The human nervous system Flashcards
homeostasis, nervous system, reflex actions, the brain
What is homeostasis?
The regulation of the internal conditions of a cell or organism to maintain optimum conditions for function, in response to internal and external changes.
Why do we need homeostasis?
Homeostasis is important for maintaining the best conditions for enzymes and cell functioning.
Give some examples of homeostasis
- Control of blood glucose concentrations
-Body temperature
-Water levels
Name the features of the nervous system as a control system
- Receptors- cells that detect changes in the internal or external environment called stimuli
- Coordination centres that receive and process information from receptors, they then release signals to coordinate the body. The brain does this and parts of the spinal cord
- Effectors are muscles or glands that bring responses to the stimuli to restore body conditions
How can you sum up the nervous system as a computer?
stimulus -> receptor -> coordinator (CNS) -> effector
What is a reflex?
A reflex is an automatic and rapid response to a stimulus that does not involve the conscious part of the brain. It helps protect the body from harm.
Which neurones are involved in reflexes?
- Sensory neurones
-Motor neurones
-Relay neurones connecting the sensory and motor neurones
What is a reflex arc?
A reflex arc is the pathway taken by nerve impulses in a reflex action. It involves sensory neurons, relay neurons, and motor neurons to quickly carry out the response to a stimulus, bypassing the brain for speed.
Explain the events that occur in a reflex arc
Stimulus eg flame is detected by receptor that passes to the sensory neurone -> chemicals diffuse across the synapse to carry an electrical impulse along the relay neurone -> chemicals diffuse across the synapse to carry an electrical impulse along the motor neurone-> effector -> muscle contracts to move the hand away response
Describe 3 main areas of the brain
- The cerebral cortex is the area responsible for consciousness, intelligence, memory and language
-Cerebellum is concerned mainly with coordinating muscular activity and balance
-The medulla controls heartbeat, movements of the gut, breathing
Describe 2 ways in which scientists can find out about the functions of the different areas of the brain
- Brain Stimulation (e.g., Electrical Stimulation):
Direct stimulation – Scientists apply electrical currents to specific brain areas to observe changes in behavior or movement.
Identifying functions – This helps identify the function of specific brain areas by noting what happens when they are activated or inhibited.
- Functional Magnetic Resonance Imaging (fMRI):
Blood flow monitoring – fMRI detects changes in blood flow, which occurs when different brain areas are active.
Non-invasive – It doesn’t require surgery or electrodes, making it safer for studying brain functions.
Real-time activity – fMRI allows scientists to observe brain activity in real-time during tasks like thinking or movement.
Describe the benefits and risks of stimulating areas of the brain and carrying out MRI scans on the brains of healthy people
Benefits:
Understanding the brain – Helps scientists learn how different parts of the brain work.
Medical advancements – Can lead to better treatments for brain diseases like Parkinson’s.
Safer diagnosis – MRI scans are non-invasive and don’t use harmful radiation.
Risks:
Brain damage – Stimulating the brain can accidentally harm important areas.
Ethical concerns – Experimenting on healthy people raises moral questions.
Expensive – MRI scans and brain stimulation require costly equipment and expertise.
