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IGCSE Biology > Unit 2^ Animal Physiology > Flashcards

Unit 2^ Animal Physiology Flashcards

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1
Q

What elements are there in Carbohydrates?

A

C H O

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2
Q

Give 3 reasons we need food: 🥘

A

> to supply us with energy 🏃🏼‍♂️

> provide materials for growth + repair🏋️‍♀️🏋️‍♂️

> help fight disease + keep body healthy 🤸🏻‍♀️🧘‍♀️🍵

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3
Q

What does a healthy/balanced diet contain?

A 
a balanced diet contains appropriate proportions of
Carbohydrates 🥖
Proteins 🥩🥓🍖🍗
Fat🧀
Vitamins 🍌🍋🍳 ☀️ 
Minerals 🥛🥩🥦
Water 💦 
Fibre 🥣🌾
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4
Q

Give 2 functions of Carbohydrates

A

1) provide ENERGY

2) breakdown fatty acids

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5
Q

Give 2 sources of Carbohydrates

A

🍞 bread

🍝 pasta

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6
Q

How and where do animals store energy

A

Animals store energy as GLYCOGEN in the LIVER

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7
Q

How and where do plants store energy

A

Plants store energy as STARCH EVERYWHERE

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8
Q

Why are fresh fruit and vegetables vital for healthy diet?

A

Because fresh 🍇 + 🌽 contain vitamins
As well as contain DIETARY FIBRE, CELLULOSE found in plant cell wall is vital for healthy diet.
> gives muscles something to push against
>keeps gut contents moving

⛔️prevents DISEASES such as BOWEL CANCER

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9
Q

What enzyme breaks down Carbohydrates (starch)

A

AMYLASE and MALTASE
breakdown the polymer of starch/ or glycogen into simple sugars —glucose (monomers) so they can be absorbed into the blood.

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10
Q

What elements do LIPIDS contain?

A

C H O + PHOSPHORUS

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11
Q

Give 2 sources of lipids?

A

🥑butter

🎣 OILY fish

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12
Q

Give 3 functions of lipids🥑🥞🧀🍟🍼🥛

A

> energy store

> insulation

> protects from damage

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13
Q

What is Carbohydrate deficiency?

A

KETOSIS

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14
Q

What does lipid deficiency cause?

A

SKIN PROBLEMS

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15
Q

What do we need to eat that produces hormones

A

LIPIDS

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16
Q

What elements are in PROTEIN.?

A

C H O + NITROGEN

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17
Q

Give 2 sources of PROTEIN

A

Meat 🥩

Cheese 🧀

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18
Q

What monomers are polymers of proteins made up of

A

Chains of amino acid (monomers)

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19
Q

Test for glucose?

A

🔵~> 🏮
Blue~> brick red

Mix glucose w/ BENEDICTS solution
HEAT 🔥

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20
Q

Test for starch?

A

🍊 ~> 💙
Orange~> blue

Mix starch w/ IODINE solution
Wait for colour change

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21
Q

Test for protein?

A

🔵~>😈
Blue~> purple

Mix protein w/ BUIRET solution
Wait for colour change

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22
Q

Test for fat?

A

🧀🍟+ 🥂🍷

Please drop of olive oil 🍸🍸🍸 in test tube and add ETHANOL (fat dissolved into it)
Then put that solution into water
A white cloudy layer should form on top of H2O
Fat has been left behind as a suspension of tiny droplets (emulsion)

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23
Q

Name a source + function of vitamin a

A

found in LIVER

stop night blindness

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24
Q

Name a source + function of vitamin b

A

Found in bananas

stops thinning of the stomach lining

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25
Q

Name a source + function of vitamin c

A

Found in LEMONS 🍋

Prevents scurvy

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26
Q

Name a source + function of vitamin D

A

Found in fish 🐟 eggs🍳 sun ☀️

Prevents SCLEROSIS + RICKETTS

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27
Q

What is vitamin d + Ca deficiency?

A

RICKETTS = bone problems

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28
Q

What do we need Calcium for, what is it found in?

A

Keeps teeth + bones strong

Found in🥛 + almonds

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29
Q

What do we need iron for, what is it found in?

A

Fe needed to make haemoglobin 🔴

Found in oats and red meat

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30
Q

What is the deficiency of iron called

A

ANAEMIA = iron deficiency

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31
Q

What do we need Mg for and where is it found?

