The Endocrine System Flashcards
What Does the Endocrine System Do?
- release hormones into the bloodstream
- help control mood, growth and development, the way our organs work, metabolism , and reproduction.
Compare the endocrine system to the nervous system.
Endocrine System
- Hormones released
- Slow and long lasting effect
- Target cells
Nervous System
- Neurotransmitter
- Quick and short term effect
- Innervated glands and muscles
The glands that make up the endocrine system
learn
- hypothalamus
- pineal gland
- pituitary gland
- thyroid gland
- parathyroid gland
- thymus
- adrenal glands
- Islets of Langerhans (a cluster of cells within the pancreas that are responsible for the production and release of hormones that regulate glucose levels)
- ovaries, testes
Where is the hypothalamus?
in the center of the brain between cerebrum and brainstem
Functions of hypothalamus
- houses the pituitary gland
- hypothalamus acts as the connector between the endocrine and nervous systems
FUNCTIONS REGULATES body temperature thirst appetite and weight control emotions sleep cycles sex drive childbirth blood pressure and heart rate production of digestive juices balancing bodily fluids
The hypothalamus hormones
Corticotropin CRH
Thyrotropin TRH
Growth hormone GHRH
Gonadotropin GnRH
Somatostatin GHIH
Corticotropin CRH
Corticotropin-releasing hormone, which helps regulate metabolism and immune response by working with the pituitary gland and adrenal gland to release certain steroids CRH
Thyrotropin TRH
Thyrotropin-releasing hormone activates the thyroid, which releases the hormones that regulate metabolism, energy levels, and developmental growth TRH
Growth hormone
Growth hormone releasing hormone GHRH
Gonadotropin
Gonadotropin-releasing hormone, which instructs the pituitary gland to release more hormones that keep the sexual organs working GnRH
Somatostatin GHIH
Somatostatin (GHIH) , also known as growth hormone-inhibiting hormones - growth hormone GH and thyroid stimulating hormone TSH
Where is the pituitary gland?
located at the base of the brain.
about the size of a pea
Why is the pituitary gland dubbed the ‘master gland’?
because its hormones control other parts of the endocrine system, namely the thyroid gland, adrenal glands, ovaries, and testes
What is the pituitary gland divided into?
anterior pituitary gland
posterior pituitary gland
Function of the anterior pituitary gland?
Prolactin
Growth hormone
Prolactin: Prolactin stimulates breast milk production and Growth hormone (GH): GH is essential in early years to maintaining a healthy body composition and for growth in children. In adults, it aids healthy bone and muscle mass and affects fat distribution.
Prolactin
Prolactin stimulates breast milk production
Growth hormone (GH):
healthy bone and muscle mass and affects fat distribution.
Does the endocrine system use positive or negative feedback?
Mostly negative
Negative feedback mechanisms act like a thermostat in the home
Which part of the Pituitary Gland is controlled by neurons?
posterior pituitary receives its signals from the magnocellular neurons.
Anterior pituitary gland hormones?
Prolactin GH Growth hormone TSH - Thyrotropin Thyroid hormones FSH LH - Luteinizing hormone ACTH - (steroid hormones especially cortisol)
FSH
follicle-stimulating hormone gametes
LH
Luteinizing hormone sex hormones
ACTH
(steroid hormones especially cortisol)
Posterior pituitary hormones?
ADH Anti-diuretic hormone
Oxytocin
ADH
Anti-diuretic hormone: acts on kidneys; reduces urine output
Oxytocin
acts on uterus/breast milk
The Kidneys
1,25 dihydroxyvitamin D - stimulates calcium absorption from the intestine
Renin - activates the Renin-Angiotensin System (RAS)
Erythropoietin - increases red blood cell production
Ovaries hormones
Estrogen
Progesterone - menstrual cycle & pregnancy
Testes
Androgens, testosterone - secondary sexual characteristics, sperm
Thymus
Releases thymosin and thymopoietin
Affects maturation of T lymphocetes
Where is the thymus?
The thymus gland is in the chest, between the lungs
Where is the pineal gland?
pineal gland is located deep in the brain in the epithalamus
Pineal
Secretes melatonin - skin colour Role in sleep/wake cycles body temperature ageing fertility
Where is the thyroid gland?
a small butterfly-shaped gland in the neck
Functions of the thyroid gland
Produces
Follicular cells - excretion of triiodothyronin (T3)
Thyroxine (T4)
Increase BMR Basal Metabolic Rate, increase bone and protein turnover, increases response to catecholamines, need for infant G& D
Thyroid C cells - calcitonin. Lowers blood calcium and phosphate levels - bone structures
Why do we need iodine in blood stream?
