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biology > Coordination And Response > Flashcards

Coordination And Response Flashcards

1
Q

explain why enzymes break down the neurotransmitters at the end of the axon terminal

A

Others they would continue to stimulate electrical impulses

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2
Q

What is the role of the retina?

A

It is the light sensitive layer containing receptor cells, cone and rod cells

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3
Q

What are two roles of the sclera

A

maintaining the shape of the eye
And moving the eyeball

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4
Q

What are three roles of the virtuous humour

A

Maintains the shape, keeps the retina against the wall, and keeps the eye wet

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5
Q

What is the role of the cornea?

A

refracts light into the eye

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6
Q

What is the role of the optic nerve?

A

Contains sensory neurones which carry impulses to the brain to be processed

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7
Q

What are two roles of the choroid

A

A dark layer and so absorbs light in order to prevent reflection of light into the eye

And nousirhses the retina with nutrients

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8
Q

Why is the choroid a very dark colored layer?

A

Because it contains many pigment cells, and blood vessels

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9
Q

What is the role of the iris

A

It controls pupil reflex and so controls how much light enters the eye

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10
Q

What is the role of the pupil

A

To allow light to enter the eye

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11
Q

Why is the pupil black

A

Because no light is escaping from the inside of the eye

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12
Q

What is the role of the conjunctiva

A

It lubricates the eyelids so that they do no stick together

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13
Q

What is the role of the aqeous humour?

A

It maintains the pressure of the eye

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14
Q

What is the role of the fovea

A

Region of the retina with the most concentrated number of cones and rods

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15
Q

Why can you see an object most clearly when directly looking at it in terms of the fovea

A

Because the fovea has a highly concentrated number of cones, which give a sharper image than rods.
And so because the fovea is in the centre of the eye the image will fall directly on the fovea

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16
Q

Explain how the eye forms an image

A

Light enters through the cornea, which travels through the pupil onto the lens, which refracts light onto the retina
The retina contains receptor cells which detect light intensity and light colour, which view the image inverted
The receptor cells send electrical impulses to the optic nerve in the brain, which The interprets the image the right way

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17
Q

Why does the eye become constricted in bright light

A

To allow only little light to enter as too much light could damage the retina

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18
Q

In bright light, explain how the circular muscles are and how the radial muscles are

A

Circular muscles contract
Radial muscles relax

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19
Q

In dim light, explain how the circular muscles are and how the radial muscles

A

Circular muscles relax
Radial muscles contract

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20
Q

How can the lens change in terms of its properties

A

It is made up of an elastic protein

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21
Q

When the object is…. Light rays are parallel when they reach the cornea

A

Far

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22
Q

Explain what happens to the lens when focusing on a far object

A

Light rays are parallel to the cornea and so do not need to be focused and refracted as much
So ciliary muscles relax
And suspensory ligaments become taught
And the lens becomes less convex and thin

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23
Q

Describe the position of the ciliary muscles and the suspensory ligaments when eyes are at rest

A

Ciliary muscles relax
Suspensory muscles become taught

(Because when eyes are at rest they are focused for long distances)

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24
Q

Explain what happens to the lens when looking at nearby objects

A

So ciliary muscles contract
And suspensory ligaments slacken
So lens becomes more convex and thick and fat
so light can be refracted and can enter the eye

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25
Q

Give two reasons why pull reflex is important for the eye

A

If light that is too bright enters the retina it could damage the rod and cone receptors

But if it is too dim it an image would not form

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26
Q

What is the stimulus for the pupil reflex

A

Light intensity

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27
Q

What is the effector in the pupil reflex

A

The iris muscles because they alter the size of the pupil

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28
Q

If someone is long-sighted, should their glasses be more convex or concave and why

A

Long sighted means they have trouble clearly viewing close objects
because the lens is not as convex as it should be and so light rays are focused behind the retina
So should wear convex lens glasses to strengthen the refraction

