Topic 5 Flashcards
1
Q
What does homeostasis mean
A
Maintaining a stable internal envitonment in response to changes both internal and external conditions
2
Q
Examples of automatic control systems
A
Nervous and hormaonal communcation systems
3
Q
What are the three main components in all automatic control systems
A
Receptors, cooridination centres and effectors
4
Q
What is the mechanism caled which keep your internal environment stable in your automatic control system
A
A negative feedback loop
5
Q
When does your body use a negative feedback loop
A
When the level of something gets too high or too low
6
Q
What happens in a negative feedback loop when something is to high
A
1,receptors detects a stimulus level is too high
2,the coordinate centre recieves and processes the informaton, then organises a response
3,effector produces a respone, which counteracts the change and restores the optimum level decreases
7
Q
What does the nervous system mean
A
That humans can react to their surroundings and cordinate their behaviour
8
Q
What makes up the nervous system
A
Central nervous system, sensory nueros, motor nuerons, effectors
9
Q
What is the central nervous system
A
It is a coordination centre. In mammals the cns is connected to the body by sensory nuerons and motor nuerons which carry electrical impulses from the CNS to the effetors
10
Q
What are receptors
A
The cells that detect stimuli. There are many types of receptors such as taste and can form larger, complex organs
11
Q
What are effectors
A
They respond to nervous impusles and bring about change, ,uscles and glands are known as effectors. Muscles contract where as glands secrete hormones
12
Q
What is a synapse
A
The connection between two neurones where the nerve signal is transfered by chemcals which diffuse across the gap. These chemicals then set of a new electrical signal in the next neuron
13
Q
What are reflexes
A
Rapid automatic responses to certain stimuli that don’t involve the conscious part of the brain.
14
Q
What is a reflex arc
A
The passage of information in a reflex (from receptor to effector) that goes through the central nervous system
15
Q
What happens in a refelx arc through the CNS
A
The nuerons the reflex arc go through the spinal cord or through or the unconscious part of the brain. What a stimulus is detected by receptors, impulses are sent along the sensory nueron to relay a neuron in the CNS. When the impulses reach a synapse between the sensory neuron on and the relay neuron, theu trigger chemicals to be rleased. These chemicals cause impulses to be sent along the relay neuron. When the impulses reach a synapse between the relay neuron and the motor neuron the same thing happens. Chemcials relased and cause impulses to be sent along the motor nueron. The impulses then travel along the motor neuron to that effect.
16
Q
What is reaction time
A
The time it takes to respond to a stimulus
17
Q
What is the brian made up of
A
Billios of interconnected nuerons
18
Q
Cebral cortex
A
The outer part which is responsible for things like conciousness, inttellegence, memory and langauge.
19
Q
Cerebellum
A
Responsible for muscle coordination
20
Q
Medulla
A
Controls unconscious activities such as breathing
21
Q
Hypothalamus
A
Has many functions like linking nervous systems via the pitutary gland
22
Q
Pituitary gland
A
Produces many hormones that regulate body conditions.
23
Q
Studying patients with brain damage
A
The effect a patient has some drain damage can tell you a lot about what that part of the brain does
24
Q
Electrically stimulating the brain
A
By pushing A tiny electrode into the tissue and giving it a small zap of electricity and stimulates the brain electrically.
By observing what stimulating different parts of the brain does, it’s possible to get an idea of what those parts do
25
MRI scans
It is a big fancy tube like machine I can produce a very detailed picture of the brain structures. Scientists use it to find out what areas of the brain are active when people are doing things like listening to music
26
What symptoms can electrical stimulation help with
Electrical stimulation of the brain can help reduce muscle tremors cost by nervous system disorders like Parkinson's disease
27
Optic nerve
Carries impulses from the receptors on the retina to the brain
28
How does the eye adjust for different light
When light receptors in the eye detect a very bright light a reflex is triggered that makes the pupil smaller. The circular muscles in the eye was contract and the radial muscles relax. This reduces the amount of light that can enter the eye. The opposite process happens in dim light making the pupil wider
29
How does they eye look at near objects
The ciliary muscles contract which slackens the suspensory ligaments. The lens becomes fat which increases the amount of light which is affected
30
How does the eye look at the distance objects
The ciliary muscles relax which allows the suspensory ligaments to pull tights, this makes the landscaping so it reflects the light as a small amount
31
What happens to long siteness (hyperopia)
Long sighted people are unable to focus on the objects. This occurs when the lens is the wrong shape and doesn't reflect the light enough for the eyeball is too short, making the images of the new objects brought into focus behind the retina.
