Nerves and Hormones Flashcards
What happens when a receptor is stimulated?
A signal is sent along neurones (nerve cells) to the brain. the brain then co ordinates the response
What are neurones?
Nerve cells that carry information as tiny signals.
What are the different types of neurone?
Sensory- Carry signals from receptors to spinal cord or brain
Relay- Carry messages from one part of the CNS to the other
Motor- Carry signals from the CNS to the effector
What is a synapse?
A gap between two neurones. Electrical signals diffuse as a chemical across a synapse and turns into an electrical signal again
What happens in a reaction:
receptor detects a stimulus - a change in the environment
sensory neurone sends impulses to relay neurone
motor neurone sends impulses to effector
effector produces a response.
What are receptors?
Groups of specialised cells that can detect a change in the environment called a stimuli.
Receptors are located in the sense organs e.g. eyes, ears
What are hormones?
Chemical substances secreted by glands which travel to target organs through the bloodstream.
How is water loss controlled?
Water loss is controlled by losing water from:
The lungs- when we exhale
The skin- through sweating
Urine- produced by the kidneys
Salt content is controlled through the skin and urine the same way
How are blood sugar levels controlled?
Blood sugar level is controlled by the release and storage of glucose controlled by insulin.
FSH:
Secreted by the pituitary gland.
- Causes an egg to mature in the ovary
- Stimulates the ovaries to release the hormone oestrogen
Oestrogen:
Secreted by the ovaries.
- Stops FSH from being produced so that only one egg matures
- Stimulates the pituitary gland to release LH (lutenising hormone) which triggers ovulation (release of mature egg)
Contraceptives:
Greatly reduces the chances of mature eggs being produced.
Contains oestrogen and progesterone which stimulates FSH production, stopping eggs maturing
Benefits of contraceptives:
Allows couples to choose when they want to start a family and when to stop having children.
Fertility treatment:
Increases a womans chance of becoming pregnant, doesnt always work.
Boosts production of mature eggs, increases chance of problems during childbirth eg premature babies
In Vitro Fertilisation:
IVF is used if quality/quantity of a mans sperm is poor. An egg is fertilised outside of the womans body and is implanted back into the uterus. FSH is used to widen the selection of eggs used for IVF.