The nervous system Flashcards
(15 cards)
The nervous system
Collect, process + respond to information in environment
Coordinate the working of different organs and cells in body
Brain + spinal cord
Conscious awareness
Receives info from sensory receptors
Sends messages to muscles and glands of body - thru spine
Peripheral Nervous system
Transmits messages via millions of neurons
Divided into two
ANS - Autonomic nervous system
SNS - Somatic nervous system
Somatic Nervous system
EXTERNAL
VOLUNTARY
functions
^ muscle movements + receives info about outside world through sensory receptors
transmits information from brain through spinal cord - muscles/effectors produce movements
Autonomic Nervous system
INTERNAL
INVOLUNTARY
functions
^ breathing, heart rate, digestion, sexual arousal + stress response
Broken into two
Sympathetic NS and Parasympathetic NS
Sympathetic NS
When SNS triggered, prepares body for rapid action necessary for flight or fight
Sends signals through adrenal medulla
responds by releasing adrenaline into blood
^ heart rate
^ breathing rate
dilates pupils
inhibits digestion
inhibits saliva production
contract rectum
Parasympathetic NS
When threat removed, ANS system relaxes, reduced stress response
Restores heart rate, blood pressure, digestion
The endocrine system
Network of glands throughout body
Glands secrete hormones into bloodstream, sent to target cells + organs
Helps regulate activity of cells + organs in the body - control vital physiological processes in body
The pituitary gland
gland - organs in body that produce hormones
Hypothalamus sends signals to pituitary glands
‘master gland’ located in brain
controls release of hormones from all other endocrine glands in the body
Produces ACTH, stimulates release of hormones from other glands
2 adrenal glands
Adrenal cortex
Adrenal medulla
Adrenal cortex
Produces cortisol
Regulates variety of bodily functions - cardiovascular, etc
more stress = more cortisol produced ( helps deal with LT stress)
Low cortisol = low blood pressure, poor immune system + inability to deal with stress
Adrenal medulla
Releases adrenaline and noradrenaline - prepares body for flight or fight
Adrenaline helps respond to short-term stress
Role of adrenaline in fight or flight
Hypothalamus activates sympathetic nervous system
SNS sends signals to adrenal medulla
Releases adrenaline into blood
Prepares body for fight or flight
Causes increase in heart rate, breathing + blood pressure so more oxygen reaches the heart and muscles - allows physical action
Increases blood blow in brain - rapid responses
Amygdala + hypothalamus
Threatened = amygdala mobilised
Sends distress signals to hypothalamus
Communicates with SNS , sends signals to adrenal medulla (releases adrenaline)
Preps body for fight or flight
Reasons got physiological changes
Increase heart rate - increase blood flow to organs (increase movement)
Increase breathing rate - increase oxygen to organs
Pupil dilation - light entry to enhance vision
Sweat production - regulate temperature
Other functions - to increase energy
AO3
“Tend and befriend” response
Not effective explaining females’ response
Females “tend” to their offspring then “befriend”, form alliances with other women
Flee at any sign of danger to offspring
Negative consequences
May not be evolved + adaptive
Helped when lives dependent on hunting
Modern day rarely require fight or flight
e.g increase blood pressure can damage blood vessels
Too much cortisol can suppress immune system
Doesn’t tell whole story
Freeze
Avoid confrontation
Looks, listens, alert