A

Need Mg for making bones

Found in green vegetables 🥦🥒🥗🥦🥦

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32
Q

How to measure energy content in food:

A

1) full test tube w/ 10cm^3 of water
2) measure temp of water before
3) burn food on mounted needle under test tube 🥨🎇
4) calculate increase in temp 🤒🤒🤒

The higher the temp increase= the more energy food has

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33
Q

Name 3 groups of people that need more energy and explain why:

A

🏃‍♀️🏃🏼‍♂️🏊‍♂️🤾‍♀️🤾‍♂️🤼‍♀️🏋️‍♂️⛹️‍♀️ACTIVE PPL
> need more protein for growth+ repair of muscles

👶 🧒AGE
> teens + children need more energy as they are growing &r generally more active

🤰🤰🤰PREGNANT WOMEN
> need more energy to provide for their babies 👼 that need to develop

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34
Q

Describe the 5 processes of digestion

A

👄 INGESTION
putting food in mouth

🧡DIGESTION
the breakdown of LARGE molecules into small molecules
MECHANICAL=> teeth + stomach muscles
CHEMICAL=> digestive enzymes

💛🔱ABSORPTION
process of moving molecules thru wall of ins testing to blood
>digested food molecules absorbed in villi lining small intestine
> WATER absorbed in large intestine 💦

❇️✳️ASSIMILATION
absorbed molecules r moved into cells (become part of)
E.g. amino acids assimilated, used to make cellular proteins

⚛️ 💩 EGESTION
not everything ingested can be digested
All undirected stuff forms faeces = removed thru anus

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35
Q

What is the enzyme and acid in the stomach

A

Hydrochloric acid and protease ; PEPSIN

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36
Q

Where are most enzymes stored/ produced

A

in PANCREAS

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37
Q

What 3 things do the VILLI need to fast absorption

A

✴️good BLOOD SUPPLY

✴️LARGE SURFACE AREA

✴️ONE- CELL THICK WALL

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38
Q

What does bile do, and where is it made + stored

A

Neutralises stomach acid + emulsifies FAT

Made in liver & is stored in GALL BLADDER

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39
Q

Why does bile need to be released

A

Because the acid in the stomach is too acidic for ENZYMES in small INTESTINE to work
So bile neutralises it and makes conditions alkaline (enzymes work best)

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40
Q

What is PERISTALSIS and why is it important

A

muscular tissue all down alimentary canal that pushes food down by contracting muscles

Otherwise, FOOD would get STUCK and we would choke

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41
Q

Give 3 things adrenaline does

A

> increases heart rate (extra blood supply to muscles to help them run away)

> triggers FIGHT or FLIGHT response

> increases blood glucose levels

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42
Q

Where does adrenaline come from

A

ADRENAL GLANDS

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43
Q

CORONARY HEART DISEASE (CHD)

A

Coronary arteries = narrowest in body, provide o2 to the heart— easily blocked by build up of fatty substances (making it narrower)

> this can reduce blood supply to heart OR CUT OFF blood supply to heart => heart attack (heart starved of oxygen)

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44
Q

Name 3 factors that increase risk of CORONARY HEART DISEASE

A

> heredity (inherit a tendency)

> high blood pressure ( puts more strain on heart)

> lack of exercise ( regular exercise reduces blood pressure + strengthens heart)

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45
Q

Name 2 types of white blood cells and what they do:

A

PHAGOCYTES = swallow pathogens + break them down w/ digestive enzymes

LYMPHOCYTES = produce antibodies specific to antigens ( markers that r distinctive to pathogen) to mark out pathogen for destruction.
Neutralise toxins & stop reproduction of pathogen

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46
Q

Describe why humans get vaccines and what it is 💉💉💉

A

When we r infected w/ a live pathogen the lymphocytes produce antibodies but this can take long (u can 💀)

To solve this problem , a vaccine is when u are injected w/ dead or inactive pathogens, these carry antigens so they trigger an immune response— so when the same live pathogen comes back, the memory cells will remember specific antibodies

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47
Q

What is a Phagocyte (70% of blood)

A

A white blood cell
‘Cell eating’
Ingests pathogen into it’s vacuole and secretes enzymes to break it down

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48
Q

What is the role and function of PLASMA

A

Liquid part of blood ( mainly 💦)

Carries blood cells around body

Carries dissolved nutrients, Co2, urea, hormones + heat

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49
Q

What is the role and function of PLATELETS in the blood?

