Topic 5 - Homeostasis + Response Flashcards
1
Q
Homeostasis definition
A
Regulation of conditions inside your body (and cells) to maintain a stable internal environment
2
Q
Examples of control systems
A
Maintain body temperature, blood glucose level + water content
3
Q
Control system components
A
Receptor cells, coordination centres (brain, spinal cord + pancreas) and effectors
4
Q
Negative feedback is used when ….
A
The level of something gets too high or too low - to bring back to normal
5
Q
Negative feedback loop example
A
Receptor detects a stimulus - level changes
Coordination centre receives and processes the information them organises a response
Effector produces a response which counteracts the change and restores the optimum level
Effectors carry on producing response as long as they are stimulated to
6
Q
CNS definition
A
Central Nervous System
In vertebrates - brain and spinal cord
In mammals - brain, spinal cord, sensory neurones + motor neurones
7
Q
Sensory neurones
A
Neurones that carry information as electrical impulses from receptors to the CNS
8
Q
Motor neurones
A
Neurones that carry electrical impulses from CNS to effectors
9
Q
Effectors
A
All your muscles and glands that response to nervous impulses
10
Q
Muscle effectors ….
Gland effectors …
A
contract
secrete hormones
11
Q
Bird + cat example coordination of response
A
Cat (stimulus) is skulking towards bird
Receptors in the Birds Eye are stimulated
Sensory neurones carry information from receptors to the CNS
CNS decides what to do about it
CNS sends information to muscles in birds wings along motor neurones
Muscles contract (effectors) and the bird flies away to safety
12
Q
What is a synapse
A
Connection between two neurones
Nerve signal is transferred by chemicals which diffuse across the gap
Chemicals the set off a new electrical signal in next neurone
13
Q
Reflexes
A
Are rapid automatic responses to certain stimuli that don’t involve the conscious part of the brain - reduce chances of injury
Passage of information in a reflex = reflex arc
14
Q
Reflex arc
A
When stimulus detected by receptors, impulses sent along a sensory neurone to the CNS (spinal cord/unconscious part of brain)
When impulses reach synapse between sensory neurone and relay neurone, trigger chemicals released causing impulses to be sent along relay neurone
Same thing happens between relay neurone and motor neurone
Along motor neurone to effector
Quicker than a normal response
15
Q
How scientists study brains
A
- studying patients with brain damage + observations of what doesn’t work
- electrically stimulating brain + observations of what it stimulates
- MRI scans - show which parts of brain are active during tasks
16
Q
Investigating reaction time
A
Required practical - ruler drop method
Measured using computer
17
Q
The sclera is the ….
A
Tough supporting wall of the eye
18
Q
The cornea is the …
A
Transparent outer layer found at the front of the eye - it refracts light into the eye
19
Q
The iris contains ….. and therefore ….
A
Muscles that allow to control the diameter of the pupil
how much light enters the eye
20
Q
The lens …..
A
Focuses the light onto the retina
21
Q
The retina contains …..
A
Receptor cells sensitive to light intensity and colour
22
Q
Ciliary muscles and suspensoirs ligaments control ….
A
The shape of the lens
23
Q
The optic nerve carries ….
A
Impulses from the receptors on the retina to the brain
24
Q
Treatments for vision defects
A
Contact lenses, laser eye surgery + replacement lens surgery
25
What are contact lenses
Why contact lenses
Two types
- thin lenses sit on the surface of eye - shaped to compensate for fault in focusing
- lightweight and almost invisible - more convenient than glasses for activities
- hard lenses or soft lenses - more comfortable but carry higher risk of infection
26
What is laser eye surgery
Changes in shape
Risk
- laser vaporises tissue, changing shape of cornea (for refraction)
- slimming down makes it less powerful to improve short sight, changing shape so more powerful improves long sight
- like all surgical procedures have risk of complications such as infection or eye reacting making vision worse
27
What is replacement lens surgery
Relative risk
- natural lens of eye is removed and artificial lens made of clear plastic is inserted in its place
- work inside the eye so carries higher risks than laser eye surgery including possible damage to the retina (could lead to loss of sight)
28
Body temp must be kept ….
