2- Organisation Flashcards
What does the right side of the heart do?
The right side pumps blood to the lungs under lower pressure to collect oxygen and remove carbon dioxide
What does the left side of the heart do?
The left side pumps blood to the body under high pressure to give body cells oxygen and take away carbon dioxide
Why is the heart called a double circulatory system?
Because there are two sides pumping blood to two different places
How efficient is the heart and why?
It is very efficient as body cells receive fully oxygenated blood quickly (higher blood flow rate)
What parts of the heart are on the right side?
- pulmonary artery
- vena cava
- right atrium
- heart valve
- right ventricle
What parts of the heart are on the left side?
- aorta
- pulmonary vein
- left atrium
- heart valve
- left ventricle
What is the purpose of the semi-lunar valves?
- The semi-lunar valves prevent blood flowing back into the ventricles between beats for pulmonary artery and aorta
How is the heart broadly structured and how does blood move through the heart?
- Separated into upper chambers called atria and lower chambers called ventricles
- The atria pump blood to ventricles. The ventricles pump blood to either the lungs (right ventricle) or the body (left ventricle)
Why is the heart muscle of the left ventricle thicker than the right?
- heart muscle of left ventricle is thicker than right. This allows the heart to contract more strongly, pumping blood at higher pressure
What is the purpose of the atrioventricular valves?
- The atrioventricular valves separate the atria and ventricles and prevent the backflow of blood
Definition of ventilation
The physical movement of air into and out of the lungs to allow gas exchange to occur
Definition of gas exchange
The diffusion of oxygen and carbon dioxide between air in the alveoli and the blood in capillaries
Definition of respiration
The exothermic reaction continually occurring in living cells to release energy from molecules in food
Function of alveoli
The site of gas exchange
Function of diaphragm and intercostal muscles
muscles involved in bringing about process of ventilation
Definition of trachea, bronchi and bronchioles
The airways through which air moves to and from the alveoli during ventilation
Adaptations of alveoli
- Many alveoli to provide increased SA for diffusion
- Thin walls to provide a shorter diffusion distance
- Good blood supply to maintain steep conc. gradient
- Good ventilation to maintain steep conc. gradient (supply fresh O2 to blood)
What is oxygen debt caused by?
The movement of lactic acid (which causes fatigue) to the liver and the use of oxygen to convert lactic acid into glucose
What is plasma?
Plasma is the liquid part of the blood
What is the function of blood plasma?
The function of blood plasma is to transport the blood cells and other substances around the body.
Examples of chemicals that are transported in blood plasma
- waste carbon dioxide
- urea
- glucose
- amino acids
- hormones
- proteins
Function of red blood cells
Transports oxygen around body
Give 3 adaptations of red blood cells
- Biconcave discs- increased surface area to volume ratio for diffusion
- Packed with haemoglobin that binds to oxygen
- No nucleus, making more space for haemoglobin
Function of white blood cells
Form part of the body’s defence system against microorganisms
What are the two types of white blood cells?
- Phagocytes
- Lymphocytes
Functions of phagocytes
Engulfs pathogens
Functions of lymphocytes
Produces antibodies and anti-toxins
What are platelets?
Fragments of cells with cell membrane and cytoplasm but no nucleus
What is the role of platelets?
They help blood clot at the site of a wound as they are captured to form a jelly-like clot that stops you bleeding to death. The clot dries and hardens to form a scab, stopping bacteria entering the body through the wound
What is the equation for cardiac output?
Cardiac output = Heart rate x stroke volume
Function of veins
Carry blood away from organs towards heart
Is blood in veins oxygenated or deoxygenated?
Deoxygenated
Pressure in veins
Low pressure
Thickness of walls in veins
Thin walls
Diameter of lumen in veins
Large lumen
Do veins have valves?
Yes
Function of arteries
Carries blood away from the heart to the organs
Pressure of blood in arteries
high pressure
Is blood in arteries oxygenated or deoxygenated?
Oxygenated
Thickness of walls in arteries
Thick walls
Lumen diameter in arteries
Small lumen
Are there valves in arteries?