To produce T3 (three iodine molecules)
T4 (four iodine molecules)
What is Graves’ disease?
Autoimmune disorder - excess thyroid hormone - goitre (enlarge thyroid) exophthalmos (bug eyes) weight loss, hunger anxiety, agitation heart palpitations
Hypothyrodism
insufficient production of thyroid hormone
Mainly affects women between 30-60 yrs old
Causes
autoimmune diseases
Atrophy of thyroid - ageing
Therapy for hyperthyroidism
radioactive iodine
Thyroidectomy
Medications
TRH Thyrotropin-releasing hormone or TSH thyroid stimulating hormone or radiation
Thyroid Tumours
Can be benign or malignant
Where are the parathyroid glands
Embedded in thyroid gland - integrated in the thyroid four to eight pea shaped glands
Functions of the parathyroid glands
Chief cells secrete parathyroid hormone
Parathyroid hormone PTH, increases blood calcium levels
Hyperparathyroidism
Hyperparathyroidism is where the parathyroid glands, which are in the neck near the thyroid gland, produce too much parathyroid hormone
- elevated serum calcium bone decalcification renal calculi apathy fatigue hypertension cardiac dysrhythmias
Hypoparathyroidism
Hypoparathyroidism is an uncommon condition in which your body produces abnormally low levels of parathyroid hormone (PTH). PTH is key to regulating and maintaining a balance of two minerals in your body — calcium and phosphorus
tetany numbness and tingling in extremities stiff of hands and feet bronchospasm laryngeal spasm carpopedal spasm depression anxiety delirium ECG changes
Where are the adrenal glands?
The adrenal glands are small glands located on top of each kidney.
Functions of the adrenal glands?
sex hormones and cortisols
Medulla (middle) of adrenal glands produce?
adrenal medulla include epinephrine (adrenaline) and norepinephrine (noradrenaline), which have similar functions.
Fight or flight
epinephrine
adrenaline
norepinephrine
similar function to adrenaline
Cortex of adrenal glands produce?
cortisol
aldosterone
cortisol
helps regulate metabolism and helps your body respond to stress
aldosterone
which helps control blood pressure
regulate salt/sodium and water
It works on;
Angiotensinogen
Angiotensin I
Angiotensin II
Glucocorticoids
Glucocorticoids are a type of corticosteroid hormone that is very effective at reducing inflammation and suppressing the immune system.
Adrenal sex hormones
androgens and estrogen (sex hormones).
Hyperfunction of adrenals/ cushing’s syndrome
causes adrenal tissue to secrete excess cortisol
symptoms, including central obesity, hypertension, type 2 diabetes, easy bruisability, abdominal striae, and myopathy.
Causes of hyperfunction of adrenals/ cushing’s syndrome
An overproduction of corticotrophin (ACTH) —the hormone that controls the adrenal gland— by the pituitary gland, which stimulates the adrenal glands to produce corticosteroids, may be one cause.
Hypofunction Adrenals / Addison’s Disease
not enough of the hormone cortisol (glucocorticoids) and, often, not enough aldosterone (mineralocorticoids) as well. Androgens in women
Where is the pancreas?
pancreas is a long, flat gland that lies horizontally behind your stomach
Functions of the pancreas?
The pancreas is a dual-functional gland, with both exocrine (digestive) and endocrine (hormonal) functions.
Where is the Islets of the Langerhans?
Islets of Langerhans are islands of endocrine cells scattered throughout the pancreas
The Islets of Langerhans contain the following cell types:
Alpha cells – these make up roughly 15-20% of Islet cells and are responsible for producing glucagon
Beta cells – these make up 65-80% of Islet cells and produce insulin and amylin
Insulin Beta cells
Decrease blood glucose levels
Glucagon Alpha cells
Increase blood glucose levels
How does insulin work?
Insulin is a hormone made in your pancreas
It works like a key to unlock cells so that glucose can enter
Glucose is then used by the body as fuel
Beta cells of pancreas are in charge of its production
What is diabetes?
Insulin resistance, can produce insulin in beta cells.
resistance of the body’s cells to obey the orders of insulin. To overcome this resistance, the beta cells secrete more insulin, and glucose is eventually forced into the cells.
Diabetes insipidus
hyposecretion of ADH
Diabetes mellitus
insulin deficiency
Diabetes Type 1
insulin dependent
Diabetes Type 2
non insulin dependent
90% cases
- risk factors obesity, inactivity, age
