chemical coordination Flashcards
(6 cards)
what is a gland?
A gland is an organ that releases or secretes a substance,
what are the two types of glands?
exocrine glands- secrete their products through a tube called a duct eg saliva secreted down salivery ducts
endocrine glands- have no duct, instead their products, the hormones are secreted into the blood vessels that pass through the gland
differences between nervous and endocrine control
Nervous system:
1) Works by nerve impulses transmitted through nerve cells
2) Nerve impulses travel fast and usually have an ‘instant’ effect
3) Response is usually short-lived
4)Impulses act on individual cells such as muscle fibres, so have a very localised effect
Endocrine system:
1) Works by hormones transmitted through the bloodstream
2) Hormones travel more slowly and generally take longer to act
3) Response is usually longer-lasting
4) Hormones can have widespread effects on different organs
main endocrine glands and their functions
pituitary gland- found at the base of the brain- FSH(stimulates egg development) LH(stimulates egg release), ADH antidiuretic hormone which acts on the kidneys, controlling the amount of water in the blood
pancreas- both endocrine and exocrine gland- secretes insulin glucagon lowers blood glucose increases blood glucose
sex organs (testes) and (ovaries) make hormones controlling reproduction
thyroid - thyroxin - controls the body’s metabolic rate
adrenals - adrenaline prepares the body for physical activity
what is adrenaline (flight or fight hormone)
when you are afraid or excited your adrenal glands secrete the hormone adrenaline
adrenaline acts at a number of target organs and tissues , preparing the body for action- fight or run away (animals)
how does adrenaline change our body to prepare us?
1) breathing rate increases - more oxygen into the body
2) heart beats faster- sending more blood into the muscles receive more glucose and oxygen for respiration
3) pupils dilate- increasing visual sensitivity to movement
4) body hair stands upright
5)mental awareness increased- reactions are faster
