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Biology Y11 > Topic 5 > Flashcards

Topic 5 Flashcards

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1
Q

What does homeostasis mean

A

Maintaining a stable internal envitonment in response to changes both internal and external conditions

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2
Q

Examples of automatic control systems

A

Nervous and hormaonal communcation systems

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3
Q

What are the three main components in all automatic control systems

A

Receptors, cooridination centres and effectors

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4
Q

What is the mechanism caled which keep your internal environment stable in your automatic control system

A

A negative feedback loop

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5
Q

When does your body use a negative feedback loop

A

When the level of something gets too high or too low

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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

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7
Q

What does the nervous system mean

A

That humans can react to their surroundings and cordinate their behaviour

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8
Q

What makes up the nervous system

A

Central nervous system, sensory nueros, motor nuerons, effectors

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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

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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

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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

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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

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13
Q

What are reflexes

A

Rapid automatic responses to certain stimuli that don’t involve the conscious part of the brain.

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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

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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.

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16
Q

What is reaction time

A

The time it takes to respond to a stimulus

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17
Q

What is the brian made up of

A

Billios of interconnected nuerons

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18
Q

Cebral cortex

A

The outer part which is responsible for things like conciousness, inttellegence, memory and langauge.

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19
Q

Cerebellum

A

Responsible for muscle coordination

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20
Q

Medulla

A

Controls unconscious activities such as breathing

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21
Q

Hypothalamus

A

Has many functions like linking nervous systems via the pitutary gland

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22
Q

Pituitary gland

A

Produces many hormones that regulate body conditions.

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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

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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

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25
Q

MRI scans

A

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

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26
Q

What symptoms can electrical stimulation help with

A

Electrical stimulation of the brain can help reduce muscle tremors cost by nervous system disorders like Parkinson’s disease

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27
Q

Optic nerve

A

Carries impulses from the receptors on the retina to the brain

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28
Q

How does the eye adjust for different light

A

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

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29
Q

How does they eye look at near objects

A

The ciliary muscles contract which slackens the suspensory ligaments. The lens becomes fat which increases the amount of light which is affected

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30
Q

How does the eye look at the distance objects

A

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

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31
Q

What happens to long siteness (hyperopia)

A

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.

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32
Q

How to counter long sitedness

A

You can use glasses with a convex lens to connect this, the lens reflects the light rays so they focus on the retina.

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33
Q

What happens to shortsitesd people (myopia)

A

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

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34
Q

How can you counter shortsightedness

A

You can use glasses with a concave lens to correct it to that the light focuses on the retina

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35
Q

What are alternatives to wearing glasses

A

Contact lenses
Laser eye sergery
Replacement lense surgery

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36
Q

What happens in laser eye surgery

A

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

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37
Q

How does the brain control body temp

A

There is a thermoregulatory centre in the brain which contains receptors that are sensitive to temperature of the blood flowing through the brain.

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38
Q

What does the thermoregulatory centre in the brain do

A

It acts a a coordinate centre where it recieves information (impulses) from the temp receptors and rtriggers the effectors automatically

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39
Q

What does the body do to cool down or heat up?

A

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

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40
Q

What does it mean when the effectors work antagonistically

A

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

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41
Q

Wwhat do effecctor do when your hot?

A

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

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42
Q

What does your body to when it is cold

A

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
Q

What are hormones

A

Chemical molecules released directly into the blood. They only affect targeted organs

44
Q

Where are hormones produced and secreted

A

Various glands called endocrine glands

45
Q

Thyroid

A

Produces thryroxine which is involving in regulating things like the rate of metabolism, heart rate and temp

46
Q

Ovaries

A

Produce oestrogen which is involveed in the menstrual cycle

47
Q

Adrenal gland

A

This produces adrenaline which is used to prepare the body for a fight of flight reaction

