TOPIC B5 - Homeostasis And Response Flashcards
What is Homeostasis?
Where your body maintains a constant internal environment.
Why is Homeostasis so important?
Because your cells need the right conditions to work properly.
You have loads of control systems that keep the conditions in your body steady. Give 4 examples:
1) keep your body temperature steady.2) blood glucose level steady.3) water level steady.4) salt level steady.
What are the control systems in your body like?
Automatic - you don’t have to think about them.
What is used to help control conditions in the body?
The nervous systems or hormones.
What 3 parts are control systems made up of?
1) Receptors.2) Coordination centres (brain, spinal cord, pancreas)3) Effectors.
If the level of something in your body is too high, what does the control system do?
Decreases the level.
When the level of something in your body is too low, what does the control system do?
Increases the level.
What is a stimulus?
A change in the environment.
If the level of something changes, what happens? Step 1.
A receptor detects a stimulus and sends information to the COORDINATION CENTRE.
A receptor detects a stimulus and sends information to the COORDINATION CENTRE. Then what happens? STEP 2.
The coordination centre receives and processes the information and organised a response.
The coordination centre receives and processes the information and organised a response. Then what happens? STEP 3.
An effector produces a response and returns the level to its optimum level.
What does the receptor do?
Detects a stimulus (change in the environment.)
Give 3 examples of receptors and where they are found:
1) Light receptors - in eyes.2) Sound receptors - in ears.3) Smell receptors - in nose.
What does the NERVOUS SYSTEM mean we can do?
React to our surroundings and coordinate our behaviour.
What parts is the Nervous System made up of? (5)
1) Central Nervous System (CNS)2) Sensory Neurones.3) Motor Neurones.4) Receptors.5) Effectors.
What does the Central Nervous System consist of?
The brain and spinal cord.
How is the CNS connected to the body?
By sensory neurones and motor neurones.
What are neurones?
Nerve cells.
What do sensory neurones do?
They carry information as electrical impulses from the receptors on the CNS.
What do motor neurones do?
They carry electrical impulses from the CNS to the Effectors.
What do Effectors do?
They respond to electrical impulses and bring about a change.
Name the 2 Effectors:
Muscles and Glands.
How do the Effectors (muscle and glands) respond to electrical impulses?
Muscles contract & glands release hormones.
What are receptors?
Cells that detect stimuli. Different receptors detect different stimuli.
The CNS is a…
Coordination centre.
What does the CNS do when it receives information from receptors?
Decides what to do about it - coordinates a response which is carried out by the Effectors.
What is a synapse? (In Reflexes)
The connection between two neurones.
Why are Reflexes good?
They can help stop you getting injured because they are quick.
What is a Reflex Arc?
The passage of information from a receptor to the effector.
Where do the neurones in the reflex arcs go through?
The spinal cord or through an unconscious part of the brain. (The part of brain not involved in thinking)
Give the 7 bullet points that summarise how your CNS coordinates a response:
1) Stimulus.2) Receptor.3) Sensory Neurone.4) CNS.5) Motor Neurone.6) Effector.7) Response.
What is the only difference between Reflexes and CNS responses?
A relay neurone is involved instead of the CNS in Reflexes. The CNS doesn’t coordinate the response.
Why does your body need to control the temperature in your body?
Because enzymes work best at specific temperatures - we don’t want them to denature.
Why does your body need to control the amount of water in your body?
Because water is required for chemical reactions.
Why does your body need to control the amount of glucose in your body?
Because glucose is needed for energy.
Why does your body need to control the amount of ions inside (salt)?
Because ions are needed by the Nervous system.
What is reaction time?
The time it takes to respond to a stimulus.
How is Reaction Time measured?
Often less than a second so it is measured in milliseconds.
What can affect Reaction Time? (3)
Factors - age, drugs or gender.
How to measure reaction time: PRACTICAL:
Hold a ruler upright between someone’s thumb and forefinger - they can’t grip it. Let go and mark down where they catch it.
Reaction Time PRACTICALThe higher the number on the ruler the…
Slower their reaction time.
What do you need to make sure to do in the reaction time practical?
Repeat the test several times and calculate the mean distance that the ruler fell.
3 variables to keep the same in the ruler practical:
1) Same person to catch the ruler each time.2) Same hand to catch the ruler (left/right.)3) Ruler should be dropped from the same height.
What are hormones?
Chemical messengers that are released in the blood by glands.
What are the glands called that release hormones? What do they make up?
Endocrine glands - they make up your Endocrine System.
Where are hormones carried to?
To particular cells in particular organs - called target organs.
What is the Pituitary Gland sometimes called?
The master gland.
Why is the Pituitary Gland known as the master Gland?
Because it produces many hormones that regulate body conditions.
What do the Hormones released by the Pituitary Gland do?
Act on other glands - they make the glands release hormones that bring about change.
What do the Ovaries (glands) produce and what do they do?
Oestrogen - involved in the menstrual cycle.
What do the Testes (glands) produce and what do they do?
Testosterone- controls puberty and sperm production in males.
What do the Thyroid Glands produce and what do they do? (3)
Thyroxine - involved in regulating things like the rate of metabolism, heart rate and temperature.
What do the Adrenal Gland produce and what do they do?
Adrenaline - prepare the body for a ‘flight or fight’ response.
What does the Pancreas produce and what do they do?
Insulin - to regulate the blood glucose level.