32
How to counter long sitedness
You can use glasses with a convex lens to connect this, the lens reflects the light rays so they focus on the retina.
33
What happens to shortsitesd people (myopia)
This occurs when the lens is in the wrong shape and reflects the light too much of the eyeball is too long. The images of distant objects are brought into focus in front of the retina
34
How can you counter shortsightedness
You can use glasses with a concave lens to correct it to that the light focuses on the retina
35
What are alternatives to wearing glasses
Contact lenses
Laser eye sergery
Replacement lense surgery
36
What happens in laser eye surgery
A laser can be used to vaporise tissue changing the shape of the cornea, slimming it down makes it less powerful I can improve short sight. Changing the shape so that it is more powerful will improve longsight
37
How does the brain control body temp
There is a thermoregulatory centre in the brain which contains receptors that are sensitive to temperature of the blood flowing through the brain.
38
What does the thermoregulatory centre in the brain do
It acts a a coordinate centre where it recieves information (impulses) from the temp receptors and rtriggers the effectors automatically
39
What does the body do to cool down or heat up?
The tem receptors detect wether the core of the body is too high or low
The thermoregulatory centre recieves imformation from the receptors and triggers the effectors
The effectors produce a response by working antogonistically
40
What does it mean when the effectors work antagonistically
One effector heats and another cools so they'll work at the same time to achieve a very precise temperature. The mechanism allows a sensitive response
41
Wwhat do effecctor do when your hot?
Sweat is produced by sweat glands and evaporates from the skin trasfering energy to the environment.
Blood vessels supplying the skin dilate so more blood flows close to the surface. This is called vasodilation which helps tranfer energ from. The skiin to the environment
42
What does your body to when it is cold
Hair stand up to trap insulating layer of skin.
no sweat is produced
Blood vesels supplying skin capillaries constrict to close off the skin's blood aupply. This is called VASOCONSTIRCTION
When you are cold you shiver too which need respiration which transfers energy to warm the body up.
43
What are hormones
Chemical molecules released directly into the blood. They only affect targeted organs
44
Where are hormones produced and secreted
Various glands called endocrine glands
45
Thyroid
Produces thryroxine which is involving in regulating things like the rate of metabolism, heart rate and temp
46
Ovaries
Produce oestrogen which is involveed in the menstrual cycle
47
Adrenal gland
This produces adrenaline which is used to prepare the body for a fight of flight reaction
48
Testes
Produce testosterone which controls puberty and sperm production in males
49
Pancrease
Produces insulin
50
Difference between nerves and hormones
Nerves- very fast action
- act for a very short time
Act on a very precise area
Hormones - slower action
- Act for a longer amount of time
- act in a more genral area
51
When can excess glucose be stored as
Glycogen in the liver and muscles
52
What organ monitors changes of glucose levls in blood
Pancrease
53
What hormones does the pancrease use to control changes in the blood
Insulin and glucagon
54
What does insulin do
Makes the liver thurn glucose into glycogen whcih reduces the glucose levels in the blood
55
What does glucagon do
Makes the liver turn glycogen into glucose
56
What does type one dyabetes mean/do
It means the patients pancrease doea not work properly and produces little to no insulin. This means that the blood glucose level can rise to high
57
What are the treatments for type 1 diabetes
Patients need insulin therapy which usually involves several injections of insulin throughout the day was likely before mealtimes.
As well as that you can do regular exercise and limit the intake of simple carbohydrates
58
Type two diabetes symptons
Type two diabetes is where a person becomes resistant to an insulin which can cause a persons blood sugar level to rise too high.
59
Risk factors to type two diabetes
Being overwieght (obesity) can increase your chances of developing this
60
How can type 2 disbetes be controlled
Eating a carbohydtare-controled diet and getting regular exercise.
