosynthesis
What is cardiovascular disease?
Disease of the heart or blood vessels
What is coronary heart disease?
When coronary arteries that supply blood to body are blocked by layers of fatty materials building up . This causes the arteries to become narrow , so blood flow is restricted and lack of oxygen to heart., which can result in a heart attack .
What are stents?
- Tubes inserted inside arteries , they keepb them open , making sure blood can pass through to heart muscles
- lower risk of heart attack and are effective for a long time and recovery time from surgery is quick
- risks of operation complications, infection during surgery or blood clots near stent called thrombosis
What are statins ?
-drugs that reduce amount of bad cholesterol present in blood stream . Slows down the rate of fatty deposits forming.
What is cholesterol?
- essential lipid produced by body and needs it to function properly . Too much of a certain type of cholesterol can cause health problems.
- too much of bad cholesterol in the blood stream can cause fatty deposits to form inside the arteries which can lead to coronary heart disease
Advantages of statins
- by reducing bad cholesterol in blood statins can reduce risk of strokes and disease
- increase amount of good cholesterol in blood stream , that can remove the bad
- statins may also help prevent some other diseases
Disadvantages of statins
- must be taken regularly
- sometimes negative side effects which could be serious (kidney failure, liver damage , memory loss)
- isn’t instant effect
What is an artificial heart ?
- if patient has heart failure, doctors may perform a heart transplant
- mechanical devices that pump blood around the body , usually only a temporary fix
- less likely to be rejected by human immune system, as usually made by metals or plastics
- surgery could lead to bleeding and infection
- artificial hearts not as efficient as healthy ones. Can get blood clots and take drugs to prevent this
How can valves be damaged?
- heart attacks, infection or old age
- valve tissue may stiffen , so wont open properly
- valve may become leaky, allowing blood to flow in both directions, so blood doesn’t circulate as effectively
How to treat damaged valves?
- replace valve , mechanical or biological
- much less drastic procedure than a whole heart transplant
- surgery can cause blood clots still
What is artificial blood?
- if someone loses a lot of blood the heart can still pump around red blood cells as long as the blood can be topped up.
- substitue used to replace blood loss
