B5 Flashcards
What’sa reaction time in a stimulus
How long it takes to respond
How are nerve signals transferred across a synapses
Chemicals diffuse across the synapses to set of new electrical impulses
What is a reflex arc
The passage of information in a reflex ( from receptor to effector )
Reflexes do not involve conscious parts of the brain . Why is this advantageous?
It means that reflexes can be rapid and automatic
What is homeostasis?
To maintain a stable internal environment, in response to changes in both internal and external condition
Give two other conditions that are controlled by homeostasis
E.g blood glucose level and body temperature
What components do all control systems include?
Receptors,a coordination centre and effectors
Why is negative feedback important
Help to maintain a stable internal environment
What does central nervous system consist of?
The brain and spinal cord
Which type of neurone carries impulses from the CNS to effectors?
Motor neurone
Why is the nervous system important in humans ?
The nervous system means that humans can react to their surroundings and coordinate their behaviour
How is the stimulus transmitted from receptors that to the CNS?
Sensory neurones carry the information from the receptors to the CNS
What is the cerebellum responsible for?
Muscle coordination
Give two things that the medulla controls?
It controls unconscious activities, such as breathing and heart rate
Suggest a part of the brain that Alzheimer’s disease affects ?
E.g the cerebral cortex (this part of the brain is responsible. For memory and language )
Why is it so difficult to study and treat the brain?
The brain is really complex and delicate
Give three new technologies used to treat vision defects ?
Contact lenses, laser eye surgery and replacement lens surgery
What is the thermoregulatory centre located ?
In the brain
Where are the receptors that detect the temperature. Of the blood located ?
In the thermoregulatory centre
How are hormones transported around the body ?
In the blood
Which gland monitors and controls blood glucose concentration?
Pancreas
Which plant hormones is used to grow cells in tissue cellular
Auxin
What does dormant mean
Seed won’t grow until it’s been through certain conditions
How could a farmer use plant hormones to kill weed without killing the plant
Auxin, would only affect the weed causing them to die
How can the plant be improved growing
Rooting powder that contains auxin so the ends are cut and will produce rapidly
Name the hormon that stimulates sperm production
Testosterone
What term is used to describe the release of an egg from an overt?
Ovulation
Describe how hormones control the growth and release of an egg
Follicle - stimulating hormone causes an egg to mature in a follicle in one of the ovaries luteinising hormone then stimulates the release of a matured egg at day 14(ovulation).
Describe the uterus changes between 1 -4 days
Oestrogen takes place.
Hormone causes lining to grow between 4 and 14 days
Towards 14- stimulates to form LH and inhibits FSH
WHats LH
LH stimulates the release of an egg
What’s an FSH
FSH stops another egg from maturing during the money cycle
Give one example of a non-hormonal method of contraception?
E.g. condom, female condom , diaphragm , spermicide , sterilisation , or abstinence
Which hormone does the contraceptive injection contain?
Progesterone
Give one ethical reason why somebody might disagree with the use of IVF
They might think that it is unethical to destroy extra embryos that are not used
Give one advantage and disadvantage of IVF
Advantage: an infertile couple is able to have a child
Disadvantage : can lead to multiply birth , mentally or physically stressful
Give three examples of substances that are removed from the body in urine
Excess water , ions and urea.
What happens in the kidneys during filtration ?
Substances are filtered out of the blood as it passes through the kidneys
Name two molecules that are absorbed back into the blood during selective reabsorption
E.g glucose and water
Suggest two reasons why you might lose more water from the body during exercise
Water will be lost from the skin in sweat and when you breathe heavily more water will be lost from the lungs
Explain how the liver and kidneys respond to eating foods high in protein
It produces ammonia as a waste product . Ammonia is toxic so it’s converted to urea in the liver . Urea is then transported to the kidneys where it filtered out of the blood and excreted from the body in urine
