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Biology > 5 - Homeostasis and Response > Flashcards

5 - Homeostasis and Response Flashcards

1
Q

What is homeostasis?

A

The process by which an organism regulates its internal conditions so that crucial reactions can happen at optimal rates.

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2
Q

What internal conditions are regulated during homeostasis?

A
  • Blood glucose concentration
  • Internal temperature
  • Water levels
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3
Q

The nervous system consists of the…

A

CNS (central nervous system) and PNS (peripheral nervous system)

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4
Q

The CNS (central nervous system) consists of…

A

The brain and spinal cord

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5
Q

The PNS (peripheral nervous system) consists of…

A

All nerves except for the brain and spinal cord.

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6
Q

What is a stimulus?

A

A change in the environment that requires a response. e.g a hot hob

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7
Q

What is the role of a receptor (e.g skin)?

A

Detects a change in the environment caused by a stimulus.

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8
Q

How does the electrical signal from a receptor reach the spine?

A

Through sensory and relay neurones.

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9
Q

What is a synapse?

A

The gap between neurones.

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10
Q

How does the electrical signal travel across a synapse?

A

Through neurotransmitter chemicals

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11
Q

Where does the electrical signal go after reaching the spine and why?

A

It travels to the brain so you can make the conscious decision to react.

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12
Q

Where does the electrical signal go after reaching the brain and why?

A

It travels to an effector so you can physically react.

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13
Q

How does the electrical signal travel to the effector (after reaching the brain)?

A

Through relay and motor neurones

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14
Q

What is a reflex arc?

A

When the electrical signal goes straight from the spine to an effector to allow for a quicker yet involuntary reaction.

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15
Q

Are glands effectors and why?

A

Yes - they secrete chemicals based on certain conditions (eg. salivary glands producing saliva when eating food)

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16
Q

What are the three main parts of the brain?

A
  • Cerebral cortex
  • Cerebellum
  • Medulla oblongata
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17
Q

What is the role of the cerebral cortex?

A

To carry out higher functions, such as memory and speech.

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18
Q

What is the role of the cerebellum?

A

To carry out motor skills, such as movement and balancing.

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19
Q

What is the role of the medulla oblongata?

A

To perform unconscious actions, such as breathing and heart rate.

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20
Q

What is the purpose of an MRI scan?

A

To allow doctors to see brain activity without having to perform surgery.

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21
Q

What is meant by the accommodation of the eye?

A

The process of changing the shape of the lens to focus light that comes from objects that are different distances away.

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22
Q

Explain the process that an eye goes through to focus an object that is far away.

A

Ciliary muscles relax
Suspensory ligaments tighten
This causes a thinner lens that only refracts the light a small amount, which focuses the light on the retina.

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23
Q

Explain the process that an eye goes through to focus an object that is close by.

A

Ciliary muscles contract
Suspensory ligaments slacken
This causes a thicker lens that refracts the light a larger amount, which focuses the light on the retina.

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24
Q

What is the role of the pupil?

A

A hole in the iris that can change size depending on the light intensity so it doesn’t damage your eye.

