endocrine system Flashcards
what is the endocrine system?
one of body’s major info systems
communicates via chemicals
acts slower than NS but has powerful effects
instructs glands to release hormones directly into bloodstream
hormones carried towards cells in target organs in body
most hormones affect cells in more than one body organ- diverse and powerful responses
e.g. thyroid gland produces thyroxine hormone
affects heart cells (increasing heart rate) and cells affecting metabolism- affects growth rates
what is a gland?
an organ in the body that synthesises substances such as hormones
e.g. thyroid gland
what is a hormone?
a biochemical substance that circulates in the blood but only affects target organs
produced in large quantities but disappear quickly
very powerful effects
what is the pituitary gland?
the ‘master gland’ in the endocrine system
controls release of hormones from all other endocrine glands in body
what is the fight or flight response?
the way an animal/human responds to stress
body becomes physiologically aroused in readiness to fight or flee from an aggressor
how do the endocrine system and ANS work together in fight or flight?
stressor perceived- hypothalamus activates pituitary gland- triggers activity in sympathetic branch of ANS
ANS changes from parasympathetic state to sympathetic state
adrenaline- stress hormone released from adrenal medulla into bloodstream
triggers physiological changes in body (e.g. increased heart rate)- creates physiological arousal necessary for FOFR
these processes immediate and automatic once threat detected
rest and digest response- once threat passed, parasympathetic nervous system returns body to resting state
works in opposition to sympathetic- reduces activities of body that were increased by sympathetic branch
e.g. S increases heart rate, PS decreases heart rate
