U3AOS1A - Nervous System Functioning Flashcards
Cambridge 3B-C
Define nervous system
- Complex, highly organised network of specialised cells that enable the brain to perceive internal & external information as well as respond appropriately
What is a neural pathway?
- A chain of neurons that connect one part of the nervous system to another
What does the central nervous system consist of?
- Brain
- Spinal CORD
What is the function of the CNS?
- Receives sensory information from the PNS
- Sends motor information to the PNS
Describe the role of the brain in the nervous system
- Regulates and guides all other parts of the NS
- Responsible for…
- Vital bodily functions like breathing, heart rate and digestion
- Receiving information from the outside world via the senses and coordinating appropriate responses
- Higher order functions like planning, thinking and learning
- Emotions, personalities, sense of humour
Describe the role of the spinal cord in the nervous system
- Cable-like column of nerve fibres that extends from the base of the brain to the lower back and is encased by a series of bones called vertebrae
- Helps brings sensory messages to the brain
- Takes motor messsages back
Describe with keywords how the spinal cord helps the brain communicate
SAME (acronym)
- Two-direction highway
- Sends sensory messages towards the brain through afferent tracts
- Sends motor messages away from the brain through efferent tracts
- Designed this way for speed
- Exception of spinal cord reflex
What would injury to the spinal cord cause?
- Brain losing sensory information and control over the body
- Severity depends on…
- Where the spinal cord is injured
- Extent of injury
- Generally, the higher up on the spine the injury is, the greater number of connections are disturbed
What does the peripheral nervous system consist of?
MOG
- Everything outside the brain and spinal cord
- Muscles, Organs and Glands
Why aren’t interneurons present in the PNS?
- Interneurons are only in the spinal cord
- The spinal is not part of the PNS
What is the function of the PNS?
- Sends sensory information to the CNS
- Recieves motor information from the CNS
What is the PNS broken down into?
-
Somatic NS
- Information to skeletal muscles to initiate voluntary movement
- Sensory information to CNS based on 5 senses
-
Autonomic NS
- Between CNS and organs and glands to ensure they are regulated without conscious awareness
Why is the autonomic NS referred to as autonomous? Is this accurate?
- Most aspects of it are self regulating and occur without conscious effort
-
Not an accurate description because some parts of the ANS we can consciously control
- For example blinking and breathing because it is linked to the cerebral cortex
When can you become consciously aware of ANS functions?
- In intense situations (can be good or bad)
- For example getting into your dream university or getting up to do an oral presentation
What are the subdivisions of the autonomic nervous system?
-
Sympathetic NS
- Prepares the body for action, to deal with a potential threat
- Activates the fight-flight-freeze response
-
Parasympathetic NS
- Maintains the body in a state of homeostasis
- Returns body to state of calm following stress or heightened arousal
- Counterbalances sympathetic
-
Enteric
- Embedded within the walls of the gastrointestinal (digestive) tract
- Extensive two-way connections with the CNS
- Can function independently of the brain and carry out its functions without communicating with the brain
- Contains living organisms called gut microbiota that maintain gut health and functioning
Name 4 examples of responses by the sympathetic NS to a threat
-
Pupils dilating
- Allows more light into the eye to see better
-
Heart rate, blood pressure and breathing rates increasing
- Accelerates oxygenated blood flow to the muscles
- Energy being diverted to muscles from functions such as digestion
- Conserves energy for responding to the threat
- Increased sugar and fat being released into the blood
- Provide energy
Why is the sympathetic nervous system dominant in the face of a threat?
- Main function is to increase arousal
- Readies body for a quick response (FFF response)
How do the sympathetic and parasympathetic NS function?
- The sympathetic and parasympathetic nervous systems do not function in an ‘on/off’ or ‘either/or’ way
- They are both active at the same time but one tends to be dominant over the other
- Parasympathetic NS dominates during normal day-to-day activities
How do the enteric nervous system and the central nervous system interact?
- Two-way; Independent and interdependent
- The ENS and CNS communicate in order to manage your wellbeing and control your digestive system
- ENS controls 90% of bodys serotonin