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2j co-ordination & control Flashcards

1
Q

2.80 understand how organisms are able to respond to changes in their environment

A
  • all living organisms need to respond to changes in environment for survival
  • nervous system coordinated by brain allows body to respond to changes in environment
  • organisms additionally have reflexes for fast involuntary actions that protect body from damage
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2
Q

2.82 understand that a coordinated response requires a stimulus, a receptor & an effector: what’s the definition of a stimulus?

A

change in the animal’s surroundings/the environment e.g. a ball thrown towards you

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3
Q

2.82 understand that a coordinated response requires a stimulus, a receptor & an effector: what’s the definition of a receptor?

A

specialised cells/organs that detect changes in environment e.g. your eye, or sensory neurones in finger detect heat

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4
Q

2.82 understand that a coordinated response requires a stimulus, a receptor & an effector: what’s the definition of an effector?

A

part of body (muscles) that carries out response to stimuli, e.g. hand catching ball, muscles in finger contract to pull finger away from heat

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5
Q

2.87 what does the central nervous system consists of, and how is it linked to sense organs (receptors)?

A

the brain and spinal cord, and linked to sense organs by nerves

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6
Q

2.88 how do reflexes work?

A
  • stimuli detected by receptors, stimulating sensory neurones that send electrical impulses to CNS
  • CNS relays impulse across the synapse to relay neurones via synaptic transmission
  • relay neurones relays impulse to motor neurones in the effector, which will quickly carry out rapid response
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7
Q

2.89 what is the role of neurotransmitters at synapses?

A

chemical messengers which diffuse across the synapse & bind w receptor molecules on membrane of next neuron

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8
Q

2.90 describe the structure and functioning of a simple reflex arc
illustrated by the withdrawal of a finger from a hot object

A
  1. receptors detect stimulus (change in temp.) & send electrical impulse along the sensory neurone
  2. sensory neurone passes the impulse to the spinal chord to a relay neurone, relay neurone then passes the impulse through spinal chord & to a motor neurone
  3. motor neurone causes the effector (arm muscle) to contract & move arm away from stimulus (fire/hot object)
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9
Q

what’s definition of a synapse?

A

the gap between neurones

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10
Q

what are the 3 types of neurones?

A

sensory neurones, relay neurones, motor neurones

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11
Q

what are the functions of the structures within a motor neurone?

A

nucleus: contains all genetic info of cell
dendrite: tree like projections which connect to diff. neurones; 1 neurone can connect to many other neurones
cell body: main section of cell, contains nucleus
axon: the long section - electrical impulses travel long distances through the axon
myelin sheath: insulates axon & speeds up transmission of impulse

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12
Q

2.91 describe the structure & function of the eye as a receptor (function/description of cornea)

A

curved transparent disc at front of eye; does most of focusing

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13
Q

2.91 describe the structure & function of the eye as a receptor (function/description of pupil)

A

circular opening whose size is controlled by iris

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14
Q

2.91 describe the structure & function of the eye as a receptor (function/description of iris)

A

ring of muscles w hole in middle (pupil); controls how much light enters eye

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15
Q

2.91 describe the structure & function of the eye as a receptor (function/description of lens)

A

soft, flexible & transparent, its shape can be changed to fine tune focusing of light onto retina

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16
Q

2.91 describe the structure & function of the eye as a receptor (function/description of ciliary muscles)

A

ring of muscle at edge of eye which circles the lens. when it contracts lens gets fatter, when relaxes lens gets thinner

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17
Q

2.91 describe the structure & function of the eye as a receptor (function/description of suspensory ligament)

A

strong fibres which attach lens to ciliary muscle

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18
Q

2.91 describe the structure & function of the eye as a receptor (function/description of retina)

A

contains light sensitive cells called rods & cones

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19
Q

2.91 describe the structure & function of the eye as a receptor (function/description of optic nerve)

A

consists of many neurones which carry impulses from retina to brain

20
Q

2.91 describe the structure & function of the eye as a receptor (function/description of fovea)

A

the region of the retina with the greatest no. of cones

21
Q

2.91 describe the structure & function of the eye as a receptor (function/description of conjunctiva)

A

a mucous membrane that covers the eye to prevent infection

22
Q

2.92 understand the function of the eye in responding to changes in light intensity

A

dim light:
- radial muscles contract and circular muscles relax
- this makes iris narrower & pupil dilates

bright light:
- circular muscles contract and radial muscles relax
- this makes iris wider & pupil constricts

23
Q

2.92 what is the receptor and the effectors in the reflex arc of the eye responding to changes in light intensity?