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29
Q

If someone is short sighted, should they way convex or concave glasses

A

Short sighted means they can not see distant objects clearly
As The lens of their eye refracts too much light INFRONT of the retina
So they should wear concave lense glasses
So that light can be refracted outwards, to counteract the over refraction of the eyes lenses

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30
Q

When you are walking and a football comes to you, explain what the stimulus, receptor, coordinator, effector and response are

A

Stimulus: moving ball
Receptor: eyes
Coordinator: CNS
Effector: Muscles in the body contracting
Response: moving away

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31
Q

What is an example of a stimulus that a bee can detect but a human can not

A

Detecting UV light

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32
Q

What is the difference between a nerve, a nerve cell and a neurone

A

A nerve has nerve cells in it which are also called neurones

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33
Q

What is the role of the axon

A

Carries electrical impulses throughout the cell body to the effector organ

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34
Q

What are two roles of the myelin sheath

A

An insulating material which prevents short circuits in a nerve cell
and speeds up the process of conduction between electric impulses

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35
Q

What is a neuromuscular joint and it’s function

A

Where the end of the axon meets the muscle
and it’s purpose is to transmit nerve impulses from the axon to the muscular fibers in order for them to contract

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36
Q

What are the two types of glands and what differentiates each

A

Endocrine glands which secrete hormones that are secreted into blood vessels because they do not contain ducts

Exocrine glands which secrete hormones through ducts

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37
Q

Give two examples of exocrine glands and their products

A

Salivary glands secrete saliva
Tear glands secrete tears

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38
Q

What is a gland

A

An organ, where cells in it secrete chemicals

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39
Q

Can hormones enter any tissues or organs? Explain.

A

No, but only if they contain the correct receptor cells

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40
Q

Name three areas of a target cell in which receptors can be found

A

Cell membrane
Cytoplasm
Nucleus

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41
Q

Give four differences between the nervous system and the endocrine system

A

-nervous system communicates message with electrical impulses that are transmitted between neurones, but endocrine system communicates messages with hormones in the blood stream

-nervous system impulses travel faster and work more instantly
than endocrine, where hormones travel more slowly and take longer to take place

-nervous system response is short but endocrine system response is longer lasting

-nervous system impulses have a localized effect and only act on individual cells
whereas endocrine hormones have more of a widespread effect which act on different organs

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42
Q

Although the nervous system primarily relies on electrical impulses to send messages, give one way in which it can be similar to what the endocrine system uses to send messages

A

The nervous system also relies on synapses which are chemicals, similar to hormones in the endocrine system

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43
Q

Name a part of the body that links the nervous and endocrine system and what it links to

A

The pituitary gland which links to the hypothalamus in the brain

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44
Q

Name an endocrine gland specific to the female body and which hormones they secrete

A

The ovaries(a sex endocrine gland), which secreted hormones such as estrogen and progesterone

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45
Q

Name three hormones released by the pituitary gland

A

-Anti diuretic hormone
-FSH
-LH

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46
Q

Name six glands and the hormones that they release

A

Pituitary gland—-) ADH, FSH, LH
Ovaries—-) estrogen and progesterone
Testes—-) testosterone
Thyroid gland —-) thyroxid
Adrenal gland —-) adrenaline
Pancreas—-) glucagon and insulin

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47
Q

Explain how the pancreas is both an endocrine and exocrine gland

A

It secretes hormones in the regulation of blood glucose (endocrine)
And secretes hormones from a duct in the pancreas to the small intestine (exocrine)

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48
Q

Name six responses that can happen when adrenaline is released

A

-glycogen from the liver is converted into glucose which is released into the blood stream to muscle cells so that they can respire faster
-blood is diverted away form the intestine and into the muscles
-heart beats faster, sending more blood and oxygen to muscles for respiration
-breathing rate becomes heavier and deeper so that more oxygen can enter for respiration
-pupils dilate for increased visual sensitivity
-blood vessels dilate so that more oxygen and glucose can be transported
-hair stands up to make animal look bigger

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49
Q

What is the storage carbohydrate in the liver called and why is it good that it is insoluble

