P2- Homeostasis Flashcards
What is homeostasis?
The regulation of conditions inside the body to maintain a stable internal environment, in response to both internal and external conditions.
Why does the body need to maintain optimal conditions?
The body needs to maintain optimal conditions for optimal enzyme action and cell function.
Examples of internal conditions:
Blood pH, blood glucose concentration
Examples of external conditions:
Room temperature, amount of fluid drank
In what order are signals passed along the control system?
receptor ➔ coordination centre ➔ effector
What is the role of a receptor?
Detects changes in the internal or external environment.
Detects a stimulus
What is the role of the coordination centre?
Interprets changes and organises a response.
Where are coordination centres found in the body?
Spinal cord, brain
What are the 2 types of effectors and how do they work?
Muscles: contract in response to a nervous impulse
Glands: secrete hormones.
What is faster, the nervous system or the endocrine system?
The nervous system is much faster acting as it relies on electrical impulses that can travel very quickly.
Which system acts more generally around the body, the nervous system or the endocrine system?
The endocrine system acts more generally as it involves releasing hormones into the blood stream which means they spread throughout the entire body.
What is negative feedback?
When levels of something get to high, they’re brought back down. When the levels of something get too low they’re brought back up.
What does negative feedback involve?
A reversing change.
What passes along nerve cells?
Electrical impulses
What is the gap between two neurones called?
A synapse
What is a synapse?
The gap between two neurones.
The nerve signal is transferred by chemicals which diffuse (move) across the gap.
These chemicals then set off a new electrical signal in the next neurone.
What is the role of a sensory neurone?
Transfers a signal from a receptor to the central nervous system.
What is the role of a motor neurone?
Transfers a signal from the central nervous system to an effector.
What is the role of a relay neurone?
To transfer a signal from a sensory neurone to a motor neurone.
What are reflexes?
A reflex is an automatic response to a stimulus. They are fast and automatic.
What is the pathway of a reflex arc?
stimulus ➔receptor ➔ sensory neurone ➔ relay neurone➔ motor neurone ➔ effector ➔ response
Reflex examples:
Bee sting, touching a hot pan
Why are reflexes important?
They protect us from harm.
