lab practical 1- endocrine system

thyroid stimulating hormone

• organ secreting: anterior pituitary gland

• stimulus: TRH released from hypothalamus stimulates TSH

• target tissue: thyroid gland

• function: produces thyroid hormone T3 and T4

melatonin

• organ secreting: pineal

• stimulus: response to day-night cycles

• target tissue: widespread

• function: affects sleep/wake patterns, regulate reproductive functions

thyroxine and triiodothyronine (T3 and T4)

• organ secreting: thyroid gland

• stimulus: TSH from anterior pituitary gland

• target tissue: widespread absorption

• function: increases heat production, metabolic rate, HR, some effects of sympathetic nervous system

calcitonin

• organ secreting: thyroid

• stimulus: high calcium levels in blood

• target tissue: kidneys and bones

• function: increase calcium excretion and deposition

parathyroid hormone (PTH)

• organ secreting: parathyroid gland

• stimulus: low calcium levels in blood

• target tissue: kidneys, bones, digestive tract

• function: increase calcium absorption, stimulate osteoclast activity

antidiuretic hormone (ADH)

• organ secreting: produced by hypothalamus but stored and released from the posterior pituitary gland

• stimulus: high blood osmolarity (too much solute), dehydration, low BP, low blood volume, angiotensin II

• target tissue: kidneys

• function: absorption of water increases blood volume and BP

aldosterone

• organ secreting: adrenal cortex

• stimulus: low blood volume and blood sodium levels

• target tissue: kidneys

• function: increase sodium and water reabsorption

atrial natriuretic peptide (ANP)

• organ secreting: atria (top chambers of heart)

• stimulus: increased stretch on atrial wall due to increased blood volume or pressure

• target tissue: kidneys

• function: decrease sodium and water reabsorption, reduce blood pressure and volume

erythropoietin (EPO)

• organ secreting: kidneys

• stimulus: increased hypoxia in cells

• target tissue: bone marrow

• function: increase red blood cell production

adrenocorticotropic hormone (ACTH)

• organ secreting: anterior pituitary gland

• stimulus: corticotropin releasing hormone (CRH) from the hypothalamus

• target tissue: adrenal cortex

• function: increases production and release of cortisol

cortisol

• organ secreting: adrenal cortex

• stimulus: ACTH from pituitary gland

• target tissue: liver cells, skeletal muscle cells, adipocytes

• function: increase metabolism, helps body prepare for stressful situations, short-term anti-inflammatory effects

epinephrine and norepinephrine (E and NE)

• organ secreting: adrenal medulla

• stimulus: sympathetic nervous system

• target tissue: most cells in the body

• function: increases HR, RR, metabolic rate, and decreases digestive rate

insulin

• organ secreting: beta cells of pancreas (bi)

• stimulus: high blood glucose levels

• target tissue: widespread effect

• function: increase glucose uptake in cells, decrease blood glucose levels

glucagon

• organ secreting: alpha cells of pancreas

• stimulus: low blood glucose levels

• target tissue: liver, skeletal muscles

• function: increase breakdown of glycogen in liver, increase blood glucose levels

prolactin (PRL)

• organ secreting: anterior pituitary gland

• stimulus: nursing

• target tissue: mammary glands

• function: milk production

oxytocin (OT)

• organ secreting: posterior pituitary gland

• stimulus: stretching of the cervix and contraction of uterus during labor, stimulation of nipples during breastfeeding

• target tissue: uterus, mammary glands

• function: positive feedback loops to progress labor, delivery, breastfeeding

  • uterus: during labor, increasing contractions

  • mammary glands: during breastfeeding, milk release