09_Endocrine System Flashcards
What is the primary function of the endocrine system?
Coordinates the activity of organs through hormones
What are hormones?
Chemical messengers released into the blood from glands
What are the three types of hormones based on their composition?
- Peptides (water soluble, e.g., insulin)
- Steroids (e.g., oestrogen)
- Amino acid derivatives (e.g., adrenaline, thyroxine)
What are the two types of glands in the endocrine system?
- Exocrine (secrete products into ducts)
- Endocrine (ductless, secrete hormones into blood)
Name three examples of exocrine glands.
- Salivary glands
- Gastric glands
- Mammary glands
What is the role of the hypothalamus in the endocrine system?
Regulates the pituitary gland and links the nervous and endocrine systems
Which hormone is known as the master endocrine gland?
Pituitary gland
What hormones are secreted by the anterior pituitary gland?
- Growth hormone (GH)
- Thyroid stimulating hormone (TSH)
- Follicle stimulating hormone (FSH)
- Luteinising hormone (LH)
- Prolactin (PRL)
- Adrenocorticotropic hormone (ACTH)
- Melanocyte stimulating hormone (MSH)
What is down-regulation in hormone sensitivity?
Decrease in the number of target cell receptors when a hormone is present in excess
What is up-regulation in hormone sensitivity?
Increase in the number of receptors on target cells when there is a deficiency in hormone
How are hormone secretions regulated?
- Nervous system signals
- Chemical changes in the blood
- Other hormones
What is the function of Growth Hormone (GH)?
- Regulates metabolism
- Stimulates insulin-like growth factors (IGFs)
- Promotes growth and division of cells
- Breaks down fats and glycogen
What is the function of Thyroid Stimulating Hormone (TSH)?
Stimulates growth and activity of the thyroid gland, increasing thyroid hormone production
What role does Prolactin (PRL) play?
- Stimulates lactation
- Prevents pregnancy during lactation
- Matures mammary glands after childbirth
What does Antidiuretic Hormone (ADH) do?
- Reduces urine output
- Stimulates reabsorption of water in kidneys
- Causes vasoconstriction to increase blood pressure
What is the primary function of Oxytocin?
- Contracts uterus during childbirth
- Contracts lactating breast
- Promotes bonding between mother and baby
What hormones are produced in the posterior pituitary gland?
- Oxytocin
- Antidiuretic hormone (ADH)
Fill in the blank: ________ is often referred to as the bonding hormone.
Oxytocin
True or False: The anterior pituitary gland synthesizes and releases hormones.
True
What factors can increase the production of Adrenocorticotropic Hormone (ACTH)?
- Hypoglycaemia
- Exercise
- Stressors (emotions, fever)
What is the precursor hormone shared by both ACTH and MSH?
Corticotropin releasing hormone (CRH)
What are the effects of Gigantism?
Excess growth hormone during development leads to massive heights
What is Acromegaly?
Excess growth hormone post puberty, leading to outward growth
What is colostrum?
First breast fluid produced after childbirth, containing water, lacto-sugar, and antibodies
How does the body respond to increased osmotic pressure?
Stimulates production of Antidiuretic Hormone (ADH) to reduce urine output
What are gland pathologies typically associated with?
Tumours or autoimmune diseases
What can disease processes in glands result in?
Hyper- or hypo-secretion of certain pituitary hormones
What does acromegaly result from?
Excess growth hormone post puberty
What are common symptoms of acromegaly?
- Large, prominent facial features
- Increased size hands and feet
- Tiredness
- Deep voice
- Impotence
- Joint pain
- Bone deformities
- Soft-tissue swellings
What is a common treatment for acromegaly?
Surgery to remove tumour
What is hyperprolactinaemia?
Excessive prolactin production
What are some causes of hyperprolactinaemia?
- Pituitary tumour
- Acromegaly
- Pharmacologic (antipsychotics)
What is a symptom of diabetes insipidus?
Polydipsia (extreme thirst)
What causes diabetes insipidus?
- Cranial: Brain trauma, tumour, encephalitis
- Renal: Chronic kidney disease, hypercalcaemia, hypokalaemia
How is diabetes insipidus diagnosed?
- 24-hr urine collection
- Urine-specific gravity
- Blood biochemistry (increased Na)
What does the pineal gland produce?
Melatonin
What affects melatonin levels?
- Night, darkness (stimulates)
- Daylight, irregular sleep patterns (reduces)
What is the role of the thymus gland?
Plays an important role in immune development
What hormones do the thymus produce?
Thymosin
What does the thyroid gland influence?
Metabolic rate and growth hormone in early life
What hormones are produced by follicular cells of the thyroid?
- Thyroxine (T4)
- Triiodothyronine (T3)
What is the major form of thyroid hormone in the blood?
Thyroxine (T4)
What does parathyroid hormone (PTH) do?
Increases blood calcium
What are common symptoms of hypothyroidism?
- Tiredness
- Weight gain
- Cold intolerance
- Depression
What condition is characterized by hyper-metabolism and elevated thyroid hormones?