- in terms of energy
- how does your body know your body temp? and skin temp?
Constant
Body has to balance amount of energy gained (eg respiration) and lost to keep core body temp
Thermoregulatory centre in brain containing receptors sensitive to temp of blood flowing in brain
The TC also receives impulses from temp receptors in skin giving info on skin temp
29
Antagonistic effectors are ….
Effectors that can work at the same time to produce a precise outcome eg optimum temp
30
Hormones are …. released directly into ….
Chemical messengers
The blood
31
Hormones are carried in blood to other parts of body but only affect …… (called ….)
Particular cells in particular organs
Target organs
32
Hormones control things in organs and cells that need ….
Constant adjustment
33
Hormones are produced in (and secreted by) various …. called …. which make up your …..
Glands
Endocrine glands
Endocrine system
34
Hormones tend to have relatively …. effects
Long lasting
35
PITUITARY GLAND produces many hormones that regulate ….
Sometimes called the ….. because these hormones act on ….directing them to …. that bring about change
Body conditions
Master gland
Other glands
Release hormones
36
THYROID produces ….. which is involved in regulating things like the rate of ….., ….. and ……
Thyroxine
Metabolism
Heart rate
Temperature
37
ADRENAL GLAND produces ….. which is used to prepare body for …..
Adrenaline
Fight or flight response
38
PANCREAS produces ….. used to regulate ……
Insulin
Blood glucose level
39
OVARIES produce ….. which is involved in the …..
Oestrogen
Menstrual cycle
40
TESTES produces ….. which controls ….. and …. in males
Testosterone
Puberty
Sperm production
41
Messages travelling on nerves
- …… action
- act for …. time
- act on …. area
Very fast
Very short
Very precise
42
Messages travelling by hormone
- …… action than nerves
- act for …. time
- act on …. area
Slower
Long
General
43
Eating food containing carbohydrate puts …. into the blood from gut
Glucose
44
The normal metabolism of cells removes ……. from blood
Glucose
45
Vigorous exercise removes …… from the blood
Much more glucose
46
Excess glucose can be stored as ….. in ….. and …..
Glycogen
Liver
Muscles
47
Level of glucose must be …..
Changes are monitored and controlled by the …. using the hormones ….. and ….. in a ……
Kept steady
Pancreas
Insulin
Glucagon
Negative feedback cycle
48
TYPE 1 DIABETES
- pancreas produces ……
- treat with …… - injections at mealtimes to make sure glucose is …..
- also help treat with limiting ….. and taking …..
Little or no insulin
Insulin therapy
Removed from the blood quickly
Intake of simple carbohydrates
Regular exercise
49
TYPE 2 DIABETES
- person becomes …..
- being …. can increase your chance of developing T2D (……)
- can be controlled by eating a …….. and getting ….
Resistant to their own insulin
Overweight
Obesity is a major risk factor of developing the disease
Carbohydrate-controlled diet
Regular exercise
50
Kidneys make urine by taking …….
Substances are ……. of the blood as it passes through - process of …..
Useful substances like ….. are then absorbed back into blood - process of …..
Waste products out of blood
Filtered out
Filtration
Glucose, some ions and the right amount of water
Selective reabsorption
51
UREA - in urine
….. can’t be stored by the body so any excess are converted into ….. which can be stored - this happens in the …… - process of …..
….. is produces as a waste product - it is toxic so is converted to ….. in the ….. - then transported to the …. where it is filtered out of blood and excreted from body in urine
Proteins and amino acids
Fats and carbohydrates
Liver
Deamination
Ammonia
Urea
Liver
Kidneys
52
IONS - in urine
- such as ….. are taken into body in food and absorbed into blood
- having wrong ion or water content in body can upset balance of ….. - having wrong mount of water can …. or mean they …..
