U3 AOS1 - DP1 Flashcards
Central Nervous System (CNS)
consists of the brain and the spinal cord and processes and coordinates responses to sensory stimuli
Two divisions of the CNS
Brain and Spinal Cord
Brain
a complex structure that receives and processes sensory stimuli from the body and coordinates responses, including voluntary movements, emotions and conscious thought
Spinal cord
a dense bundle of nerves that carries sensory information from the body to the brain and motor information from the brain to the body
Two main roles of the spinal cord
To carry incoming sensory information from the body (peripheral nervous system) towards the brain for processing and to carry motor information initiated by the brain towards the body (peripheral nervous system)
Spinal Reflex
an involuntary and unconscious response to a stimulus involving the spinal cord, which occurs without input from the brain
Spinal reflex - model answer
Sensory receptors in the (something) detect the (something) stimulus
Sensory neurons carry sensory message (stimulus) in an afferent direction to the CNS.
Interneurons intercept the message and produce a motor response.
Motor neurons carry response message in an efferent direction to the skeletal muscles.
Skeletal muscles perform a reflex response (what is the response) without input from the brain.
Peripheral nervous system
all the nerves outside of the central nervous system that carry messages between the central nervous system and muscles, organs and glands throughout the body
Peripheral nervous system subdivisions
Somatic nervous system and autonomic nervous system
Somatic nervous system
carries sensory information to the central nervous system and motor information to the body. It also controls skeletal muscles, voluntary movement and is conscious
Autonomic nervous system
controls the body’s internal environment in self-regulated manner, which means that it performs most of its functions without conscious awareness (unconscious / involuntary). It controls visceral muscles
Subdivisions of the Autonomic nervous system
Sympathetic nervous system and Parasympathetic nervous system
Sympathetic nervous system
increases our arousal, readying the body for a quick response. Fight/flight response
Examples of responses by the sympathetic nervous system
- pupils dilating to allow more light into the eye to see better
- heart rate, blood pressure and breathing rates increasing to accelerate oxygenated blood flow to the muscles in order to respond to the threat
- energy being diverted to the muscles from functions such as digestion to conserve energy for responding to the threat
Parasympathetic nervous system
maintains a balanced internal state, otherwise known as homeostasis and it restores the body to a calm state after a threat has passed. Freeze response.
Examples of responses by the parasympathetic nervous system
Heart rate and breathing rate drops
Temperature drops
Unconscious response.
any response of our nervous system that does not require awareness eg. shivering when cold and sweating when hot
Conscious response.
any response of the nervous system that requires awareness. eg. putting a jumper on if you feel cold
