Chapter 34:Nervous System Flashcards
Name two main parts of the central nervous system in humans
Brain ,spinal cord
Difference between CNS and PNS
The CNS is made up of brain and spinal cord while the PNS is the network of nerves in the rest of the body.
What is a neuron
a nerve cell
Name the three types of neurons
Sensory Neurons
Interneurons
Motor Neurons
What does PNS stand for?
Peripheral Nervous System
What does CNS stand for?
Central Nervous System
What are sensory neurons?
They carry impulses from receptors to sense organs to the CNS
What are motor neurons?
They carry impulses from CNS to effector organs.
What are interneurons?
They carry information between sensory and motor neurons
What is the function of the dendrite?
carry impulses towards cell body
What is the function of the axon?
carry impulses from cell body
What is the function of the cell body?
forms neurotransmitter chemicals
What is the function of the schwaan cell?
forms neurotransmitter chemicals
What is the function of the myelin sheath?
insulates the electrical impulses
What is the refractory period?
Neuron must recover for a fraction of a second before it can transmit again
What is the all or nothing effect?
If a stimulus is too weak or does not meet the threshold the nerve impulse is not carried.
What is a synapse?
a region where two neurons come into close contact.
What is the function of the synapse?
Transmit impulse
Control the direction of the impulse
How does the nervous system work?
- Stimulus detected
- Message passes along neurons
- Messages are processed
- Neurons stimulate the muscles/gland to respond
What is a nerve impulse?
An electrical impulse caused by the flow of ions across the membrane which travels along the dendrites and axon to the neurotransmitter swelling.
How does a nerve impulse work?
- The nerve impulse reaches the Threshold.
- The inside of the axon becomes positive and the outside becomes negative.
- Energy is supplied to the nerve impulse.
- Refractory Period occurs.
What happens near the synapse?
1.Neurotransmitter molecules released into synaptic cleft
2.They diffuse across the cleft and bind to receptors on the post-synaptic neuron.
3.Neurotransmitter molecules are rapidly broken down by enzymes and then reabsorbed by the pre-synaptic neuron
.
Examples of Neurotransmitters:
Acetylcholine
Noradrenaline
Dopamine
Serotonin
What is a synaptic cleft?
is the tiny gap between two neurons at a synapse
What protects the brain?
meninges
cerebrospinal fluid
skull
What is the function of cerebrum?
Movement Intelligence Emotion Receiving Information From Sense Organs language Personality
Cerebellum
Motor Movement Coordination
Balance
Walking
Medulla Oblongata
Involuntary processes
Hearbeat
Breathing
Blood Pressure
Hypothalamus
Homeostasis Body Temperature Hunger Thirst Sleep Osmoregulation
Pituitary Gland
Hormones
Nervous System Disorder
Name:Parkinsons
Cause:the failure to produce a muscle neurotransmitter called dopamine in a part of the brain which results in failure to control muscle contraction
Symptoms:Trembling in hands and legs,stiffness and weakness
Treatment:Physiotherapy
How the spinal cord protected?
Vertebrae
meninges
What is in white matter?
axons
What is in grey matter?
Dendrites and cell body
Dorsal Root
contains sensory neurons
Ventral Root
contains motor neurons
Central Canal
contains cerebrospinal fluid
What is Reflex Action?
It is an automatic,involuntary,unthinking response to a stimulus.
Examples Reflex Action:
blinking
gag reflex
Advantage of Reflex Action
Fast response so protect the body from damage