No
Function of capillaries
Links arteries and veins
Pressure of blood in capillaries
Very low pressure
Is blood in capillaries oxygenated or deoxygenated?
Oxygenated + deoxygenated
Thickness of walls in capillaries
Walls are one cell thick
Lumen diameter in capillaries
Very small lumen
Are there valves in capillaries?
No
What is the purpose of the coronary artery?
It supplies the cardiac muscle with oxygen and glucose which enables the heart to carry out respiration so that is can contract
What happens when someone has 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 to the cardiac muscle, resulting in a lack of oxygen for the heart muscle. This means that the muscle cells carry out less aerobic respiration and energy release. The heart beats less effectively and it can lead to a condition called angina. If the coronary artery becomes completely blocked it will lead to a heart attack (or myocardial infarction)
What is the fatty material that builds up in the coronary arteries when someone has CHD?
The fatty material is made of a lipid called cholesterol
Where does cholesterol come from?
Cholesterol comes from the diet (in saturated fat)
Where is cholesterol synthesised?
In the liver
What are two treatments for coronary heart disease?
Statins and stents
What are statins?
- Drugs used to reduce blood cholesterol (by blocking an enzyme in the liver) which slows down the rate of fatty material deposit
Pros of statins
Lower cholesterol effectively and therefore an effective prevention
Cons of statins
- Must be taken long-term
- If you forget to take them they are less effective
- Take time to work
- Undesirable side effects in some people
What are stents?
- A very tiny expandable metal mesh used to keep coronary arteries open
- enables blood to flow more easily
How do stents work?
- The very tiny expandable metal mesh is placed inside a blood vessel
- Inflated using a tiny balloon
- Balloon removed but stent remains inflated
Pros of stents
- drugs do not have to be taken long-term
- can remain in place for a long time
Cons of stents
- risks during surgery (e.g. complications, infections)
- risk of blood clotting
What are the two main faults in heart valves?
- The heart valve tissue might stiffen, preventing the valve from opening fully
- The heart valve might develop a leak
How can faulty heart valves be replaced?
- Biological valves - valves from humans or other mammals
- Mechanical valves
Pros of biological valves
- anti-clotting drugs are not needed
- does not make noises
Cons of biological valves
- ethical issues surrounding the use of animal tissues
- not as long lasting (10-15 years), may need to be replaced- more than one operation
- may be rejected
- need to take anti-rejection medication
Pros of mechanical valves
- long-lasting (decades)
- no ethical issues
- no risk of rejection
- no risk of disease transmission
Cons of mechanical valves
- must take anti-clotting medication which can have side-effects
- can hear valves opening and closing
What is the natural resting heart rate controlled by?
A group of cells that act as the pacemaker
Where is the natural pacemaker found?
In the right atrium
What does the natural pacemaker do?
Produces an electrical signal that spreads through the heart muscle to make it contract
What are artificial pacemakers?
Electrical devices used to correct irregularities in the heart rate - send strong regular signals to ensure the heart beats properly
Pros of artificial heart transplants
- can be used until a donor heart is ready
- can also be used to rest a diseased heart
- freely available - more likely to be available as manufactured
- no risk of rejection
Cons of artificial heart transplants
- cannot be used long-term
- risk of blood clotting - need to take anti-clotting medication
- very expensive
Pros of biological heart transplants
- Most effective at pumping blood around the body
- Long-term treatment for heart disease
Cons of biological heart transplants
- Not always available - have to wait for a donor heart that is a tissue match- many people die before they get the chance to have a transplant
- Possible rejection by the immune system - need to take immunosuppressant medication
- risk of blood clots - but smaller than artificial
What happens when there is heart failure (in terms of solutions)?
- In case of heart failure a donor heart, or heart and lungs can be transplanted
- Artificial hearts occasionally used to keep patients alive whilst waiting for a heart transplant- or allow the heart to rest as an aid to recovery
Definition of health
Health is a state of both physical and mental well-being
What factors lead to someone being ‘healthy’?
