BIOH111 o Cell Module o Tissue Module o Integumentary system o Skeletal system o Muscle system o Nervous system o Endocrine system Endeavour College of Natural Health endeavour.edu.au 1
Textbook and required readings o Glands: Principles of anatomy and physiology. Tortora et al; 14 th edition: Chapter 18; sections 18.1, 18.9, 18.10, 18.11, and 18.12 o Hormonal axes: Hiller-Sturmhofel & Bartke, 1998 Endeavour College of Natural Health endeavour.edu.au 2
BIOH111 ENDOCRINE SYSTEM MODULE o Session 23 (Lectures 43 and 44) Hormones, hormone receptors and molecular basis of hormone action and regulation o Session 24 (Lectures 45 and 46) Hypothalamus and pituitary, thyroid and parathyroid glands structure and function o Session 25 (Lectures 47 and 48) - Pineal, thymus, adrenal, pancreas and reproductive glands structure and function and hormonal axes o Session 26 Integration of nervous and endocrine systems Endeavour College of Natural Health endeavour.edu.au 3
BIOH111 Lectures 47 and 48 Pineal, thymus, adrenal, pancreas and reproductive glands (structure and function) and hormonal axes Department of Bioscience endeavour.edu.au
Lecture 47: Pineal, thymus and adrenal glands Objectives Define the structure of pineal and thymus gland and relate it to the secretion of their hormones Define the structure of adrenal gland and relate each structural component to the secretion of respective hormones Define regulation of adrenal gland hormones secretion Pancreas and reproductive glands (ovaries and gonads) Define the structure of pancreas and relate it to its function in secretion of hormones and enzymes Describe regulation of blood glucose levels Describe functions of reproductive glands Define and describe actions of other endocrine glands and factors Lecture 48: Hormonal axes Define and describe the structure and function of the 4 major hormonal axes: HPA, HPT, Female HPG and Male HPG Endeavour College of Natural Health endeavour.edu.au 5
ENDOCRINE GLANDS Endeavour College of Natural Health endeavour.edu.au 6
PINEAL GLAND o Structure: small gland attached to 3 rd ventricle of the brain; part of epithalamus; cells - pinealocytes & neuroglia o Function: production of melatonin: responsible for setting of biological clock secretion produces sleepiness occurs during darkness due to lack of stimulation from sympathetic ganglion Jet lag and seasonal effective disorder treatment is bright light Endeavour College of Natural Health endeavour.edu.au 7
THYMUS GLAND o Hormones promote the proliferation and maturation of T cells: some examples include: thymosin thymic humoral factor thymic factor thymopoietin Endeavour College of Natural Health endeavour.edu.au 8
ENDOCRINE GLANDS Endeavour College of Natural Health endeavour.edu.au 9
ADRENAL GLAND o Location: superior to the kidneys o Structure: 3x3x1cm in size and weighs 5 grams; consists of an outer cortex and an inner medulla Endeavour College of Natural Health endeavour.edu.au 10
1. Adrenal cortex o Structure and function: regulated by hormonal actions; divided into three zones, each secretes different hormones: 1. Zona Glomerulosa (outer zone) - secretes Mineralocorticoids 2. Zona Fasciculata (middle zone) secretes glucocorticoids 3. Zona Reticularis (inner zone) secretes androgens histology of adrenal cortex Endeavour College of Natural Health endeavour.edu.au 11
Blood flow through the adrenal gland pt-br.infomedica.wikia.com Endeavour College of Natural Health endeavour.edu.au 12
Hormones of adrenal cortex 1. Mineralocorticoids: 95% of hormonal activity due to aldosterone Functions: regulate mineral balance increase reabsorption of Na + with Cl -, bicarbonate and water promotes excretion of K + and H + 2. Glucocorticoids 95% of hormonal activity is due to cortisol Functions: regulate glucose metabolism and resistance to stress: increase rate of protein catabolism & lipolysis provide resistance to stress by increasing ATP production reduce immune responses and anti-inflammatory effects 3. Androgens Functions: regulate masculinization Small amount of male hormone produced insignificant in males; may contribute to sex drive in females; converted to oestrogen in postmenopausal females Endeavour College of Natural Health endeavour.edu.au 13
Regulation and action of aldosterone Kidneys renin/angiotensin (juxtaglomerular cells) Liver Lungs Adrenal cortex aldosterone Kidneys (glomerulae) Endeavour College of Natural Health endeavour.edu.au 14
Regulation of glucocorticoids o Negative feedback Endeavour College of Natural Health endeavour.edu.au 15
o Structure: chromaffin cells receive direct innervation from sympathetic nervous system 2. Adrenal medulla o Function: production of epinephrine & norepinephrine hormones that cause fight-flight behavior (these hormones are sympathomimetic - effects mimic those of sympathetic NS) homepage.smc.edu Endeavour College of Natural Health endeavour.edu.au 16
PANCREAS o Structure: flattened organ located posterior and slightly inferior to the stomach; consists of head, body and tail, 12 cm in length o Function: classified as both an endocrine (Islets of Langerhans) and an exocrine (acini) gland Endeavour College of Natural Health endeavour.edu.au 18
Islets of Langerhans o 1 to 2 million pancreatic islets; each contains 4 types of endocrine cells: 1. Alpha cells (20%) produce glucagon 2. Beta cells (70%) produce insulin 3. Delta cells (5%) produce somatostatin 4. F cells (5%) produce pancreatic polypeptide Endeavour College of Natural Health endeavour.edu.au 19
Acini cells o Contain zymogen granules that contain digestive enzymes and are released by secretion This aspect will be covered in more detail in BIOH111 Endeavour College of Natural Health endeavour.edu.au 20
Delivery of pancreas products Hormones from Islets are drained straight into the blood This aspect will be covered in more detail in BIOH111 Enzymes from acini cells are drained into pancreatic duct WHY?? Endeavour College of Natural Health endeavour.edu.au 21
REGULATION OF BLOOD GLUCOSE LEVELS o Negative feedback mechanisms regulate secretion of glucagon and insulin: o Low blood glucose stimulates release of glucagon o High blood glucose stimulates secretion of insulin Endeavour College of Natural Health endeavour.edu.au 22
Why do we need insulin secreted in response to increase in blood glucose levels? So cells can bring glucose transporter to the plasma membrane by regulated secretion.. - revision STIMULUS (insulin interacting with its receptor) Which cells do you think this process happens in and why?
