Human Nervous system Flashcards
what do all animals need to do in order to survive in their environments
respond
what are coordinating systems
systems that allow communication between the receptors and the effectors of the body so that correct reactions to any change in the environment can be bought about
what are the 2 coordinating systems that humans have
- nervous co-ordinating system
- endocrine co-ordinating system
what is the nervous system
the bodys control and comms centre
*constant flow between the environment, the brain and different parts of the body
how does the nervous system function?
- sensory function= sensory receptors that detect changes in the external environment
- integration function= central nervous system receives the information and decides which effectors need stimulus
- motor function= effectors bring about appropriate responses
what are stimuli
physical or chemical changes in the environment which are capable of causing a response in an organism
what are some examples of different external stimuli
light
temperature
sounds
atmospheric pressure
what are some examples of internal stimuli
blood pressure
tension in muscles
blood pH
what is the central nervous system (CNS) made up of
a concentrated mass if interconnected neurons that are grouped together to form
- the brain
- the spinal cord
what’re the brain and spinal cord responsible for
- processing all the info from our senses
- keeping our organs and reflexes functioning
- directing our movements, thoughts and feelings
how is the central nervous system protected
-3 connective tissue membranes called meninges
-space between 2nd and 3rd layer acts as a cusion
-the skull
what is cerebro-spinal fluid
a fluid formed from blood plasma in special area in the walls of the ventricles(spaces in the brain)
what is the brain
upper part of the spinal cord that is enclosed in a bony cranium
what is the structure near the top of the brainstem called
the cerebellum
what is the structure near the lower part of the brainstem called
medulla oblongata
what is the mass thatholds together the two hemispheres of the brain together
corpus callosum
which is a mass of myelinated nerve fibres that are bundled into large tracts
what are the folds on the surface of the cerebrum for
to enlarge the surface area so that a large amount of brain cells can fit into a small cavity
what do the outer 3mm of the cerebrum form?
the cerebral cortex
what is the frontal lobes function
- memory
- emotions
- intellegence
-voluntary movements - imagination
- judgement
- reasoning
what is the function of the parietal lobe
- sensory
- spelling
- skin sensations
- interprets hot&cold
what is the function of the temporal lobe
- speech
- language
- memory
- sound
- smell
- taste
what is the function of the occipital lobe
- vision
why is the cerebellum called ‘the tree of life’
white matter of the cerebellum looks like branches of a tree and the grey matter looks like the leaves (foliage)
what are the functions of the cerebellum
- processes information and uses it to coordinate the actions of the voluntary muscles
- controlling muscle tone
- uses information from inner ear to help maintain posture and balance
what are the functions of the hypothalamus
controls the autonomic system (homeostasis)
- body temp
- water balance and thirst
- food intake
- sleep-wake cycles
Centre for emotional response and behaviour
- pain, pleasure, fear, rage
- biological rhythms and drives(sex drive)
Controls functioning of pituitary gland
- secreting hormones (ADH)
- controlling the release of hormones
how many pairs of spinal nerves are in the PNS
31 pairs
what are the functions of the medulla oblongata
- pathway for impulses to and from the brain
- reflex centre
- breathing
- heart beat
- blood pressure
- swallowing - controls less important reflexes
- sneezing
- coughing
- salivating
what is the spinal cord
elongated rod of nervous tissue that extends from the medulla obl through the foramen magnum
approximately how long is the spinal cord
45cm long
what is the peripheral nervous system
nerves that link the CNS to the receptor and the effectors of the body.
how many pairs of cranial nerves are there in the PNS
12 pairs
what are the functions of the PNS
- collects all info from receptors and transmits the info by impulses along sensory neurons to the CNS(sensor function)
- transmits impulses from CNS by motor neurons to effectors(motor function)
what is the motor division made up of
- somatic nervous system
- autonomic nervous system
what is the function of the somatic nervous system
conducts impulses from the CNS to skeletal muscles so it controls all voluntary movements
what is the function of the autonomic nervous system
conducts impulses from CNS to cardiac muscle, smooth muscle and glands so it controls the functioning of involuntary muscles and glands
what is the autonomic nervous system made up of
- sympathetic nervous system
- parasympathetic nervous system
what is the function of the sympaathetic nervous system?
