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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. - PowerPoint PPT Presentation
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ENDOCRINE SYSTEM
CTLI Training: 12,13 July 2011
H.C.Adonis
HOMEOSTASISLIVER SKIN
PANCREAS LUNGS
KIDNEYS
glucoseAmino acidsIns
ulin &
glu
cago
n
ureum Excess water, salts, ions
oxygen
carbondioxideureum
Excess
water,salts,h
eat
HOMEOSTASIS: Main ideasMaintenance of constant internal environment in
the body/keeping conditions in tissue fluid constant
WHY?Cells dependant on tissue fluid to function
optimallyHOW?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?
RECEPTORS: detect
stimuli/change
EFFECTORS (glands): react on
stimuli
HOMEOSTATIC CONTROL CENTRE:
THE BRAIN(hypothalamus) Nerve
impulses/Hormones in bloodstream
Nerve impulses
stimuli responsesFeedback
CHEMICAL vs NERVOUS COORDINATION
CHEMICAL COORDINATIONCo-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 actingHas long-lasting effects
NERVOUS COORDINATIONCo-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 actingHas more short-term effects
HUMAN ENDOCRINE SYSTEM• Ductless glands• Release hormones
directly into bloodstream or lymph.
Endocrine
glands• Release secretions in
ducts to be carried to body cavity or outside of body i.e. saliva, tears etc.
Exocrine glands
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!
POSITION OF GLANDS
HORMONES SECRETED
FUNCTION / EFFECT OF HORMONES
ENDOCRINE GLANDS: locationHypophysis / pituitary
gland
Thyroid gland
Pancreas
Adrenal glands
Ovaries
Testes
ENDOCRINE GLANDS: location & function
Pituitary gland/hypophysis
Located at base of brain, attached to hypothalamus
Nerve fibres from 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
HYPOPHYSIS / PITUITARY GLAND
HYPOPHYSIS HORMONES: Anterior lobe
TSH• Stimulates the thyroid to
secrete the hormone thyroxin
GROWTH HORMONE(STH)
• Promotes growth of skeleton and muscles by stimulating synthesis of proteins
FSH• Stimulates development
of primary follicles in ovaries into Graafian follicles
LH • Stimulates ovulation
PROLACTIN• Stimulates the mammary
glands to produce milk after the birth of a baby
HYPOPHYSIS HORMONES: Posterior lobe
ADH (Anti-diuretic
hormone)
• Controls re-absorption of water into blood from renal tubules
OXITOCIN
• Cause muscle contractions in uterus during birth
• Triggers milk release during breastfeeding
ENDOCRINE GLANDS: location & functionThyroid: 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
THYROID GLAND
Functions of thyroxineIncreases 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
Thyroid DisordersOver secretion:Hyperthyroidis
mm
• Increased metabolic rate• Weight loss• Increased heart rate,
respiration rate and blood pressure
• Increased irritabilityUnder secretion:Hypothyroidism
• Causes very low metabolism• In children: cretinism• In adults: myxoedema
Cretinism • Abnormal growth• Mental retardation• Do not reach sexual maturity
Myxoedema
• Mental decline, physical lethargy
• Thickening of skin, increase in body mass
THYROID DISORDERS
HYPERTHYROIDISM HYPOTHYROIDISM
HOMEOSTATIC CONTROL
THYROID HYPOPHYSIS
More TSH
less TSH
Less thyroxin
More thyroxin
NEGATIVE FEEDBACK SYSTEM
GROWTH DISORDERS
HYPOSECRETION HYPERSECRETIONGigantism &
AcromegalyDwarfism
ENDOCRINE GLANDS: location & function
PancreasTwo 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 Langerhans have endocrine function and secretes 2 hormones directly into bloodstream i.e. glucagon and insulin
Alpha cells secrete glucagon and beta cells produce insulin
Insulin and glucagon responsible for homeostatic control of blood glucose levels through negative feedback system
PANCREAS
PANCREAS
INSULIN & GLUCAGON: Homeostatic control
INSULIN: Beta cells
• Stimulates absorption of glucose to body cells
• Stimulates conversion of glucose to glycogen in liver and muscles
• Inhibits conversion of glycogen to glucose
GLUCAGON:
Alpha cells
• Stimulates conversion of glycogen to glucose in the liver
• Inhibits conversion of glucose to glycogen
LOW BLOOD GLUCOSE1.
2. glucagon
Blood glucose levels return to normal , feedback to
hypothalamus
Low blood glucose(stimulus)
3.
4.
HIGH BLOOD GLUCOSEHigh blood glucose(stimulus)
insulin
Blood glucose returns to normal, feedback to hypothalamus
1.
2. 3.
4.
HOMEOSTATIC CONTROL: BLOOD GLUCOSE
DIABETES mellitus: Type 1Dysfunction 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 throughsweating.
SYMPTOMS:Frequent urinationIncreased hungerInexplicable weight lossRepeated infectionsImpaired visionExhaustion and dizziness Wounds that heal slowly
Treatment and management
Daily insulin injectionA specially adapted dietRegular testing of blood sugar
levels
Type 2 diabetesCharacterised by insulin resistanceLife style disease
CAUSES:Overweight and obesityInactivityAgeTREATMENT AND MANAGEMENT
Maintain normal body mass through balanced dietRegular exerciseOral 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.
ADRENAL GLANDS
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 activityALDOSTERONE:Steroid hormone that regulates ionic balance of tissue fluid
ENDOCRINE GLANDS: location & functionGonades: 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 & ovariesTESTOSTERONE 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
END