A

Glycogen
It is good that it is insoluble so that it can easily be broken down into glucose

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50
Q

Where it insulin produced

A

Produced in the pancreas

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51
Q

Which hormone lowers blood glucose levels and which hormone raises blood glucose levels

A

Insulin lowers blood glucose levels
Glucagon raises blood glucose levels

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52
Q

Explain why after a meal, the blood leaving through the hepatic vein has less glucose than the blood entering from the hepatic portal vein

A

Because the blood that travels through the hepatic portal vein has transports all the absorbed glucose from the small intestine into the liver
Here insulin stimulates liver cells to convert glucose into glycogen
So glucose leaving the blood through the hepatic vein is much less

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53
Q

Explain the difference between type one diabetes and type two diabetes

A

Type one diabetes is when the pancreas does not produce enough insulin to control blood glucose levels and often occurs at a young age

Type two diabetes is when the body has been making insulin yet because there is so much glucose in the blood due often because they eat too many carbohydrates and high in sugar diets, enough insulin can not be produced and so becomes resistant

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54
Q

Explain how you can test if someone has diabetes

A

Can use colored strips to see if glucose is present in the urine

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55
Q

When a person has diabetes, explain how being thirsty can control their blood glucose levels

A

Because high blood glucose concentration stimulates receptors in the hypothalamus, which cause you to feel thirsty

And so by drinking water you can dilute the blood and lower glucose concentrations

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56
Q

Explain why insulin is not taken in the form of a tablet

A

Insulin is a protein
And so would be broken down by the enzyme protease in the gut

Thus it is taken in the muscle tissue where it can be absorbed

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57
Q

What is homeostasis

A

The maintenance of a constant internal environment

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58
Q

Explain why the body should not have too little water
And then explain why the body should not have too much water

A

Should not have too little water as that will effect the osmosis in cells and they may plasmolyse
Should not have too much water as there will be too much pressure in the body

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59
Q

Explain what happens in the body when you are dehydrated

A

Rise is detected by the osmoregulators in the brain,
so Hypothalamus releases more ADH,
so collecting duct is moser permeable
So less urine is released

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60
Q

Explain what happens in the body when you have a lot of water in your body

A

Osmoregulators detect the change
And signal the hypothalamus to release less ADH
So that the collecting duct is made less permeable
So that more water can be release in the urine

61
Q

Explain the ovarian cycle (the cycle of the follicle)

A

-In an ovary, there are many cells that can become an egg ( a sex cell)
-One of these cells begins to become one as it grows inside a follicle which is a ball of cells
-Ovulation occurs and the egg bursts out of the follicle
-After traveling through the oviduct, if fertilization does not take place the remainder of the follicle becomes a corpus luteum and this deteriorates and stops making progesterone
-But if fertilization does take place, the remainder of the follicle stimulates progesterone

62
Q

Name the four hormones in the menstrual cycle and their roles (some may have two or three)

A

FSH- matures and develops the egg cell
Oestrogen- stimulates the lining of the uterus to grow + inhibits FSH + Stimulates LH
LH- stimulates the egg cell to grow
Progesterone- maintains the lining of the uterus + inhibits FSH and LH from developing a new egg

63
Q

what is the function of the menstrual cycle

A

To control the development of the lining of the uterus so that if an egg is fertilized, the embryo can grow

64
Q

Where in the female reproductive system is an egg fertilized?