- right balance must be maintained by the …. by …. into blood
sodium
amount of water in cells due to osmosis (too much or little)
damage cells
don’t work as well as normal
kidneys
reabsorption
53
WATER - in urine
- body has to constantly balance the ……
- We lose water from skin in … and from lungs when …
- we cannot control how much is lost with the above so the amount is balanced by amount we ….. and amount ……
Water coming in against the water going out
Sweat
Breathing out
Consume
Removed by the kidneys in urine
54
Concentration of urine is controlled by hormone called …. - released into bloodstream by the ….
brain monitors …. and instructs ….. to release …. into blood according to how much is needed
anti-diuretic hormone (ADH)
pituitary gland
water content of blood
pituitary gland
ADH
55
Whole process of water content regulation is controlled by ….
Negative feedback
56
If the kidneys don’t work properly, …… and you lose your ability to ….. - results in ….
Waste substances build up in the blood
Control the levels of ions and water in your body
Death
57
People with kidney failure are kept alive by having ….. where …..
OR they can have a ……
Dialysis treatment
Machines do the job of the kidneys
Kidney transplant
58
Dialysis has to be done …… to keep concentrations of ….. in the blood at normal levels and to remove ….
Regularly
Dissolved substances
Waste substances
59
In a dialysis machine, the person’s blood flows between …. Surrounded by ….. - the membranes are permeable to things like …. But not to …..
Partially permeable membranes
Dialysis fluid
Ions and waste substances
Big molecules like proteins
60
Dialysis fluid has the same concentration of ……. As …. - this means that ……
Dissolved ions and glucose
Healthy blood
Useful dissolved ions and glucose won’t be lost from the blood during dialysis
61
In dialysis only …… diffuse across the barrier
Waste substances (eg urea) and excess ions and water
62
Patients with kidney failure have to have a dialysis session ….. - each session takes ….
Three times a week
3-4 hours
63
Dialysis can cause …..
Blood clots or infections
64
Dialysis is not a ….. and is ….. for the NHS
Pleasant experience
Expensive
65
Dialysis can …… until a ….. is found
Buy a patient with kidney failure valuable time
Donor organ
66
The only cure for kidney failure is ….
A kidney transplant
67
Healthy kidneys are usually transplanted from people who …. - and is on the ……
Have died suddenly
Organ donor register
68
69
Kidneys can also be transplanted from people who are …. But there is a …..
Still alive
Small risk to the person donating the kidney
70
There is also a risk that the donor kidney can be ….. - patient is treated with ….. to prevent this but it can still happen
Rejected by the patients immune system
Immunosuppressant drugs
71
Transplants are ….. than dialysis and are more ….. due to amount of hours patients spend on dialysis but there is a …..
Cheaper (in the long run)
Convenient
Long waiting list for kidneys
72
In men, the main reproductive hormone is …. - produced but the ….. and stimulates …..
Testosterone
Testes
Sperm production
73
In women the main reproductive hormone is …. - produced by the …. And is involved in ….
Oestrogen
Ovaries
Menstrual cycle
74
Stage 1 of menstrual cycle
Day 1 - menstruation starts - uterus lining breaks down for about 4 days
75
Stage 2 of menstrual cycle
Uterus lining builds up again from day 4 - 14 into a thick spongy layer full of blood vessels ready to receive a fertilised egg
76
Stage 3 of menstrual cycle
An egg develops and is released from ovary at day 14 - called ovulation
77
Stage 4 of menstrual cycle
The wall is maintained for about 14 days until day 28 - if no fertilised egg has landed on the uterus wall by day 28 then the spongy lining starts to break down and cycle starts again
78
FSH (….)
Produced in the ….
Causes …..
Stimulates …..
