The Nervous system Flashcards
Define neuron
a single nerve cell
function of a sensory neuron
carry electrical messages (ion) from the peripheral nervous system to the CNS
function of a motor neuron
carry electrical messages away from the CNS to the peripheral nervous system
function of an interneuron
converts sensory messages to motor messages in the brain/spinal cord
Neurotransmitter
a chemical produced by the synaptic knob that carry an electrical impluse across the synaptic cleft to the next neuron
reflex action
immediate,involuntary and automatic response to a stimulus not under consious control
reflex arc
pathway taken by a reflex action through the spinal cord
grey matter
rich in cell bodies
white matter
rich in axons
where is the CNS
brain and spinal cord
Peripheral nervous system
all nerves that feed into the CNS
Enzymes
biological catalyst
What is the nervous system composed of
Central Nervous System- brain + spinal cord.
Peripheral Nervous-all other nerves in body
What do nerves do
carry messages around the body in the form of electrical messages called ions.Nerves are made up of nerve cells called neurons
What are the three types of neurons
sensory neuron, motor neuron,interneuron
Dendrite
located @ one end of the neuron, picks up electrical impluses from axon of previous cell
cell body
contains a nucleus and controls the activities of the neuron
schwann cells
produce myelin sheath. these cells form a protective layer
myelin sheath
fat rich layer that acts as a insulator and speeds up rate of transmission of electrical impluse
receptor
group of cells that detect a stimlus
axon
carries electrical impluse along a nerve
synaptic knob
found at end of axon, produces neurotransmitter
synaptic cleft
gap between axon of one neuron and dendrite of another neuron
synapse
region including axon of one neuro and dendrite of another neuron
neurotransmitter
chemical produced to carry electrical impluse across a synptic cleft (eg dopamine)
threshold
minium stimulus needed to cause an impluse to be carried in a neuron
breifly describe the all of nothing
if a stimulus is not enough, there is no impluse crried. If there is enough stimulus the impluse is carried and changes its permibility to ions. It causes the postive charge to move
what is the speed of impluse dertimined by
presence or absence of myelin sheath
How is nerve impluse transmitted across synptic cleft
electrical impluses arrives at synaptic knob.
synaptic knob produces neurotransmitter that diffuses across the synaptic cleft.
combined with receptors on postsynaptic neuron.
neurotransmitter broken down by enxymes and reabsorbed by presynaptic neuron.
functions of synpses
transmit impluses from neuron to neuron or an effector.
control direction of the impluse, they allow only one way flow.
the prevent the overstimulation of effectors.
central canal
contins cerebrospinal fluid
Dorsal root
carries sensory neurons
ventral root
carries motor neurons
ganglia
carries groups of cell bodies
Name a deficiency disease associated with the nervous system stating
a. Cause
b. Symptoms
c. Treatment
d. Prevention
Parkinsons disease
a.failure to produce dopamine
b.hand tremors,ridgid muscles,loss of sutomatic movements.
c.physiothreapy, special aids, medication that mimics/ produces dopamine.
d. no prevention
what is reflex action
Immediate, involuntary and automatic response of the body to a stimulus not under conscious control
describe the mechanism of relfex action
receptors detect harm.
impluse carried to spinal cord via sensory neuron and through dorsal root.The sensory neuron synpses with other neurons. impluse converted into motor neuron via interneuron, it is passed on to motor neuron via ventral root. muscle recieves the impluse
Note: relfex actions can be inhibited
differences between nerves and horomones
Nerves
electrical messages
fast travelling
short lasting effect on target area
specific target area
immediate response time
Horomones
Chemical messages
slow travelling
long lasting effect on target area
general target area
slow response time
What is the front brain called
forebrain
what is the back brain called
hindbrain
list the layers of the head and its purposes
Skull, cerebofluid,meniges membrane
Name the functions of the cerebrum
its the largest part of brain.
voluntary movement, memory,thinking, intelligence
Name the functions of the hypothalamus
regulate homeostasis ( maintains a constant interal enviorment in the body inc body temp, thirst
Name the functions of the pituatary gland
produces TSH, GH(Growth horomone), FHS (Follicle stimulating horomone)
Name the functions of the Cerebellum
corrdinates movement, balance, hand-eye coordination
Name the functions of the Medulla oblongata
contains invlountary movement including breathing, heartrate and swallowing.
Name the functions of the thalamus
sends messages to different parts of the brain