A

In the oviduct/fallopian tubes
(Same thing)

65
Q

What day does Ovulation usually occur in the cycle

A

14

66
Q

!Explain the process of how the hormones interact in the menstrual cycle (6)

A

1- Hypothalamus in Pituitary gland stimulates the release of FSH, which travels in the blood to the ovaries, which matures an egg in the follicle
2-follicle develops into egg cell and At the same time, FSH triggers the ovaries to produce oestrogen which causes the lining of the uterus to thicken
3- Oestrogen then inhibits FSH by telling the Pituitary gland to stop releasing FSH, and when oestrogen reaches high levels, it stimulates the release of LH which causes ovulation (the mature egg to be released)
5-The remainder of the follicle now becomes a corpus lutum which stimulates the release of progesterone, called negative feedback
6a-this maintain the lining of the uterus, and if fertilization occurs it will continue to line it and until the placenta is made the corpus letterman will continue releasing progesterone
b-and if not fertilized, progesterone levels will fall and the egg will be released and woman will have a period c-and progesterone also inhibits FSH and LH so that a new egg is not matured and released

67
Q

Where is estrogen and progesterone produced, and where is FSH and LH created

A

Estrogen and progesterone -Ovaries
FSH and LH- pituitary gland

68
Q

Explain how a woman has a period

A

When the egg cell is released, but is not fertilized during ovulation, the thick lining of the uterus begins to shed and so the cells and the egg are released as blood

69
Q

Give three examples where negative feedback takes place in the body

A

The menstrual cycle, where progesterone inhibits FSH and LH from producing and maturing egg
control of blood glucose, when glucose levels change then insulin is altered
Osmoregulation, as when water content rises or decreases level of ADH returns it to normal

70
Q

Give an example of negative feedback in the menstrual cycle

A

When progesterone is released, it inhibits the release of LH and FSH so that another egg is not released and matured
This is negative feedback because the body has detected a change in conditions and is working to return it to normal

71
Q

What is a hometherm? And give two examples of them

A

An organism that keeps its body temperature constant, despite changes in the surroundings

Mammals and birds

72
Q

Give a reason why fish swim faster in the summer than in the winter

A

They are not homeotherms so the temperature in their body is correlated to the temperature in surroundings

So chemical reactions happen much faster in the heat but slow down in winter

73
Q

Give one advantage of humans being able to control their internal body temperature

A

Metabolism is kept constant and so all chemical reactions in the cells of the body can function predictably

74
Q

Give four functions of the human skin

A

Controls heat loss
Impermeable so prevents water loss
Touch outer layer prevents mechanical damage
acts as a sense organ for touch and temperature changes

75
Q

Give the description and function of each layer of skin

A

1)Epidermis -is made of dead skin cells that prevents microorganisms from entering and prevents water loss
2)Dermis-contains sensory receptors, sweat glands and blood vessels
3)Hypodermis- fat layer which insulates the body

76
Q

Give three structures located in the dermis of the skin that help with temperature control

A

Sensory detectors, blood vessels, sweat glands

77
Q

Explain how sweat glands control temperature in warm conditions

A

Hypothalamus detects change and sends nervous impulses to the skin
body produces more sweat which is secreted onto the surface of the skin
when this liquid evaporates, it transfers energy from body’s heat from skin into environment
which cools you down

78
Q

Explain why sweating in a rainforest may not cool you down as much

A

Rainforest has humid environment
And sweat only has cooling effect when it evaporates
And cant evaporate in an environment that is densely filled with water vapour

79
Q

Explain a method to control heat loss in cold environments with hair on skin

A

-hypothalamus detects a change in body temperature and sends nervous impulses to skin
-hair erector muscles are pulled upright
- this traps a large layer of air next to the skin and hair is a bad conductor, so body is insulated

80
Q

Explain why hairs on skin fall down in hot weather

A

-hypothalamus detects a change in body temperature and sends nervous impulses to skin
-hair erector muscles on skin relax to avoid trapping as much air as possible as air is good insulator
-thin layer of trapped air means as much heat can be lost as possible

81
Q

Explain the process of vasodilation:

A

-hypothalamus detects an uprise in body temperature and sends nervous impulses to skin
-ARTERIOLE muscles relax and CAPILLARIES dilate
-more blood flows through the capillaries near the skin
- so more heat is lost to the surroundings by RADIATION

82
Q

Explain why people become red when they are hot

A

Body is responding to change in temperature
So sphincter muscles relax and arterioles near the skin dilate
So more blood is supplied to to capillaries near the skin
Heat loss is most effective near the skin because it is closest to the surroundings

