The Endocrine System Flashcards
Distinguish between exocrine and endocrine glands.
- ENDOCRINE - Synthesise/store chemical messengers. They have no ducts, very rich blood stream. Hormones secreted directly into blood. - EXOCRINE - Glands with ducts. Secretions reach target through these ducts. More involved in digestion and sweat.
Define the term hormone and describe how hormones can be classified according to their chemical composition
- Hormones - chemical messengers that are secreted into the blood stream. They act on specific receptors or cells. They are released from specialised cells that form together to form specialised tissue which form specialised glands.
- CATEGORIES-
- Steroid - lipid soluble, direct effect on genes.
- Peptide - water soluble, can’t pass through membrane, utilise receptors
- Amines - a cross between both of the above.
What hormones are released from the hypothalamus?
- Thyrotropin-Releasing Hormone (TRH)
- Growth-Hormone Releasing Hormone (GhRH)
- Corticotropin Releasing Hormone (CRH)
- Gonadotropin-releasing Hormone (GrH)
What hormones are released by the pituitary gland?
- POSTERIOR-
- Anti-Diuretic Hormone (ADH)
- Oxytocin
- ANTERIOR -
- Thyroid Stimulating Hormone (TSH)
- Prolactin (PRL)
- Adrenocorticotrophic Hormone (ACTH)
- Leutinizing Hormone (LH)
- Follicle Stimulating Hormone (FSH)
- Human Growth Hormone (hGH)
What hormones are released from the thyroid gland?
- Thyrotropin-Releasing Hormone (TRH)
- Thyroid Stimulating Hormone (TSH)
- Thyroxine (T4)
- Tri-iodothyronine (T3)
What hormones are released by the adrenal gland?
- Adrenaline/Noradrenaline
- Aldosterone
- Cortisol
- Adrogens (e.g. Testosterone)
What hormones are released by the pancreas?
- Insulin
- Glucagon
What hormones are released by the ovaries?
- Oestrogen
- Progesterone
What hormones are released by the testes?
- Testosterone
What hormones are produced by the heart?
Atrial Natriuretic Peptide (ANP)
What hormones are produced by the kidneys?
- Erythropoietin (EPO)
- Calcidiol
What hormones are produced by the brain?
- Brain Natriuretic Peptide (BNP)
What hormones are produced by the small intestine?
- Cholecystokinin (CCK)
- Secretin
What hormones are produced by the pineal gland?
- Melatonin
What hormones are produced by the parathyroid gland?
- Parathyroid Hormone (PTH)
What hormones are produced by the placenta?
- Hunan Chorionic Gonadotrophin (hCG)
- Progesterone
What hormones are produced by the thymus?
- Thymosin
Identify the main neurotransmitter of the Autonomic Nervous System (ANS) and identify their site of release
- Acetylecholine (ACh) - 2 classes: nicotinic (ganglionic synapse in both divisions) and muscarinic (target tissue of post-ganglionic parasympathetic neurones.
Outline the structural and functional organisation of the Autonomic Nervous System (ANS)
2 divisions - sympathetic and parasympathetic
- Sympathetic division - mobilised bodily resources in response to threat by speeding up heart rate and respiration and drawing stored energy “fight or flight”
- Parasympathetic division - replenishes bodily resources by promoting digestion and slowing down other bodily processes “rest and digest”
What hormone is responsible for the reabsorption of WATER ONLY in the nephron?
Anti-diuretic hormone (ADH)
Thyroxine is an example of:
An amine hormone
What are the main hormone producing glands?
- Hypothalamus
- Pituitary gland (anterior and posterior)
- Thyroid gland
- Adrenal gland
- Pancreas
- Ovaries
- Testes
What are the hormone-producing tissues (that are not classic endocrine glands)
- Heart
- Kidney
- Brain
- Small intestine
- Pineal gland
- Parathyroid gland
- Placenta
- Thymus
What is the function of Thyrotropin-releasing hormone (TRH)?
