Endocrine systems Flashcards
What cells do hormones act in?
Only in cells with correct membrane receptor proteins (target cells)
What is communication by hormones also known as?
Humoral
What are examples of endocrine glands?
Hypothalamus
Parathyroid
Thyroid
Pancreas (islets)
Pituitary
Adrenal
What are steroids made from?
Cholesterol
What are examples of steroids?
Cortisol
Testosterone
Oestrogen
Progesterone
What are the two amino acid derivatives of non-steroid hormones?
Amines and Iodinated amino acids
What are examples of amines?
Adrenaline
Noradrenaline
Melatonin
What are examples of iodinated amino acids?
Triiodothyronine
Tetraiodothyronine
What are examples of peptide short chain hormones?
Oxytocin
Melanocyte stimulating hormone
Somatostatin
What are examples of long chain peptide hormones?
Growth Hormone
Insulin
Glucagon
PTH
Calcitonin
Secretin, CCK, gastrin
What is the inactive hormone called?
Precursor form
Where does the pre-hormone become the prohormone?
Endoplasmic reticulum
Where is the prohormone converted to active hormone?
Golgi Apparatus
Where are active hormones secreted from?
Vesicles
What are glycoproteins?
Proteins with attached carbohydrate groups to amino acids
What are examples of glycoproteins?
Follicle stimulating hormone
Thyroid stimulating hormone
Luteinizing hormone
What are local tissue hormones?
Hormone like substances which have a paracrine effect
What are examples of local tissue hormones?
Prostaglandins
Thromboxanes
What are functions of local tissue hormones?
Haemostasis
Inflammation
Mucosal Protection
Blood flow regulation
What are two common second messengers?
cAMP and Ca++
Can steroid hormones pass directly through outer cells into intracellular receptors?
Yes
What happens do hormones once they have made their effect?
They are excreted or metabolised
What are most hormone systems controlled by?
Negative feedback control
What is the name for excess secretion?
Hypersecretion
What is the name for decreased secretion?
Hyposecretion
What is the sensitivity of target cells related to?
Number of membrane receptors
What is the name for more receptors?
Upregulation
What is the name for fewer receptors?
Downregulation
What is hyperfunction?
-Excess production & secretion
-Upregulation of receptors
-Failure to metabolise hormone
What is the hypothalamus responsible for?
Thermoregulation
Hormone Secretion
Circadian Rhythms
Motivation
Emotions
What type of hormones does the hypothalamus secrete?
Primary hormones
Trophic hormones
What are the hypothalamuses’ motivations?
Thirst
Feeding
Sexual Behaviour
What is the area between the pituitary gland and hypothalamus called?
Infundibulum
Through which vessels do AP pass in the hypothalamus?
Hypothalamic-pituitary portal vessels
How do hormones produced in the hypothalamus pass to the posterior pituitary?
Along nerve axons
What are examples of hypothalamic hormones?
Corticotropin releasing hormone (CRH)
Gonadotrophin releasing hormone (GRH)
Growth hormone releasing hormone (GHRH)
Thyrotropin releasing hormone (TRH)
Somatostatin (SS) (GH Inhibiting Hormone)
Prolactin releasing hormone (PLRH)
Dopamine (DA)
What are examples of anterior pituitary hormones?
-Adrenocorticotropic hormone
(ACTH)
-Follicle stimulating hormone (FSH)
-Luteinising hormone (LH)
- Thyroid stimulating hormone
(TSH)
-Growth hormone (GH)
- Prolactin (PL)
What is corticotrophins?
Hormones released as a result of stress
Stimulate production of cortisol
What are gonadotrophins?
Control gamete and sex hormone production
Stimulate production of (LH) or (FSH)
What are thyrotropin?
Regulates production of thyroid hormones
Stimulate production of (TSH)
What are somatotrophins?
Growth hormone secreted by pituitary gland
What are prolactin’s?
Enables animals to produce milk
What are posterior pituitary hormones?
-Antidiuretic hormone (ADH)
-Oxytocin
-These are produced by neurons
in the hypothalamus and pass
along the axons to the posterior
part of the pituitary
Which nuclei produces antidiuretic hormones?
Paraventricular nucleus
Which nuclei produces oxytocin?
Supraoptic nucleus
What is antidiuretic hormone?
Promote the retention of water by the kidneys and increase blood pressure.
What is oxytocin?
Plays a role in social bonding, reproduction, childbirth, and the period after childbirth.
What hormones are produced in thyroid?
Thyroid hormones
T3,T4
Calcitonin
Where would you find the thyroid gland?
In neck anterior to the trachea
What is calcitonin produced by?
Para-follicular C cells
What are the purposes of T3 and T4?
T4 is a precursor for T3, which is more potent
-Increase metabolic rate of all cells
-determines basal metabolic rate
-essential for normal foetal and childhood growth
-Permissive effect on action of adrenaline by upregulating adrenoreceptors
What are disorders associated with under secretion of thyroid hormones?
Hypothyroidism
Cretinism, Myxoedema
What are disorders associated with over secretion of thyroid hormones?
Hyperthyroidism
Grave’s Disease
What is thyroid swelling associated with?
Iodine deficiency
What does low levels of thyroxine result in?
Increased secretion of TSH (Thyroid stimulating hormones)
How many parathyroid glands are there and where are they found?
4-5, on deep surface of the thyroid gland
What is the purpose of insulin?
Released when blood glucose is high and lowers blood glucose
What would inhibit secretion of insulin?
Adrenaline
Sympathetic nerves
Somatostatin
When is glucagon secreted?
Low blood glucose levels
What are functions of glucagon?
Glycogenolysis in liver
Gluconeogenesis in liver
Lipolysis and ketone synthesis
What are some clinical features of diabetes mellitus?
Polyuria ( increase urine production)
Polydipsia ( increase fluid intake, thirst)
Glucose in urine
Skin and oral diseases
Where would you find the adrenal glands?
Lie on top of the kidneys
What do the adrenal glands produce?
Corticosteroids
HISTOLOGY OF ADRENAL GLAND
What is the function of cortisol?
-Metabolic effects
-permissive effects
-Anti-inflammatory
-immunosuppressant
What is the function of aldosterone?
-Promotes reabsorption of Na+ and H20 in Kidney
-Increases excretion of H+, K+
What are androgens responsible for?
Puberty growth spurt
What is Cushing’s syndrome?
Excess glucocorticoid
What is an adreno-genital syndrome?
Excess androgens, early puberty