B5 - Homeostasis and Response Flashcards
What is homeostasis?
Maintaining stable internal conditions despite changes in the environment
Why does the body need to maintain optimal conditions?
For optimal enzyme action and cell function
What is the role of the receptor?
Detect changes in the internal or external environment
What is the role of a coordination centre?
Interpret changes and organise a response
Name two coordination centres in the body
Brain and spinal cord
Name the two types of effectors and what they do.
Muscles : contract
Glands : release hormones
Which acts faster, the nervous system or endocrine system? Explain why
Nervous system is faster, it relies on electrical impulses that travel very quickly
Which acts more generally, the nervous or endocrine system? Explain why
Endocrine, it usually involves releasing hormones into the bloodstream so they spread throughout the body
What does homeostasis rely on?
Negative feedback
What does negative feedback mean?
When the levels of something are too high, they are brought back down to optimum (and vice versa)
How does negative feedback work?
Any change in the system causes an action that reverses the change
What passes along nerve cells?
Electrical impulses
What is the gap between two neurones called?
Synapse
What is released across a synapse?
Chemicals
What are two parts of the central nervous system (CNS)?
Brain and spinal cord
What does a receptor do in the nervous system?
Detect a stimulus
What is the role of a sensory neurone in the nervous system?
Transfer a signal from the receptor to the CNS
What is the role of a motor neurone in the nervous system?
Transfer a signal from the CNS to the effector
What is the role of a relay neurone in the nervous system?
Transfer a signal from a sensory neurone to a motor neurone
What is the pathway of a reflex arc? (7 parts)
Stimulus -> Receptor -> Sensory Neurone -> Relay Neurone -> Motor Neurone -> Effector -> Response
What is a reflex?
An automatic response to a stimulus
Use two words to describe reflexes, one is about the speed
Fast and automatic
Why are reflexes important?
They protect us from harm
How many hemispheres is the cerebral cortex split into?
2
What are the 3 roles of the cerebral cortex?
1) Consciousness
2) Interpreting senses like hearing & vision
3) Memory
What are the 2 roles of the cerebellum?
1) Muscle coordination
2) Balance
What does the medulla coordinate? (general)
Unconscious activities
Where in the brain is the medulla found?
In the brain stem
What are the 2 things the medulla regulates?
1) Breathing rate
2) Heart rate
What does the hypothalamus do?
Regulate body temperature
What regulates our body temperature?
Hypothalamus
Name 3 ways scientists study the brain
1) Study people with brain damage
2) Stimulate different parts of the brain electrically
3) Scanning the brain
Name 3 types of scans for the brain
CT scan, PET scan, MRI scan
What does the CT scan use?
X-Rays
What does the PET scan use?
Radioactive chemicals
What does the MRI scan use?
Magnetic fields
What are the 3 reasons that the brain is difficult to treat?
1) Poor access - encased within the skull
2) Possibility of negative effects - mental illness to infection
3) Hard to target with medications - very complicated
