Endocrine system Flashcards
Endocrine system
-made up of glands and hormones
-regulates growth, metabolism and sexual development
-responses to stress and injury
-homeostasis
Control of hormone secretions
-hypothalamus releases hormone
-pituitary stimulates hormone
-target gland secretes hormones
Pituitary gland
-base of brain, hypophyseal fossa
-attaches to hypothalamus via pituitary stalk/ infundibulum
-consists anterior and posterior sections
-master gland
Posterior pituitary
hormones secreted
-secretes oxytocin- uterus contract, lactation
-secretes ADH which control water levels in the body
Anterior pituitary
hormones secreted
-prolactin/ PRL- stimulates milk production in women’s breasts
-growth hormone/ GH- stimulates growth in children and maintains healthy body composition. In adults it maintains muscle and bone mass
-ACTH- stimulates production of cortisol
-thyroid stimulating hormone/ TSH- stimulates thyroid gland to make thyroid hormones which regulate metabolism, energy, growth etc
-luteinizing hormone- reg. testosterone and oestrogen
-follicle stimulating hormone- sperm production and release of eggs
Thyroid gland
location, function
-inside neck
-anterior to trachea and below thyroid cartilage (adam’s apple)
-controls metabolism
Thyroid hormones
-thyroxine (T4) & tri-iodothyronine(T3) - increase rate cells release energy from carbs
-calcitonin- regulates blood conc of calcium
Basal metabolic rate-
how many calories the body must consume to maintain life
Thyroid disorders and symptoms
-goiter- too little iodine causes thyroid to swell
-hypothyroidism- cause reduce growth, intellectual disability (children), weight gain (adults)
-hyperthyroidism (grave’s disease)- restlessness, weight loss, anxiety, can cause goiter
Parathyroid gland
-located behind thyroid
-4 tiny glands help maintain calcium and phosphorous levels
-secretes parathyroid hormone which takes calcium from bones to make it available in the blood
Adrenal glands
-above each kidney
-outer portion= adrenal cortex
-inner portion= adrenal medulla
Hormones of adrenal medulla
-epinephrine and norepinephrine
-increase HR, BR, BP (fight or flight)
Hormones of adrenal cortex
Aldosterone-mineralocorticoid, maintains BP, conserves Na, excrete K
Cortisol- glucocorticoid, keeps blood glucose levels stable
Adrenal sex hormones- androgens (male) oestrogens (female)
Clinical points adrenal glands
-Cushing’s syndrome (hypersecretion of cortisol)- blood glucose remains high, too much Na retained, puffy skin, masculinising effects in women eg. hirsutism (facial hair)
-Addison’s disease (hyposecretion of cortisol)- decreased Na, dehydration, low BP, increased pigmentation in skin
Pancreas
-large gland behind stomach
-maintains blood sugar levels
-islets of Langerhans which secrete glucagon and insulin
-glucagon- liver break down glycogen into glucose
-insulin- decreases blood sugar conc
