Nerves and hormones Flashcards
What are your sensory organs and what receptors do they contain?
Your eyes (light receptors), ears (sound receptors), nose (smell receptors), tongue (taste receptors) and skin
What are stimuli?
light, sound, pressure, pain, chemicals and changes in position and temperature
What is the Central Nervous System?
It consists of your spinal cord and brain, and is where all the information from the sensory organs are sent
What do neurons do?
They transmit the information as electrical impulses
What are effectors?
Muscles and glands that respond to electrical impulses
What are synapses and how does information travel across them?
They are gaps which connect two neurons, and the electrical impulse in the neuron triggers chemical which go across the gap and set off a new electrical impulse in the next neuron
What are reflexes?
They are automatic responses to stimuli
What do reflexes do?
They help prevent injury
What is the reflex arc?
The passage of information in a reflex
What does a reflex arc consist of?
The stimulus triggers the receptor, which sends an electrical impulse down the sensory neuron, then crosses a synapse to the relay neuron, then crosses another synapse to the motor neuron, then reaches an effector which responds
What are hormones?
Chemical messengers sent in the blood, carried by the blood plasma to activate target cells
Where are hormones produced?
Glands
What are the differences between nerves and hormones?
Nerves are very fast and precise, but only last for a short time, whereas hormones are slower and act in a more general way, but last for a long time
What is the menstrual cycle?
The monthly release of an egg from a woman’s ovaries, and the build up and break down of the lining of the uterus
What happens on day 1?
The uterus lining starts to break down so bleeding starts
What happens on day 4?
The lining of the uterus starts to build up again, so bleeding stops
What happens on day 14?
An egg is released from the ovary
What happens on days 14-28?
The wall of the uterus is maintained and if on fertilised egg has landed on the uterus, the whole cycle begins again
What does FSH do and where is it released?
It causes and egg to mature in one of the ovaries and stimulates production of oestrogen and it is produces in the pituitary gland
What does oestrogen do and where is it released?
Stops release of FSH and causes release of LH, and it is produced in the ovaries
What does LH do and where is is released?
It stimulates the release of an egg and is produced in the pituitary gland
How does oestrogen reduce fertility?
It prevents the release of an egg and if taken every day it inhibits the production of FSH, so egg development is stopped
How does progesterone reduce fertility?
It stimulates the production of thick cervical mucus which stops the sperm from reaching the egg
What are the pros of the pill?
It is over 99% effective at preventing pregnancy and reduces the risk of some types of cancer
