Divisions and Subdivisions of the nervous system Flashcards
what is the function of the nervous system
the nervous system enables the brain and body to exchange neural messages and communicate with one another via neurons
what type of messages are neural messages
electro-chemical
what are the three types of neurons
motor/efferent neurons, sensory/afferent neurons, interneurons
motor/efferent neurons
transmit neural messages about motor movement from the central nervous system to the peripheral nervous system
sensory/affarent neurons
transmit neural messages about bodily sensations from the peripheral nervous system to the central nervous system
interneurons
transfer neural messages between sensory neurons and motor neurons. make up the central nervous system (brain and spinal cord)
what are the divisions of the nervous system
the central nervous system and peripheral nervous system
what are the subdivisions of the PNS
the somatic nervous system and autonomic nervous system
what is the somatic nervous system comprised of
sensory/afferent pathways which are composed of sensory neurons and motor/efferent pathways which are composed of motor neurons
what are the two types of responses
concious and unconcious
concious response
deliberate and voluntary actions that are intentionally initiated by the brain and performed by the body
what systems are used in a concious response
the central nervous system and brain and the somatic nervous system are connected
unconcious response
automatic and involuntary actions that are performed by the body independently of the brain and without concious awareness in response to sensory stimuli
what systems are involved in an unconcious response
physiological responses of the autonomic nervous system and the spinal reflex
how are unconcious responses beneficial
adaptive and protective mechanisms that aid in survival
what makes up the CNS
the spinal cord and brain (both comprised of interneurons)
spinal cord
a cable of nerve tissue that extends from the brain, connecting it to the peripheral nervous system
what are the two roles of the spinal cord
acts as an ascending tract and descending tract
ascending tracts
transmit sensory messages from the PNS to the brain
descending tracts
transmit motor messages from the brain to the PNS
role of the brain in the CNS
acts as a control centre. 1.recieves sensory info 2. processes, intergrates and organises it 3. intiates a bodily response to the skeletal muscles to respond to stimuli
role of the PNS
transmits neural messages between the CNS and the body
what is the PNS comprised of
every neuron (motor and sensory) in the body outside of the CNS (brain and spinal cord)
somatic nervous system
a division of the PNS that transmits neural messages related to voluntary motor movement through skeletal muscles in response to sensory stimuli
autonomic nervous system
a division of the peripheral nervous system that regulates visceral muscles, organs and glands and transmits neural messages to the central nervous system about their activity
what are the seven steps of the somatic nervous system
- sensory receptors detect stimuli 2. sensory neural message is transmitted via affarent pathways in the somatic nervous sytem 3. and then up ascending tracts of the spinal cord 4. \ brain processes this sensory info, coordinating and initiating a concious motor response 5. motor neural message is transmitted via efferent pathways in the spinal cord down descending tracts 6. and then the somatic nervous system to skeletal muscles 7. skeletal muscles carry out the concious motor response
autonomic nervous system
involvrf in unconcious physiological responses and controls viscera; muscles, organs and glands that are predominatley self-regulating and do not require concious control
what are visceral muscles, organs and glands
muscles, organs and glands that are not connected to the skeleton and are self regulating
what are the branches of the autonomic nervous system
the sympathetic nervous systenm and parasympathetic nervous system
what is the sympathetic nervous system
becomes dominant when a person is confronted with a threat or stressor, when dominant physiological responses occur to energise the body (involved in fight/flight)
parasympathetic nervous system
becomes dominant during rest and physical inactivity, when dominant, physiological responses occur that maintain optimal and balancing functiong/homeostatis
what changes depending on parasympathetic/sympathetic is dominant
the unconcious physiological responses of the visceral muscles/organs and glands
what are the unconcious physiological responses of the sympathetic nervous system
heart rate increases to increase blood flow and breathing rate increases as lung airways expand (both enable high levels of physical activity). pupils dilate allowing more light to enyter the eyes (improving vision). adrenal glands secrete stress hormones (energises body). sweat glands are activated, increasing perspiration. digestion and salvation is inhibited, as well as bladder relaxes (conserves energy) and body releases more glucose to energise the body
what are the unconcious physiological responses of the parasympathetic nervous system
heart beats at a steady and regular rate (that supports optimal and balanced functioning). lung airways constrict, (enabling a steady and regular breathing rate). pupils contrict (allowing for an appropriate amount of light to enter the eyes for adequate vision). adrenal glands do not secret stress hormones, sweat glands are regulated (controlling perspiration). digestion occurs normally, saliva is stimulated. the bladder constricts and urination is controlled. the body releases less glucose (to rest and prevent the depletion of energy stores)
spinal reflex
an unconcious response to sensory stimuli that is initiated by interneurons in the spinal cord independently of the brain. the path along which the neural signal is transmitted as part of the spinal reflex is called the reflex arc
purpose of the spinal reflex
to protect the body from injury/harm and increase chances of survival, is considered an adaptive response
what are the three types of specialised neurons and their purpose in the spinal reflex
sensory/affarent (detects sensations), interneuron/rely neuron (links motor and sensory neurons in spinal cord), motor/efferent (enable response)
steps of the spinal reflex
- a dangerous/harmful sensory stimulus is detected by sensory recpetors, which transmited this message via sensory neurons in the SNS to the spinal cord 2. an interneurons in the spinal cord relays this sensory neural signal from a sensory neuron to a motor neuron as a motor neural signal, initiating an unconcious and automatic motor response 3. the motor message is transmitted via motor neurons in the SNS to skeletal muscles, which carry out the unconcious motor response 4. the sensory message continues to travel up ascending tracts in the spinal cord to the brain. The brain then registers the sensation that triggered the spinal reflex
