homeostasis and response Flashcards
(138 cards)
1
Q
what is the average normal body temperature
A
37 degrees
2
Q
what are the three main components in automatic control systems
A
- receptor
- coordinate centre
- effector
3
Q
what does the receptor do
negative feedback
A
detects a change
level is too high or too low
eg. a rise in temperature, high or low
4
Q
what does the coordinate centre do?
in negative feedback
A
- receives and processes information
- organises a response
5
Q
what do the effectors do
negative feedback
A
carries out the response which counter acts the change
restores the optimum level
6
Q
what problems could effectors create and how is it solved?
A
- effectors keep producing responses told by the coordinate centre
- effectors could change the level too much taking it away from the ideal (e.g temp)
- it is solved by the receptor recognising this and teh process happens again
7
Q
what is a stimuli
A
changes in the enviroment
8
Q
how are multicellular organisms and single- celled organisms different when responding to stimuli
A
single celled - can just respond to the enviroment
multicellular - cells have to communicate with each other first
9
Q
what are the different parts of the nervous system
A
- central nervous system ( CNS) which consists of teh brain and spinal cord
- sensory neurons
- motor neurones
- effectors
10
Q
what do sensory neurones do?
A
carry information as electrical impulses from the receptors to the CNS
11
Q
what is negtive feedback
(receptor)
A
negative feedback counteracts changes
if stimuls level is too high then it will decrease it through receptor,coordinate centre and effector
if stimulus is too low then it will increase it through receptor, coordinate centre and effector
eg temp
12
Q
Why does the body need to maintain optimal conditions?
A
For optimal enzyme action and cell function
13
Q
in what order are signals passed along the control system?
A
receptor -> coordinate centre -> effector
14
Q
Where are the coordination centres located in the body?
A
- Spinal cord
- Brain
15
Q
Name the two types of effectors and state what they do.
A
muscles - contract
glands - secrete hormones
16
Q
Is the nervous system or the endocrine system faster acting?
A
nervous system
17
Q
why is nervous system faster than the endocrine system?
A
the enrvous systems relies on electrical impulses that can travel very quickly
18
Q
Which system acts more generally across the body, the nervous system or the endocrine system?
A
endocrine
invloves releasing hormones into blood stream that get spread across the body
19
Q
Homeostasis relies on a system of __________ __________, meaning whenever the levels of something get too high they’re brought back down, and whenever the levels of something get too low, they’re brought back up.
A
negitive feedback
20
Q
what si teh structure of nerve cells
A
- long
- thin
- branched connections
21
Q
what is a synapse
A
the gap between two neurones
22
Q
how does a synapse work
A
- gap between two nuerones is a synapse
- the nerve signal is transferred by chemicals which diffuse across the gap
- the chemicals then set off a new electrical signal in the next neurone
23
Q
what does the central nervous system do?
A
- takes in sensory information
- decides what is meant to be done
- send orders to teh rest of the body
24
Q
what makes up the central nervous system?
A
- spinal chord
- brain
25
how does the central nervus system recieve information about whats happening in the body?
through sensory neurones which gets its information through receptors that pick up a stimuli
26
how does the central nervous system send impulses back out to the body?
through motor neurones which the goes to the effectors
27
what is the order of teh central nervous system coordinating a response to a stimuli?
stimuli -> receptor -> sensory neurone --> central nervous system -> motor nuerone -> effector -> response
28
what are reflexes
rapid,automatic responses to certain stimuli that dont involve the conscious part of the brain
29
why are reflexes good?
they can reduce the chances of being injured
30
what are example of reflexes
if someone shines a light into your eye you eye automatically gets smaller so less light gets into the eye
31
what is the definition of a reflex arc
the passage of information from receptor to effector is a reflex arc
32
describe the pathway of the reflex arc from the stimulus to the effector
- receptors detect stimulus
- impulse travels along sensory neuron
- goes to CNS
- impulse reaches synapse between sensory nuerone + relay nuerone
- impulse reaches synapse between relay + motor nuerone
- impulse travels down motor nuerone until it reaches effector
33
What passes along nerve cells?
electrical impulses
34
What is the gap between two neurones called?
synapse
35
What is released across a synapse?
chemicals
36
What is the role of a receptor?
to detect a stimulus
37
What is the role of a motor neurone?
