12.3 - 12.4 Flashcards
What does a basic structure of neurone consists of
dendrite
Cell body
Axon
Myelin sheath
Node of ranvier
Synaptic knob
Cell body characteristics and function
Consists of nucleus and many cytoplasmic projections (dendrites)
Integrates signals and coordinates metabolic activities
Dendrite function and characteristics
Short branches of cell body
Receive nerve impulse and send them to sell body
Axon characteristics and function
Elongated branch of body cell
Carries nerve impulses out of cell body to other neurones or effectors
Myelin sheath characteristic and function
Insulating membrane coating axon
Protect neurones
Insulator for electrical impulses
Provide nutrients for axons
Node of ranvier characteristic and function
Parts of axon not insulated by myelin sheath along regular gaps
Helps accelerate flow of nerve impulses by allowing nerve impulses to jump from one node to the other
Sypnatic knob characteristics and function
Swelling at the end of axon branch
Send signals to effector or other neurones
Types of neurones
Motor neurone
Sensory neurone
Relay neurone
Motor neurone function and location and characteristics
Receive from relay neurone
Send to effector
Ventral root of spinal nerve
Cell body at the end connected to an axon which is connected to synaptic knob
Sensory neurone location function and characteristics
Recieve from sensory organ receptors
Send to central nervous system
In dorsal root (Cell body in dorsal root ganglion)
Cell body attached to in the middle of axon
Relay neurone Location Function and characteristics
Sensory neurones - Relay neurone - Central nervous system - relay neurone - motor neurone
In grey matter
Contain no axons
What are synapses and its function
A narrow gap separating sypnatic knob from neurone dendrites
Transfer electrical signals carrying information across synapses to move from neurone to neurone
Control type of impulses that pass through them
Explain the process of transmission of impulse across synapses
Electrical impulse reach sypnatic knob
Stimulate sypnatic vesicales
Neurotransmitters released to synapse
Neurotransmitters diffuse through synapses combining to specific receptor protein
Receptor protein is on dendrite of receiving neurone
Binding stimulates initiation of next impulse
Impulse transmitted through the neurone
Voluntary action characteristics
Actions done consciously and done on our own will
Involves somatic nervous system
Controlled by cerebral cortex
Involves reaction of skeletal muscles
Involuntary actions
Actions that occur automatically without us being conscious
Involves autonomous nervous system
Controlled by medulla oblongata and hypothalamus
Involves reaction of smooth muscles and glands
Describe pathway of voluntary actions
Stimulus - Receptor - via sensory neurone - Cerebrum (Interprets) - via motor neurone - effector (Skeletal muscle) - response
Two types of involuntory actions
Three neurone reflex arc
Two neurone reflex arc
What is reflex action
Fast response from a stimulus without being controlled by brain (pulling away hand when touching sumn hot)
What is reflex arc
nerve pathway involved in reflex action
Describe three neurone reflex arc
Stimulus - sensory receptor - produce nerve impulse - sensory neurone - spinal cord - relay neurone (synapse) - motor neurone (synapses) - effector
Importance of reflex actions
Spontaneuos response without waiting for instructions from the brain (avoid injuries)
Since reflex actions involve spinal cord , brain can focus on higher level thinking
desribe two neurone reflex arc
stimulus - stretch receptor- nerve impulse - sensory neurone - spinal cord - motor neurone (Sypnapses) - effector - response
Example of two neurone reflex arc
knee jerk or patellar reflex
In knee jerk what are the what is the muscle that stimulates stretch receptor and what is and happens to the effector muscle
quadricep muscle
quadricep muscle also which contract and cause leg to jerk to front
List nervous system diseases
Multiple sclerosis
