5.Endocrine System Flashcards
Describe the endocrine system
-network of glands and organs located throughout the body
-glands secrete hormones directly into the circulation of the blood stream
Function of endocrine system
-regulates a range of bodily functions through the release of chemical messengers; hormones
-receives and sends messages (chemical) to other parts of the body
What are glands
-organs that secrete substances (often hormones)
What is the endocrine gland
-ductless gland that secrets hormones directly into the bloodstream
What is the structure of hormones
chemical substances secreted directly into bloodstream by a gland of the endocrine system which acts on target cells of the body
Function of hormones
-affect the activity of target cells
-acts as chemical messengers, controlling and coordinating activities throughout the body
Contrast the endocrine and nervous system
-glands VS nerve cells
-chemical communication VS electrical and chemical communication
-slower transfer VS faster transfer
-Longer duration of effects VS shorter
Main role of hypothalamus is endocrine system
Maintains homeostasis by stimulating other glands to secrete hormones
Identify hormones released by hypothalamus
-corticotropin-releasing hormone
-growth hormone-releasing hormone
Function of Corticotropin-releasing hormone
stimulates the adrenal gland to release corticosteroids that play a role in metabolism and immune repose
Function of growth hormone-releasing hormone
stimulates pituitary gland to secrete human growth hormone
location of pituitary gland
lies below the hypothalamus (more anterior)
Main function of the pituitary gland
regulates growth and reproduction
identify hormones released by pituitary gland
Human growth hormone
adrenocorticotropic hormone
Luteinising hormone
Follicle stimulating hormone
Prolactin
oxytocin
thyroid stimulating hormone
Human growth hormone function
regulates growth and physical development
Adrenocorticotropic hormone function
stimulates adrenal glands to secrete steroid hormones i.e cortisol
Luteinising hormone function
controls oestrogen and testosterone production as well as ovulation
Follicle stimulating hormone function
controls production of eggs and sperm
Melatonin function
regulates sleep-wake cycles
such as the diurnal and circadian rhythms
Thyroid stimulating hormone function
stimulates thyroid glands to release thyroid hormones i.e thyroxine, triiodothyronine and calcitonin
Oxytocin function
aids lactation and childbirth
Antidiuretic hormone function
increases water reabsorption in kidneys
Pineal gland function
to secrete melatonin in responds to light levels and in turn regulates sleep and wake cycles
Pineal gland function
controls circadian and diurnal rhythms -sleep wake cycles
Describe the role of the suprachiasmatic nucleus
-receives signals from the eyes (about light levels) and sends messages to the pineal gland (via hypothalamus) to influence the secretion of melatonin and hence sleepiness
High light levels means
less melatonin /less drowsiness and vice versa
Outline importance of sleep
-repair muscle/body cells
-consolidate neural pathways (memory)
-conserve energy
List 5 symptoms of poor sleep
-affective=high irritability, loss of personality/dull
-behavioural- decreased motor control + clumsiness
-cognitive=poor memory and decreased focus
Function of thymus gland
-development and maturation of T cells
-produces thymosin which stimulates immune cell growth
Structure of thyroid gland
butterfly shaped and 2 lobes
Function of thyroid gland
metabolism (rate at which energy is broken down)
Function of triiodothyronine and thyroxine
regulates body temperature, metabolism and heat rate
Function of calcitonin
regulates calcium levels in body
stores Calcium in bones
CAN inhibit the kidneys re-uptake of calcium
Structure of parathyroid glands
4 glands embedded into posterior surface of thyroid glands
Function of parathyroid hormone
-regulates Ca, P, Mg levels in blood and bones
-stimulates release of Ca from bones into bloodstream
What does the kidney do to calcium
converts vitamin d into calcitriol which helps increase Ca absorption from intestines into blood
Alpha cells
pancreatic islets that break down glycogen stores in liver and muscle cells into glucose hence increasing BGL
Beta cells
pancreatic islets that convert excess glucose into glycogen in liver and muscle cells hence decreasing BGL to WNL
Structure of adrenal glands
superior to each each kidney and made of medulla (inner) and cortex (outer)
Identify Hormones released by adrenal glands
adrenaline & noradrenaline-medulla
cortisol-cortex
aldosterone
Adrenaline & noradrenaline function
-responsible for fight or flight (sympathetic NS)
-increase HR, metabolism,
-pupils dilate
-divert blood to vital organs and muscles
Cortisol function
influences metabolism, BSL, anti inflammatory effects
Aldosterone function
regulates salt and water levels in blood, in turn regulates BP
Identify hormones released by ovaries
oesterogen and progesterone
Oestrogen function
helps regulate female development and growth in breasts
regulates menstrual cycle
Progesterone function
regulates menstrual cycles
vital in pregnancy
Whats testosterone released by
testes
Testosterone function
-sex drive/male libido
-bone mass
-fat distribution
-muscle mass/strength
-produce RBC’s and sperm
Prolactin function
regulates milk production
ADH function
increases water reabsorption in kidneys
ACTH function
stimulates adrenal glands to release steroid hormones i.e cortisol
