B10 - Human Nervous System Flashcards
(54 cards)
What is homeostasis?
The regulation of the internal conditions of an organism to maintain optimum conditions for function in response to changes
What does homeostasis do?
Maintains optimal conditions for enzyme action and all cell functions
What does homeostasis control?(3)
- Blood glucose concentration
- Body temperature
- Water levels
What is the function of the nervous system?
Enable humans to react to their surrounding and coordinate their behaviour
What is the Central nervous system made up of?
Brain and spinal cord
How does information get to the CNS?
Information from receptors passes along neurones as electrical impulses to CNS
What is the function of the CNS? Give two examples
Coordinate the response of effectors
e.g muscles contracting
e.g glands secreting hormones
How are neurones adapted to carry out the function of the nervous system?(3)
- Long axon insulated with myelin sheath to carry messages up and down the body
- Tiny dendrites which receive impulses from other neurones
- Synapses(gaps) for electrical impulse to go across
Give the 5 stages in a reflex arc
Stimulus –> Receptor –> Sensory Neurone –> Relay Neurone–> Motor neurone –> Effector —> Response
What is a stimulus?
A change in environment
What is a sensory neurone?
Impulse is transmitted from receptor to CNS
What is a motor neurone?
Impulse is transmitted from CNS to the effector
What is a reflex action?
A response that is automatic and rapid that does not involve the conscious part of the brain
Why are reflex actions important?
They are quick responses that help with survival
What is a synapse?
A gap in which two neurones join together
What happens at the synapse?
- An impulse arrived at the first axon and synapse
- Neurotransmitters/chemicals are released into the synapse
- Neurotransmitters travel and bind to the second axon
- Impulse is created in the second axon
Explain 4 stages that happen during the reflex arc
- Receptor detects stimulus, passes impulses along sensory neurone
- Junction(tiny gap) between sensory + relay called a synapse - chemical is released which diffuses across the gap and an electrical impulse passes along the relay neurone
- Another synapse between the relay and motor, chemical is released along the motor neurone
- Impulse arrives at the effector - a muscle that contracts
RP7 - Investigation into effect of a factor on human reaction time(8)
- Student A rests their elbow on the edge of a table while student B holds a ruler between student A’s thumb and forefinger
- Student B drops ruler without warning
- Student A catches the ruler and records the distance the ruler fell
- Repeat 5 more times, identify outliers and calculate and average
- Convert distance into reaction time
- Studen A drinks caffeinated drink and waits 15 mins
- Repeat 1-5
- Compare reaction time between caffeine and no caffeine
RP7 - Control variables of this practical?
Age, same student in both trials, tiredness, caffeine, start position of ruler
RP7 - How could you improve the equipment used in ruler drop tests?
Ruler with finer scale in mm
RP7 - When testing reaction time using the ruler drop test you aren’t testing reflex actions, why not?
You are using the conscious part of the brain
RP7 - What should caffeine do to reaction time?
Reduce it
RP7 - What should distractions do to reaction time?
Increase it
What is the brain and what does it do?(2)
- An organ that controls complex behaviour
- Made of billions of neurones and has different regions for different functions