To transfer a signal from the CNS to an effector
38
What is the role of a relay neurone?
o transfer a signal from a sensory neurone to a motor neurone
39
what are hormones
they are chemical moelcules that are released directly into the blood
40
what do motor nuerones dp
carries electrical impulses from the CNS to the effectors
41
what is released along a synapse
chemicals
42
what are examples of different types of receptors
sound,taste,touch
43
what does homeostasis do?
it regulates the conditions inside your body in response to internal and external change
44
what does the receptor do
nervous system
detects a stimuli
45
what do effectors do
nervous system
carries out the response
46
what are examples of internal conditions
Blood Ph
blood glucose concentration
47
what system does homeostasis rely on
negitive feedback
48
what do hormones do
they control things in organs can cells that need constant adjustment
49
what are target organs
the particular organs with particular cells that hormones can affect
50
do hormones have long or short lasting effects
they tend to have long lasting effects
51
what are the different endocrine Glands
pituitary glands
thyroid
ovaries (females)
adrenal gland
pancreas
testes (male only)
52
what does the pituitary gland do
produces many hormones that regulate the body
53
why is the pituitary gland called the master gland
the hormones it releases can act on other glands directing them to release hormones that can bring change
54
what does the thyroid do
produces thyroxine
- thyroxine is involved in regulating things like the rate of metabolism, heart rate and temperature
55
what does the adrenal gland do
produces adrenaline
used to prepare the body for 'fight or flight'
56
what do the ovaries do
produce oestrogen which is involved in the menstrual cycle
57
what does the pancreas do
produces insulin
used to regulate the blood glucose level
58
what does the testes do?
produces testosterone which controls puberty and sperm production
59
what are the differences in nerves and hormones
nerves: Fast action, act for short time, act on a very precise area
hormones: slower action, act for long time,act in a more general way
60
why do our cells need a decent amount of glucose
so they have a constant supply of glucose that they can use for respiration
61
What happens if blood glucose concentrations fall too low?
there wont be enough glucose for tissue cells to respire
62
after eating does our blood glucose levels increase or decrease
increase
63
Which organ detects changes in blood glucose concentration?
the pancreas
64
what is added if glucose levels are too high
insulin
65
what is added if glucose levels are too low
glucagon
66
what happens if blood glucose levels are too high
| step by step
- blood with too much glucose enters
- insulin is secreted by pancreas into blood stream
- insulin will bind to receptors in liver and muscle cells and tell the tells to take in the glucose that is floating around in blood
- for long term storage the liver and muscle cells turn glucose into glycogen
- blood glucose concentration is reduced
67
What are the two main organs that insulin stimulates to absorb glucose from the blood?
liver
muscles
68
When glucose is absorbed by the liver for long term storage, what molecule is it converted to?
glycogen
69
what is the difference between glucagon and glycogen
glucagon is a hormone
glycogen is a large molecule made up of lots of glucose molecules
70
what happens when blood glucose levels are too low
| steps
- blood with little glucose enters
- glucagon is secreted by pancreas
- glucagon binds to cells in the liver and takes the glycogen and break it down into glucose
- glucose is then released by the liver
- blood glucose levels are then increased
71
what is diabetes
a condition that affects your ability to control your blood sugar levels
71
what is type 1 diabetes
where the pancreas produces little or no insulin
71
how is type 1 diabetes managed
People with type 1 diabetes have to inject insulin after meals because they don't produce it themselves. They also have to monitor their diets (for example not have too much sugary food), and also exercise regularly.
71
Is type 1 diabetes a temporary, or lifelong condition?
life long
71
what is type 2 diabetes
when a person becomes resistant to their own insulin
( the body still produces it but the tissues become resistant)
71
what can increase your chance of developing type 2 diabetes
being over weight
72
how can diabetes type 2 be controlled
by eating a carbohydrate controlled diet and getting regular exercise
72
Which age group is more likely to get type 2 diabetes
older people
72
what happens in puberty
your body starts releasing set hormones that trigger secondary sexual characteristics like facial hair in men
73
how many stages does the menstrual cycle have
4 stages
74
what happens in stage one of the menstrual cycle
day1 - menstruation starts + the uterus lining breaks down for about four days
75
what happens in stage two of the menstrual cycle
day 4 -14 the uterus lining builds up again
- into a thick spongy layer full of blood vessels - ready to receive a fertilised egg
76
what happens in stage three of the menstrual cycle
an egg develops and is released - day 14
this is called ovulation
77
what happens in stage four of the menstrual cycle
wall is then maintained until day 28
if no fertilised egg lands on uterus wall by day 28 the spongy lining breaks down and cycle starts again.
78
what are the four hormones that controls the menstrual cycle
FSH - follicle stimulating hormone
oestrogen
LH - luteinising hormone
progesterone
79
How long does the average menstrual cycle last?
28 days
80
where is FSH produced
the pituitary gland
81
what does FSH do
- causes an egg to mature in one of the ovaries in a structure called a follicle
- stimulates the ovaries to produce oestrogen
82
where is oestrogen produced
in the ovaries
83
what does oestrogen do
- causes lining of the uterus to grow
- stimulates the release of LH which causes the release of and egg
- inhibits (stops) the release of FSH
84
where is LH produced
in the pituitary gland
85
what does LH do
stimulate sthe release of an egg
86
where is progesterone produced
in the ovaries by the remains of a follicle after ovulation
87
what does progesterone do?