Hyperthyroidism
What is a common cause of hyperthyroidism?
Graves’ disease
What does calcitonin do?
Lowers blood calcium levels
What are the parathyroid glands responsible for?
Producing parathyroid hormones
What is a treatment for hyperparathyroidism?
Surgery to remove the tumor
What are symptoms of hypoparathyroidism?
- Muscle cramps
- Tingling lips
- Dry hair
- Brittle nails
What hormone is deficient in diabetes insipidus?
ADH (Antidiuretic hormone)
What does the number next to T4 and T3 reflect?
The number of iodine atoms
Which thyroid hormone is the more active form?
Triiodothyronine (T3)
What do parafollicular cells produce?
Calcitonin
List four symptoms of hypothyroidism.
- Tiredness
- Weight gain
- Cold intolerance
- Depression
State two signs of hyperthyroidism.
- Goitre
- Exophthalmos
Name two ways parathyroid hormone increases blood calcium.
- Increases osteoclast activity
- Increases kidney reabsorption of calcium
What is one cause of hypoparathyroidism?
Surgery or radiation
What effect might hypoparathyroidism have on muscles?
Muscle cramps and spasms (tetany)
What effect might hyperparathyroidism have on bone?
Increased risk of osteoporosis
What hormones are produced by the adrenal cortex?
- Glucocorticoids
- Mineralocorticoids
- Sex hormones
What is the primary hormone produced by the adrenal medulla?
Adrenaline (epinephrine)
What stimulates the release of adrenaline?
- Exercise
- Shock
- Emotional stress
What effect does adrenaline have on the heart?
Increases heart rate and contraction, causing an increase in blood pressure.
What is the role of adrenaline in blood vessels?
Vasodilation in heart, brain, and skeletal muscles; vasoconstriction in the digestive tract.
How does adrenaline affect metabolism?
Increases metabolism in the thyroid and blood glucose and triglycerides in skeletal muscle/liver.
What is the primary function of glucocorticoids?
Regulate metabolism and resistance to stress, mostly cortisol.
List the activities of glucocorticoids.
- Stimulating gluconeogenesis
- Proteolysis
- Lipolysis
- Production of glucose by the liver
- Reduces immune response
- Anti-inflammatory effects
- Weak reabsorption of sodium and water from kidney tubules.
What are mineralocorticoids primarily responsible for?
Maintaining water and electrolyte balance, primarily aldosterone.
What triggers the secretion of aldosterone?
- Low blood pressure or blood volume
- High blood potassium.
What are the main functions of sex hormones?
Primarily androgens, which promote the production of pubic and axillary hair and increase muscle mass.
What is Cushing Syndrome?
A rare disorder characterized by prolonged exposure to abnormally high levels of cortisol.
List some common causes of Cushing Syndrome.
- Corticosteroid medication
- Adrenal adenoma
- Pituitary tumour.
What are some signs and symptoms of Cushing Syndrome?
- Central weight gain
- Moon face
- Buffalo hump
- Insulin resistance
- Depression
- Easy bruising.
What is Addison’s Disease?
Adrenal insufficiency caused by hypo-functioning of the adrenal cortex, leading to a deficiency of mineralocorticoids and glucocorticoids.
What are the main causes of Addison’s Disease?
- Atrophy of the adrenal gland (often autoimmune)
- Abrupt cessation of steroids.
What is the main function of the pancreas?
Has both endocrine and exocrine functions; regulates blood glucose levels.
What do alpha cells in the pancreas produce?
Glucagon.
How does insulin affect blood glucose levels?
Lowers blood glucose levels by stimulating cells to uptake glucose.
What stimulates the production of glucagon?
Low blood sugar, exercise, and stress.
What is Diabetes Mellitus?
A metabolic disorder associated with hyperglycaemia due to a deficiency of insulin.
List the types of Diabetes Mellitus.
- Type I: Autoimmune
- Type II: Insulin resistance
- Secondary
- Gestational.
What are common signs and symptoms of Type I Diabetes?
- Polydipsia
- Polyuria
- Polyphagia
- Glycosuria.
What is the primary treatment for Type I Diabetes?
Insulin.
What characterizes Type II Diabetes?
Insulin resistance leading to hyperglycaemia.
List some signs and symptoms of Type II Diabetes.
- Polydipsia
- Polyuria
- Polyphagia
- Acanthosis nigricans.
What are the complications of chronic hyperglycaemia?
- Heart disease
- Retinopathy
- Nephropathy
- Peripheral neuropathy.
What is ketoacidosis?
A condition where ketones accumulate due to low glucose supply, potentially leading to coma or death.
What are the signs of hypoglycaemia?
- Shaking
- Sweating
- Extreme hunger
- Confusion.
What is the function of histamine?
Causes inflammation through vasodilation and increased blood vessel permeability.
What role do prostaglandins play in the body?
Act as chemical messengers involved in many body processes.
What is the role of erythropoietin?
Stimulates red blood cell production.
