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aqa gcse biology free > T2 animal tissues, organs and systems > Flashcards

T2 animal tissues, organs and systems Flashcards

1
Q

how does the double circulatory system work

A
  • right pump sends deoxygenated blood to the lungs where it becomes oxygenated and returns back to the heart
  • left pump sends the newly oxygenated blood around the body, by the time this blood returns to the heart, it has returned to a deoxygenated state
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2
Q

why is the wall of the left ventricle thicker

A

has to pump blood at a higher pressure around the whole body

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3
Q

how is the heart rate controlled

A

group of cells in the RA (sinus node) which act as a pacemaker

release waves of electrical activity which cause the heart muscle to contract

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4
Q

how can an abnormal heart rhythm be treated

A

artificial pacemaker which sends out electrical signals to correct the heart’s rhythm

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5
Q

how are arteries adapted

A

thick muscle layer - adds strength to resist high pressure at which blood is pumped out by the heart

thick elastic layer - allows arteries to stretch and recoil in order to withstand high pressure

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6
Q

how are veins adapted for their function

A

wider cross-section (lumen) as unoxygenated blood is carried towards the heart at low pressure. The blood moves slower and against gravity so a larger lumen is needed to ensure it is transported efficiently.

valves - prevent backflow of blood

thinner walls than arteries as blood is at lower pressure

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7
Q

how are capillaries adapted for their function

A

f: enable transfer of substances between the blood and tissues

walls are 1 cell thick - short diffusion path

permeable walls - substances can diffuse across

narrow lumen - blood moves slowly, more time for diffusion

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8
Q

explain how the lungs are ventilated by the action of intercostal muscles

A

IM contract

ribcage moves upwards and outwards

diaphragm flattens and volume of chest increases

increased volume results in decreased gradient

air is drawn into lungs down pressure gradient

inverse occurs when air moves out of the lungs

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9
Q

describe how gas exchange occurs at the alveoli

A

O2 diffuses from the alveoli into the capillary bloodstream down its concentration gradient

CO2 diffuses from the capillary into the alveoli down its concentration gradient

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10
Q

describe how alveoli are adapted for gas exchange

A

small and arranged in clusters - larger SA

rich blood supply - maintains concentration gradient

thin alveolar wall - short diffusion pathway

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11
Q

equation for breathing rate

A

number of breaths / number of minutes

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12
Q

substances transported by plasma

A 
red blood cells
white blood cells
platelets
carbon dioxide
urea
products of digestion
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13
Q

purpose of red blood cells in blood

A

transport of oxygen around the body

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14
Q

how are red blood cells adapted for their function

A

biconcave shape - increased SA to vol ratio

no nucleus - more room for haemoglobin to bind to O2

contain haemoglobin - binds to O2

small so can pass through tiny capillaries

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15
Q

purpose of white blood cells in blood

A

form part of the immune system, which protects the body from invading pathogens

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16
Q

how are white blood cells adapted for their function

A

have a nucleus - contains DNA which codes for proteins

can produce antibodies and antitoxins

can engulf and digest pathogens (phagocytosis)

can change shape allowing them to squeeze through walls of blood vessels into blood tissues and engulf harmful microorganisms

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17
Q

purpose of platelets in blood

A

small cell fragments which aid the clotting of blood at the site of a wound

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18
Q

why is the function of platelets important

A

aid in the process of blood clotting (conversion of fibrinogen to fibrin).

as a result, red blood cells are trapped in the fibrin network, forming a clot which prevents excessive bleeding.

scab formation prevents bacteria from entering

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19
Q

what is coronary heart disease

A

occurs when the coronary arteries that supply the heart muscle become blocked with a buildup of fatty material

this restricts the supply of oxygen to the heart, possibly leading to a heart attack or death

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20
Q

what is a stent and how does it work

A

metal mesh tube that is inserted into a blocked artery so that it remains open.

stent is inflated using a balloon, which is later removed to allow blood to flow freely

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21
Q

advantages and disadvantages of stents

A

A: insertion can be carried out without general anaesthetic

quick recovery time

lower the risk of a HA

D: risk of postop infection

risk of blood clots at site of stent

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22
Q

what are statins

A

drugs which reduce the level of LDL (bad) cholesterol which contributes to the development of CHD

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23
Q

advantages and disadvantages of statins

A

A: reduced risk of strokes, CHD and HAs

increased level of HDL (good) cholesterol

D: has to be taken continuously

may have side effects

effect may not be immediate

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24
Q

what is heart bypass surgery

A

surgery where blocked coronary arteries are replaced with sections of veins taken from other parts of the body

