nervous system functioning Flashcards
What are the 3 functions of the nervous system?
- Receive info
- Process info
- Coordinate response
What is the role of the CNS?
- Process info from internal (ANS) and external (SNS) environment
- Activate appropriate responses
What is the role of the brain
- Receive and process information from neural pathways
- Direct action
- Make decisions (conscious)
What is the role of the spinal cord?
- Receives sensory info from body (via PNS), sends to brain for processing
- Receives motor info from brain sends to PNS
- responsible for simple motor reactions (spinal reflexes)
What is the role of the PNS?
- Carries info to the CNS from internal (muscles, organs, glands) and external environments (sensory organs)
- Carries info from CNS to appropriate muscle, organs, glands
What is the role of the somatic NS?
- Carries sensory info to CNS
- Carries motor info from CNS
- controls voluntary movement via skeletal muscles
Outline how somatic NS is involved in responses
- Stimulus is detected/received by sensory receptors on organ
- sensory info transmitted to brain/spinal cord of CNS via sensory neurons and the spinal cord
- brain process info & formulates conscious decision to initiate motor movement
- motor info transmitted to muscle via motor neurons
- activates movement
What is the role of the ANS?
- controls activity of internal muscles, organs, glands (involuntary)
- Regulate internal environment to keep us alive
What is the role of the sympathetic NS?
- automatically arouses & energises body to prepare it to confront or escape a threat
- Increase activity of most visceral muscles, organs, glands for vigorous physical activity
What is the role of the parasympathetic NS?
- Counterbalances the effects of the sympathetic NS; calms body once threat has passed
- Keeps body functioning at optimal level (efficiently)
- Maintains homeostasis
What are the physiological changes in parasympathetic and sympathetic NS?
parasympathetic: pupils constrict, salivary glands increase production, decrease heart rate, lungs contract, stomach stimulated digestion, liver decreases glucose release, intestine increases digestion, bladder contract
sympathetic: pupils dilate, salivary glands decrease production, increase heart rate, lungs expand, stomach inhibit digestion, liver increase glucose release, intestines decrease digestion, bladder relaxes
Explain why heart rate increase (1), breathing rate increase (2), pupils dialating (3), digestion is surpressed (4), increase glucose release (5) aids in survival.
1: blood moves faster-> taking O2 & glucose to muscles= more energy
2: more O2 intake= more glucose= more energy for musces
3: take in more light= enhance vision to see threats better
4: conserve energy-> energy can be directed to muscles
5: provide body more energy to deal w/ threat
What is the difference between conscious and unconscious responses to stimuli?
Conscious: reactions involve awareness/paying attention
- Usually voluntary, intentional, goal-directed
Unconscious: don’t involve awareness/can’t control occurence
- involuntary, unintentional, automatic
why is a spinal reflex adaptive?
- does not require conscious awareness/brain= faster reaction time
- increases our survival/minimising harm to body from stimulus because it saves time
What is a reflex arc?
- unconscious, involuntary, automatically occurring response to certain stimuli w/o any involvement from the brain
Outline the processes involved in the spinal reflex arc
- sensory neurons carry sensory info via the PNS to the spinal cord
- interneurons immediately relay motor info telling the body to move
- motor response occurs while brain receives original sensory message
What is the role of the neuron?
- Receive, process, transmit info to other cells.
- Form neural pathways for info to be carried
What are dendrites and its role?
branch- like extension of a neuron
- Detect and receive info from other neurons
- Passes info to soma for integration
What is the axon and its role?
singular tube like extension
- Transmit info to other neurons
What is myelin and its role?
fatty substance
- Surround and insualte axon
- Prevent interferences
- Allow messages to travel faster
What are axon terminals and its role?
small branches with knob like tips at the end of the axon
- Store and secrete vesicles containing neurotransmitters
What is the synapse and the components of it?
Site of communication between adjacent neurons
- terminal buttons of pre-synaptic neurons
- synaptic gap (space b/w neurons where neurotransmitters are released)
- dendrites of post-synaptic neuron
What is a neurotransmitter and its role?
- chemical substances produced by a neuron
- Carries messages to other neurons or cells
what is the lock and key process?
used to explain how neurotransmitters communicate neural information
Explain the lock and key process
- Each neurotransmitter has a chemically distinct shape like a unique key that can only bind to a corresponding shaped receptor site on the dentrites of the postsynaptic neuron like a key only fitting into the correctly shaped lock.
- only opens and activates the neuron when accessed by the right key.
- Allows neurotransmitter to cause excitatory or inhibitory changes to posynaptic neuron
What is an inhibitory effect?
- block or prevent postsynaptic neuron from firing
What is an excitatory effect?
- stimulate or activate a postsynaptic neuron
What is glutamate and its role?
Primary excitatory neurtransmitter in CNS
- Makes post synaptic neurons more likely to fire
- enhances neural transmission
What is GABA and its role?
Primary inhibitory neurotransmitter in CNS
- Makes post-synaptic neurons less likely to fire
- Involved in fine-tuning neurotransmission at an optimal level.
why it is important to have both excitatory and inhibitory neurotransmitters?
- both are needed for optimal lvl brain function
- Excitatory neurotransmitters ensure neurons perform a specific function
- inhibitory neurotransmitters make sure that over-excitation doesn’t occur and damage neurons
What are the 4 key motor symptoms of Parkinson’s?
- tremor
- muscle rigidity
- slowness of movement
- postural instability
Describe tremor
- continuous, involuntary shaking of the body
Describe muscle rigidity
- muscles are stiff, tight, unable to relax
Describe slowness of movement
- difficulty starting new movements/stopping ongoing movements
- decrease in fine motor movements
Describe postural instability
- cannot maintain steady, upright posture
- balance problems= difficult to prevent falling
- walking disturbances
What are some non-motor symptoms of Parkinson’s
- decreased sense of smell
- fatigue
- increased sensitivity to to temperature+sweating
- mental health (confusion, panic, anxiety, depression)
- impaired cognitive functioning (thinking, planning, decision making, memory)
What is Parkinson’s diesease?
- neurodegenerative disorder with motor & non-motor symptoms
Why is Parkinson’s described as a neurological and degenerative disorder?
- involves interference to NS functioning
- symptoms progressively worsen over time
How does Parkinson’s interfere with neurotransmission function (biological reason for motor symptoms)?
- dopamine is responsible for sending messages for smooth motor movement
- progressive death of dopamine producing neurons in substantia nigra
- lower levels of dopamine= slower/ fewer/irregular messages about voluntary movement sent to brain
- An inadequate message would be sent to skeletal muscles to perform the motor task= motor symptom
What is the role of dopamine agonist in Parkinson’s disease?
- Similar shape to dopamine= can bind to dopamine receptor= messages about movement can send