Balanced diet, good sleep, regular exercise, access to healthcare
Definition of disease
A disease is a condition that can cause ill health
What can disease be caused by?
Disease can be caused by bad lifestyle choices, genetic factors or pathogens unrelated to lifestyle
What are the two main types of diseases?
Communicable or non-communicable
What is a communicable disease?
A communicable disease can be spread from person to person, or from animal to person
What are communicable diseases caused by?
Viruses, bacteria, parasites and fungi
Give 7 examples of communicable diseases
- chickenpox
- gonorrhoea
- malaria
- covid
- polio
- veruca
- salmonella
What is a non-communicable disease?
A non-communicable disease is one that can’t spread from person to person
Give 4 examples of non-communicable diseases
- cancer
- coronary heart disease
- diabetes
- asthma
What do risk factors do?
A risk factor increases the chance that a person will develop a certain disease.
What are examples of lifestyle risk factors?
- diet
- sleep
- exercise
- alcohol / smoking
What are examples of environmental risk factors?
- ionising radiation
- UV light from the sun
- second-hand tobacco smoke (passive smoking)
- air pollution
What is a cardiovascular disease?
A cardiovascular disease is any disease that affects the heart or blood vessels e.g. valve disease, CHD, strokes, etc.
What are the risk factors for cardiovascular diseases?
- High fat diet and obesity can lead up to the build up of cholesterol inside artery walls leading to CHD and strokes
- Lack of exercise leads to a weakening of the heart muscle which can lead to cardiovascular disease
- Too much salt can lead to a high blood pressure which can lead to heart disease
How can obesity lead to Type 2 diabetes?
- If people eat a carbohydrate-rich diet their blood sugar levels become too high
- In healthy people insulin is released to lower blood glucose
- over time repeatedly eating carbohydrate rich food can lead to liver cells failing to respond to insulin
- This leads to blood glucose levels becoming too high
- This leads to symptoms of type II diabetes
What are the effects of alcohol on the body?
- Alcohol is processed in the liver where it is turned into other molecules that can be excreted
- However, too much alcohol kills liver cells and can lead to fatty liver disease, liver cirrhosis and liver cancer
- too much alcohol can lead to alcohol related brain damage (ARBD) and is associated with dementia
- Alcohol is also addictive
What are the effects of smoking on the body?
Cigarettes contain many harmful chemicals which kill epithelial cells, paralyse cilia and mutate DNA. This leads to:
- Emphysema - the fusing of alveoli into larger sacs due to death of epithelial cells with smaller surface area leading to breathlessness
- Bronchitis - inability to remove mucus due to paralysed cilia
- Lung cancer - mutations in DNA can lead to cancer developing
Effects of smoking during pregnancy
Smoking during pregnancy can lead to babies born with:
- low birth weight
- birth deformities
- increased risk of SIDS (sudden infant death syndrome). - - There is also a relationship between smoking and miscarriage risk
Effects of alcohol use during pregnancy
Drinking alcohol during pregnancy can lead to foetal alcohol syndrome. This can lead to birth deformities, brain damage and learning disabilities in babies. It is unknown if there is a safe limit, so advice is not to do it
Radiation and cancer
- Radiation leads to mutations in DNA
- Sometimes these mutations can lead to cancer
What is cancer a result of?
Cancer is a result of mutations (changes to DNA) that cause uncontrolled cell division and growth
What does cancer result in?
It results in the formation of a tumour (a collection of cells that forms a growth)
What are the two types of tumours?
Malignant
Benign
Do malignant or benign tumours invade other tissues?
Malignant
Do malignant or benign tumours form secondary tumours?
Malignant
Are malignant or benign tumours cancerous?
Malignant
Do malignant or benign tumours spread in the blood?
Malignant
Are malignant or benign tumours localised in a membrane?
