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Biology Paper 2 > Unit 6: Response & Heart rate > Flashcards

Unit 6: Response & Heart rate Flashcards

1
Q

What does coordination involve?

A

nervous system and endocrine system

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2
Q

How do organisms increase their chance of survival?

A

by responding to changes in the environment

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3
Q

What is the endocrine system

A

releases hormones secreted by glands which travel to target cells

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4
Q

what are the divisions of the peripheral nervous system

A

autonomic
somatic

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5
Q

What is the function of the sensory neurons

A

possess receptors which are stimulated by a specific stimulus

impulse is transmitted to sensory to CNS

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6
Q

What is the motor neuron

A

transmit impulses to the effector (muscle/gland)

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7
Q

What is the relay neuron?

A

act as a link between sensory and motor

found in CNS

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8
Q

What is the function of the cell body

A

contains nucleus and other cell organelles

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9
Q

what is the axon

A

conducts nerve impulses

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10
Q

what is the mylein sheath

A

contains lipids and surrounds the axon
provides electrical insulation

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11
Q

What are the nodes of ranvier?

A

gaps in the myelin sheath along the axon

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12
Q

What are synaptic knobs

A

allow communication with other neurons/effectors

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13
Q

What is a reflex

A

rapid automatic involuntary response to a stimulus

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14
Q

what is a reflex arc

A

pathway taken by impulses during a reflex action

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15
Q

how many neurons are involved in a simple reflex

A

3 neurons

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16
Q

What happenes during a simple reflex

A
  • receptors detect stimulus and transmit impulses along the sensory neurons to CNS
  • sensory neurone synapses with relay neurone which passes impulse to motor neurone
  • impulses are transmitted along motor neurons to the effector
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17
Q

What are the advantages of Reflexs

A
  • prevent damage to tissues
  • escape from predators
  • detect changes so homeostasis can be achieved
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18
Q

What is a stimulus

A

a detectable change in the external/internal environment that produces a response in an organism

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19
Q

What are the function of taxes and kineses

A

maintain mobile organisms in a favourable environment

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20
Q

What is a Taxes

A

innate behavioural response
- whole animal/cell

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21
Q

What is a taxis

A

simple response in which direction of movement of the organism is determined by the direction of the stimulus

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22
Q

Which way can organisms move in taxes

A

towards (+ve) or away (-ve) from a directional stimulus

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23
Q

What is +ve phototaxis

A

movement of simple photosynthesising organisms towards light
increases their chance of survival

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24
Q

What is chemotaxis

A

movement towards/away from a high concentration of a particular substance

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25
What is kineses
involves a change in the **rate of movement** and change in **rate of turning**
26
What is a tropism?
the growth of part of a plant in response to a **directional stimulus**
27
what phototropism occurs in plant **shoots**
positive Shoots grow towards the light so leaves can absorb light for photosynthesis
28
what phototropism occurs in plant **roots**?
negative Roots grow away from the light
29
what is geotropism?
Grown towards/away from gravity
30
What geotropism occurs in roots?
positive roots grow towards gravity Increases the probability that roots will grow into soil and absorb water and mineral ions
31
What geotropism occurs in shoots
negative and positive Shoots grow away OR towords gravity
32
what is hydrotropism?
growing towards/away from water
33
what hydrotropism occurs in roots
positive roots grow towards water
34
What hydrotropism occurs in shoots?
negative Shoots grow away from water
35
what is chemotropism
Growing towards/away from chemicals
36
what chemotropism occurs in roots?
positive AND negative Roots grow towards or away from **certain** chemicals
37
What is indoleacetic acid (IAA)
auxin A plant growth factor that stimulates plant growth
38
Where is IAA produced?
in growing regions of a plant (shoots/tips) It then diffuses from these growing regions to other tissues It’s eventually an activated underrated by enzymes
39
How is IAA produced in the shoot?
cells in the shoot to produce IAA that diffuses down the shoot and is distributed equally stimulating upward growth of the shoot
40
how is IAA affected by a unidirectional light stimulus on the shoot?
causes the **movement of IAA from the illuminated side to the shaded side** of the shoot
41
what happens as the concentration of IAA builds up on the shaded side of the shoot
stimulates greater elongation of the cells on the shaded side the shaded side **grows faster**, causing the shoot to **bend towards the light**
42
what effect does a high concentration of IAA have on roots?
Inhibits growth
43
Which part of the route detects a gravitational stimulus?
The root **tip** A decapitated root does not show a geotropic response
44
The heart is myogenic. What does this mean?
Muscular contractions of the heart originate from within the heart muscle itself
45
What is the function of the heart rate increasing during exercise?
Increases blood to muscles bringing more oxygen/glucose and getting rid of carbon dioxide
46
what is the sinoatrial note?
act as a pacemaker and **initiates the heartbeat** Patch of modified muscle cells in the wall of the right atrium which **produces regular waves of electrical impulses**
47
How does the atria contract?
impulses spread rapidly through the walls of the right/left atrium causing the atria to contract together
48
What happens before atrioventricular node reacts?
there is a **0.15 second delay before** the AV node reacts to ensure the atria is empty and ventricles are full of blood and contract after the atria
49
what happens after the AV node reacts?
impulsive from the AB note travel rapidly through the purkyne tissue in the bundle of his to all parts of the ventricle
50
What happens when impulses reach the ventricles?
venteicles are stimulated to contract together starting at the bottom of the heart to push to blood up and out into the arteries
51
What neurotransmitter causes an increase in heart rate
**noradrenaline** by the sympathetic neurones
52
what neurotransmitter causes the slowing down of the heart rate
the release of **acetylcholine** by the parasympathetic neurones
53
What regulates heartrate
the cardiac centre in the medulla
54
how is heart rate sped up
medulla sends more impulses along the sympathetic neurone to the SAN noradrenaline is released from sympathetic neurones stimulating SAN
55
how is heart rate slowed down
medulla sends more impulses along the parasympathetic neurones to the SAN acetylcholine is released; inhibiting SAN
56
What effect does the increase in respiration during exercise have?
increases production of CO2
57
What is the effect of the increase in CO2 during exercise
CO2 dissolves in blood producing carbonic acid lowering the pH by increasing the conc oh H+ ions **chemoreceptors in the aortic and carotid bodies are stimulated**
58
What are the function of chemoreceptors
transmit more impulses to the cardiac centre in the medulla this increases heart rate by transmitting more impulses from the medulla via sympathetic neurones to the SAN
59
What happens when heart rate is returned to resting rate
conc of CO2 in blood had been reduced fewer impulses are transmitted from chemoreceptors to medulla
60
What is the respiratory centre?
*in the medulla* receives impulses from the chemoreceptors and increases rate of ventilation
61
What effect does increased blood flow to the heart have on the cardiac muscle?
causes cardiac muscle to **contract more strongly** pumping out an increased volume of blood
62
What are baroreceptors
*located in wall of aorta and carotid artery* detect increase in blood pressure
63
What happenes if blood pressure is above normal
baroreceptors send more impulses to medulla **stimulating the cardioinhibitory centre** and **inhibiting the cardioacceleratory** centre
64
How is the heart rate decreased
more impulses are sent from the cardiac centre along parasympathetic neurones to the SAN preventing heart from overworking

Biology Paper 2 (15 decks)

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