The Human Nervous System Flashcards
How do cells carry out respiration to release energy from glucose?
they use enzymes
what do enzymes and cells require in order to work?
very stable conditions
enzymes cant work well if…
the conditions around them change too much
homeostatis definition?
the maintenance of a constant internal environment
what three things does your body maintain?
- your blood glucose concentration
- body temp
- water balance
Explain the three stages of the automatic control system..
-receptor cells detect the changes in the environment
- the receptor cells pass information to a coordination centre
- the coordination centre receives and processes the information from the receptor cells
-the coordination centre now sends instructions to the effector
the job of the effector is to carry out the response or restore the optimum level
what do scientists call a change in the environment?
a stimulus
what is the job of the effector?
to carry out the response or restore the optimum level
What are the two parts of the nervous system?
- Central nervous system
- other nerves going to or from the nervous system
Explain the automatic control centre in TERMS OF NEURONES
Receptors detect a stimulus and send electrical impulses down neurones to the central nervous system
The CNS is the coordination centre. This now sends electrical impulses down other neurones to effectors and the effectors being about a response
What are effectors usually? (2 things)
- A muscle that contracts
- a gland that secretes a hormone
What are the two key roles of the nervous system?
- enables humans to react to their surroundings
- coordinates their behaviour
What is one way that shows how humans react to their surroundings?
The Reflex Arc
Explain the reflex arc in terms of neurones when you touch a hot object..
-The stimulus is detected by a receptor
-Electrical impulses now pass from the receptor along a sensory neurone to the CNS.
at the end of the sensory neurone is a synapse a chemical is released there which diffuses across to a relay neurone and reaches another synapse
once again a chemical is released
the chemical triggers an electrical impulse in the motor neurone
the electrical impulse now passes down the motor neurone to an effector in this case a muscle
the muscle now contracts and pulls the hand away from the heat
pulling the hand away is a response
What is a stimulus?
something in the environment
What is a receptor?
something you use to touch it
What is at the end of a sensory neurone?
and what happens there?
A synapse
a chemical is released
just give the stages for the reflex arc..
stimulus receptor sensory neurone synapse relay neurone synapse motor neurone effector response
Why are reflexes automatic and rapid?
There is no decision making from the conscious part of the brain
In the reaction time practical what are the..
independent
dependent and control variables?
independent- person being tested
dependent- reaction time
control- starting distance between thumb and 1st finger
Explain the Reaction Time Practical..
X measures the reaction time of Y
Y sits on a stool with upright posture
Y then places their forearm of their dominant arm across the table with their hand overhanging the edge
X holds the ruler vertically
The 0cm mark should be between Y’s first and thumb finger
X tells Y to prepare to catch the ruler with their thumb and first finger as quickly as possible when it drops
X records the measurement on the ruler that is in level with the top of Y’s thumb
this is repeated several times to calculate a mean
What are two other tests using reaction time?
- if caffeine affects reaction time
- non dominant hand vs dominant
What organ system is the brain part of?
The CNS
What does the brain control and how does it do this?
controls the complex behaviour
by containing billions of interconnected neurones
What is the top section of the brain called (the wormy one)
celebral cortex
What are the celebral cortex’s functions?
language
memory
consciousness
what is the bottom back part of the brain called (the shell one)
cerebellum
What are the functions of the cerebellum?
controls our balance
coordinates our movement