A

receptor: retina (detects light intensity)
effectors: muscles of the iris

24
Q

2.92 understand the function of the eye in focusing on near objects (accommodation)

A

light rays entering eye are spreading out (diverging) so lens needs to refract light to ensure it focusses onto retina:
- ciliary muscles contract
- meaning suspensory ligaments are therefore slack
- lens not stretched out so becomes thicker with more convex shape
- therefore more refraction of light

25
2.92 understand the function of the eye in focusing on **distant** objects (accommodation)
light rays entering eye **almost parallel** when they reach cornea, so lens **doesn't** need to refract them much to focus light onto retina: - ciliary muscles **relax** - therefore suspensory ligaments pulled **tight** - lens pulled thin & has less convex shape - therefore **less refraction** of light
26
what's the definition for accommodation?
the changes that take place in the eye which allow us to see objects at **different distances**
27
2.93 describe the role of the skin in temperature regulation, with references to sweating, vasoconstriction & vasodilation (too cold)
- **hairs stand on end** from erector muscles: hairs trap layer of air which provides **insulation** for conduction of heat - **less** sweat released: therefore less heat loss via evaporation - **vasoconstriction:** arterioles supplying capillaries near surface of skin get **narrower** - they **constrict**. **less** blood flows through capillaries near surface of skin, therefore **less** heat lost by **radiation** - effect for all is less heat lost
28
2.93 describe the role of the skin in temperature regulation, with references to sweating, vasoconstriction & vasodilation (too hot)
- **hairs lie flat:** insulating layer of air **not** formed - **more** sweat released: when it **evaporates**, heat energy taken away from skin as **evaporation of water requires energy** - **vasodilation:** arterioles supplying capillaries near surface of skin **widen** - they **dilate**. **more** blood flows through capillaries near surface of skin, therefore **more** heat lost by **radiation** - effects for all is more heat lost
29
2.94 what are the sources and functions of adrenaline?
source/gland: adrenal gland function: increases heart & breathing rate for fight, fright or flight response
30
2.94 what are the sources and functions of insulin?
source/gland: pancreas function: causes liver & muscles to take up glucose and convert it to glycogen for storage
31
2.94 what are the sources and functions of testosterone?
source/gland: testes function: stimulates development of male secondary sexual characteristics
32
2.94 what are the sources and functions of progesterone?
source/gland: ovaries function: maintains uterus lining and controls development of secondary female sexual characteristics
33
2.94 what are the sources and functions of oestrogen?
source/gland: ovaries function: stimulates uterus lining to develop & the development of female secondary sexual characteristics
34
2.95B what are the sources and functions of ADH?
source/gland: pituitary gland function: reduces amount of water lost in urine
35
2.95B what are the sources and functions of FSH?
source/gland: pituitary gland function: stimulates an egg to mature in the ovary
36
2.95B what are the sources and functions of LH?
source/gland: pituitary gland function: stimulates release of an egg from ovary (ovulation)
37
2.83 do plants respond to stimuli?
yes
38
2.84 describe the geotropic responses of roots
- during growth, auxin produced at tip will accumulate on **underside** of root due to **gravity** - as auxins **inhibit growth** of root cells, cells on underside of root won't grow, whilst cells on upperside will continue to grow larger & elongate (inc in elasticity allows cell to absorb more water to grow larger in size) - as result, root grows **downwards towards direction of gravity - positive geotropism**
39
2.84 describe the geotropic responses of stems
- during growth, auxin produced at tip will accumulate on **underside** of stem due to **gravity** - as auxins **promote growth** of stem cells, cells on underside of stem will continue to grow larger & elongate (inc in elasticity allows cell to absorb more water to grow larger in size), whilst cells on upperside grow at slower rate - as result, stem will grow **upwards against direction of gravity - negative geotropism**
40
2.84 describe the phototropic responses of stems
- during growth, auxin produced at tip will be **redistributed** by **light receptors** to **shaded side** of stem - as auxins **promote growth** of stem cells, cells on shaded side will grow larger & elongate (inc in elasticity allows cell to absorb more water to grow larger in size) - whilst cells on **unshaded** side exposed to light will grow at **slower rate** - as result, stem will **grow towards direction of light - positive phototropism,** allowing plant to **maximise the absorption of light** for photosynthesis
41
2.84 describe the phototropic responses of roots
- during growth, auxin produced at tip will be **redistributed** by **light receptors** to **shaded** side of root - as auxins **inhibit growth** of root cells, cells on shaded side won't grow - whilst cells on unshaded side exposed to light will grow larger & elongate (inc in elasticity allows cell to absorb more water to grow larger in size) - as result, root grows **against** direction of light - **negative phototropism**
42
2.85 what is the role of auxin in the phototropic response of stems?
auxin **changes the elasticity** of cells to alter the growth of cells, therefore **changing direction of growth** (inc in elasticity allows cell to absorb more water, causing size of cell to inc & bend towards specific direction) also kinda covered in 2.84
43
what is the definition for a tropism?
the growth of a plant towards a directional stimulus
44
definition for phototropisms?
growth responses to light from one direction
45
definition for geotropism?
the growth response towards/away from gravity

Biology (17 decks)

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