83
Q

Explain the process of vasoconstriction

A

-hypothalamus detects an uprise in body temperature and sends nervous impulses to skin
-ARTERIOLE muscles contract and narrow, and CAPILLARIES constrict
-less blood travels through the capillaries near the skin
-so less heat is loss form the blood by RADIATION

84
Q

Give one reflex action that occurs when there is a drop in body temperature

A

Shiveirng

85
Q

Explain how the body responds with shivering when exposed to cold environment

A

Muscles begin to contact and relax rapidly
So that metabolic rate increases
So that a large amount of heat energy is generated to keep the body warm

86
Q

Give three ways the body responds to being in hot temperature

A

Vasodilation
Sweating
Hair erection

87
Q

Give two ways the body responds to cold temperatures

A

Shivering
Vasoconstriction

88
Q

Which hormone stimulates male sexual secondary characteristics

A

Testosterone

89
Q

What is the source of Oestrogen

A

The ovary

90
Q

Why do cells not store glucose

A

Because it is soluble and has an osmotic effect

91
Q

If represented in a graph, are insulin levels higher than glucose levels as soon as you eat or lower

A

Higher

92
Q

Describe the process of touching a hot object (exam answer)

A

1)Stimulus is detected and pain receptor cells in the skin detect the pain
2)they then send electrical impulses along a sensory neurone to the CNS
3)In the CNS electrical impulses are passed along a relay neurone through a synapse
4) the impulses are then passed along a motor neurone through a synapse
5)the impulse then travels to an effector like the muscle cells which contracts and moves you away from the hot object which is the response

93
Q

Explain how being a large emperor penguin can help you survive better than a small penguin in very low temperatures (2)

A

Because you have a small surface area to volume ratio
so less heat will be lost and boy temperature will be maintained

94
Q

Explain how having a thick layer of fat below the skin helps penguins to survive (2)

A

It insulates the body
which reduces heat loss

95
Q

explain how penguins having muscles that operate the feet, in the body , rather than on the ground, benefits them (3)

A

Muscles will stay insulated and will be able to contract
as less heat loss
because aerobic respiration reactions will not be slowed down or stopped
Because enzymes will be at optimum temperature

96
Q

Penguins huddle together to maintain their body temperature so explain how this behavior is an advantage to them

A

less heat is lost because smaller surface area to volume ratio
So they can maintain body temperature
And so can stay PROTECTED and SHELTERED

97
Q

If testing the effect of growth hormone on milk production of a cow, give two variables of the cow that need to be kept the same

A

Mass of cow
Species of cow

98
Q

Explain how pasteurized milk which contains hormones, is made non-harmful for humans, by the stomach

A

Protease enzymes secreted will digest the hormones as it is a protein
Hydrochloric acid released will acidify conditions and thus denature the protein

99
Q

Explain how oxygen levels would change if moving from room temperature environment to cold environment

A

Oxygen levels would increase
Because aerobic respiration would increase
In order to prevent heat loss

100
Q

Explain the body helps maintain blood glucose levels after a meal

A

Insulin is secreted from the pancreas
Which transports glucose to the liver in order to be converted into glycogen
So there is then less glucose in the blood

101
Q

Explain why the finger tips are more sensitive than the rest of the hand

A

Because it has MORE RECEPTORS that are close to the surface of the skin

102
Q

What is the tough protective outer layer of the eye called

A

The sclera

103
Q

What is the nerve that connects the eye to the brain called

A

Optic nerve

104
Q

What is the definition of a hormone (2)

A

A chemical secreted from glands
Which travel to target organs and cause a change

105
Q

Where in the eye is it detected to change the size of the eye because of light intensity stimulus

A

The retina

106
Q

Scientists make conclusions about humans from studying animal behaviour. Suggest two reasons why these conclusions may not be valid.