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25
What is the role of the cornea?
A transparent outer layer where light enters the eye.
26
What is the role of the sclera?
A white tough outer layer that protects the eye.
27
What are the names of the retina cells?
Rods and Cones
28
What is the role of a rod cell?
Rods detect light intensity
29
What is the role of a cone cell?
Sensitive to red, blue or green wavelengths which then makes up all the colours we can perceive.
30
Where do the signals from the eye travel and how?
They travel to the brain via the optic nerve.
31
What is the name given to short-sightedness?
Myopia
32
What is the name given to long-sightedness?
Hyperopia
33
What type of lens is used to treat myopia?
Concave lens
34
What type of lens is used to treat hyperopia?
Convex lens
35
What is thermoregulation?
The brain detecting blood temperature and then sending nervous and hormonal signals to effectors to increase/decrease your body temperature.
36
What happens (in terms of sweat) to the body when it is too hot?
Sweat glands produce water, which evaporates and takes away heat.
37
What happens (in terms of blood vessels) when your body is too hot?
Blood vessels dilate (widen), this is called vasodilation, to increase the rate of blood flow to the skin, which increases the rate of heat loss.
38
What happens (in terms of hairs) to the body when it is too cold?
Hairs stand up on end to trap air, creating a layer of insulation.
39
What happens (in terms of shivering) to the body when it is too cold?
You shiver, which causes muscles to produce more heat.
40
What happens (in terms of blood vessels) when your body is too cold?
Blood vessels constrict (narrow), this is called vasoconstriction, to decrease the rate of blood flow to the skin, which reduces the rate of heat loss.
41
What is the endocrine system?
The system of glands that secrete hormones to send signals to effectors, transported via the blood.
42
The endocrine system is ________ than the nervous system.
slower
43
What is the role of the pituitary gland?
The gland that sends signals to all other glands in the endocrine system.
44
What is the role of the thyroid?
Control things such as growth and metabolism.
45
What is the role (in simple terms) of the pancreas?
Secretes insulin (and glucagon) to control blood sugar.
46
What is the role of the adrenal glands?
Releases adrenaline
47
What is the role of the testes?
Produces sperm
48
What is the role of the ovaries?
Releases eggs and secretes hormones.
49
How does the body respond to high blood glucose levels?
- The pancreas secretes insulin - This causes glucose to move from the bloodstream into cells to be used for respiration. - The excess glucose is converted into glycogen as an energy store.
50
How does the body respond to low blood glucose levels?
- The pancreas secretes glucagon - This causes the liver and muscle to convert glycogen back into glucose. - This is an example of negative feedback.
51
What is Type I diabetes?
When the pancreas is unable to produce enough insulin. This means that injections are needed.
52
What is Type II diabetes?
When cells don’t absorb glucose as they should. The risk of Type II diabetes is increased from obesity.
53
Water is lost (in the body) through ________, ________ and ________.
exhalation, sweating and urinating.
54
What happens to excess water in the body?
Less ADH is made in the kidneys, so more water is sent to the bladder, where it is then combined with urea to make urine.
55
What is urea made from?
Urea is made from ammonia (NH₃) which is produced from excess proteins broken down into amino acids by the liver.
56
What happens to cells if there is too much water in the body?
- Water moves into the cells through osmosis. - Cells become turgid and can burst.
57
What happens to cells if there is not enough water in the body?
- Water moves out of the cells through osmosis. - Cells become flaccid
58
What do kidneys do (in terms of filtering)?
Kidneys filter out glucose and useful minerals and ions for the body to use.
59
What is ADH and what is its purpose?
Anti-diuretic hormone: Is produced in the pituitary gland and travels to the kidneys where it causes the tubules to reabsorb more water into the bloodstream so less goes to the bladder.
60
What is negative feedback?
The process where a response to a change contradicts the change, and therefore conditions return to normal.
61
What should be the response to kidney failure?
Dialysis - This is where blood is filtered by a machine.
62
What happens if there is not a proper response to kidney failure?
Ammonia and urea can build up, which will be poisonous.
63
What is FSH and what is its purpose?
Follicle stimulating hormone: Produced from the pituitary gland. Causes eggs to mature and the ovaries to produce oestrogen.
64
What is oestrogen’s purpose?
Causes the uterus lining to thicken, and inhibits (stops) the production of FSH so that no more eggs produce until the next cycle. It also causes the pituitary gland to produce LH.
65
What is LH and what is its purpose?
Luteinising Hormone - Causes the egg to be released, which starts to travel to the uterus where a sperm cell can fertilise it (in the oviduct)
66
What is progesterone’s purpose?
Secretes from the ovaries to maintain the uterus lining.
67
How does FSH-inhibiting pills work as contraceptives?
It stops the eggs from maturing.
68
How does a progesterone injection work as contraception?
It stops the eggs from being released.
69
How do FSH-inhibiting pills work as contraception?
70
How does a progesterone injection work as contraception?
Stops the eggs from being released.
71
How does the implant work as contraception?
Stops the eggs from being released.
72
How does a condom work as a contraceptive?
Stops the sperm from entering the vagina.
73
How does a diaphragm work as a contraceptive?
Stops the sperm from entering the vagina.
74
How does the IUD (copper coil) work as a contraceptive?
Stops the egg from embedding in the uterus lining.
75
What are 3 fertility treatments?
- FSH injection - LH injection - IVF (in-vitro fertilisation)
76
Explain the process of IVF (in-vitro fertilisation)
- Eggs are harvested from the woman after inducing their release - They are then fertilised in a lab with the father’s sperm - Any embryos that develop are inserted back into the uterus (where they will hopefully embed in the lining and grow normally)
77
What is the success rate of IVF?
Very low
78
What is a possible unintended result of IVF?
It may cause multiple embryos to develop.
79

Biology (7 decks)

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