6.6 HORMONES, HOMEOSTASIS AND REPRODUCTION Flashcards
ESSENTIAL IDEA
hormones are used when signals need to be widely distributed
ENDOCRINE SYSTEM
a stimulus is received and processed
hormones are secreted directly into the blood
the action of hormone change the condition of the tissue
this change is monitored though feedback
most hormonal change = negative feedback
KEY ENDOCRINE GLANDS 8
pineal gland
pituitary gland
thyroid gland
thymus
adrenal gland
pancreas
ovary
testes
BLOOD GLUCOSE IS MONITORED BY
pancreatic cells
FASTING
reduces blood sugar
BLOOD SUGAR INCREASES
by absorption of glucose from digestion in the intestine
EXAMPLE OF NEGATIVE FEEDBACK
glucoregulation
GLUCOREGULATION USES
negative feedback
hormones insulin/glucagon
IF BLOOD GLUCOSE IS TOO TOO HIGH
B cells of pancreas produce insulin
insulin stimulates uptake of glucose to cells
insulin stimulates liver/ fat cells to store glucose as glycogen
lead to decrease in blood glucose
IF BLOOD GLUCOSE IS TOO LOW
alpha cells of pancreas produce glucagon
glucagon stimulates liver to break down glycogen into glucose
leads to increase blood sugar
TYPE 1 DIABETES
early onset
hereditary, weak relationship
trigger needed: illness
beta cells destroyed
insulin production stops
TYPE II DIABETES
adult onset
hereditary, strong relationship
related to obesity and poor diet
fewer insulin receptors in liver
less sensitivity to insulin
DIABETES
reduced ability to control blood glucose through insulin
THYROXIN SOURCE
thyroid gland
THYROXIN TARGETS
most body cells
THYROXIN EFFECTS
increases metabolic rate/ rate of protein synthesis
increases heat production/ increased respiration
LEPTIN TREATMENT FOR OBESITY
EXPERIMENT ON MICE
obese mice possess two recessive alleles and consequently do not produce any leptin
obese mice treated with leptin saw large weight loss
LEPTIN TREATMENT FOR OBESITY
HUMAN FAILURE
most people have naturally high levels of leptin
if linked to leptin obesity in people is due to resistance of the appetite control to leptin
very few patients in the clinical trial experienced weight loss
many patients experienced side-effects such as skin irritations
SRY GENE
gene on the Y chromosome causes embryonic gonads to develop into testes and secrete testosterone