A

1-humans and animals have different nervous systems that’s unction in different ways
2-they respond to different stimuli

107
Q

Give three ways in which animals having large ears helps to keep cool

A

1)small surface area to volume ration so more heat loss
2)more blood capillary supply so more vasodilation can take place
3)can flap their ears to keep cool

108
Q

Is acclamation a reflex action or a voluntary response

A

Reflex

109
Q

In a diagram of the eye, what do the two dots represent that are next to the lens

A

The ciliary muscles

110
Q

Name an effect(not role) of insulin

A

Converts glucose into glycogen

111
Q

Explain the changes that take place in the uterus through a menstrual cycle(3)

A

the lining is thickened and repaired
and is then maintained for a few days
If egg is fertilized it will continue to be maintained
but if egg is not fertilized it will shed and break down into a period

112
Q

Give two reasons why having sexual intercourse by relying on your menstrual cycle is not a reliable form of birth control

A

Because periods can be irregular and the length of ovulation can vary

Sperm can also survive in the Fallopian tube

113
Q

What is the role of Oestrogen

A

Repairs the uterus lining

114
Q

Explain why when moving from cold to hot environment the diameter of the arteries near the skin expand and the volume of blood also increases

A

Due to VASODILATION
Where arteries expand
To allow MORE blood to flow CLOSER to the skin So that more heat can be lost
In order to control HEAT LOSS and prevent ENZYMES from denaturing

115
Q

Explain what would happen to a person with a detached retina (2)

A

-they would have no connection to the optic nerve
-so brain would not be able to make out an Image and so would not be able to see, and could be blind

116
Q

What is the name for controlling the concentration of the blood

A

Osmoregulation

117
Q

Does the endocrine system respond to stimuli

A

Yes
(Eg blood glucose concentration drops or temperature in surroundings drops)

118
Q

What are the five sense organs of the body

A

Eyes, ears, nose, tongue, skin

119
Q

Why are reflexes useful

A

Reduce your chance of injury and harm

120
Q

What is stimulus, sense organ and effector in this scenario:
When a hungry animal sees a source of food and moves towards it

A

Stimulus: sight of food
Sense organ: eyes
Effector: muscle cells

121
Q

Describe how information about light entering through the eye is sent to the brain(2 marks)

A

When light hits the retina, electrical impulses
are send through the optic nerve to the brain

122
Q

Describe the reflex arc which is triggered by bright light entering the eye (6mark)

A

1)stimulus is the bright light
2)But photoreceptors in the retina of the eye detect the bright light
3)this sens electrical impulses through the sensory neurones
4) which synapse with relay neurone in the CNS
5) impulses then synapse with motor neurones
5)which then travel to the effector which in this case are the circular and radial muscles of the iris
6)circular muscles contract and radial muscles relax and constrict the pupil which is the response

123
Q

Give two ways that a cyclist loses water in his body when cycling on a heat day

A

Through the skin by sweating
Through his lungs by breathing

124
Q

Explain the response of a sweat gland when a person is cold(2 mark)

A

Sweat gland produces less sweat
Because sweat transfers heat energy from skin to surroundings when it evaporates and thus provides a cooling effect
So less sweat is produced to reduce heat loss and keep the body warm

125
Q

Give two ways in how drugs can interfere with how neurones act

A

Chemicals released CNS interfere with the neurotransmitters between synapses
Or can block the actions of these neurotransmitter

126
Q

Name four types of receptors

A

Mechano receptors
Thermo receptors
Chemoreceptors
Photorecpetors

127
Q

Give two properties of reflex actions

A

Instant
Involuntary

128
Q

What is a synapse

A

The point of cummincation between two neurones

129
Q

In which neurone is the cell body located outside of the CNS

A

The sensory neurone

130
Q

Difference between sensory neurone and motor neurone

A

Sensory neurones carry electrical impulses from the sense organs in the body to the CNS
motor neurones carry electrical impulses from the CNS to the effector in the body

131
Q

The fibre from the sensory receptor to the cell body is…….. whilst the fibre from the cell body to the CNS is…….

