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Biology > Topic 1: Lifestyle, Health and Risk > Flashcards

Topic 1: Lifestyle, Health and Risk Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Describe and explain the structure of arteries

A

A narrow lumen to maintain high BP.
Elastic fibres stretch and recoil to maintain pressure
Collagen fibres for strength and support
Endothelium protects against damage + provides a smooth surface so there’s less resistance to blood flow
Thick, smooth layer of muscle contract and relax to dilate and constrict blood vessels

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2
Q

Describe and explain the structure of capillaries

A

The endothelium is one cell thick to ensure a short diffusion distance.
Small lumen slows down blood flow so exchange can occur

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3
Q

Describe and explain the structure of veins

A 
wide  lumen. 
valves to prevent backflow. 
Endothelium
Thinner layer of muscle and elastic fibres
Collagen fibres
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4
Q

What is the cardiac cycle?

A

The heart pumps blood through ‘systole’and ‘diastole’. The contraction and relaxation together= heartbeat.

1) Atrial systole
2) Ventricular systole
3) Cardiac diastole

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5
Q

How is flow ensured?

A

Semilunar valves in blood vessels.

Placement of larger veins between muscles. Muscle contraction squeezes veins and pumps blood

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6
Q

what is an open circulatory system?

A

A simple heart pumps blood between cavities.
Blood circulates in open areas.
Substances diffuse between blood and cells.

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7
Q

what is a closed circulatory system?

A

Blood is enclosed within vessels, generating higher pressure.
Blood travels from arteries to capillaries and returns via venules to veins.

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8
Q

what is a double circulatory system?

A

Right ventricle pumps deoxygenated blood to the lungs, left ventricle pumps oxygenated blood around the body.
This means that blood flows twice through the heart for each circuit.

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9
Q

What happens in atrial systole?

A

Atria fill with blood from the superior or inferior Vena Cava/Pulmonary Vein. Atrioventricular valves open.
Blood flows into the ventricles.
Atria contract.
There is high pressure

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10
Q

What happens in ventricular systole?

A

Ventricles fill with blood.
Semi-lunar valves open, AV valves close.
Ventricles contract, pushing blood to the pulmonary artery
There is high pressure

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11
Q

What happens in cardiac diastole?

A

Low pressure.
Atria and ventricles relax.
Semi-lunar valves close.
Coronary arteries fill.

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12
Q

Describe the events of atherosclerosis

A

The endothelium becomes damaged.
There is an inflammatory response causing white blood cells to move into the artery wall.
A fatty deposit (atheroma) builds up.
Calcium salts and fibrous tissues build up, causing a plaque.
The artery loses elasticity, narrows and hardens.
Causes a rise in blood pressure and dangerous positive feedback because high bp further damages the endothelium

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13
Q

what are the consequences of atherosclerosis?

A

Increases chance of blood clots blocking the narrowed artery. Cells are permanently damaged.
May result in heart attack, stroke, tissue death, angina and aneurism.
An artery may burst due to build up of blood.

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14
Q

describe the clotting cascade reaction

A

When a blood vessel is damaged, collagen is exposed. Platelets stick to exposed collagen and become spheres instead of flattened discs.
Platelets release the protein thromboplastin.
This activates an enzyme which catalyses prothrombin into thrombin in the presence of Vitamin K and Ca2+ ions.
This then catalyses the reaction of soluble fibrinogen into insoluble fibrin. Fibrin traps platelets and red blood cells to form a clot.

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15
Q

Describe and explain the structure of the heart

A

4 chambers and main blood vessels:
pulmonary vein (lungs to LA), pulmonary artery (RA to lungs)
aorta (from LV to body), vena cava (from body to RV),
AV valves separate atria from ventricles
SL valves -separate arteries from ventricles
Valve tendons - prevent AV valves turning inside out due to pressure
Septum - muscle and connective tissue prevents 02 and de 02 blood mixing
Coronary artery - wrapped around the heart to supply O2 and glucose in blood to cardiac muscle

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16
Q

Why does thrombosis occur?

A

Thrombosis (blood clotting) prevents blood loss when a blood vessel is damaged.
it prevents entry of pathogens.
It provides a framework for repair.

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17
Q

What are the main factors of a single circulatory system?

A

Low activity and do not need to maintain temperature so less energy needed
Blood is at low pressure and flow is slow

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18
Q

Explain how an atheroma can lead to dead heart muscle

A

An atheroma blocks and narrows the coronary artery, depriving the heart muscle of oxygen and glucose.
Lack of oxygen causes muscle cells to die as they cannot do aerobic respiration.
Anaerobic respiration builds up lactic acid which causes angina, denatures enzymes and kills muscle cells.