ENDOCRINE GLANDS Endeavour College of Natural Health endeavour.edu.au 24
OVARIES AND TESTES o Ovaries Hormones produced: oestrogen, progesterone, relaxin & inhibin Function: regulate reproductive cycle, maintain pregnancy & prepare mammary glands for lactation Ovary o Testes Hormone produced: testosterone Function: regulate sperm production & secondary sexual characteristics Testis Endeavour College of Natural Health endeavour.edu.au 25
OTHER HORMONES AND GROWTH FACTORS o Several body tissues also contain endocrine tissue and produce and secrete hormones: 1. Eicosanoids family of local hormones produced by all cells in the body from omega-3 and omega-6 fats; function: smooth muscle contraction, glandular secretion, blood flow, platelet function, nerve transmission, metabolism (e.g. prostaglandin) and influences on WBCs and inflammation (e.g. leukotrienes) 2. Growth factors family of proteins secreted by most cells in the body; act in autocrine or paracrine manner through cell membrane receptors; function in differentiation and/or proliferation; e.g. epidermal growth factor (EGF), fibroblast growth factor (FGF), insulin-like growth factor (IGF) Endeavour College of Natural Health endeavour.edu.au 26
Non assessable Revision Read one of the following: section 18.16 or Homeostatic Imbalances (Tortora, p 652) and define following terms: aging, pituitary gland disorders, diabetes insipidus, thyroid and parathyroid gland disorders, Cushing s syndrome, Addison s disease and pancreatic islet disorders. Then in groups of 2-3 think about: - What are the risk factors for these processes, conditions and disorders? - Describe structural and comment on molecular level changes that occur in these muscle disorders and conditions. - Link the described causes and affected muscle physiology to comment on possible treatments of these disorders within your particular interest. Endeavour College of Natural Health endeavour.edu.au 27
Lecture 47: Pineal, thymus and adrenal glands Objectives Define the structure of pineal and thymus gland and relate it to the secretion of their hormones Define the structure of adrenal gland and relate each structural component to the secretion of respective hormones Define regulation of adrenal gland hormones secretion Pancreas and reproductive glands (ovaries and gonads) Define the structure of pancreas and relate it to its function in secretion of hormones and enzymes Describe regulation of blood glucose levels Describe functions of reproductive glands Define and describe actions of other endocrine glands and factors Lecture 48: Hormonal axes Define and describe the structure and function of the 4 major hormonal axes: HPA, HPT, Female HPG and Male HPG Endeavour College of Natural Health endeavour.edu.au 28
Hormonal axis CONTROL OF HORMONE SECRETION Hypothalamus +/- Pituitary gland Endocrine gland Tropic hormone + +/- Direct regulation +/- Positive and negative loops Hormone Y Receptor Target organ Action Endeavour College of Natural Health endeavour.edu.au 29
DIRECT REGULATION OF BLOOD GLUCOSE LEVELS - revision o Negative feedback mechanisms regulate secretion of glucagon and insulin: o Low blood glucose stimulates release of glucagon o High blood glucose stimulates secretion of insulin Endeavour College of Natural Health endeavour.edu.au 30
DIRECT REGULATION OF CALCIUM BLOOD LEVELS - revision Blood calcium level directly controls the secretion of calcitonin and parathyroid hormone via negative feedback loops that do not involve the pituitary gland: Endeavour College of Natural Health endeavour.edu.au 31
Hormonal axis HORMONAL AXES general overview Hypothalamus +/- Pituitary gland Endocrine gland Tropic hormone + +/- Positive and negative loops Hormone Y Receptor Target organ Action Endeavour College of Natural Health endeavour.edu.au 32
METABOLIC AXIS - HPA Regulation: Circadian rhythm Stress Blood volume Hypothalamus: CRH ADH Pituitary gland: ACTH Gland/target: Adrenal cortex Kidney Target hormones: Cortisol Androgen Function: Stress Water balance Hiller-Sturmhofel & Bartke, 1998 Endeavour College of Natural Health endeavour.edu.au 33
METABOLIC AXIS - HPT Regulation: Thyroid hormone levels Hypothalamus: TRH Pituitary gland: TSH Gland/target: Thyroid Target hormones: T4/T3 Function: Metabolism Hiller-Sturmhofel & Bartke, 1998 Endeavour College of Natural Health endeavour.edu.au 34
METABOLIC AXIS - FEMALE HPG Regulation/ Hormone : Estrogen, Progesterone, Androgen, Prolactin, Inhibin Estrogen Stress Hypothalamus: GnRH Dopamine Pituitary gland: LH FSH Prolactin Gland/target: Gonads (ovaries) Breast Function: Reproduction Lactation Hiller-Sturmhofel & Bartke, 1998 Endeavour College of Natural Health endeavour.edu.au 35
METABOLIC AXIS - MALE HPG Hypothalamus: GnRH Pituitary gland: LH FSH Gland/target: Gonads (testes) Target hormones: Testosterone Function: Reproduction Hiller-Sturmhofel & Bartke, 1998 Endeavour College of Natural Health endeavour.edu.au 36
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