Homeostasis And Response 🧪 Flashcards
1
Q
What are the names of the pills taken for contraception? What do they prevent?
A
TAKEN DAILY
Progesterone only pill - makes mucus thick and sticky so sperm cannot penetrate the egg
Combined pill- oestrogen and progesterone restricts FSH preventing the egg to mature
2
Q
Positives and negatives of contraceptive pills?
A
Positive- effective
Negative - increased chance of breast cancer and blood clots
Have to take daily, if miss risk pregnancy
3
Q
What are the 3 other contraceptions that contain progesterone
How long do they last?
Positives + Negatives ?
A
Patch - week
IUD implant -yearly prevent embryo from implanting
Injection - monthly
Positive more convenient
Neg- not protected from STI’s
4
Q
What does progesterone do?
A
Stops eggs being released and maturing
5
Q
What are the two barrier methods of contraception ?
Positive + Negative
A
Condom - reduced risk of STI’s
Diaphragm
Covered in spermicide- gel that kills sperm before it reaches the egg
6
Q
What are the surgical procedures of contraception?
A
Sterilisation - tie Fallopian tubes preventing egg reaching uterus
Men- prevents sperm from leaving the penis
7
Q
List all the forms of contraception
A
Abstinence
IUD
progesterone pill
Combined pill
Sterilisation
Patch
Injection 
8
Q
What are the two ways to treating fertility?
A
Pill releases FSH (mature)
and LH allowing the egg to be released (ovulation)
IVF
9
Q
What is phototropism?
A
When a plant shoots / grows toward the light
10
Q
Explain the experiment that scientists do to show phototropism?
A
Remove tips of shoots
Does not grow toward light
Because hormone called auxins are at the tips causes the plant to bend towards the light
Concludes that the tips only produce auxins
11
Q
What material do scientists put on the tip of the shoots ? What does it do? What can you conclude ?
A
Foil, prevents any light from being detected by auxins , so plant does not grow towards the light
Tell us that tips are sensitive to light.
12
Q
What are the stages of shoots growing ? What do auxins trigger?
A
- Auxins produced on the tip of the shoot
Auxins trigger cell growth
- Light caused auxins to focus on the darker sides of the shoots
- Auxins now spread down the shoot, causing darker sides on the shoots cells to grow faster than cells on lighter sides.
- Causes shoots to grow towards the light
13
Q
What is gravitropism?
A
What roots grow towards gravity
14
Q
Explain how gravitropism occurs
A
Auxins are produced in the root
But gravity causes it to be concentrated on the lower side
This inhibits cell growth
Causing the lower side to grow more slowing than the upper side
Causing the roots to grow towards gravity
15
Q
What does Auxins do in roots
A
Inhibits growth
16
Q
Why is Gibberellins important?
A
Starts germination of seeds
17
Q
Why is ethene important in plants ?
A
Controls cell division and the ripening of fruits
18
Q
What are Auxins 3 main uses?
A
Weed killers in gardens
Rooting powders
promoting growth in tissue culture
19
Q
What are gibberellins 3 used?
A
End seed dormancy - force a seed to germinate earlier
Encourage plants to flower
Make fruit grow larger
20
Q
What are ethene’s use in fruit products?
A
Triggers ripening for goods in demand that were just picked and stored
21
Q
What is kidney dialysis?
A
A machine that contains a semi permeable membrane.
Which mimics the nephron tubules.
When the patients blood passes over excess ions and urea diffuse from the high concentration of blood
into the low concentration of dialysis fluid.
22
Q
Disadvantages of kidney dialysis
A
Takes 3-4 hours 3 times a week
Risk of blood clot/ infections
Expensive
23
Q
Advantages of kidney Transplant?
A
Gives patient more time to find kidney donor
24
Q
What happens if a patient is unable to receive kidney dialysis?
A
Tissues become damaged
25
Why are immunosuppressant given to patients recovering a donor kidney ?
They have to take it for life , it caused the body to not destroy foreign cells from the donated kidney
26
How can patients revive a donor?
From other registered donors who have recently died
or family members
Have to be a tissue match
27
Disadvantages of kidney transplants?
Kidneys can be rejected by the body
Need to take immunosuppressants for life making them