A

Platelets release chemicals to make blood clot 🧣 when we cut ourselves 🗡

They ‘plug’ the damaged area + stop u from losing blood

Platelets held together by mesh protein (FIBRIN)

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50
Q

What is the main function of red blood cells?

A

to TRANSPORT O2 🌬🌪

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51
Q

Name the 2 parts of the central nervous system

A

🐥peritheral nervous system

🧠 central nervous system( brain + spinal chord)

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52
Q

Where is the location of the sensory neurons and what is their function?I

A

sensory neuron:

located in spinal chord + down a limb

CARRY signals from receptors to CNS

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53
Q

Where is the location of the motor neurones and what is their function?

A

motor neurons:

Located in spinal chord

CARRY impulses from brain(CNS) to effector

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54
Q

What 3 things are ALWAYS needed for a response

A

🐲stimulus

🐲receptor

🐲effector

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55
Q

What do receptors do

A

Detect the change in environment (stimulus is the trigger)

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56
Q

What is a reflex action?

A

a FAST + AUTOMATIC response to a potentially dangerous stimulus

SUBCONSCIOUS = skips deciding in 🧠 which wastes time

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57
Q

Describe what happens (in terms of reflex arcs and neurons) what happens when you touch a flame 🔥

A

1) receptors in skin detect stimulus (🔥)
2) the impulse is carried by SENSORY NEURONS〰️> to spinal chord
3) now RELAY NEURONS 🔝 carry signal to 🧠

4)the impulse is sent by MOTOR NEURONS~~> to the effector
which generates a response=🤽🏻‍♂️

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58
Q

What is a SYNAPSE

A

A synapse, is when 2 neurons meet they have a tiny gap between them

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59
Q

How does a synapse work

A

When the electrical impulse travels along the neuron
it arrives at a gap (the synapse) the end of the sac is filled with neurotransmitters, these are chemicals that diffuse out thru the gap
and BINDS to the chemical receptors
generating a response

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60
Q

What does the iris reflex do? 👁 👁

A

It controls the amount of light that enters the eye 👁 by changing the diameter of pupil.

bright light 💡 = pupil CONSTRICTS—less light in eye //circular muscles contract, radial muscles relax 😽

dim light 🌚= pupil DIALATES—more light in eye// circular muscles relax, radial muscles contract 🙀

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61
Q

When the eye is looking at a distant object what do the ciliary muscles do, and what do the suspensory ligaments do?

A

Looking at distant object

Ciliary muscles= relax
Suspensory ligaments= pulled TIGHT

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62
Q

When the eye is looking at a nearby object what do the ciliary muscles do, and what do the suspensory ligaments do?

A

Looking at near by object

Ciliary muscles = contract
Suspensory ligaments= slack

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63
Q

What is HOMEOSTASIS? + give 2 examples

A

⚖️ maintenance of constant internal environment

E.g. body temp🤒 & body water content 💧

64
Q

What is the optimum temperature of human body and what part of brain 🧠 monitors body temp?

A

37^C

THERMOREGULATORY centre = part of 🧠 dat monitors body temp.

65
Q

When it is hot describe how the body responds:

A

1) SWEAT glands secrete sweat 😓
to evaporate + cool body

2) VASODILATION: blood vessels supplying skin capillaries dilate to bring heat to surface of the skin
To lose the heat

66
Q

When it is cold describe how the body responds:

A

1) HAIR FOLLICLES stand up
Hair erector muscles contract to trap insulating layer of air to keep warm

2) VASOCONSTRICTION = blood vessels supplying the capillaries constrict
To stop heat going to the surface + escaping (keeps heat IN)

3) SHIVER = small muscles contractions generate heat

67
Q

What receptor detects a rise/fall in blood glucose levels?

A

PANCREAS

68
Q

When the blood glucose levels rise, what happens?

A

when blood glucose levels 🔝

INSULIN (hormone which tells the liver) is released by pancreas

The LIVER then absorbs the glucose + stores it as glycogen

Negative feed back= insulin stops being released

BGL BACK TO NORMAL

69
Q

What is a hormone

A

A chemical messenger sent in the blood

70
Q

When the blood glucose levels fall, what happens?

A

when blood glucose levels 👇🏿

GLUCAGON (hormone which tells the liver) is released by pancreas

The LIVER then turns the glycogen into glucose 🍫

Negative feed back= glucagon stops being released

BGL BACK TO NORMAL

71
Q

What is type 1 diabetes and what consequences does it have?

