Endocrine 1 Flashcards
Name the 8 glands of the Endocrine System
Pituitary Gland, Pineal Gland, Thyroid and Parathyroid Gland, Thymus Gland, Adrenal Gland, Pancreas, Testis (male) and ovaries (female)
What is the Endocrine System
a collection of glands that secrete hormones into the blood, which then travels to target cells throughout the body
Describe the role of target cells of a given hormone and given an example
only the target cells for a given hormone have receptors that bind and recognise that hormone
for example, thyroid-stimulating hormone (TSH) binds to receptors on cells of the thyroid gland but not to other cells as they don’t have TSH receptors
In which 3 ways is hormone secretion regulated
signals from the nervous system
chemical changes in the blood
other hormones
What is the main function of the Endocrine System
to maintain homeostasis by monitoring the environment of the body and responding to change
Name 4 things the Endocrine System can do
regulate the activity of smooth muscle, cardiac muscle and some glands
alter metabolism
initiate growth and development
influence reproductive processes
What does the endocrine system work on the process of
positive and negative feedback loop
Give an example of a positive feedback loop
during childbirth = oxytocin stimulates contractions of the uterus, uterine contractions = stimulate more oxytocin = more uterine contractions
Give 2 details about positive feedback loops
usually occur when the body wants a quick response, cannot be maintained for long periods of time
Give an example of a negative feedback loop - where patient is too hot and so needs to cool down
target set point is 37 degrees - a rise above this is sensed by the hypothalamus = sweat = sweat evaporates and heat is removed, vasodilation = blood vessels are nearer skin surface = heat lost by convection
causes a temp drop
Give an example of a negative feedback loop - where patient is too cold and so needs to warm up
need to inhibit above responses, develop goose bumps to ‘pull’ skin in to conserve heat, vasoconstriction = prevents heat loss from the blood at the skin surface, body temp will increase until set body temp reached
Describe the role of the pituitary gland
regulates other endocrine glands, secretes growth hormone
Describe the role of the thyroid gland and the 4 parathyroid glands
regulates metabolic rate
Describe the role of the thymus gland
assists in development of the immune system
Describe the role of the 2 adrenal glands
regulates fluid and sodium balance, emergency warning system under stress
Describe the role of the 2 ovaries/2 testes
controls development of secondary sex characteristics and functioning of sex organs
Describe the role of the pancreas/pancreatic islets
helps regulate blood sugar
Describe the role of the pineal gland
believed to regulate biorhythms and moods and stimulate the onset of puberty
Describe the link between the hypothalamus and the pituitary gland and where each is found
the pituitary gland is controlled by the hypothalamus, the hypothalamus sits in the brain below the thalamus, the pituitary gland lies below in the pituitary fossa
Which 6 hormones are released by the anterior pituitary gland
Human Growth Hormones - regulates growth
Thyroid-Stimulating Hormone - controls thyroid secretions
Luteinising Hormone and Follicle Stimulating Hormone - regulates the menstrual cycle, maintain pregnancy, prepare mammary glands for lactation
Adrenocorticotropic Hormone - stimulates adrenal glands
Prolactin - initiates milk production
Melanocyte-Stimulating Hormone - thought to influence brain activity
Which 2 hormones are stored and released by the posterior pituitary gland
Oxytocin - enhances contractions during childbirth, stimulates milk release after delivery, responsible for parental caretaking behaviour toward young offspring
Antidiuretic Hormone - determines the amount of water excreted from the body
Describe Antidiuretic Hormone (ADH) and high blood osmotic pressure and low blood volume
high blood osmotic pressure/ low blood volume due to dehydration/haemorrhage/diarrhoea/excessive sweating stimulates the hypothalamus to synthesise and release ADH
ADH targets kidneys = retain more water = decreases urine output, sudoriferous (sweat) glands reduce their activity thus reducing water loss by perspiration from the skin
Smooth muscle in blood vessel walls - constricts lumen of the vessel and increasing blood pressure
Describe ADH and low blood osmotic pressure and high blood volume
low osmotic pressure/high blood volume = inhibits the hypothalamus = reduces/stops ADH secretion = kidneys then retain less water by forming a larger volume of urine = secretory activity of sweat glands increases/arterioles dilate = blood volume and osmotic pressure of bodily fluids return to normal
Give 9 stimulants of ADH
Pain, Stress, Trauma, Anxiety, Acetylcholine, Nicotine, Morphine, Tranquilizers, Some anaesthetics
What causes Diabetes Insipidus
Hypo secretion of ADH or non-functional ADH receptors
Describe the thyroid gland
butterfly-shaped, located in the anterior neck, inferior to the larynx, upper border is level at C5, lower border is level at T1
Describe how the thyroid gland uses iodine and its roles
uses iodine from the diet to produce the hormones thyroxine (T4) and triiodothyronine (T3), it produces calcitonin - important in maintenance of serum calcium level, helps control metabolism, heart rate and body temp growth and development, increased secretion of the thyroid hormones caused by cold environment, hypoglycaemia, high altitude and pregnancy
Describe the Parathyroid Glands
4 small, rounded masses partially embedded in the posterior surfaces of the thyroid gland
Describe the role of the parathyroid glands
produce parathyroid hormone (PTH) that
regulates calcium, magnesium and phosphate in the blood and bones
increases the number and activity of osteoclasts
Describe the Pancreas
located in the curve of the duodenum,
Endocrine Function - secreting glucagon, insulin, somatostatin and pancreatic polypeptide from islets of langerhans
Exocrine Function - secreting digestive enzymes into the duodenum
Describe the difference between glucagon and insulin
Glucagon = to increase blood glucose when necessary Insulin = to reduce blood glucose when necessary
Describe the regulation of Glucagon and Insulin Secretion
Glucagon causes the liver to increase glucose production = this is released into the blood and blood glucose level rises = if blood glucose level continues to rise = hyperglycaemia = inhibits release of glucagon = hyperglycaemia stimulates the secretion of insulin by the pancreatic islets = reduces glucose levels causing blood glucose level to fall= drops too low then stimulates release of glucagon
Describe the links between digestion and exercise with glucagon and insulin
Digestion provides strong stimulation of insulin release
Exercise which causes blood glucose level to fall will stimulate glucagon secretion