A

Dendron
Axon

132
Q

!DESCRIBEthe process of how electrical impulses are transported between two neurones

A

1)electrical impulse travels down the axon of the first neurone and reaches the axon terminal
2)This stimulates the neurone to release chemical messengers called NEUROTRANSMITTERS
3) these DIFFUSE across the synapse BETWEEN THE NEURONS from high conc to low conc to the second neurone
4)these bind with receptors on the membrane of the second neurone which stimulates it to generate electrical impulses which travel down the axon

133
Q

Do reflexes rely on the brain or the spinal chord

A

Spinal chord
(Because spinal chord is where involuntary and instantaneous impulses are sent
And spinal chord does not need to have any processing down like the brain does)

134
Q

Describe the reflex arc of touching a hot object

A

1-RECEPTOR in the skin cell detects a STIMULIS which is the heat
2-electrical impulses travel across the sensory neurone which when reaches the axon terminal, this stimulates neurotransmitters to be released which diffuses across the synapse and stimulates electrical impulses and these travel through the relay neurone which is located in the central nervous system which is a COORDINATOR
3-these electrical impulses travel through the relays neurone which when reaching the axon terminal again, stimulates the release of neurotransmitters which diffuse across the synapse and are then generated into electrical impulses again which travel through the motor neurone
4-motor neurone carries electrical impulses through to the EFFECTOR LIKW the muscle cell
5-muscle cell contracts and pulls away hand which is called the RESPONSE

135
Q

Explain the role of adrenaline during exercise (4 marks)

A

1)The body needs more oxygen during exercise for aerobic respiration to produce ATP
2)So adrenaline can increase heart rate and breathing rate so that more oxygen is taken in and so that blood carrying the oxygen can be transported around the body at a faster rate
3)Adrenaline can also make the blood vessels dilate so that they carry more blood in them so more oxygen
4) Adrenaline also diverts blood from the intestine to the muscle cells to be used for aerobic respiration

136
Q

What is the role of glucagon

A

Changes glycogen into glucose when blood glucose levels fall too low

137
Q

Give an example of positive feedback

A

When the blood stimulates platelets to clot the blood

138
Q

Explain what happens to the volume of urine released on a hot day and why

A

Less volume released because
There is less water in the blood due to
More water being released through sweating to increase heat loss
So more ADH is released to make the collecting duct more permeable and to absorb more water to maintain water levels of the body

139
Q

Define the term hormone

A

A chemical messenger
Secreted by an endocrine gland
To a target organ or organs
To cause a change in the body

140
Q

How does insulin lower blood glucose levels

A

When blood glucose levels are HIGH
The PANCREAS releases the hormone insulin THROUGH THE BLOOD
which stimulates THE LIVER TO ABSORB glucose
and convert glucose into glycogen
Thus blood glucose levels are lowered

141
Q

SUGGEST why oryx are less active in the summer than in the winter

A

Because the weather is warmer
So they want to prevent themselves from sweating a lot to preserve water in their bodies
And their is less food available and thus less water in their food that they can obtain

142
Q

When licking a dandelion, a chemical called a diuretic is released which makes you urinate more. Explain how (5 marks)

A
  1. (diuretic) enters blood / travels in blood;
  2. pituitary / hypothalamus; 3. less ADH;
  3. collecting duct;
  4. less permeable;
  5. less water (re)absorbed / less water into blood;
143
Q

What is the role of the hormone thyroxine

A

Controls the Body’s metabolic rate

144
Q

Name two parts of the cell where receptors can be found

A

Cell membrane
Cytoplasm

145
Q

What can recreational drugs do at the synapse

A

They can interfere with the synapse, causing electrical impulses to be transmitted to different parts of the body

146
Q

What is the role of synapses

A

They ensure that impulses travel in one direction

147
Q

Difference between nerve and neurone

A

À Nerve consists of many bundles of neurones. Neurones are thé cells

148
Q

If glucose levels too high what can happen

A

Cells of the body can lose water by osmosis

biology (16 decks)

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