A

Bod can’t make insulin
To take in glucose
So it can’t make ATP

72
Q

Where are hormones produced

A

Hormones r produced in glands

73
Q

Give 3 main differences between the 🖤NERVOUS system vs. 💚ENDOCRINE system

A

🖤electrical impulse
💚chemical message

🖤very FAST message
💚SLOW message

🖤SHORT LIVED response
💚LONG LASTING response (e.g. growth)

74
Q

Why do organisms need to respond to stimuli?

A

Organisms need to respond to stimuli

to maximise chance of survival

75
Q

What are AUXINS

A

Plant growth hormone

Stimulate elongation process or inhibit growth depending on need

76
Q

What is phototropism and geotropism

A

Plant growth response to light = phototropism

plant growth response to gravity = geotropism

77
Q

Are SHOOTS in plants, positively or negatively phototropic(light)

A

POSITIVELY PHOTOTROPIC
> auxin accumulates in shadier side of shoot
> auxin promotes growth in shaded side causing shoot to bend 🌱
> TOWARDS THE SUN 🌞

78
Q

Are plant SHOOTS negatively or positively GEOTROPIC

A

NEGATIVELY GEOTROPIC
>when shoot grows side ways gravity produces more auxin on lower side
> this auxin promotes growth on lower side, causing shoot to bend upwards
> AWAY from gravity 🌵

79
Q

What does auxin do to the roots to make them positively GEOTROPIC

A

AUXIN inhibits growth in lower side of roots

Stops lower side from growing
So root bends DOWNWARDS

80
Q

What is EXCRETION

A

Excretion =

removal of waste products (or substances in excess requirements)

81
Q

State 2 main functions of the urinary system

A

🌼removal of urea

🌼regulation of blood concentration (thru reabsorption of H2O back into the blood)

82
Q

What is the nephron and where is it found

A

Nephrons are in the kidneys

>they’re tiny filtering units which remove urea from the blood

83
Q

What is the 1st stage in the nephron. Give description.

A

1) ULTRAFILTRATION
blood from renal artery flows thru glomerulus(bundle of capillaries)
The high pressure squeezes water,urea, salts + glucose out of blood into Bowman’s capsule
BUT big molecules (like blood cells + proteins) stay in blood

The filtered liquid= glomerular fluid

84
Q

What is the 2nd stage in the nephron. Give description.

A

2) REABSORPTION
useful substances are SELECTIVELY reabsorbed
>in 1st coiled tubule all glucose reabsorbed by active transport
>salts pumped out+ water reabsorbed
> now 2nd coiled tubule carries ‘it’ {urea + salt} into collecting duct

85
Q

What is the 3rd (last) stage in the nephron. Give description.

A

3) RELEASE OF WASTE
remaining substances form urine this continues out the nephron ..
thru the ureter + down to bladder==
Stored till released by urethra

86
Q

What is OSMOREGULATION

A

OSMOREGULATION is the body balancing water coming in + out

Too conc= conc urine🌞
Too dilute= dilute urine💦

87
Q

What is the role of ADH

A

(Anti Diuretic Hormone) 💧
hormone that CONTROLS water content

  • makes u wee LESS
  • makes collecting duct more permeable
  • released by pituitary gland
88
Q

What enzyme is in the saliva

A

Amylase 👄

89
Q

What is dietary fibre

A

Indigestible plant material = cellulose

Which helps prevent constipation and bowel diseases

90
Q

Give 3 differences between meiosis and mitosis

A

In mitosis there is one cell division whereas in meiosis there r 2

In mitosis two daughter cells r produced whereas in meiosis 4 daughter cells r produced

Daughter cells produced by meiosis are HAPLOID
whereas daughter cells produced by mitosis r DIPLOID

In mitosis there is NO genetic variation in the daughter cells, in meiosis there IS GENETIC VARIATION in the daughter cells

91
Q

Give 3 differences between ASEXUAL and SEXUAL reproduction

A

In SEXUAL REPRODUCTION, specialised cells (gametes) fuse together whereas
in ASEXUAL REPRODUCTION there r no specialised gametes

Asexual reproduction produces GENETICALLY IDENTICAL CELLS whereas
Sexual reproduction produces GENETIC VARIATION

Asexual reproduction is FASTER than sexual reproduction

92
Q

What is a disadvantage of ASEXUAL REPRODUCTION

A

Since all the offspring are clones, they have no GENETIC VARIATION so if selection pressure (e.g. climate) changes they can’t adapt

93
Q

What process does a zygote undergo to develop into an embryo

A

MITOSIS

94
Q

What happens in the kidney nephron?

