Paper 2: Homeostasis and Response Flashcards
1
Q
What is homeostasis
A
The constant regulation of an internal environment
2
Q
Why is homeostasis needed
A
To maintain internal environments for metabolism and to respond in fluctuations in internal and external environment
3
Q
Name examples of what is regulated in body
A
Blood glucose levels, body temperature, CO2 levels aswell as water levels
4
Q
What are the 2 systems that control homeostasis called and what type of systems are they
A
Nervous system and endocrine system
Automatic control systems
5
Q
What is a synapse
A
The gap where 2 neurons meet
6
Q
How are signals passed through the synapse
A
Through chemical neurotransmitters
7
Q
Why are neurotransmitters used across the synapse
A
Electrical signal cannot pass over the gap
8
Q
How is signals passed through neurons
A
- Electrical signal arrives at the end of a neuron and cause certain neurotransmitters to pass across the synapse
- These neurotransmitters bind to specific receptors on the other neuron, these receptors only produce an electrical signal if they receive a neurotransmitter
9
Q
What is a stimuli
A
A change in the environment
10
Q
Describe the full nervous system response to a stimuli
A
Receptors detect a stimuli and send an electrical signal along the sensory neuron.
Sensory neuron passes this signal to the CNS. Relay neurons then pass this signal from the spine to the brain where a response towards the stimuli is calculated.
The CNS sends this response along a motor neuron as an electrical signal, this reaches an effector which carries out the response
11
Q
2 Examples of a receptor
A
Rods and cones in the eye
Skin cell
12
Q
2 Examples of effectors
A
Muscle
Gland
13
Q
Label a neuron
A
Cell membrane
Cytoplasm
Nucleus
Dendrite
Axon
Axon terminal
Myliemn Sheath
14
Q
What is the axon
A
Long body of the nerve cell which passes electrical signals along it
15
Q
What is the mylen sheath
A
Fatty cells that insulate the electrical signals passed through the axon
16
Q
What is the dendrite purpose
A
Connect to other neurons to from a network
17
Q
Label the endocrine system
A
Pituitary gland
Thyroid gland
Thymus
Adrenal gland
Pancreas
Testis
Ovaries
18
Q
What is a reflex
A
A fast and automatic response
19
Q
What is a reflex arc
A
The pathway which carries information about a reflex action
20
Q
How does a reflex work
A
Stimulus is detected by receptor cell and electrical impulse is sent through sensory neurons
Relay neurons pass this impulse into the CNS (unconisous part of brain)
A response is automatically sent along the motor neurons to the effector cells
21
Q
Differences between responses of nervous and hormonal
A
Hormone Nervous
Slow Fast
General area Specific area
Long duration Short duration
22
Q
What are hormones
A
Chemical messengers that active a response
23
Q
What hormones does the pituitary gland do in the menstrual cycle
A
FSH and LH
24
Q
How does the pituitary gland act as a master gland
A
It controls the release of other hormones in the body by other glands
25
Is diabetes 1 or 2 for fat people
2
26
What is type 1 diabetes
When the persons pancreas does not produce enough insulin to control blood sugar so blood sugar raises
27
How to treat type 1 diabetes
Insulin injections
28
What is type 2 diabetes
The effector cells no longer respond to the insulin produced by the pancreas
29
How to treat type 2 diabetes
Make lifestyle choices like reducing on glucose in diet
30
Why is testosterone needed
Causes the production of sperm
31
Function of pancreas
Control blood sugar levels
32
What type of loop is the blood glucose regulation loop
Negative feedback
33
How does the body respond to low glucose level
Pancreas releases glucagon hormone
This causes cells to release glucose
Liver and muscle cells convert stored glycogen into glucose
34
How does the body respond to high glucose levels
Pancreas releases insulin that causes cells to absorb glucose
Liver and muscles convert the glucose into stored glycogen
35
What is ovulation and which hormone causes it
Egg is released from the ovaries into the uterus each month
Oestrogen
36
What is menstruation
Lining of the uterus being shed when the woman is not pregnant
37
Where is FSH produced and what does it cause and how does it effect other hormones
Pituitary gland
An egg to develop in an ovary
Stimulates oestrogen production
38
Where is oestrogen produced and what does it cause and how does it effect other hormones
Ovaries
Causes ovulation and the lining of the uterus to build up
Stimulates LH production limits FSH
39
Where is LH produced and what does it cause and how does it effect other hormones
Pituitary gland
Causes ovulation
Stimulates production of progesterone (indirectly)
40
Where is progesterone produced and what does it cause and how does it effect other hormones
