control of heart rate and tropism

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How does a photoreceptor work?
light hits receptor and bleaches light-sensitive pigments- chemical change alters membrane so more permeable to sodium causing generator potential, action potential sent along bipolar neurone to optic nereve to brain
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Explain the differences between rods and cones and where they are mainy located
rods- peripheral retina, black/white, very sensitive but low visual acuity as many join to one neurone. cones-fovea, colour, low sensitivity but high visual acuity as joint to one neurone
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How do drugs affect synaptic transmission?
1-agonists active receptor 2-antagonist block receptor 3-inhibt enzyme that breaks down neurotransmitter 4-stimulate release of neurotransmitter pre-neurone 5-inhibit release of neurotransmitter
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What are the 2 types of tropism that plants show?
phototropism- shoots positive phototropism whereas roots negative. geotropism-shoots negatively geotrophic whereas roots positve
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What is a plant growth factor?
a chemical which slows down or speeds up growth in a plant
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Describe the actions of auxin
produced in tips and diffuses backwards to stimulate cells to elongate, high conc in roots inhibits growth.
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How does indoleacetic acid control tropisms?
phototropism-IAA moves to shaded parts to curve the shoot towards light or root away. geotropism-IAA moves to underside to shoots grow upwards and roots grow downwards
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Describe the structure of the nervous system
1)CNS-brain and spinal cord 2)peripheral NS-neurone connected to CNS. 2 systems: 1)somatic NS-controls consious activity 2)automatic NS-unconsious. 2 system: 1)sympathetic NS-fight or flight 2)parasypathetic NS-rest and digest
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How are internal stimuli detected?
baroreceptors (pressure receptors) in aorta, vena cava and carotid arteries which setect blood pressure and chemorecptors in aorta, carotid arteries and medualla which monitor oxygen and carbon dioxide in blood and ph
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What happens to the heart rate when high/low blood pressure is detected?
high-medulla sends impulses to parasympathetic neurone which secrete acetylcholine, bind to SAN to reduce heart rate. Low-impulse to sympathetic neurones, secrete noradrenaline which binds to SNA to speed up heart rate
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What happens to heart rate when high O2/low CO2/high pH is detected? what happens if the opposite is detected?
meduall sends impulse to parasympathetic neurones which secrete acetlycholin, bind to SNA to decrease heart rate. opposit=sympathetic release noradrenalin to increase heart rate
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Card 2

Front

Explain the differences between rods and cones and where they are mainy located

Back

rods- peripheral retina, black/white, very sensitive but low visual acuity as many join to one neurone. cones-fovea, colour, low sensitivity but high visual acuity as joint to one neurone

Card 3

Front

How do drugs affect synaptic transmission?

Back

Preview of the front of card 3

Card 4

Front

What are the 2 types of tropism that plants show?

Back

Preview of the front of card 4

Card 5

Front

What is a plant growth factor?

Back

Preview of the front of card 5
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