A

1) blood from the renal artery goes into the glomerulus and small molecules (water + urea + salts) r squeezed out into Bowmans capsule.

2)Fluid passes along to the 1st coiled tubule and glucose is reabsorbed back.
Then in the loops of Henlé more water +ions r reabsorbed

3) remainin substances form urine: water, salt ions + urea. And leave down the ureter stored in the bladder until released by urethra

95
Q

Smoking can increase the risk of developing coronary heart disease. 🚬
Explain how coronary heart disease can cause death (5 marks)

A

Smoking causes CHD which is the narrowing of the arteries, specifically the coronary arteries which supply blood to the heart.

The build up of cholesterol means these arteries are narrower and therefore less blood is supplied to the heart.

Because the heart gets less blood, it doesn’t get enough oxygen which means the heart muscles are starved of oxygen.

This starving of oxygen causes a heart attack which can be fatal

96
Q

Why do multicellular organisms need transport systems

A

Multicellular organisms have a low SA:vol ratio so they need a transport system

97
Q

Why do unicellular organisms not need a transport system? + Give 2 examples of a unicellular organism

A

Single called organisms don’t need a transport system cos their SA:vol ratio is very high

They can rely on diffusion for movement of substances in + out

Amoeba,euglena + paramecium

98
Q

Give 3 things the blood transports

A

🥩o2 from lungs to rest of body

🥩Co2 from body to the lungs

🥩nutrients (glucose) from gut to all parts of body

🥩urea from liver to kidneys

99
Q

What is a single circulatory system

A

A system where the blood is pumped from the heart to the gas exchange organ & then to the rest of the body

❤️🌬🕺🏻

100
Q

What is a double circulatory system

A

A system where the blood is pumped from the heart to the gas exchange organ, then back to the heart & then to the rest of the body

❤️🌬❤️🕺🏻

101
Q

What 3 things is the human circulatory system comprised of?

A

❣️the heart= the pump

❣️blood vessels—carry the blood around the body:
•arteries =carry blood away from the heart
•veins= carry blood towards the heart
•capillaries= carry blood thru organs

❣️blood= the transport medium

102
Q

Describe the cardiac cycle (5 steps)

A

❤️blood enters atria— it can not pass thru cos bicuspid+ tricuspid valves r closed

❤️walls of ATRIA contract, raising pressure of the blood forcing valves open

❤️blood goes thru valves and fills VENTRICLES which raises pressure which closes the bicuspid + tricuspid valves. Blood can’t return to atria

❤️ventricles contract + pressure increases which forces the pulmonic + aortic valves open.

❤️PULMONARY ARTERY carries blood to lungs
AORTA carries blood to all parts of the body
As ventricles empty the high pressure in the aorta+ pulmonary closes their valves

103
Q

How is the structure of the heart adapted for its function?

A
  • it’s divided into a left side and a right side by a muscle called the septum. The right pumps blood to lungs and the left to all other parts of body
  • valves ensure that blood can flow only in one direction thru the heart
  • walls of atria very thin = they can be stretched to receive blood
  • walls of heart r made of CARDIAC MUSCLE which can contract/relax continuously without becoming fatigued
104
Q

What do valves in veins do?

A

Prevent blood from flowing backwards

105
Q

What is adrenaline?

A

A hormone which triggers the ‘fight or flight’ response, it increases heart rate

106
Q

What does the medulla in the brain do

A

It releases nerve impulses telling heart to beat faster

107
Q

What is meant by the term systemic circulation

A

Blood circulated to other parts of the body to unload o2

108
Q

What is meant by the term pulmonary circulation

A

Blood circulated to the lungs to be oxygenated

109
Q

What is an antibody

A

A protein produced by lymphocytes which binds to antigens on pathogens— antibodies are specific to antigens

110
Q

What is an antigen

A

Tell tale markers on pathogens recognised by white blood cells as foreign~~ triggers immune response

111
Q

What are lymphocytes + what do they do

A

Cells which detect antigen on pathogen and produce antibodies which stick to pathogen and mark them out for DESTRUCTION

