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ENDOCRINE SYSTEM CTLI Training : 12,13 July 2011 H.C.Adonis. HOMEOSTASIS. LIVER. SKIN. ureum. glucose. Excess water,salts,heat. Amino acids. Insulin & glucagon. oxygen. carbondioxide. PANCREAS. LUNGS. Excess water, salts, ions. ureum. KIDNEYS. HOMEOSTASIS: Main ideas.
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HOMEOSTASIS LIVER SKIN ureum glucose Excess water,salts,heat Amino acids Insulin & glucagon oxygen carbondioxide PANCREAS LUNGS Excess water, salts, ions ureum KIDNEYS
HOMEOSTASIS: Main ideas • Maintenance of constant internal environment in the body/keeping conditions in tissue fluid constant • WHY? • Cells dependant on tissue fluid to function optimally • HOW? • Various systems that help in maintaining tissue fluid/internal environment constant i.e. nervous system, excretory system, respiratory system, ENDOCRINE SYSTEM. • Various systems need to be coordinated in order for body to function as a unit. • HOW ARE THESE SYSTEMS COORDINATED?
CHEMICAL COORDINATION: Endocrine System Communication through the use of hormones: results in slower responses NERVOUS COORDINATION: Nervous system Communication takes place via neurons: results in quick responses
HOW DOES CHEMICAL COORDINATION TAKE PLACE? HOMEOSTATIC CONTROL CENTRE: THE BRAIN (hypothalamus) Nerve impulses Nerve impulses/Hormones in bloodstream RECEPTORS: detect stimuli/change EFFECTORS (glands): react on stimuli stimuli responses Feedback
CHEMICAL vs NERVOUS COORDINATION CHEMICAL COORDINATION Co-ordinates different systems in the body to work together Involves hormones transported in the bloodstream in small quantities Has general and local effects on the body Is slower acting Has long-lasting effects NERVOUS COORDINATION Co-ordinates different parts of the body to work together Involves isensations that are transported via neurons in the form of impulses Has specific targets/effectors Is very fast acting Has more short-term effects
ENDOCRINE SYSTEM • Endocrine system co-ordinates the body’s organs to help maintain homeostasis • Based on the production of chemical messengers called HORMONES. • Hormones control body processes that require several organs of the body to interact for a combined effect. • Are chemical "messengers“, secreted by glands. • Moves very slowly. • Most hormones are proteins and some are steroids. • Hormones have specific target organs • Regulatory effect – stimulate OR inhibit • Do not function in isolation – integrated with other hormones Functions controlled by hormones include: • activities of entire organs • growth and development • reproduction • sexual characteristics • usage and storage of energy • regulate water content (osmoregulation) • ionic (salt) regulation • regulation of blood glucose level
ENDOCRINE GLANDS: position + function • IMPORTANT!
ENDOCRINE GLANDS: location Hypophysis / pituitary gland Thyroid gland Pancreas Adrenal glands Ovaries Testes
ENDOCRINE GLANDS: location & function • Located at base of brain, attached to • hypothalamus • Nerve fibresfrom hypothalamus runs into posterior lobe • Known as “master gland” • Consist of anterior (adenohypophysis) and posterior lobe (neurohypophysis) • Anterior lobe releases: • TSH (Thyroid-stimulating hormone) • Growth hormone (STH) • FSH (Follicle-stimulating hormone) • LH (Luteinising hormone) • Prolactin • Posterior lobe releases: • ADH (Anti-diuretic hormone) • Oxytocin Pituitary gland/hypophysis
ENDOCRINE GLANDS: location & function Thyroid: consist of two lobes on either side of trachea, just below larynx Produces and secretes hormone thyroxin The element iodine, essential for production of thyroxin Shortage could result in enlarged thyroid / goitre
Functions of thyroxine • Increases basal metabolic rate (amount of energy the body needs to function when body is at rest) • Increases breathing rate and heart rate • Development and functioning of nervous system • Normal growth and development of important organs
HYPERTHYROIDISM HYPOTHYROIDISM THYROID DISORDERS
HOMEOSTATIC CONTROL More TSH Less thyroxin THYROID HYPOPHYSIS More thyroxin less TSH NEGATIVE FEEDBACK SYSTEM
HYPOSECRETION HYPERSECRETION • Gigantism & Acromegaly • Dwarfism GROWTH DISORDERS
ENDOCRINE GLANDS: location & function • Two types of cells: • Pancreatic cells • Islets of Langerhans(small groups of cells) • Pancreatic cells have exocrine function and secrete pancreatic juice into pancreatic duct which leads to duodenum • Islets of Langerhanshave endocrine function and secretes 2 hormones directly into bloodstream i.e. glucagon and insulin • Alpha cells secrete glucagon and betacells produce insulin • Insulin and glucagon responsible for homeostatic control of blood glucose levels through negative feedback system Pancreas
LOW BLOOD GLUCOSE 1. Low blood glucose(stimulus) 2. 3. glucagon Blood glucose levels return to normal , feedback to hypothalamus 4.
HIGH BLOOD GLUCOSE 1. High blood glucose(stimulus) 2. 3. insulin Blood glucose returns to normal, feedback to hypothalamus 4.
DIABETESmellitus: Type 1 • Dysfunction of beta cells, little or no insulin is produced - can cause elevation of glucose level in blood. • The excess glucose is now removed from the body through urine. • Excess glucose is also removed through sweating. SYMPTOMS: Frequent urination Increased hunger Inexplicable weight loss Repeated infections Impaired vision Exhaustion and dizziness Wounds that heal slowly
Treatment and management • Daily insulin injection • A specially adapted diet • Regular testing of blood sugar levels
Type 2 diabetes • Characterised by insulin resistance • Life style disease CAUSES: Overweight and obesity Inactivity Age TREATMENT AND MANAGEMENT Maintain normal body mass through balanced diet Regular exercise Oral medication or insulin
ENDOCRINE GLANDS: location & function Adrenal glands Located at top of each kidney ; consist of outer cortex and inner medulla Adrenal cortex produces hormone aldosterone. Adrenal medulla produces adrenalin.
Effects of Adrenalin & Aldosterone: ADRENALIN: • Known as “fight or flight” hormone • Increases heart rate - more blood with oxygen and glucose to muscles • Increases blood pressure due to vasoconstriction of vessels in skin- more blood to muscles ,heart and brain • Increases conversion of glycogen to glucose – increase glucose levels in blood which releases energy • Increase rate and depth of respiration – more oxygen absorbed in blood • Increase muscle tone – muscles can react faster • Pupils dilate – allow more light into eye for improved vision • Increase sweat production – cool body during activity ALDOSTERONE: Steroid hormone that regulates ionic balance of tissue fluid
ENDOCRINE GLANDS: location & function Gonades: testes and ovaries Testes located outside body in scrotum Interstitial cells (Leydig cells) produces hormone testosterone Ovaries located in abdominal cavity, on either side of uterus Graafian follicles produce hormone oestrogen Corpus luteum produces hormone progesterone
GONADS: Testes & ovaries TESTOSTERONE • Secondary male sex characteristics • Role in development of male sex organ during puberty • Neccesary for maturation and quality of sperm cells OESTROGEN • Secondary female sex characteristics • Role in development of female sex organs during puberty • Responsible for thickening of endometrium and preparation for implantation PROGESTERONE • Responsible for further thickening of endometrium and maintenance therof during pregnancy • Suppresses release of FSH and LH