61
What is the main reproductive hormone in men
Testosterone
62
What is testostrone
Produced by the testes and stimulates sperm production
63
What is the reproductive hormone in women
Oestrogen
64
What is oestragon
Produced in the ovaries, causes the lining of the uterus to grow and stimulates the release of LH which causes the release of an egg and inhibits release of FSH
65
What is stage one of the menstral cylce
The uterus lining breaks down for about four days. The pituitary gland releases FSH and the follicles immature
66
What happens at stage two of the mentral cycle
```
The uterus lining builds up again from 4 to 14 days, into a thick spongy layer full of blood vesels, ready to fertilise an egg. Oestrogen:
Stops FSH (prevents more eggs developing)
Starts LH release. Ovary: Eggs begin to develop
```
67
What happens at stage 3 of the menstral cycle
An egg develops and is released from the ovary at day 14 - ovulation. High LH level:
Causes follicle to bust & release egg into oviduct
68
Stage 4 of the menstral cycle
The wall is maintained for about 14 days until day 28. If no fertlised egg has landed on the uterus wall by day 2, the lining starts to break down.
69
What does FSH do
Produced in the pituitary gland. Causes an egg to mature in one of the ovaries, in a structure called a follicle.
Stimulates the ovaries to produce oestragen
70
What does progestrone do
Produced in the ovaries by the remains of the follicle after ovulation. Maintains the lining of the uterus during the second half of the cycle. When the level of progesterone falls, the lining breaks down. Inhibits the release of LH and FSH
71
What does LH do
Produced in the pituitary gland it stimulates the release of an egg at day 14
72
How can oestragen by used in contraception
If oestragen is taken every day to keep the level of it permanently high, it inhibits the production of FSH and after while the egg development and production stop and stay stopped
73
How is progesterone during used to reduce fertility
By stimulating the production of the thick mucus which prevents any sperm getting through and reaching an egg
74
Oral contraceptives (e.g the pill)
The pill is an oral contraceptive containing oestrogen and progesterone. It's over 99% effective but can cause side-effects like headaches and nausea and it doesn't protect against sexually transmitted disease. Some contraceptive pills only contain progesterone, they have fewer side-effects than the mixed pill the women must take the pill very regularly
75
Injection/implant
A tiny tube inserted under your skin by a doctor and slowly release progesterone. Contraceptive injections also use progesterone.Contraceptive implant can last up to 3 years. Has a 99.95% chance of working. Injection lasts 2 to 3 months
76
Contraceptive patch
Patch like the mixed pill contains a mixture of oestragen and progesterone. You stick the patch on the skin and the hormones are absorbed directly into the blood. Patches need to be replaced every seven days
77
Intrautrine device (IUD coil)
It is a T-shaped device that is inserted into the uterus to kill sperm and prevent implantation of a fertilised egg. The two main types of plastic that released progesterone add copper that prevents sperm surviving in the uterus
78
Barrier (e.g condoms)
Methods such as with a condom which is a thin latex she placed over the penis to collect the semen within the egg and sperm meeting. A diaphragm or cap is a thin rubber diaphragm placed over the cervix before sex to prevent entry of sperm.
79
Spermicide
Can be used alone as a form of contraception is not effective. They ar chemicals that kill or disable sperm
80
Sterilisation
It involves cutting or tying the fallopian tubes or the sperm duct. It is a permanent procedure. For men it is a vasectomy
81
Abstinence
It is there anyway to completely be sure that this pandemic to meet them not having intercourse
82
How are hormones used to increase fertility (pros/cons)
Hormones FSH and LH can be given to women in a fertility drug to stimulate ovulation and help women get pregnant. However it doesn't always work that is very expensive. Also too many eggs could be stimulated result in an unexpected multiple pregnancies which could cause stillbirth and miscarriage
83
What is IVF
IVF involves collecting eggs from the woman's ovaries and fertilising them in a lab using man's sperm.
