B1.2 - Nerves and Hormones Flashcards
What is a neurone?
A cell that transmits electrical nerve impulses, carrying information from one part of the body to another.
What three neurones are involved in a reflect action?
Sensory, relay and motor neurones
What is the function of a sensory neuron?
Carry impulses from the receptor to the spinal cord.
What is the function of a relay neuron?
Carry impulses through the spinal cord and up to the brain and from the brain back along the spinal cord.
What is the function of a motor neuron?
Takes impulses from the spinal cord to an effector.
What is the function of a receptor?
Cells that detect stimuli or changes in the environment. E.g. Eyes, ears, tongue, nose, skin.
What is the function of an effector?
Can be a muscle that is made to contract or a gland that secretes a chemical for example a hormone.
What is the function of a synapse?
The junction of two nerve cells
Describe what happens in a reflex arc
When pain is detected by a receptor, it sends an impulse along a sensory neurone to a relay neurone in the spinal cord. The relay neurone sends an impulse in an arc via a motor neurone to an effector, a muscle, which contracts. This is called a reflex action. It is automatic and very quick.
Why do we need to maintain a constant body temperature?
Body temperature is kept around 37˚C because this is the best temperature for enzymes which speed up chemical reactions inside the body.
What is a hormone?
A chemical messenger
Where are hormones produced?
Glands
How do hormones travel around the body?
In the bloodstream
Which glands control the menstrual cycle?
Pituitary gland
What is the role of follicle stimulating hormone (FSH)?
Stimulates the ovary to produce a follicle. The follicle produces oestrogen.