Ovaries
Uterus lining maintains
Inhibits production of LH
41
How does the pill work
Inhibits FSH production
42
How does a contraceptive injection work
Contains progesterone to limit amount of eggs put into uterus
43
How do condoms work
Sperm cant reach egg to fertilize it
44
How do Intrauterine devices work
Attacthed to uterus, releases hormones, prevents implantation by sperm
45
How do spermicide agents work
Kill sperm
46
How does abstaining from intercourse work
No sperm can fertilise egg
47
How does surgery work for not getting pregants
Tube that passes sperm from testies to penis are sealed
fallopian tubes are sealed for females, ovulation can't occur
48
How can infertility be solved
Injecting the woman with FSH and LH in a fertility clinic
IVF
49
What are the stages of IVF
1. Woman is given FSH and LH to stimulate ovulation
2. Eggs are fertilized in a lab with a man's sperm
3. Eggs develop into embryos
4. Blasocyst is inserted into the woman's uterus
5. Pregnancy continues as usual
50
Negative of IVF
Stressful and emotional
Success rates are low
Higher chance of multiple births
51
What does adrenaline do
Increase heart rate and breathing rate, vasodilation, supply brain and muscles with more oxygen
52
What is thyroxine produced by
Thyroid gland
53
What does thyroxine do and how
Stimulates metabolism by controlling how quickly oxygen and food react
54
2 negative feedback loops in body
Blood sugar
Thyroxine production
55
Thyroxine production flow chart
Hypothamamus
l
Thyroxine Releasing Hormone TRH
l
Pituitary Gland
l
Thyroxine Stimulating Hormone TSH
l
Thyroid Gland
l
Thyroxine
56
What if the metabolism becomes too low
Hypothalamus is stimulated
57
What if the metabolism becomes too high
Hypothalamus is inhibited
58
What is the steps involved in measuring reaction time
1. One person sits on a chair upright and places their forearm on the table so their hands hang over the end of the table
2. The other person places the 0cm on the ruler between the person's thumb and index finger, with their thumb and index finger as far apart as possible
3. Drop the ruler and the partner catches the ruler
4. Read where their thumb is to how much cm the ruler fell before they caught that
5. Repeat
6. Swap roles
7. Convert cm into reaction time
59
What does the cerebral cortex do
Consciousness, intelligence, language and memory
60
What does the medulla do
Controls unconscious functions like heartbeat
61
What does the cerebellum do
Muscle coordination and balance
62
How can you studying the brain by looking at people who have suffered brain damage
By looking at how the person behaves with that injury we can see what the part of their brain that was injured was necessary for
63
How do you study the brain by electrically stimulating it
Electrodes inserted into brain tissue, this stimulates part of the brain, the response is observed to see what this part of the brain's role is
64
How do you study the brain by MRI scanning
By scanning a brain using mri while a person is doing a specifc action we can see which part of the brain allows that action to happen
65
Label eye from left to right
Cornea, sclera, iris, pupil, ciliarly muscle, suspension ligament, choriod, retina, fovea, optic nerve
66
Retina function
Contains rods and cones for detecting light
67
Optic nerve
Contains neurons that pass on impulses between the eye and brain
68
Sclera
Protects the eye
69
Cornea
Focuses light on the retina
70
Iris
Made up of circular and radial muscles which can dilate the pupil
71
Cililary muscles
Alter the shape of the lens
72
Suspensory ligaments
Attach cillary muscles to the eye
73
When the light intensity is high how does the pupil decrease
Radial muscles relax
circular muscles contract
74
How does the pupil dilate in low light
Radial muscles contract
Circular muscles relax
75
To focus near objects the lens in the eye needs to become _____er and how
Thicker, to make the light refract more
Thick is done by the contraction of the cilliary muscles CONVEX
76
To focus far objects the lens in the eye needs to become _____er and how
Thinner, to make the light refract more
Thin is done by the relaxion of the cilliary muscles CONCAVE
77
2 types of vision defects
Myopia
Hyperopia
78
What can't you focus on with myopia
Long distance things
79
What causes myopia
When the eye is elongated or the lens is too fat
Light focuses before reaching retina
80
How to solve myopia
Concave lense
81
What is hyperopia
Can't focus on near objects
82
Causes of hyperopia
Eye is too short, or lack of elasticity in the eye
Light focuses after the retina
83
What solves hyperopia
A convex lens
84
What is body temperture
37 degrees
85
Where is the thermoregulatory centre
Hypothalamus
86
Why is the body at 37 degrees
So enzymes can work optimally