works together with the adrenalin hormone in emergencies. the stimulation of these nerves= more oxygen, glucose and blood being sent to the muscle to release more energy for the action
what is the function of the parasympathetic nervous system
enebles the body to rest and recover from sympathetic stimulation
NOT A FLASHCARD JUST NOTES**
parasympathetic sysem and the sympathetic system are involuntary reflexes
when conditions cahnge the auonomic system
- adjust blood pressure and body temp
-moves blood to where it is most needed
- increases/decreases digestive secretions
what does nervous tissue consist of
neurons and neuroglia
what is the role of glial cells
critical role in making myelin and supporting and protecting the neurons
what is the composition of a neuron
membrane, cytoplasm, nucleus and cell organelles
what is the function of the long, thin processes of a neuron
make it possible for nerve impulses to be carried for a long distance
what are the typical fibres of neuron
dendrites and an axon
what do dendrites do?
conduct imulses towards the cell body
what is the structure of a dendrite
short, tapering processes that branch extensively to provide a large surface area to receive signals from other neurons
what does an axon do?
conducts impulses away from the cell body
what is the structure of an axon
each neuron has a single axon. an axon branches extensively at its end to form terminal branches
what are the 3 different types of neurons
- sensory/unipolar neuron
- connector neuron
- motor/multipolar neuron
what is a sensory/unipolar neuron
afferent neurons because they carry impulses from receptors towards the CNS
(where the sensation occurs)
what is a connector neuron/ interneuron
multipolar neurons found in the CNS.
they receive impulses from sensory neurons and pass them on to other neurons
(make up 99% of neurons in body)
what is a motor/multipolar neuron
efferent neurons because they carry impulses away from the CNS to effectors to bring about the correct response
what direction do impulses travel in the neuron
from the dendrites to the cell body and then down to the axon
what are neurilemma
collective name for outer sheath made up of Schwann Cells
what are nerves
your mom lol jk
bundles of neurons are caled nerves in the PNS and makes a big passageway in the CNS
what is the function of nerves
carry impulses from receptors to the CNS
and from the CNS to the effectors
what is a nerve impulse
a minute electrical signals or a wave of depolarisation that is caused by a stimulus
what is the gap that separates neurons called?
synaptic cleft+adjacent membrane= synapse
what is a neurotransmitter
a chemical substance released from axon terminals at a synapse to carry impulses across the gap
what is a myoneural synapse
the synapse between the terminal branches of a motor neuron and a muscle
why are synapses important
- flow of impulses in in one direction since the trasmitter are only in the axon terminal knobs
- allow for the dispersal of impulses to other neurons
- allow filtering out of unecessary or unimportant stimuli
what is the reflex arc?