Benign
Risk factors for cancer
- Genetic factors (e.g. breast cancer)
- Carcinogens (e.g. alcohol, smoking)
- Older age
- Viruses (e.g. HPV)
- Ionising radiation (UV light, X-rays, gamma rays)
upper epidermis
Transparent to allow light to enter leaf for photosynthesis, secretes waxy cuticle (impermeable to water) which helps prevent water loss
lower epidermis
transparent to allow light to enter leaf for photosynthesis, contain holes called stomata (stoma) and guard cells (which surround stomata)
Palisade mesophyll
Column shaped cells that are tightly packed
containing many chloroplasts to absorb more light
maximising photosynthesis
Spongy mesophyll
contain large air spaces
that increases surface area to volume ratio for diffusion of gases
speeding up gas exchange
Gas exchange in a leaf
- Higher concentration of CO2 in atmosphere than inside the leaf
- CO2 diffuses into leaf through open stoma into air space in spongy mesophyll
- CO2 diffuses through cell wall + cell membrane of mesophyll cell, dissolves in cytoplasm + diffuses into chloroplast
Function of guard cells
The function of guard cells is to control the rate of water loss through the stomata which also affects the rate of gas exchange
What does turgid mean?
Lots of water available
What does flaccid mean?
Little water available
What is transpiration?
Transpiration - loss of water from leaves
1. evaporation from spongy mesophyll cells
2. Diffusion out of the stomata
Definition of the transpiration stream
Transpiration stream - movement of water from roots to leaves via xylem, and the evaporation and diffusion from stomata
Function of the xylem
Transports water and dissolved ions
Adaptations of the xylem
- No top + bottom walls to form a continuous hollow tube for movement of water + ions
- Outer walls strengthened with lignin to help support the xylem vessel
The transpiration stream
- Water is lost from the leaf due to evaporation of water from the mesophyll cells
- This evaporated water then diffuses through the stomata and is lost to the surrounding atmosphere
- This whole process is called the transpiration stream
- Transpiration in turn causes the drawing up of water from the roots through xylem vessels. It occurs in one direction, roots to leaves
What factors affect the rate of transpiration?
Air movement
Temperature
Light intensity
Humidity
What is the effect of air movement on the rate of transpiration?
The more air flow there is, the more water vapour is lost
What is the effect of temperature on the rate of transpiration?
Higher temperature particles have more kinetic energy, water evaporates faster
What is the effect of light intensity on the rate of transpiration?
Faster rate of photosynthesis and therefore the guard cells are more turgid, so stomata are open, and more water is lost
What is the effect of humidity on the rate of transpiration?
Less humidity, less water in the air, more water evaporates
Definition of translocation
Translocation is the transport of dissolved sugars from leaves (sources) through the phloem tissue to regions of storage or use (sinks)
Phloem tissue structure
- Phloem tissue is made of elongated living cells with end walls with pores. Collectively these form long phloem tubes
- Sugars (Sucrose) and amino acids (called cell sap) can move in both directions in the phloem
Root hair cells adaptations
- Root hair cells are found all over the surface of the roots of a plant
- They have long cytoplasmic projections that extend into the soil to increase surface area for absorption of water and ions
- They contain many mitochondria to provide lots of energy through aerobic respiration for active transport of ions into the root
- They have a large vacuole which contains a concentrated solution to encourage movement of water into the root hair cell by osmosis
Name two tissues in the leaf that transport substances around the plant
The xylem and phloem
How does closing the stomata help a plant?
reduces water loss / prevents wilting
Describe how water moves from roots to the leaves.
It moves by the transpiration stream, in the xylem
Plant roots absorb water mainly by osmosis.
Plant roots absorb ions mainly by active transport.
Explain why roots need to use the two different methods to absorb water and ions.
-solution in soil is more dilute than in root cells
- so water moves from the dilute to the more concentrated region
- concentration of ions in soil less than that in root cells
- so energy needed to move ions
Symptoms of coronary heart disease
Pains in the chest and possible heart attack
Symptoms of faulty valves
- Fatigue
- Shortness of breath due to lack of blood leaving the heart
Symptoms of total heart failure
Chest pains, fatigue, shortness of breath due to heart failure
What is a potometer used for?
A potometer is used to measure the rate of transpiration of a plant under different conditions
How does a potometer measure the rate of transpiration of a plant under different conditions?
By measuring the rate of uptake of water