48
Q

Testes

A

Produce testosterone which controls puberty and sperm production in males

49
Q

Pancrease

A

Produces insulin

50
Q

Difference between nerves and hormones

A

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
Q

When can excess glucose be stored as

A

Glycogen in the liver and muscles

52
Q

What organ monitors changes of glucose levls in blood

A

Pancrease

53
Q

What hormones does the pancrease use to control changes in the blood

A

Insulin and glucagon

54
Q

What does insulin do

A

Makes the liver thurn glucose into glycogen whcih reduces the glucose levels in the blood

55
Q

What does glucagon do

A

Makes the liver turn glycogen into glucose

56
Q

What does type one dyabetes mean/do

A

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
Q

What are the treatments for type 1 diabetes

A

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
Q

Type two diabetes symptons

A

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
Q

Risk factors to type two diabetes

A

Being overwieght (obesity) can increase your chances of developing this

60
Q

How can type 2 disbetes be controlled

A

Eating a carbohydtare-controled diet and getting regular exercise.

61
Q

What is the main reproductive hormone in men

A

Testosterone

62
Q

What is testostrone

A

Produced by the testes and stimulates sperm production

63
Q

What is the reproductive hormone in women

A

Oestrogen

64
Q

What is oestragon

A

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
Q

What is stage one of the menstral cylce

A

The uterus lining breaks down for about four days. The pituitary gland releases FSH and the follicles immature

66
Q

What happens at stage two of the mentral cycle

A 
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
Q

What happens at stage 3 of the menstral cycle

A

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
Q

Stage 4 of the menstral cycle

A

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
Q

What does FSH do

A

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
Q

What does progestrone do

A

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
Q

What does LH do

A

Produced in the pituitary gland it stimulates the release of an egg at day 14

72
Q

How can oestragen by used in contraception

A

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
Q

How is progesterone during used to reduce fertility

A

By stimulating the production of the thick mucus which prevents any sperm getting through and reaching an egg

74
Q

Oral contraceptives (e.g the pill)

A

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
Q

Injection/implant

A

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
Q

Contraceptive patch

A

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
Q

Intrautrine device (IUD coil)

A

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
Q

Barrier (e.g condoms)

A

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
Q

Spermicide

A

Can be used alone as a form of contraception is not effective. They ar chemicals that kill or disable sperm

80
Q

Sterilisation

A

It involves cutting or tying the fallopian tubes or the sperm duct. It is a permanent procedure. For men it is a vasectomy

81
Q

Abstinence

A

It is there anyway to completely be sure that this pandemic to meet them not having intercourse

82
Q

How are hormones used to increase fertility (pros/cons)

A

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
Q

What is IVF

A

IVF involves collecting eggs from the woman’s ovaries and fertilising them in a lab using man’s sperm.

84
Q

How does IVF work

A

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
Q

Pros/cons to IVF

A

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
Q

Why are some people agianst IVF

A

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
Q

How do micro tools/techniques improve success rates of IVF

A

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
Q

Fight or flight reaction

A

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
Q

What is thyroxine

A

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
Q

When would thyroxine be released

A

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
Q

How do the kidneys act as filters to clean blood?

A

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
Q

What happens to useful products in filtration

A

Substances like glucose, ions and the right amount of water are then absorbed back into this is called selective reabsoption

93
Q

What happens with urea

A
  • 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
Q

Why must ions leave the body

A

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
Q

How do ions leave the body

A

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
Q

Water in the body (filtered out)

A

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
Q

How is the concentration of urine controlled by a hormone

A

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
Q

How are people with kidney failure kept alive

A

By having dialysis treatment where machines do the job of the kidneys or they have a kidney transplant

99
Q

Why does dialysis have to be done regualy

A

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
Q

In a dyalisis machine what happens to the flow of blood

A

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
Q

Cons of dialysis

A

Long
Can cause infections or blood clots
Not a pleasant experience being on a dialysis machine
Expensive to run for NHS

102
Q

How can donor kidneys be rejected

A

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
Q

What molecules pass through the kidney’s filtering proccess

A

Blood cells and large protiens that are too big

104
Q

How does ASH work in a negative feedback loop

A

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.

Biology Y11 (3 decks)

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