- maintains the lining of uterus in second half of cycle - when progesterone levels fall lining breaks down
- it inhibits (stops) the release of LH and FSH
88
what hormones can be used to prevent fertility
oestrogen
progesterone
89
how does oestrogen reduce fertility
- if it is taken every day the levels will be permanently high
- oestrogen inhibits the production of FSH and after a while egg development will stop
90
how does progesterone reduce fertility
it stimulates the production of thick mucus which prevents sperm getting through and reaching the egg
91
what is the pill
a oral contraceptive with produces oestrogen and progesterone
92
what are the positives and negatives of the pill
its over 99% effective
can cause side effects like headaches and nausea and it doesn't protect against STD
93
what are examples of contraceptives that contain hormones
contraceptive patch
pill
implant
injection
IUD
94
what is a contraceptive patch
patch worn on skin
contains oestrogen and progesterone
lasts one week
95
what is the contraceptive implant
inserted under the skin of the arm
releases continuous amounts of progesterone
it can last for up to 3 years
96
what is a contraceptive injection
injection
contain progesterone
lasts 2-3 months
97
what is IUD
T-shaped device inserted into uterus to kill sperm and stop ferilisation
98
what are the two different types of IUD
plastic - release progesterone
copper- prevents sperm surviving in the uterus
99
what are condoms
worn over the penis to stop sperm entering vagina
female condoms worn inside the vagina
only contraception that stops STD
100
what is a diaphragm
a shallow plastic cup that fits over the cervix to form a barrier
- has to be used with spermicide
101
what is spermicide
a substance that disables or kills sperm
- can be used alone as a form of contraception but not as effective
102
what is sterilisation
cutting or typing Fallopian tubes - female
sperm duct - male
these are permanent
103
what are natural methods of contraception
finding out when when in menstrual cycle women is most fertile and avoid intercourse on those days
- not very effective
104
what is the only way to completely make sure that the sperm and egg dont meet
abstinence
105
what is the cervix
entrance to the uterus
106
how can hormones be used to increase fertility
FSH and LH can be given to stimulate ovulation
107
what is a pro of using hormones to increase fertility
it helps women get pregnant when previously they couldn't
108
what are the cons of using hormones to increase fertility
it doesn't always work
expensive
too many eggs could be stimulated
109
what is IVF
it involves collecting eggs from the women ovaries and fertilising them in a lab using the mans sperm
110
what does IVF stand for
in Vitro fertilisation
111
what are the stages of IVF
- LH and FSH given to mature and release egg
- sperm collected from males and eggs collected from female
- sperm fertilises egg
- the fertilised eggs are left to grow in laboratory incubator
- once embryos are large enough they are transferred to women uterus so it can develop into a fetus
112
what is the benefit of IVF
it can give the couple a child
113
what are the disadvantages of IVF
- mutiple births can happen if more then one embryo grows into a baby - higher risk of miscarriage
- success rate of IVF is slow
- physically stressful - abdominal pain,vomiting
114
what is Intra-Cytoplasmic Sperm Injection (ICSI)
Sperm is injected into an egg cell with a tiny needle
115
Why are embryos kept in an incubator whilst in the laboratory?
To provide the optimum temperature for enzymes and thus cell growth
116
why are some people against IVF?
creates 'designer babies' - parents choosing an embryo with preferred characteristics
unused embryos are usually destroyed - destroying potential human life
117
what advances in technology have improved IVF
- advances in microscope techniques
- micro tools to remove single cells to make sure embryo is healthy
- time lapse imaging - embryo can be constantly monitored
118
where are the adrenal glands
just above the kidney
119
why is adrenaline released
in reponse to scary or stressful situation
120
what does adrenaline do?
- increase heart rate
- increase blood pressure
- increase blood flow to muscles
- increases blood sugar levels
121
Adrenaline causes the conversion of which substances?
Glycogen ➔ glucose
122
where is the thyroid gland
in the neck
123
Which organ is thyroxine released from?
thyroid gland
124
What is the main role of thyroxine?
to increase your metabolic rate ( the speed at which chemical reactions occur in the body while it is at rest)
125
where is TSH released from
the pituitary gland
126
thyroxine is produced in response to......
TSH ( thyroid stimulating hormone)
127
Does thyroxine stimulate or inhibit the pituitary gland from releasing TSH?
inhibit
128
Does TSH stimulate or inhibit the thyroid gland from releasing thyroxine?
stimulate
129
Describe what will happen when thyroxine levels are too high.
Thyroxine inhibits the pituitary gland from releasing TSH.
Less TSH means the thyroid gland won't release as much thyroxine.
Thyroxine levels fall back to normal over time.
130
is glucose a carbohydrate,lipid or protein
carbohydrate
131
describe how basal metabolic rate is increased
regular exercise especially strength training, as muscles burns more calories than fat
increase in adrenaline produced by the adrenaiine gland