Follicle stimulating hormone
Pituitary gland
An egg to mature in one of the ovaries in a follicle
The ovaries to produce oestrogen
79
Oestrogen
Produced in the ….
Causes …
Stimulates release of ….
Inhibits release of ….
Ovaries
The lining of uterus to grow
LH (causes release of egg)
FSH
80
LH (…)
Produced by ….
Stimulates the ….
Luteinising Hormone
Pituitary gland
Release of an egg at day 14 (ovulation)
81
Progesterone
Produced in …. by ….
It ……
When level of progesterone falls, ….
Inhibits release of ….
Ovaries
Remains of follicles after ovulation
Maintains lining of uterus during second half of cycle
Lining breaks down
LH + FSH
82
Oestrogen can be used to …… so it can be used as a contraception
Prevent the release of an egg
83
If oestrogen is taken every day to keep its level ….., it inhibits …. and after a while …..
Permanently high
FSH production
Egg development and production stops
84
Progesterone also reduced fertility eg by stimulating the production of … which prevents …..
Thick mucus
Any sperm getting through and reaching the egg
85
The pill is an ….. containing ….. (known as the ….)
Oral contraceptive
Oestrogen
Progesterone
Combines oral contraceptive pill
86
The pill is over …..% effective at preventing pregnancy but it can cause side effects like ….. and doesn’t protect against ….
99
Headaches and nausea
Sexually transmitted diseases
87
Progesterone only pill has ….. and is just as ….
Fewer side effects
Effective
88
Contraceptive patch has hormones …….
Each patch lasts ….
Oestrogen and progesterone
One week
89
Contraceptive implant - in …..
Releases continuous amount of ….. which stops the ovaries …., makes it hard for …… and stops any fertilised egg from ……
Can last for …..
Arm
Progesterone
Releasing eggs
Sperm to swim to egg
Implanting in the uterus
3 years
90
Contraceptive injection contains ….
Each dose lasts for …
Progesterone
2-3 months
91
An IUD is a ….. inserted into the uterus to …..
Plastic IUDs release …..
Copper IUDs prevent ….
T-shaped device
Kill sperm and prevent implantation of fertilised egg
Progesterone
The sperm surviving in uterus
92
Condoms are the only form of contraception that ….
Will protect against STDs
93
A diaphragm is a …… to form a barrier - must be used with a …..
Shallow plastic cup that fits over the cervix
Spermicide to disable/kill the sperm
94
Sterilisation involves the …. In a female or the …… in a male - this is a …. Procedure but there is a very small chance that …..
Cutting or tying the fallopian tubes
Sperm duct
Permanent
The tubes can rejoin
95
….. is only way to be completely sure the sperm and egg don’t meet
Abstinence
96
Hormones can be used to …..
Increase fertility
97
Some women have levels of … that are too low to cause the eggs to mature - this means …..
so the hormones …… can be given to women as a fertility drug to ….
FSH
no eggs are released and woman can’t get pregnant
FSH and LH
Stimulate ovulation
98
Using hormones to increase fertility cons = 2x
It doesn’t always work - doing multiple times can be expensive
Too many eggs stimulated resulting in unexpected multiple pregnancies (twins, triplets etc)
99
IVF involves the ….. and …. in a lab using the man’s sperm
Collection of eggs from the woman’s ovaries
Fertilising them
100
IVF treatment can also involve ICSI (…..) where the …..
Intra-Cytoplasmic Sperm Injection
Sperm is injected directly into an egg
101
Fertilised eggs are then ….. in a …
Grown into embryos
Laboratory incubator
102
Before egg collection, ….. are given to stimulate ….
