Flashcards
responding to change
Cards in this deck (25)
- 1Cells called receptors detect stimuli (changes in the environment). State some receptors and the stimuli they detect.■ receptors in eyes - sensitive to light
■ receptors the ears - sensitive to sound and sensitive to changes in position
■ receptors on the tongue and in the nose - sensitive to chemicals
■ receptors in the skin - sensitive to touch,pressure, pain and temperature - 2Draw a labelled diagram of a light receptor cell
- 3Describe a simple reflex action■ impulses from a receptor pass along a sensory neurone to the CNS
■ chemicals released at synapse
between sensory and relay neuron diffuse across gap
■ chemicals released at the synapse between a relay neurone and motor neurone , impulse goes to effector that brings about the response - 4what is an effector ?the effector is either a muscle or a gland, a muscle responds by contracting and a gland responds by releasing (secreting) chemical substances.
- 5how is the amount of water in the body controlled?water leaves the body via the lungs when we breathe out and via the skin when we sweat to cool us down, and excess water is lost via the kidneys in the urine
- 6How is ion content controlled ?Ions are lost via the skin when we sweat and excess ions are lost via the kidneys in the urine
- 7Why is it important to control body temperature and how is it done?to maintain the temperature at
which enzymes work best
by:
- sweating
- shivering - 8Why must blood sugar be controlled and is it doneto provide the cells with a constant supply of energy.
- insulin - 9What are hormones and how are they transported around the bodyHormones are chemical messengers secreted by glands and are usually transported to their target organs by the bloodstream.
- 10Describe the function of the 3 main hormones in the menstrual cycle■ (FSH) is secreted by the pituitary gland and causes eggs to mature in the ovaries and stimulates the ovaries to produce oestrogen
■ (LH) stimulates the release of eggs
■ oestrogen is secreted by the ovaries and inhibits the further production of FSH. - 11Describe how oral contraceptives can prevent pregnancyoral contraceptives that contain hormones such as oestrogen and progesterone inhibit FSH production so that no eggs mature
- 12Describe the problems with early birth control pills and how they have been improved– the first birth-control pills contained large amounts of oestrogen. These resulted in significant side effects
– birth-control pills now contain a much lower dose of oestrogen, or are progesterone only
– progesterone-only pills lead to fewer side effects - 13describe how IVF worksa mother is given FSH and LH to stimulate the maturation and release of several eggs.
The eggs are collected from the mother and fertilised by sperm from the father. The fertilised eggs develop into embryos. One or two embryos are inserted into the mother’s uterus (womb). - 14How do hormones control phototropism and gravitropismPlants produce hormones coordinate and control growth. Auxin controls phototropism and gravitropism
The responses of plant roots and shoots to light, gravity and moisture are the result of unequal distribution of hormones, causing unequal growth rates. - 15Why do roots grow down ? (gravitropism)Caused by unequal distribution of auxin
1.in the root more auxin acculturates on the lower side due to gravity
2. the root grows more on the side with least auxin, (inhibits growth of cells on lower side of root) making it bend and grow towards the force of gravity
3. when it has grown down the auxin becomes evenly spread again - 16why do shoots grow up ?Caused by unequal distribution of auxin
1.in the shoot more auxin acculturates on the lower side due to gravity
2. the shoot grows more on the side with most auxin making it bend and grow up away from the force of gravity
3. when it has grown up the auxin becomes evenly spread again - 17Explain why shoots grow towards the light ?Caused by unequal distribution of auxin
1. more auxin accumulates on the shaded side of the shoot
2. auxin causes shaded side to grows faster
3. therefore shoot bends towards the light - 18give 3 uses of plant hormones by farmers1. weed killers (hormones) are used to kill unwanted plants (broad leaved )
2. when cuttings are taken from plants hormones are used to encourage roots to grow before the cutting is planted
3. some hormones are used to encourage fruit to ripen - 19name 3 stimuli which affect humanslight , sound , chemicals, touch , pain, temperature changes
- 20what is a reflex and why are they importanta rapid automatic response to a stimuli
they protect us from damage - 21what are the differences in action between nerves and hormonesnervous actions are -
1. quicker
2. affect last a shorter period
3. nervous action affects specific target
4. hormones travel in blood , nervous impulse involves neurones - 22describe issues with IVFpros:
helps couples have babies
cons
1. IVF is expensive
2. some people think it is unethical when older woman have babies by IVF
3. extra embryos may be destroyed - 23describe the issues with the contraceptive pillpros
1.have helped reduce family size which 2.can reduce poverty
allows woman to plant their pregnancies
cons
1.the contraceptive pill can cause side effects
2. some people object to its use for ethical or religious reasons - 24How long is the menstrual cycle and when approximately does ovulation occurtakes 28 days , with ovulation about 14 days into the cycle
- 25draw a picture of the reflex arc
Information
- Description
- dfdfee.dddddddddddddd..dddddddddd,,ddddddd
- Created by
- gfhgfhg gfhgfhg
- Views
- 315
- Tags
- Rating