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25
consequences of leaky heart valves
blood flows in wrong direction, causing the heart to become less efficient. patients may become breathless and die
26
what types of valves can replace leaky valves
mechanical - made of metal or polymers biological - taken from animals (pigs, humans)
27
advantages and disadvantages of mechanical valves
A: last for a very long time D: need to take meds to prevent blood clotting around valve
28
advantages and disadvantages of biological valves
A: work very well - no meds D: only last 12-15 years
29
purpose of an artificial heart
intended to support a patient's heart while they wait for a suitable donor heart
30
advantages and disadvantages of artificial hearts
A: less likely to be rejected by immune system allows damaged heart time to rest to help recovery D: risk of infection due to surgery risk of blood clots have to take blood-thinning drugs
31
what is a communicable disease
disease caused by a pathogen which can be transmitted from one person to another
32
how can diet affect health
too little food / lack of nutrition - anaemia, vitamin deficiencies too much / too much unhealthy - obesity, type 2 diabetes
33
how can stress affect health
prolonged stress is linked to wide range of health problems including heart disease, cancers and mental health issues
34
how can life situations affect health
life factors such as location, gender, financial status, ethnic group and healthcare provision can impact a person's mental and physical health
35
give examples of how health problems can interact
infection with certain viruses can lead to cancer (hepatitis > liver cancer) compromised immune system can lead to higher risk of infection with communicable diseases immune reactions caused by a pathogen can trigger allergic reactions problems with physical health can lead to mental health issues
36
what is a risk factor
aspect of a person's lifestyle or a substance found in the body or the environment which can increase the risk of a disease
37
what is a casual mechanism
mechanism which demonstrates how one factor biologically influences another
38
how does obesity affect the development of type 2 diabetes
obesity is linked with the onset of type 2 diabetes - a disease in which the body stops responding to insulin
39
how does alcohol affect liver and brain function
excessive long-term alcohol use may lead to liver cirrhosis (scarring of liver) increases risk of liver cancer damages brain tissue and nerve cells
40
how does smoking affect the development of lung disease and lung cancer
tar in tobacco can damage the alveoli of the lungs, leading to COPD tar also damages the cells which line the lungs, leading to lung cancer
41
how does smoking and alcohol affect unborn babies
carbon monoxide from tobacco smoke reduces the amount of O2 the foetus receives, which can lead to premature birth or stillbirth alcohol passes across the placenta and damages the developing foetus. Once born, the baby may have a number of deformities and health problems as part of foetal alcohol syndrome.
42
how do carcinogens affect the development of cancer
ionising radiation is a type of carcinogen which can cause mutations in DNA, potentially leading to cancer
43
what is cancer
development of a tumour as a result of uncontrolled cell division
44
what is a benign tumour
tumour contained in 1 location, usually within a membrane not cancerous and don't invade other parts of the body can grow large very quickly - may cause damage to another organ
45
what is a malignant tumour
tumour that can spread around the body via the blood and lymphatic system can invade other tissues (metastasis) cells divide more rapidly and have a longer lifespan disrupts healthy tissues and may lead to death
46
give examples of factors which can lead to cancer
``` genetics smoking obesity ionising radiation - UV light and X-rays viral infections - HPV and cervical cancer ```
47
arteries function
transport blood from the heart to the organs carry oxygenated blood (aside from pulmonary artery)
48
when/where do veins form
when capillaries join up after passing through the body
49
veins role
transport deoxygenated blood (aside from pulmonary vein) from the organs back to the heart
50
what happens when a heart beats
- blood enters via the atria - once filled with blood, atria contracts, forcing blood down into the ventricles below - ventricles contract, forcing blood to exit the heart
51
what type of blood enters through RA
deoxygenated, from the body
52
what type of blood enters through LA
oxygenated, from the lungs
53
important veins
vena cava - heart receives deoxygenated blood from the body through it pulmonary vein - heart receives oxygenated blood from lungs through it
54
important arteries
aorta - heart pumps out oxygenated blood to the body through it pulmonary artery - heart pumps out deoxygenated blood to the lungs through it coronary arteries - supply the heart muscle with oxygenated blood
55
what does deoxygenated blood enter the heart via
RA
56
what is air breathed into the lungs through
trachea (windpipe)
57
what does the trachea divide into
2 tubes - bronchi
58
what does the bronchi divide into
bronchioles
59
what do the bronchioles divide into
tiny air sacs - alveoli
60
what blood arrives at the alveolus
deoxygenated blood
61
what increases the rate of diffusion in the alveoli
- larger surface area - concentration gradient - temperature
62
what is blood
a tissue made of a fluid called plasma with 3 parts to it
63
what makes up blood plasma
platelets, white blood cells, red blood cells
64
how does oxygen and carbon dioxide move between the air and the blood
via diffusion in the alveoli
65
which chamber of the heart has the thickest wall
left ventricle
66
where do waste products move out of the cells and into the blood
capillaries
67
deoxygenated blood arrives at the lungs from the heart via which artery
pulmonary artery
68
deoxygenated blood arrives at the heart from the body via which vein
vena cava
69
what do red blood cells contain that bind with oxygen in the lungs
haemoglobin

aqa gcse biology free (25 decks)

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