the nervous system Flashcards
(36 cards)
Depolarisation
Voluntary responses
mainly under conscious control, but some voluntary movements, such as walking, require less conscious attention.
the two types of involuntary response
autonomic and reflex
autonomic response
regulate the body’s internal environment
reflex response
mainly affect those muscles that are normally under voluntary control.
The 2 main components of the nervous system
- CENTRAL NERVOUS SYSTEM
- PERIPHERAL NERVOUS SYSTEM
What does the CNS consist of
- brain
- spinal chord
What does the PNS consist of
- nerves
- ganglions
What is a ganglion
A cluster of nerve cells
What is a nerve
A bundle of fibres composed of neurones that connect body parts to the CNS
What are the 2 types of neurones that the PNS consists of
- Autonomic
- somatic
What are the 2 components of automatic neurones
Sympathetic (fight or flight) and parasympathetic (rest or digest)
What happens during sympathetic responses
- heart rate increases
- blood pressure increases
- pupillary response
- adrenaline and glucose levels rise
- digestion levels decrease (less focus needed on it)
What happens during a parasympathetic response?
- blood pressure lowers
- heart rate lowers
- lower adrenal & glucose function
- increased function of digestive system
What are the components of somatic nerves
Motor and sensory
what are the main types of nerves?
- motor neurone
- sensory neurone
- inter neurone (relay)
lengths of the dendrites and axon in a motor neurone
- short dendrites
- long axon
where are the dendrites and cell body located in a motor neurone
IN the spinal chord & the axon is OUTSIDE the spinal chord
what is the function of the motor neurone
to conduct the impulse to the effector (muscle or gland)
lengths of the dendrites and axon in a sensory neurone
- long dendrites
- short axon
what is the function of a sensory neurone
- to carry messages from peripheral sense organs to the CNS
- conduct impulses to the spinal chord
where are the cell body and dendrite located in the sensory neurone?
- OUTSIDE the spinal chord
- cell body is located in the **dorsal root ganglion **
what is the function of an interneurone
- relay message from sensory neurone to motor neurone
- is used as a quick bypass since full circle is too long- used ONLY for threats
- chain between sensory & motor neurone
key features of a reflex response
- rapid
- reduces damage to tissues
- does NOT have to be learnt