84
How does IVF work
The treatment can also involve a technique called intracytoplasmic sperm injection with sperm is injected directly into an egg. The fertilised eggs are they grown into embryos in a level to be better. Once the embryos are tiny balls of sales one or two of them are transferred into the woman's uterus FSH and LH are given before egg collection to stimulate several eggs to mature
85
Pros/cons to IVF
Pro is facility treatment can give an infertile couple a child
Cons can be multiple births, the success rate of IVF is low, emotional and physical stress for the woman with them having a strong reaction to the hormones
86
Why are some people agianst IVF
Process of IVF often results in a nuisance embryos eventually destroyed which is thought of as unethical. Genetic testing of abuse before implantation also raises ethnical issues as some people think it could lead to the selection of preferred characteristics
87
How do micro tools/techniques improve success rates of IVF
Specialised liquid tools have been developed to use on the egg and sperm under a microscope and to remove single cells from an embryo for genetic testing. The development of time lapse imaging means that the growth of the embryos can be continuously monitored to help identify those more likely to result in a successful pregnancy
88
Fight or flight reaction
Adrenaline is released in response to stress for scary situations where your brain to text fear or stress and says nervous impulses to the adrenal glands which respond by secreting adrenaline. The body triggers the increase of oxygen and glucose into cells in the brain and muscle
89
What is thyroxine
It is a hormone released in the thyroid gland in the neck and regulates the basil metabolic rate which is the speed at which chemical reactions in the body occur or the body is at rest. It is also important for processes in the body like protein synthesis for growth and development. 
90
When would thyroxine be released
When the level of TSH in the blood becomes to high then its secretion of TSH from the pituitary gland is inhibited. It is released in respose to TSH.
91
How do the kidneys act as filters to clean blood?
Kidneys make urine by taking waste products out of blood. Substances that are'nt too big are filtered out of the blood as it passes through the kidneys. This procces is called filtration.
92
What happens to useful products in filtration
Substances like glucose, ions and the right amount of water are then absorbed back into this is called selective reabsoption
93
What happens with urea
- protiens can't be stored in the body so any excess amino acids are converted into fats and carbohydrates, which can be stored. This occurs in the liver and involves deamination.
- Ammonia is produced as a waste product from this process
- ammonia is toxic so it's converted to urea in the liver. Urea is then transported to the kidneys where it's filtered out of the blood and excreted from the body in urine.
94
Why must ions leave the body
If the ion content of the body is wrong, this could upset the balance between ions and water, meaning too much or too little water is drawn into cells by osmosis. Having the wrong amount of water can damage cells or mesn they don't work as well as normal.
95
How do ions leave the body
Some ions are lost in sweat however this amount is not regulated so the right balance of ions in the body must be maintained by the kidneys. The right amount of ions is reabsorbed into the blood after filtration and the rest is removed from the body in urine
96
Water in the body (filtered out)
The body has to constantly balance the water coming in against the water coming out. Will use water from the skin in sweat and from the lungs when breathing out. We can't control how much we lose in these ways so the amount of water is balanced by the amount we consume end of the month removed by the kidneys in urine
97
How is the concentration of urine controlled by a hormone
The concentration of urine is controlled by a hormone called auntie diuretic hormone (ADH). This is released into the bloodstream by the pituitary gland. The brain monitors the water content of the blood and instruct the pituitary gland to release ADH into the blood according to how much is needed. This whole process is a negative feedback loop
98
How are people with kidney failure kept alive
By having dialysis treatment where machines do the job of the kidneys or they have a kidney transplant
99
Why does dialysis have to be done regualy
To keep the concentration of dissolved substances in the blood at normal levels, and remove waste substances. Many patienets have to do it three times a week with each session taking 3-4 hours.
100
In a dyalisis machine what happens to the flow of blood
Blood flows between a paricually permeable membrane surrounded by dialysis fluid. The fliud has the same concentration of dissolved ions and glucose as heakthy blood meaning the useful dissolved ions and glucose won't be lost from the blood during dialysis. Only waste and exccess ions/water diffuse across the barrier.
101
Cons of dialysis
Long
Can cause infections or blood clots
Not a pleasant experience being on a dialysis machine
Expensive to run for NHS
102
How can donor kidneys be rejected
There is a risk that the donor kidney to be rejected by the patient's immune system. The patient is treated with drugs to prevent this from happening.
103
What molecules pass through the kidney's filtering proccess
Blood cells and large protiens that are too big
104
How does ASH work in a negative feedback loop
If water concentrstion is too low (too many salts) the pituitary gland rleases more ADH which tells the kidney's tubules to reabsorb more water.