Stimulates the anterior pituitary gland to release thyroid-stimulating hormone (TSH)
What is the main function of growth-hormone releasing hormone (GHRH)
Stimulates the release of human growth hormone (hGH) from the anterior pituitary gland
What is the main function of Corticotropin Releasing Hormone (CRH)
Stimulates the release of adrenocorticotrophic hormone (ACTH) from the anterior pituitary
What is the main function of Gonadotropin-Releasing Hormone (GnRH)
Stimulates the release of Follicle Stimulating Hormone (FSH) and Luteinising Hormone (LH) from the anterior pituitary gland
What is the main function of Anti-Diuretic Hormone (ADH)
Retention of water in the kidneys
What is the main function of Oxytocin
Contracts smooth muscle in the uterus during labour controlled by POSITIVE FEEDBACK
What is the main function of Thyroid Stimulating Hormone?
Regulates the production of hormones from the thyroid gland
What is the main function of prolactin?
Production of breast milk
What is the main function of Adrenocorticotrophic Hormone (ACTH)
Stimulates production of Cortisol from the adrenal glands
What is the main function of Luteinising Hormone (LH)
Main control of the reproductive system (triggers ovulation and production of testosterone/progesterone)
What is the main function of Follicle Stimulating Hormone (FSH)
Regulates the function of the ovaries and testes (promotes maturation of follicles)
What is the main function of Human Growth Hormone (hGH)
Maintaining normal body structure and metabolism
What is the main function of Thyrotropin Releasing Hormone?
Stimulates the release of Thyroid Stimulating Hormone (TSH)
What is the main function of Thyroid Stimulating Hormone (TSH)
Stimulates the break down of thyroglobulin into Thyroxine (T4) and Tri-iodothyronine (T3)
What is the main function of Thyroxine (T4) and Tri-iodothyronine (T3)
Play vital roles in digestion, heart and muscle function, brain development and maintenance of bones.
What is the main function of Adrenaline/Noradrenaline
Prepares body for ‘fight or flight’ response
What is the main function of aldosterone?
Regulates sodium and water regulation in the kidneys thus having an affect on blood pressure. Promotes reabsorption of sodium, water follows
What is the main function of cortisol?
Stress response and metabolism
What is the main function of testosterone?
Responsible for the physical characteristics in males
What is the main function of insulin?
Lowers blood glucose levels
What is the main function of glucagon?
Raises blood glucose levels (antagonist to insulin)
What is the main function of oestrogen?
Secondary sexual characteristics in females
What is the main function of progesterone
Important in menstrual cycle, causes breaking down of endometrium and levels rise drastically after fertilisation
What is the main function of Atrial Natriuretic Peptide (ANP)
Lowers blood pressure by decreasing heart rate
What is the main function of Erythropoietin (EPO)
Red blood cell production
What is the main function of Calcidiol?
Calcium homeostatis
What is the main function of Brain Natriuretic Peptide (BNP)
Vasodilation and help kidneys excrete sodium and water
What is the main function of Cholecystokinin (CCK)
Stimulates the digestion of fats and proteins, can reduce gastric motility and secretion
What is the main function of Secretin?
Regulates water homeostatis, can reduce gastric motility and secretion
What is the main function of Melatonin
When taken as medication - resets cardiac rhythm to help with sleep deprivation and jet lag
What is the main function of Parathyroid Hormone (PTH)
Regulates calcium levels in the plasma
What is the main function of Human Chorionic Gonadotropin (hCG)
Maintains and establishes early pregnancy
How are hormones regulated?
- hypothalamus connects with pituitary glands.
- releasing hormones are released from the hypothalamus and travel to the pituitary gland where they cause the release of stimulating hormones
- these act on endocrine glands which release anther hormone to act on target tissue.
- controlled with mostly negative feedback (oxytocin is positive feedback)
Describe the hormone-induced physiological changes that occur when a person is stressed
- The sympathetic nervous system sends out impulses to glands and smooth muscles and causes the adrenal glands to release adrenaline/noradrenaline - fight or flight:
- raised heart rate and BP -pupils dilate -vasoconstriction -smooth muscles relax -non-essential systems shut down
Describe the neurones of the sympathetic nervous system
- short pre-ganglionic neuron
- ACh released
- long post-ganglionic neuron
- Adrenaline/Noradrenaline released into target tissue
Describe the elements of parasympathetic neurones
- long pre-ganglionic neurone
- ACh released
- short post-ganglionic neurone
- ACh released into target tissue
Thyroxine is an example of:
An amine hormone