FSH + LH
Several eggs to mature
103
Downsides to IVF 3x
- multiple births - more risky for the mother and babies (higher risk of stillbirth/miscarriage)
- success rate of IVF is low - stressful + often upsetting especially if multiple failures
- emotionally stressful + physically stressful for women - some have strong reaction to hormones eg abdominal pain, vomiting, dehydration
104
Advances in tech to improve IVF
- improved microscope techniques have improved success rate of IVF
- specialised micro tools developed to use on eggs and sperm under microscope - also used for genetic testing
- development of Timelapse imaging shows growth of embryos continuously monitored to identify those who are more likely to result in successful pregnancy
105
People against IVF because…
Process often results in unused embryos that are eventually destroyed - people think this is unethical as each embryo is a potential human life
Genetic testing of embryos before implantation raises ethical issues as some people think it could lead to selection of preferred characteristics eg gender
106
Adrenaline is released by the …..
Adrenal glands
107
Adrenaline is released in response to ….. - brain detects it and sends ….. to adrenal glands which …..
Stressful or scary situations
Nervous impulses
Respond by secreting adrenaline
108
Adrenaline gets body ready for …. By triggering mechanisms that …….
Fight or flight
Increase supply of oxygen and glucose to cells in brain + muscles eg increase heart rate
109
Thyroxine plays an important role in …. - the speed at which …..
Thyroxine is also important for …..
Regulating basal metabolic rate
Chemical reactions in the body occur while the body is at rest
Loads of processes in the body such as stimulating protein synthesis for growth and development
110
Thyroxine is released in response to ….. which is release from the ….
Thyroid stimulating hormone (TSH)
Pituitary gland
111
Auxin is a ….. that controls ……
Plant hormone
Growth near the tips of shoots and roots
112
Auxin controls growth of plant in response to ….. (…..) and …. (….)
Light
Phototropism
Gravity
Gravitropism/geotropism
113
Auxin is produced in the …. and moves … to stimulate the ……which occurs in the cells just behind the tips
Tips
Backwards
Cell elongation (enlargement) process
114
If the tip of a shoot is removed, ……
No auxin is available and the shoot may stop growing
115
Extra auxin ….. in the shoot but …… in the root to produce the desired result
Promotes growth
Inhibits growth
116
When a shoot tip is exposed to light, more auxin accumulates on the side that …… than the side that is ….
So cells grow (elongate) …. so the shoot ….
Is in the shade
Is in the light
Faster on the shaded side
Bends towards the light
117
When a shoot is growing sideways, gravity produces ……. With more auxin on the ….. - causing the ……. Which bends the shoot …..
An unequal distribution of auxin in the tip
Lower side
Lower side to grow faster
Upwards
118
A root growing sideways has more auxin on its ….. - but in a root auxin …. Meaning cells on the …. Elongate faster and the root bends ….
Lower side
Inhibits growth
Top
Downwards
119
Auxins are helpful for …….. for example 3x
Controlling plant growth
- Killing broad leaved weeds by disrupting their normal growth patterns while leaving grass and crops unharmed
- Growing from cuttings with rooting powder - to produce clones of a good plant fast
- growing cells in tissue culture - auxin added to growth medium to stimulate cell division to form roots and shoots
120
Gibberellin stimulates 3x
Seed germination
Stem growth
Flowering
121
Uses of gibberellin x3
- controlling dormancy so they germinate at times of year they wouldn’t normally
- inducing flowering - no need for change in environment to cause flowering - also can increase size of flowers
- growing larger fruit - seedless varieties of fruit often do not grow as large as seeded fruit but they will grow this large if gibberellin used
122
Ethene gas is produced by ….. which influences the growth of the plant by controlling …. - also stimulates ….. that cause ….
Aging parts of a plant
Cell division
Enzymes
Fruit to ripen
123
Commercially ethene is used to ….. while they are ….. or during ….
Speed up ripening of fruits
Still on the plant
Transportation
124
Ripening can be delayed while fruit is in storage by …… or reduce amount of …..
Also some chemicals that can be used that ….
Adding chemicals that block ethene’s effect on the fruit
Ethene the fruit can produce
React with ethene to remove it from the air
