B5 Flashcards
What is homeostasis?
Maintaining a stable internal environment in response to changes in both internal and external conditions.
Homeostasis is critical for the proper functioning of cells and processes like enzyme action.
Why is homeostasis important for cells?
Cells need the right conditions to function properly.
This includes optimal conditions for enzyme action.
What are the main components of automatic control systems in the body?
Receptors, coordination centres, and effectors.
Coordination centres include the brain, spinal cord, and pancreas.
What mechanism do automatic control systems use to maintain stability?
Negative feedback.
Negative feedback helps counteract changes that disrupt homeostasis.
What is a stimulus in the context of homeostasis?
A change in the environment.
Stimuli can be related to various factors like temperature, glucose levels, or water content.
What role does the coordination centre play in homeostasis?
Receives and processes information, then organizes a response.
It acts as a control hub for responding to stimuli detected by receptors.
How do effectors contribute to homeostasis?
They produce a response that counteracts changes and restores optimum levels.
Effectors can include muscles or glands that enact the necessary changes.
Fill in the blank: The level of something that is too high or too low is detected by a _______.
receptor
True or False: Negative feedback mechanisms operate consciously.
False.
Negative feedback processes occur automatically without conscious thought.
What happens if effectors continue to be stimulated without regulation?
They may cause the level to change too much away from the ideal.
This highlights the importance of continuous feedback in maintaining homeostasis.
What is the primary function of the nervous system?
To respond to stimuli and coordinate behavior
Organisms need to respond to changes in the environment to survive.
What are receptors?
Cells that detect stimuli
Different types of receptors include taste receptors and sound receptors.
What is the Central Nervous System (CNS) composed of in vertebrates?
The brain and spinal cord
The CNS is connected to the body by sensory and motor neurones.
What do sensory neurones do?
Carry information as electrical impulses from receptors to the CNS
They play a crucial role in transmitting sensory information.
What are effectors?
Muscles and glands that respond to nervous impulses
Effectors can contract muscles or secrete hormones.
What is the role of motor neurones?
Carry electrical impulses from the CNS to effectors
They facilitate the response of muscles and glands.
How does the CNS coordinate a response?
Receives information from receptors and decides on a response
The response is executed by effectors.
Fill in the blank: The CNS is a __________ centre.
coordination
It integrates sensory input and determines appropriate actions.
What is a stimulus?
A change in the environment that triggers a response
Examples include spotting a predator or changes in light.
Describe the pathway of information from a stimulus to a response.
Stimulus → Receptor → Sensory neurone → CNS → Motor neurone → Effector
This pathway illustrates how the nervous system processes information.
True or False: All effectors are muscles.
False
Effectors include both muscles and glands.
What happens when a bird spots a cat?
The bird’s receptors are stimulated, and it flies away
This is an example of the nervous system responding to a threat.
What type of cells cover the retina of the eye?
Light receptor cells
These cells are essential for vision.
What is the connection between two neurones called?
A synapse
How is the nerve signal transferred across a synapse?
By chemicals that diffuse across the gap
What do the chemicals released at a synapse do?
They set off a new electrical signal in the next neurone
What are reflexes?
Rapid, automatic responses to certain stimuli
Do reflexes involve the conscious part of the brain?
No, they do not involve the conscious part of the brain
Give an example of a reflex action in response to bright light.
Pupils automatically get smaller
What hormone is released automatically when someone gets a shock?
Adrenaline
What is the passage of information in a reflex called?
A reflex arc
Through which parts of the nervous system do the neurones in reflex arcs go?
Through the spinal cord or an unconscious part of the brain
What type of neurone carries impulses from receptors to the CNS in a reflex arc?
Sensory neurone
What happens when impulses reach a synapse between the sensory neurone and the relay neurone?
Chemicals are released and cause impulses to be sent along the relay neurone
What connects sensory neurones to motor neurones in a reflex arc?
Relay neurones
What happens when impulses reach the motor neurone in a reflex arc?
Chemicals are released and cause impulses to be sent along the motor neurone
What is usually the effector in a reflex action?
A muscle
Fill in the blank: Reflexes help prevent _______.
[injury]
True or False: Reflex actions require conscious thought.
False
What does the muscle do in response to a reflex action?
It contracts and moves away from the stimulus
Why are reflexes quicker than normal responses?
Because they do not require conscious thought
What is Reaction Time?
How quickly you respond
Reaction time can often be less than a second.
What effect does caffeine have on reaction time?
Caffeine can speed up a person’s reaction time.
What is the first step in measuring reaction time with a ruler?
The person being tested should sit with their arm resting on the edge of a table.
How should the ruler be positioned for the reaction time test?
Hold a ruler vertically between their thumb and forefinger with the zero end level with their thumb and finger.
What should the person do when the ruler is dropped?
Try to catch the ruler as quickly as they can.
How is reaction time measured in the ruler test?
By the number on the ruler where it’s caught.
What indicates a slower reaction time in the ruler test?
The further down the ruler it’s caught (higher number).
What should be done after the initial reaction time test?
The person should have a caffeinated drink and wait ten minutes before repeating the test.
What must be controlled to ensure a fair test?
Use the same person to catch the ruler, same hand, drop from the same height, and no caffeine before the test.
What should the person avoid after the experiment?
Drinking any more caffeine for the rest of the day.
How can reaction time be measured using a computer?
By clicking the mouse or pressing a key as soon as a stimulus appears on the screen.
What advantage do computers have over manual methods in measuring reaction time?
They remove the possibility of human error from the measurement.
In what unit can computers record reaction time?
Milliseconds.
What does using a computer for reaction time testing eliminate?
The possibility that the person can predict when to respond.
Fill in the blank: The mean distance that the ruler fell is used to work out the reaction time in _______.
seconds
What two components make up the central nervous system?
The brain and the spinal cord
What is the main responsibility of the brain?
It controls and coordinates all complex behaviours
What are the key functions of the cerebral cortex?
- Consciousness
- Intelligence
- Memory
- Language
What does the medulla control?
Unconscious activities such as breathing and heartbeat
What is the function of the cerebellum?
Muscle coordination
What is a neuroscientist?
A scientist who studies the brain
How can scientists learn about the brain’s functions?
By studying effects of brain damage on patients
What happens if a specific area of the brain is damaged?
It can reveal what that area is responsible for
What is the purpose of electrically stimulating the brain?
To observe effects on muscle contraction and movement
What is an MRI scanner used for?
To produce detailed pictures of the brain’s structures
What can MRI scans reveal?
Active areas of the brain during specific tasks
Fill in the blank: Knowledge of how the brain works has led to the development of treatments for _______.
[disorders of the nervous system]
What is one example of a treatment for nervous system disorders?
Electrical stimulation of the brain to reduce muscle tremors
True or False: The brain is simple and easy to study.
False
What risks are associated with investigating brain function?
- Physical damage to the brain
- Increased problems with brain function