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19
Q

How does the position of an atheroma affect the amount of damage done to the heart muscle?

A

the area of dead heart muscle will be downstream of the atheroma, so the higher the placement of the atheroma in the artery, the more the damage.

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20
Q

How does a double circulatory system lead to a high metabolic rate?

A

blood flows through the heart twice for each complete circulation.
This reduces the time for blood to circulate round the whole body.
This causes a high metabolic rate because 02 and substances for metabolic processes are delivered faster to cells.

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21
Q

describe and explain pressure differences in the atria and ventricles during the cardiac cycle.

A

pressure changes are smaller in the atrium because it has less cardiac muscle than ventricles, and doesn’t have to push blood as far.

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22
Q

What are the risk factors for atherosclerosis and therefore CVD?

A
  • Genetics (genetic predisposition to high blood pressure etc.)
  • Age (arteries become less elastic with age)
  • Diet (can increase cholesterol and BP)
  • Gender (oestrogen makes arteries more elastic)
  • High blood pressure (can udamage endothelium)
  • High cholesterol levels
  • Smoking (nicotine narrows arteries, smoke damages endothelium)
  • Physical inactivity (increases obesity risk)
  • Obesity (increases blood pressure etc.)
23
Q

What is a correlation?

A

A change in one variable is acompanied by a change in the other. Remember - and + correlations.
Correlations determine what risk factors are for a particular disease

24
Q

Why do we need to be wary about correlations?

A

correlations dont mean variables are casually linked. Correlation does not imply causation! Because of this experiments must have control variables, so they have a null hypothesis: they assume seran no difference entre an experimental or a control group and test it w statistical analysis

25
Q

Define a cohort study.

A

Follows a large group of people over time to see who develops the disease in order to determine risk factors/the cause.

26
Q

Define a case control study.

A

A group with the disease and a control group are compared to work out risk factors.

27
Q

Give adv and disadv of cohort studies

A

They provide the best info about the causation of a disease because you follow people from exposure to occurence of a disease
You can calculate cumilative incidences, which are the most direct measurement of risk of developing the disease.
You can examine a range of outcomes caused by one exposure eg smoking
Good for rare exposures.
BUT long, £££, not good for rare diseases

28
Q

Give adv and disadv of case control studies

A

Shorter and hence cheaper. V useful for rare diseases as u select the cases yourself. Suitable for diseases w/ a long latent period eg cancer.
BUT not good to find rare causes as you wouldn’t find a sufficient number of these in the study.
Less adept at showing a casual relationship, more prone to bias.

29
Q

Why must a study have a representative sample?

A

The study’s conclusions must represent the target population and ensure they dont miss out any groups eg <18s, seniors, employed ppl etc. Ensure minimal dropouts as this can affect representation of the target pop

30
Q

How does a study have reliable results?

A

valid data measures what its supposed to. Questionnaires are less valid.
Reliable method produces repeatable and reproducible results which are similar when done by different ppl at different times.
Diagnosis MUST be clear to ensure diff doctors record and measure symptoms in the same way.

31
Q

Why must a study have a large sample size?

A

must be large enough to produce non coincidental results. Larger sample= more acurate estimates.

32
Q

Why must a study have control variables?

A

This makes sure there is strong, specific correlations, and the risk factor identified is not due to something else. Eg high BP in one group could be a risk factor UNLESS the group is older- age???

33
Q

What things affect BP?

A

Speed of the blood (stronger heart leads to increased stroke volume)
Blood volume (increases w/ higher salt intake)
Heart rate affected by caffeine, hormones, exercise

34
Q

What is glycogen?

A

A polysaccaride
The main energy storage molecule in animals
Formed from many alpha glucose molecules joined together by 1, 4 and 1, 6 glycosidic bonds.
Large number of side branches meaning that the molecule can be hydrolysed easily and energy can be released quickly.
It is relatively large but compact, maximising the amount of energy it can store.

35
Q

What are lipids? Give differences between saturated and unsaturated lipids.

A

Lipids are biological molecules which are only soluble in organic solvents.
Saturated lipids don’t contain c-c double bonds. straight chain, form many intermollecular attractions which need mucho energy to break, so solid at room temp
• Unsaturated lipids have C-C double bonds. Kinked chain, weaker intermolecular forces, so lower melting point.

36
Q

Give some uses for lipids

A

They electrically insulate the mylein sheath

they make up phospholipids in the cell membrane

37
Q

What do we need energy for?

A

AT, cell division, movement, muscle contraction, reproduction, thermoregulation etc

38
Q

What is the equation for BMI?

A

weight (kg)/ height (m)2

39
Q

What number is considered dangerous for a waist:hip ratio for men and women?

A

men must be 0.9 or below. Women must be 0.85 or below

40
Q

why is cholesterol combined w/ proteins?