Antibodies are specific to antigen .. so next infection ur IMMUNE — some cells remember specific antibodies for specific pathogen and stay in blood as MEMORY CELLS

112
Q

State 3 ways RED BLOOD CELLS r adapted for their function

A

Their function is carrying OXYGEN

  • no nucleus = allows for more room for O2
  • biconcave shape = allows for efficient gas exchange of O2 in + out
  • contains haemoglobin = iron containing protein which combines w o2 to form OXYHAEMOGLOBIN
113
Q

State the location + function of relay neurones

A

Relay neurones are located in the CNS

+ they carry info round the brain/CNS 🧠

114
Q

What does the pigment underneath the sclera in the eyes function?

A

The pigment in the CHOROID (underneath sclera) stops light being reflected around the eye

115
Q

Describe the IRIS REFLEX to bright light 👁

A

👁 STIMULUS (bright light)

👁RECEPTOR (retina)

👁Sensory neurones in optic nerve

👁unconscious part of brain

👁 motor neurones in nerve to iris

👁 EFFECTOR (iris, circular muscles contract +radial slack)

= response (change in size of pupil)

116
Q

Where is insulin produced?

A

Pancreas

117
Q

What does the CNS consist of

A

Brain + spinal chord

118
Q

What would happen if we didn’t have specific receptors

A

If we didn’t have specific receptors— a cell will not respond to a hormone at all

119
Q

Name the source, role + effect of insulin

A

Source :
pancreas

Role:
control blood sugar levels

Effect:
stimulates liver to turn glucose into glycogen storage

120
Q

Name the source, role + effect of Adrenaline

A

Source :
adrenal glands

Role:
prepare body for fight or flight response

Effect:
increases heart rate, increases blood flow to muscles + increases glucose levels

121
Q

Name the source, role + effect of testosterone

A

Source:
Testes

Role:
Main male sex hormone

Effect:
Promotes secondary male sexual characteristics— facial hair, muscles develop, deepening of voice

122
Q

Name the source, role + effect of progesterone

A

Source:
Ovaries

Role:
Supports pregnancy 🤰

Effect:
Maintains lining of the uterus

123
Q

Name the source, role + effect of oestrogen

A

Source:
Ovaries

Role:
Main female sex hormone

Effect:
Controls menstrual cycle + promotes secondary female sexual characteristics (hips widen, development of breasts + pubic hair)

124
Q

Why are diabetics typically ‘thirsty’

A

Because there blood glucose concentration is high, so the hypothalamus tells person to drink to DILUTE THE BLOOD

125
Q

What kind of reproduction produces sexual variation in offspring ?

A

SEXUAL cos fertilisation is random meiosis= non identical cells produced w only half the chromosomes (sex cells)

126
Q

Describe the process of fertilisation

A

🍢 sperm approaches egg (long tail flagellum helps it swim)

🍢🥚 the sperm penetrates the cell membrane of the egg: the sperm nucleus enters

🥠an extra membrane stops more sperm from entering

👼🏼sperm nucleus + egg nucleus fuse

127
Q

What liquid are the sperm mixed in

A

The sperm are mixed in semen which is ejaculated from the penis into the vagina

128
Q

What are sperm

A

Male gametes made in testes

129
Q

What are ova

A

Ova are female gametes

an egg (ovum) is produced every 28 days + released into the oviduct for ovulation

During the eggs time in the oviduct the sperm may fertilise it, but if it didn’t it’s broken up + passed out of vagina (menstrual cycle)

130
Q

Describe what happens when an egg is fertilised

A

The fertilised egg will develop into an embryo and implant itself in the uterus

It then will develop a placenta = allows embryo to obtain o2 + nutrients, also to get rid of waste products(urea+co2)

Placenta secretes female hormone PROGESTERONE = maintains pregnancy + prevents aborting

131
Q

What separates the mothers blood from the babies blood?

A

Chorionic villi

132
Q

What is the function of the umbilical cord

A

The umbilical cord carries babies blood to mother

from FETUS to PLACENTA(umbilical artery carries deoxygenate blood w urea+ co2)

from PLACENTA to FETUS Umbilical vein carries oxygenated blood containing nutrients + o2)

133
Q

What is the function of amniotic fluid and what membrane encloses the developing embryo?