87
3 responses that happen when we become too hot
Vasodilation- Veins closer to surface where they lose heat
Hairs lie flat- So heat is not trapped under them
Sweating- When sweat evaporates heat is lost
88
3 responses that happen when we become too cold
Vasoconstriction- Veins away from surface where thy lose heat
Hairs stand on end- Insulating air around th body caused by erector cells
Shivering- Muscles contract rapidly producing heat
89
What is the control of water and minerals in the body called
Osmoregulation
90
Why is it important that water levels ouside cells are maintained
So they don't become turgid or plasmitised
91
If the concentration of water outside the cell is higher what type of solution is it and what happens to the cell
Hypotonic
Turgid/bursts due to osmosis
92
If the concentration of water outside the cell is lower what type of solution is it and what happens to the cell
Hypertonic
Plasmitised due to osmosis
93
How is water lost in the body
Sweating, breathing
94
How do we osmoregulate if we don't have enough water in the body
Excess water and minerals are removed from urine by kidneys
95
How does the body store excess protiens and amino acids
It can't
96
Steps the body does to get rid of excess protien (amino acids)
1. Damination of excess amino acids forms ammonia
2. Ammonia is converted to urea as it is toxic
3. Liver cells release urea into blood stream
4. Blood is filtered at kidneys and urea is filtered out
97
How is blood transported to the kidneys
Renal artery
98
What is it called when nutrients are absorbed back into the body after entering the nephron
Selective reabsorbtion
99
Which substances do not go into the nephron into the first place
Blood cells and large proteins because they are too big
100
Which substances are selectively reabsorbed
Glucose, salt ions, some water
101
What happens to the substances not selectively reabsorbed
Waste products like urea are dissolved in water to form urine, transported along the ureta and stored in bladder
102
How do you treat kidney failure 2 ways
Organ transplant
Kidney dialysis
103
How does a kidney dialysis machine work
1. Unfiltered blood taken from body
2. Blood mixed with anti-coagulants
3. The blood is pumped into dialysis which separates patients blood from the fluid of the dialysis machine using a partially permeable membrane
4. The blood flows in opposite direction to dialysis machine to maintain concentration gradient
5. Glucose and salt ions move from the dialysis fluid into the blood, urea moves from the blood into the fluid by diffusion
6. Blood is pumped back into body
104
Advantages of kidney dialysis
Person with kidney failure can still be healthy
Reduces urea levels in blood
Maintains glucose levels
Allows ions and water to stay in blood
105
Disadvantages of kidney dialysis
Expensive
Restrictions on diet
time consuming
Only effective for a limited amount of time
Have to be constantly monitored
106
How does the body control the concentration of water in blood apart from kidneys
Hypothalamus gets the pituitary gland to produce ADH
107
How to decrease likelihood of an organ being rejected
Match the antigens of the donor with that of the reciever
Immuno-supprestant drugs
108
Advantages of kidney transplant
Patients lead a normal lifestyle
Cheaper than dialysis overall
109
Disadvantaged of kidney transplant
Shortage of organ donors
Rejection
Infection
Risks, bleeding
110
What is a positive tropism
A plant's movement towards something
111
What is a negative tropism
A plant's movement away from something
112
What is phototropism
A plant's response to light
113
How do plants grow toward light
Auxin hormones move to the side away from light
Auxin cause cells to be made rapidly on the shaded side, bending the plant towards light
114
How do plants grow up against gravity
Auxins move to the lower side, causing that to grow more, bending the shoot up
115
How do roots grow down
Auxins move to the bottom and INHIBIT the plant's growth at the bottom causing the top to grow more, bending the plant down
116
What does the gibberellin hormone do
Starts seed germination
117
What does ethene do in plants
Produced in plants as they age
Controlls cell division
118
Practical on the effect of light on the growth of newly germinated seedlings
Germinating seeds:
1. Cotton wool in 3 petri dishes
2. 10ml of water to be added
3. 10 seeds in each petri dish
4. Place seeds in warm place to germinate
5. Add water if wool becomes dry
1. Make sure there is now equal seeds in each petri dish, with non-germinated seeds removed
2. Place 1 in a dark place like a cuboard, place one in partial light, place one on a windowsill with alot of light
3. Measure height of seedlings every day for 5 days, measure their full height
4. Compare heights at the end