A

cholesterol is a lipid so its insoluble in water. So, in order to be transported in the bloodstream, it combines with proteins to make soluble lipoproteins.
Hay 2 transport lipoproteins: HDL and LDL

41
Q

Describe and explain HDLs

A

high density lipoproteins. They have more protein and less cholesterol.
Triglycerides combine w chol and protein to form HDLs.
HDLs transport cholesterol from tissues to the liver to break down, lowering blood chol levels and preventing atheromas. This reduces CVD risk

42
Q

Describe and explain LDLs

A

Low density. Triglycerides from our diet combine w chol and protein to form LDLs. LDLs transport chol to cells.
LDLs bind to receptor sites on cell membranes and are absorbed so cholesterol can maintain and make cell membranes

43
Q

How does an increase in LDLs increase blood chol levels?

A

excess LDLs overload membrane recpetors, causing high blood cholesterol.
This is deposited in artery walls, forming atheromas and increasing CVD risk.

44
Q

What are Ca channel blockers?

A

Block Ca channels in muscle cells lining the arteries. For muscles to contract, Ca must pass via channels into the muscle cells. If Ca cant pass, muscles and blood vessels cant constrict, thus lowering BP. This reduces CVD risk
Side affects: headache, dizziness, swollen ankles, arrythmia, flushing. Can be fatal, so not prescribed to people who’ve had a heart attack.

45
Q

What are diuretics?

A

Diuretics increase urine volume produced by kidneys, getting rid of excess fluids and salt. This lowers blood volume and cardiac output, which lowers BP. This reduces CVD risk
Side effects include nausea, muscle cramps and dizziness.

46
Q

What are diuretics?

A

Diuretics increase urine volume produced by kidneys, getting rid of excess fluids and salt. This lowers blood volume and cardiac output, which lowers BP. This reduces CVD risk
Side effects include nausea, muscle cramps and dizziness.

47
Q

What are ACE inhibitors?

A

ACE inhibitors reduce blood pressure by blocking the production on angiotensin, a hormone that causes vasoconstriction. Reducing vasoconstriction reduces BP. This reduces CVD risk
Side effects of ACE inhibitors: dizziness, arrhythmia, dry cough

48
Q

Describe anticoagulants/ Platelet inhibitory drugs

A

Aspirin reduces the stickiness of platelets and risk of clot formation. But can be ineffective, ppl are allergic
Clopidogrel reduces platelet aggregation and clotting. Aspirin and clopidogrel combined are more effective but hay serious risk of bleeding in the gastrointestinal tract.
Warfarin interferes with vitamin K production and affects the synthesis of clotting factors. But the risk of bleeding>aspirin

49
Q

Describe statins

A

Statins lower blood cholesterol levels by blocking the enzyme which produces cholesterol in the liver.
Side effects include nausea, inflammation, constipation, diarrhoea. It’s important not to solely rely on statins to lower blood cholesterol levels – they’re most effective when combined with a healthy diet.

50
Q

What is a stroke? How can a blood clot cause a stroke?

A

Blood clots reduce blood flow to the brain.
Less oxygen and glucose reaches the brain.
There is less aerobic respiration and ATP produced.
The brain needs ATP to function, w/o it a stroke occurs

51
Q

What are non-starch polysaccharides and why should we eat these in our diet

A

These non-starch polysaccharides, a.k.a. soluble fibre, lower blood cholesterol as they are only partially digested, forming a gel that traps and prevents cholesterol absorption. They are found in fruit, veg, beans, pulses and some grains
This reduces CVD risk

52
Q

Why should we include oily fish in our diet?

A

Oily fish contain Omega three fatty acids, a group of Polyunsaturated fatty acids. These fatty acids are essential for cell function, reduce CVD risk and joint inflammation.

53
Q

Why do we need to include fruit and veg in our diet?

A

They contain antioxidants and are often non-starch polysaccharides. Plants have sterols that lower LDL cholesterol levels, reducing CVD risk.
Products containing sterols like yogurts have been created, but they’re v expensive.

54
Q

What are the types of valves and blood vessels in the heart?

A

The superior and inferior vena cava pump deoxygenated blood to the right atria
the AV valve connecting the right atria and ventricle is called the tricuspid valve
Blood from the right ventricle pumps blood to the lungs via the pulmonary artery. The type of SL valve which opens and shuts is called the pulmonary valve
Oxygenated blood comes from the lungs via the pulmonary vein. The left atria fills with blood, and the mitral valve (another type of AV valve opens). Blood flows into the ventricles
The left ventricle pumps blood to the body via the aorta. Another type of SL valve, called the aortic valve, opens and shuts due to pressure

Biology (6 decks)

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