More prone to disease
Long waiting lists
28
Advantages of kidney transplant ?
Cheaper in the long run
Less time consuming
29
What is one affect of adrenaline
Dilated pupils
30
What is the best temp for the human body
37.4
31
How is bloods temperature changed within the body ?
Blood is cooled in the stomach and flows into the brain
32
How does decay occur in a heap of dead plants? What do the organisms do ?
Microorganisms digest enzymes and conduct aerobic respiration producing carbon dioxide relating nitrate
33
How does decay occur in plants?
Carbon dioxide is taken up by plants by diffusion via stomata and is used for photosynthesis to make glucose
34
What happened to nitrate in decay?
Taken up the roots by active transport to make amino acids to make phosphate for DNA
35
List and explain the parts of the eye
Sclera - hard outer layer protecting the eye
Ciliary muscle - works together w/
Suspensory ligament- controls the thickness of the lens for accommodation
Cornea- clear layer that refracts light
Pupil - whole that lets light through
Iris- controls the size of the pupils to prevent damage
Retina- detects light
Optic nerve- sends electrical signals to brain
36
Explain parts of the brain
Bottom -medulla - controls unconscious activities eg. Heart rate
Middle - cerebellum- controls muscle coordination
Top- cerebral cortex - controls consciousness and memory
37
Why is it hard to study brains ?
Delicate and complex
Can cause physical damage
38
What are the 3 ways we can study the brain?
Studying damages brains - see how it effects the person
ESB- electrically stimulating brain - know certain parts of brains
MRI scans - what areas of the brain are active
39
Why is it better to measure reaction times with the computer?
1. More precise remove any human error
2. Record in milliseconds - accurate
40
Describe the accommodation of an near object.
NEAR OBJECTS CCC
ciliary muscles contract ,
suspensory ligaments relax
this causes the lens to slacken ,
allowing more light to refract from the lens , making it easier to see the object.
41
Describe the accommodation of a far object in the eye.
Suspensory ligaments contract
Ciliary muscles relax
Stretches lens , making it thin
Less light is refracted
Easier to see distant object
42
What is myopia? How can it be corrected ?
When the image focuses at a shorter distance before reaching the retina - convex lens is needed - refracts light so it can focus in retina
43
What is hyperopia? How can it be correct?
When the image forms after the retina concave lens needed for image to meet retina
44
What are the three things we can to to fix vision
Contact lenses
Laser eye surgery
Replacement eye surgery
45
Explain how the iris changes the size of the pupil in dim light
Radical muscles contact , circular muscles relax this causes the pupil to dilate along more light to enter the eye so that you can see better
46
Explain the iris reflex if an eye in bright light
Circular muscles contract , radical muscles relax causing the pupil to become smaller to allow less light to damage the retina
47
What do enzymes in cells require?
Very stable conditions to work
48
What is homeostasis?
The regulation of internal conditions to keep to maintain optimum conditions in response to internal and external changes
49
What are the internal conditions of homeostasis keeps constant?
Glucose levels
water levels
body temperature
50
What does homeostasis consist of?
Automatic control systems
51
What can the homeostasis control system contain?
Hormones - Slow on a general area and takes a long time
or nervous systems-quick on the precise area and takes a short amount of time
52
Explain the control automatic system
Receptor cells in skin - Detect a stimulus- Passes info To brain spinal cord or pancreas-
coordination centre -Receives and processes information to from the receptor cells to
effector -passes into a muscle or a gland producing a response to restore optimum level
53
Explain the nervous system
Receptor cells detect a stimulus and send electrical impulses down neurons to the CNS (Coordination centre)
The sends of the electrical impulses down other neurons to the effector
Which brings a response Causing a muscle to contract Or a gland to secrete hormones