the pathway followed by impulses from a receptor to an effector to bring about a reflex action
what are the 5 essential parts of the reflex arc
- receptor
- sensory neuron
- connector neuron
- motor neuron
- effector
what is a reflex action
a fast automaticw response by an effector organ toa stimulus received by a receptor organ
what is a reflex action
a fast automaticw response by an effector organ toa stimulus received by a receptor organ
what is a reflex action
a fast automaticw response by an effector organ toa stimulus received by a receptor organ
what is a reflex action
a fast automatic response by an effector organ to a stimulus received by a receptor organ
what are the 2 different reflexes
- somatic reflexes- activate skeletal muscles
- autonomic reflexes- activate smooth or cardiac muscle
where could reflex centers be situated
brain- controlling reflexes like sneezing or breathing
spinal cord- controlling primitive reflexes like moving your hand from the ‘danger’
what is the significance of the reflex arc
- enables the body to respond quickly
- natural safety mechanisms that are mainly for protecting the body from danger
what are some examples of reflexes
- sneezing to clear nasal passages of irritants
- blinking
- yawning
- coughing
what is Alzheimer’s disease
incurable and terminal disease and is the most common form of dementia
what causes Alzheimer’s disease
no one knows, probably a combination of genetic factors
how common is Alzheimer’s disease
- not associated with any race, gender or culture
- people over the age of 65
what are the symptoms of Alzheimer’s disease
(in the early stages the most commonly recognised symptom is short term memory loss )
-confusion, irritability, aggression
- mood swings
- difficulty finding the rght words
- long-term memory loss
- withdrawal from society
what is the life expectancy after being diagnosed with Alzheimer’s
approx 7 years
eventually die because body functions are gradually lost
how can Alzheimer’s be treated
NO CURE
mental stimulation, good diet, exercise can be possible preventions and good ways to manage the disease
what are the 4 steps to drug dependency
- experimental stage
- recreational phase- drugs only used when offered
- regular-use stage - making sure you always have a supply for once or twice a week
- dependency phase(addict)- drugs become the most important aspect in life
what do drugs affect in nerves
synapses and the functioning of neurotransmitters
how can drugs be classified
according to the reactions caused:
1. hallucinogens
2. stimulants(uppers)
3. depressants(downers)
what do hallucinogens do
distort reality which results in hallucinations and delusions.
mood swings that can vary from euphoria to depression
what is one of the most common hallucinogens
dagga
what are some street names for dagga
ganja, pot, weed, grass, cannabis, marijuana, dope
what are the ‘ups’ of dagga
sense of complete relaxation and euphoria
what are the ‘downs’ of dagga
panic attacks, hallucinations, flashbacks and memory loss
what effects does dagga have on the CNS
contains mind altering substances called THC
THC stimulates the release of the neurotransmitter, dopamine(stimulates pleasure centre of brain)
what is the greatest danger of smoking dagga
can lead to people experimenting with other drugs
-dagga is known as a gateway drug
what are depressants
suppress or delay brain functions
what are the street names of heroin
smack, mud, china white
what is the most dangerous and addictive narcotic
heroin
what is a narcotic
a substance that can be habit-forming, dulls the sense, relieves pain or induces sleep
what are the ‘ups’ of heroin
sense of warmth and wellbeing, while senses of pain and insecurity are blocked out (a ‘rush’)
what are the ‘downs’ of heroin
in 6-8 hours nausea, vomiting, chills, sweating and muscle and bone pain occurs.
what effects does heroin have on the CNS
-heroin passes very rapidly through the blood-brain barrier and it mimics endorphins (creates feeling of wellbeing and bliss)
-the brain send fewer of its own endorphins and this causes and imbalance= rapid mood changes and confusion
what are endorphins
One of several substances made in the body that can relieve pain and give a feeling of well-being.
what is one of the most significant effects of heroin use?
addiction
what happens with regular use of heroin
a tolerance develops, so more heroin needs to be used to achieve the same effects
what are some withdrawal symptoms of heroin
drug craving, restlessness, muscle and bone pain and vomiting
what are stimulants
the substances stimulate the brain and increase the heartbeat= hyperactivity and excitability
what are 2 common stimulant drugs
ecstasy and tik
what are the street names of ecstasy
Adam E, roll, XTC
what are the ups of ecstacy
enhanced sense of pleasure, increased confidence, energy, peacefulness
what are the downs of ecstasy
blurred vision
sweat
clench teeth and bite inside of their cheeks
seizures
nausea & vomiting
what effects does ecstasy have on the CNS
causes neurons to release an excess amount of serotonin that isnt reabsorbed
(depletion of serotonin)
what are some negative after effects of ecstasy
-exhaustion and sleep problems
-anxiety
-drug craving
what can repeated use of ecstasy cause
-extreme depression and paranoia
- damage serotonin producing cells
- liver, kidney and cardiovascular failure
what are some street names for tik
- speed
- ice
- crank
- crystal straw
what is the stimulant drug that is called tik
methamphetamine
what are the ups of tik
increased alertness
energy
heightened sense of sexuality and euphoria
what are the downs of tik
aggression
violence
psychotic behaviour
