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Biololgy IGCSE continued 13-21 > 14: Coordination and response > Flashcards

14: Coordination and response Flashcards

1
Q

Where do electrical impulses travel?

A

Along neurones

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2
Q

What does the central nervous system (CNS) consist of?

A

The brain and the spinal cord

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3
Q

What does the peripheral nervous system (PNS) consist of?

A

The nerves OUTSIDE the brain & spinal cord

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4
Q

Describe the role of the nervous system

A

Coordination and regulation of body functions

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5
Q

Identify sensory, relay & motor neurones

A
  • Sensory neurones are long and have a cell body branching off the middle of the axon
  • Relay neurones are short and have a small cell body at one end with many dendrites branching off it
  • Motor neurones are long and have a large cell body at one end with long dendrites branching off it
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6
Q

Describe a simple reflex arc

A

stimulus –> receptor –> sensory neurone –> relay neurone –> motor neurone –> effector –> response

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7
Q

Describe a reflex action

A

A means of automatically and rapidly integrating and coordinating stimuli with the responses of effectors (muscles and glands)

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8
Q

What is a synapse?

A

A junction between two neurones

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9
Q

Describe the structure of the synapse

A
  • the presence of vesicles containing neurotransmitter molecules
  • the synaptic gap
  • receptor proteins
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10
Q

Describe events at a synapse

A
  1. the impulse stimulates the release of neurotransmitter molecules from vesicles into the synaptic gap
  2. the neurotransmitter molecules diffuse across the gap
  3. neurotransmitter molecules bind with receptor proteins on the next neurone
  4. an impulse is then stimulated in the next neurone
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11
Q

Which direction do synapses travel in?

A

They only travel is ONE direction

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12
Q

Describe sense organs

A

Groups of receptor cells responding to specific stimuli: light, sound, touch, temperature & chemicals

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13
Q

Function of the cornea

A

Refracts light

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14
Q

Function of the iris

A

Controls how much light enters the pupil

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15
Q

Function of lens

A

Focuses light on to the retina

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16
Q

Function of retina

A

Contains light receptors, some sensitive to light of different colours

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17
Q

Function of optic nerve

A

Carries impulses to the brain

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18
Q

What is the pupil reflex?

A
  • dim light the pupil dilates (widens) in order to allow as much light into the eye as possible
  • bright light the pupil constricts (narrows) in order to prevent too much light entering the eye and damaging the retina
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19
Q

What is the pupil reflex in terms of antagonistic action?

A

DARK –> radial contract, circular relax, wide pupils, more light enters
BRIGHT –> radial relax, circular contract, narrow pupils, less light enters

20
Q

Explain accomodation to view near objects

A

The ciliary muscles contract (the ring of muscle decreases in diameter)
This causes the suspensory ligaments to loosen
This stops the suspensory ligaments from pulling on the lens, which allows the lens to become fatter
Light is refracted more

21
Q

Explain accomodation to view distant objects

A

The ciliary muscles relax (the ring of muscle increases in diameter)
This causes the suspensory ligaments to tighten
The suspensory ligaments pull on the lens, causing it to become thinner
Light is refracted less

22
Q

Describe distribution of rods and cones in the retina of a human

A

Rods = all over the cells (other than the area where the optic nerve attaches to the retina)
Cones = in the blind spot

23
Q

Function of rods

A

Greater sensitivity of rods for NIGHT VISION

24
Q

Function of cones

A

3 diff types of cones
- absorbs ligth of different colours for colour vision

25
Q

Describe a hormone

A

A chemical substance, produced by a gland and carried by the blood, which alters the activity of one or more specific target organs

26
Q

Adrenal glands secrete which hormone?

A

Adrenaline

27
Q

The pancreas secretes which hormone?

A

Insulin and glucagon

28
Q

Testes secrete which hormone?

A

testosterone

29
Q

Ovaries secrete which hormone?

A

Oestrogen

30
Q

Describe adrenaline & what happens

A

The hormone secreted in ‘fight or flight’ situations and its effects are:
- increased breathing rate
- increased heart rate
- increased pupil diameter

31
Q

How does adrenaline affect the metabolic activity?

A
  • increases the blood glucose concentration
  • increases heart rate
32
Q

Difference between nervous & endocrine system
- what it contains
- what it moves
- speed
- length of effect

A

nervous: nerves, brain, spinal cord | endocrine: glands
nervous: electrical impulse | endocrine: chemical hormone
nervous: speed - very fast | endocrine: speed - slower
nervous: length of effect = short (until nerve impulses stop)| length of effect = longer (until hormone is broken down)

33
Q

Describe homeostasis

A

the maintenance of a constant internal envionrment

34
Q

How does insulin affect blood glucose concentration?

A

It decreases it

35
Q

What is negative feedback

A

It is the concept of homeostatic control with a reference to a set point

36
Q

How does negative feedback work?

A

If a factor (e.g. blood glucose or temperature) INCREASE, the body’s response is to make it DECREASE
…vise versa

37
Q

Describe the control of blood glucose concentration in the liver
1. role of insulin

A

Insulin = secreted when HIGH sugar blood levels, stimulates liver cells to convert glucose –> glycogen
- levels FALL

38
Q

Describe the control of blood glucose concentration in the liver
1. role of glucagon

A

Glucagon - secreted when LOW blood sugar levels, stimulates liver cells to convert glycogen into glucose
- levels INCREASE

39
Q

Treatment of Type 1 diabetes

A

Type 1 diabetes = blood glucose levels are not able to be regulated as the insulin-secreting cells in the pancreas are not able to produce insulin
BLOOD GLUCOSE LEVELS ARE OFTEN TOO HIGH!!

Treatment = injecting insulin
extra insulin causes the liver to convert GLUCOSE INTO GLYCOGEN, which REDUCES the blood glucose level

40
Q

How do you maintain a constant internal body temperature in mammals?

A

Insulation, sweating, shivering & the role of the brain

41
Q

How do you maintain a constant internal body temperature in mammals?

A

vasodilation & vasoconstriction of arterioles supplying skin surface capilliaries

42
Q

Describe gravitropism

A

a response in which parts of the plant grow towards or away from GRAVITY

43
Q

Describe phototropism

A

a response in which parts of a plant grow towards or away from THE DIRECTION OF THE LIGHT SOURCE

44
Q

Explain role of auxin in controlling shoot growth

A
  1. auxin is made in the shoot tip
  2. auxin diffuses through the plant from the shoot tip
  3. auxin is unequally distributed in response to light & gravity
  4. auxin stimulates cell elongation
44
Q

Explain role of auxin in controlling shoot growth

A
  1. auxin is made in the shoot tip
  2. auxin diffuses through the plant from the shoot tip
  3. auxin is unequally distributed in response to light & gravity
  4. auxin stimulates cell elongation

Biololgy IGCSE continued 13-21 (7 decks)

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