A

Amniotic fluid protects baby from sudden movements + bumps

The membrane enclosing embryo is the AMNION

134
Q

Give the 3 stages of birth

A

1) dilation of cervix - neck of uterus (cervix) widens to allow bby thru
2) delivery of baby - strong contractions of uterus muscles push bby out
3) baby born, then after it placenta + amnion membrane pushed out

135
Q

What is the role of oestrogen in the development of female secondary sexual characteristics

A

In girls pituitary hormones control release of oestrogen which causes

1) extra hair on underarms
2) hips widen
3) breasts develop
4) menstruation begins

136
Q

Give the definition of fertilisation

A

The fusion of a male + female gamete to produce a zygote that undergoes cell division + develops into an embryo

137
Q

What is the function of the oviduct

A

(Oviduct= aka Fallopian tube)

Is a muscular tube which carries ovum from the ovary to the uterus

138
Q

What does the scrotum contain ?

A

The scrotum contains the testes

139
Q

What does TESTOSTERONE do

A

It causes male secondary sexual characteristics to develop, e.g…

🚹facial hair

🚹muscles develop

🚹deepening of voice

🚹FSH stimulates sperm production

🚹testicles + penis enlarge

140
Q

What does OESTROGEN do

A

It causes female secondary sexual characteristics e.g..

🚺 extra hair on underarms

🚺hips widen

🚺breasts develop

🚺Menstruation begins

141
Q

What’s the largest artery in the body

A

Aorta

142
Q

What organ is responsible for hydrochloric acid secretion

A

Stomach

143
Q

Describe how smoking damages the lungs (5 marks)

A

🚬 EMPHYSEMA = decreases SA of alveoli — blood carries less o2 (May need o2 tank)

🚬 BRONCHITIS = cilia damaged + cant sweep mucus out, mucus blocks airways = smokers cough

🚬carcinogens cause LUNG CANCER

🚬tar makes lungs thick with black

144
Q

What causes smokers cough

A

Cilia damaged, cant sweep mucus out, mucus blocks the airways= smokers cough

145
Q

Other than damaging the lungs what other damaging effects can smoking have

A

😖CHD = increases blood pressure leads to heart having to work harder and a build of cholesterol on the arteries making them narrower

😖CARBON MONOXIDE = binds to haemoglobin instead of oxygen

😖NICOTINE = highly addictive stimulant— causes heart to beat faster

146
Q

Explain why reducing the blood supply to the heart muscle can cause a heart attack

A

When muscles aren’t getting enough blood, they’re not getting enough o2

The heart muscles r starved of oxygen and therefore can’t respire properly

This forces them to respite ANAEROBICALLY which causes lactic acid to build up

This lactic acid can denature enzymes/proteins

147
Q

Where is urea made

A

Liver

148
Q

Hepatic

A

To do w the LIVER

149
Q

Renal

A

To do w the KIDNEYS

150
Q

Describe what happens after an ovum is fertilised by a sperm in the oviduct

A

FERTILISED egg (zygote) develops into an embryo implants itself in the uterus.

Then it develops a placenta = allows it to obtain o2 + nutrition as well as get rid of waste (urea + co2)

Placenta secretes female hormones PROGESTERONE = maintains pregnancy + prevents aborting

151
Q

What is ovulation

A

When an egg develops and is released from the ovary at day 14

152
Q

Describe the 4 simple stages of the menstrual cycle

A

Stage 1) menstruation starts : uterus lining breaks down {days 1-4}

Stage 2) the uterus lining builds up again: thick layer of blood vessels ready to receive fertilised egg {days 4-14}

Stage 3) an egg develops + is released from ovary at day 14= OVULATION

Stage 4) the wall is then maintained {days 14-28}
If no fertilised egg by day 28– uterus lining breaks down + cycle begins again

153
Q

Describe the role of OESTROGEN in the menstrual cycle

A

Oestrogen …

🍬 produced in ovaries

🍬 causes uterus lining to grow

🍬 stimulates release of LH

[ LH causes release of egg]

154
Q

Describe the role of PROGESTERONE in the menstrual cycle

A

Progesterone…

🍓produced by ovaries by remains of follicle after fertilisation

🍓 maintain uterus lining (in stage 2 of menstrual cycle)

🍓 inhibits release of LH + FSH

155
Q

Where are faeces stored?

A

Faeces are stored in the rectum

156
Q

Describe the role of enzymes in cells

A

Enzymes are biological catalysts which speed up metabolic reactions

IGCSE Biology (6 decks)

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