54
What are neurones?
Nerve cells
55
What is a key role to the central nervous system?
It allows humans to react to their surroundings And coordinate to their behaviour done through the reflex arc

56
Explain the reflex arc system
A receptor (skin cell) in your fingertips detects a stimulus like heat
Electrical impulses are passed From the receptor along a sensory neuron to the central nervous system
Remember that sensory neurons are connected to receptors which allows us to sense our environment
That’s the synapse a chemical is released
This diffuses across a relay neuron into the central nervous system where it triggers an electrical impulse
The electrical impulse now passes along the relay neuron and reaches another synapses- Which triggers an electrical impulse in the motor neuron
Electrical impulse passes down motor neuron into an effector on which would be a muscle because it’s a contract for you to be your finger away from the heat- Response

57
What kind of response is a reflex arc?
Automatic and rapid - You’re not a conscious thing made by the brain is a reflex
58
Explain how we measure reaction time
A possible sit down with good posture and place a full on of the dominant arm across the table- Hand hovering over the edge
Person to hold the ruler vertically 0 cm mark should be between persons thumb and first finger
Person one then tells person to to be ready - Drops Ruler into hand - person 1 has to catch the ruler as quickly as they can
Go and measure the top of the persons thumb on the ruler
and person 1 has a quick rest
then we repeat several times and the mean is calculated

Then we use a conversion table to change this into reaction times
Then we switch places and repeat
This allows us to see the two people have different reaction times
The independent variable is the person having the reaction time
Dependent variable is reaction time
Control variable is the distance between the ruler and the persons finger and thumb before the drop
Conditions in the room the same -Background noise lighting
That after measurements
If we change the control variables this may influence a dependent variables I don’t know longer be valid or fair test

59
What other independent variables can we test in the reaction time practical?
The fact of practice we could get somebody to catch the ruler several times and then test them to see if it influences their reaction time
We could see if it’s depending on the hands. We can test of the dominant hand of the non-dominant hand with same person
We can test the chemicals may affect
reaction time like caffeine
Measurement about of cola half an hour before experimentIn issue would be that there may be other chemicals affecting
reactive time so we use one cola with no caffeine and one of her with caffeine to see the differences
I need to check that it’s safe so we need to check that we have no allergies or hot conditions and that the chemicals we use are not Hazardous
60
Where is your body temperature monitored And controlled?
In the brain thermoregulation System
61
What does the tHermoregulation centre Contain?
Receptors that That are sensitive to the temperature of the Blood 
62
What does the skin do in the thermoregulatory centre?
Contains temperature receptors that send electrical impulses down the sensory neurons to the Thermoregulatory centre
63
What does the thermoregulatory centre do?
Send an electrical impulses down sensory neurons
64
What are the two processes In the thermoregulatory centre
Vasodilation-sweat is released from sweat glands on the skin surface
and the sweat evaporates which takes energy from the
body cooling the body down
Skincare blood capillaries dilate and get to larger to get nearer to the skin surface-
More blood can flow into the capillaries and heat can transfer out of the blood
Causing the body temperature to return back to its optimum level
 Vasoconstriction- hairs stand on ends pocketing heat
Blood capillaries constrict become narrower and get away from the skin surface 
Through the capillaries Less heat is lost
We start to shiver our muscles contract
To shiver of bodily cells of the high energy from respiration this releases heat and warms the body
No sweat 😉 
65
Explain what’s in the endocrine system
Testes- male reproductive organ produces sperm testosterone
Adrenal gland- produces adrenaline in flight or fight response
Pituitary gland- master gland produces hormones that can act on other glands
Thyroid- Growth , metabolic rate, temperatures
Ovaries- Menstrual cycle eggs in women oestrogen
Pancreas- Releases insulin to regulate
blood glucose levels
66
What is the Endocrine system?
A system of glands that secrete hormones directly into the blood stream
 transfers hormones all around the body but some hormones are just for some specific target organ
67
What are the differences between the nervous system and endocrine system
nervous system is electrical impulses- quick and precise short lasting
Endocrine -Uses hormones that are carried into the bloodstream- slower
General area long lasting
68
How many the concentration of glucose rise?
After meal rich in carbohydrates
69
Describe how the body reacts to blood high in glucose 
Blood high glucose flow blood
- detected by pancreas-
released insulin -
insulin and blood  high in glucose flows to liver -
insulin triggers glycogen reducing glucose back to normal level
70
Describe how the body reacts to blood with little glucose in it
Blood with little glucose - detected by pancreas- glucagon released - blood and glucagon absorbed and detected by liver - glucagon triggers glycogen back to glucose - BGL back to optimum level 
71
What is type one diabetes?
Well somebody cannot release enough insulin- Have to inject themselves- It’s a controlled diet of simple carbohydrates regular exercise 
72
What is type two diabetes?
Where is somebody can’t react to their own insulin produced by their own body so causes blood sugar levels to rise rapidly can be caused by obesity
Exercise and a control diet
73
Why does the blood glucose concentration fall and rise rapidly within the day?
Because the concentration of blood because is controlled by the balance between insulin and glycogen
74
Why is controlling blood glucose levels and negative feedback cycle?
Because producing insulin and glycogen has an opposite affect
75
What happens if the blood becomes to dilute?
Water moves into the blood by osmosis and bursts damaging body cells
76
What are the three ways we lose water?
Exhaling from lungs
Through sweat from skin- Contains sodium ions and waste product Urea

Loss of water via the kidneys in urine
77
Why can’t the body control how much ions, sweat water is lost?
It’s part of the bodies temperature control system
78
What is the kidneys job
Acts as a filter to clean blood
79
What process does the kidney go through?
Filtration Filters out substances like waste products
useful substances in the blood like glucose and ions and the right amount of water is absorbed
back called selective reabsorption
80
What is deamination?
Proteins get Broken down to amino acids Releasing the chemical ammoniathat they’re broken down into cannot be stored in the body
so access amino acids are converted into fats and carbohydrates which can be stored in the liver
81
What is a waste product of deamination?
Ammonia
82
What is ammonia converted to and why?
It’s the product of proteins being broken down into this chemical
It’s toxic so it’s converted into Urea in the liver And it transferred back into the kidneys and filtered out the body in urine
83
Why do we remove ions from my body?
If you have too much or too little ions this could upset the balance between ions and water
affecting the osmosis of body cells which can damage cells and make them not work
84
How do we control the concentration of urine
ADH which is released to our bloodstream by the pituitary gland
Brain monitors the water content in blood and instructs the pituitary gland to release ADH
Controlled by negative feedback this means if it gets too high or low the mechanism will be triggered that brings her back to normal
85
What happens if water content in our body increases?
Receptor in the brain 🧠 detects water content to high
the coordination centre in the brain receives the information and coordinates a response
the pituitary gland releases less ADH so there’s less water absorbed from the kidney tubules decreases the permeability-
so water content decreases
86
Explain what the body does if water content is too low?
Receptors in the brain detect that water levels are too low
sends info to coordination centre and coordinates a response
pituitary gland releases more ADH the water is reabsorbed from the kidney tubules increasing the permeability
Increase in the water content
87
Explain the menstrual cycle
Once women start to mature egg start maturing and get released every 28 days
-Ovulation
Day 1- Uterus lining gets thick and spongy- eggs makes it down uterus
If sperm is at present and cannot be fertilised
Egg in beds into the uterus wall and it may develop into a baby
If it doesn’t get fertilised at the last day it gets released both the egg your uterus lining are released into your period
88
Explain the four hormones is needed in the menstrual cycle
FSH -Causes the egg to mature
LH -causes the egg to be released into the uterus (Ovulation)
Oestrogen and progesterone -involved in maintaining the uterus lining in case the egg is fertilised
89
Explain how the hormones affect the stages of the menstrual cycle
Stage one –FSH is released by the pituitary gland-FSH travels to the egg In the ovaries cause of it to mature
But also triggers the ovaries to create oestrogen-This causes the lining of the uterus to become thick and also stop the pituitary gland from releasing more FSH
This causes the pituitary gland to release LH now which releases the egg into the uterus (ovulation)
This triggers progesterone To be released - This stops the pituitary gland from releasing LH and FSH
Keeps the uterus lining thick incase a Fertilised egg implants
If fertilisation does not take place the level of progesterone falls
Uterus lining and the egg is released causing the women’s have a period
90
Explain how We are investigating the light intensity and how it affects growth
Get a petri dish and put cotton wall and soak with equal volumes of water
Independent variable – light intensity
Dependent variable – height of seedlings

Control variable – the amount of time in each condition. Amount of water soaked in cotton type of seeds
Place 10 mustard seeds In each petri dish
Leave dishes in warm places to allow the seed to germinate
Water seeds every day with the same volume of water
After a few days the seeds will germinate into seedlings 🌱
Make sure that the same number of seedlings 🌱 are in each petri dish
measure the height of each seedling make sure the stems are held straight but don’t damage the seedlings 🌱
Now paid the three dishes in different conditions one in full sunlight one dish impartial lights then another in a dark cupboard
Measure length of each seedling a week and then Calculator mean
height of seedlings are similar for full and partial light but are bent due to phototropism as shoots grow towards the light
however the height of the seedlings in the dark are taller as auctions are continuing to grow to find light but them but have yellow leaves
-this is because once they have used up all their energy is no light for photosynthesis
