Download presentation
Presentation is loading. Please wait.
1
The Endocrine System
2
The Endocrine System collection of glands that produce hormones that regulate metabolism, growth and development, tissue function, sexual function, reproduction, sleep, and mood and other functions secrete hormones (chemical messages) directly into the circulatory system to be carried towards distant target organs coordinates whole body to maintain homeostasis accessory organs: (secondary endocrine functions) kidney, liver, heart and gonads
3
Regulation and Communication
Animals rely on two systems for regulation endocrine system system of ductless glands secrete chemical signals directly into blood chemical travels to target tissue target cells have receptor proteins slow, long-lasting response nervous system system of neurons transmits “electrical” signal & release neurotransmitters to target tissue widely dispersed fast, short-lasting response
4
Regulation by Chemical Messengers
Neurotransmitters released by neurons Hormones release by endocrine glands hormone carrier By blood neurotransmitter Target cell Pheromones Hormones Local Regulators Chemical signal from 1 individual to another individual Chemical signal from endocrine gland through blood to target cell Chemical signal from one cell to an adjacent cell Eg. ant trail; sex phermones Eg. peptide, steroid hormones Eg. cytokines, growth factors, nitric oxide (NO)
5
Classes of Hormones Protein-based hormones polypeptides
small proteins: insulin, ADH glycoproteins large proteins + carbohydrate: FSH, LH amines modified amino acids: epinephrine, melatonin Lipid-based hormones steroids modified cholesterol: sex hormones, aldosterone
6
Hormones Action on Target Cells
Protein-based hormones (Peptide) Water-soluble Bind to receptors on plasma membrane & triggers signal transduction pathway Affects protein activity already present in cell Rapid response Short-lived Eg. oxytocin, insulin, epinephrine Lipid-based hormones (steroid) Lipid-soluble Enters cell & binds to intracellular receptors Causes change in gene expression (protein synthesis) Slower response Longer life Eg. androgens (testosterone), estrogen, progesterone, cortisol animation
7
Action of Lipid (Steroid) Hormones
8
Action of Protein Hormones
Uses Signal Transduction Pathway o Secondary Messenger System
9
Action of Epinephrine (adrenaline)
Liver cells break down glycogen and release glucose Blood vessels to skeletal muscles dilate Blood vessels to intestines constrict
10
Benefits of a Secondary Messenger
11
Hormones and Homeostasis
Negative feedback “more gets you less” stimulus triggers control mechanism that inhibits further change body temperature sugar metabolism Positive feedback “more gets you more” stimulus triggers control mechanism that amplifies effect lactation labor contractions
12
Negative Feedback Stimulus & Response in opposite directions
Thyroid hormones Blood Ca2+ levels Blood glucose levels
13
Positive Feedback Stimulus and response in same direction Pressure on uterus oxytocin released causing more pressure
14
Nervous System Control of Body Temperature
15
Endocrine Control Regulation of Blood Sugar (Insulin and Blucagon)
16
Diabetes Mellitus Type I diabetes (10%):deficiency of insulin Insulin-dependent Autoimmune disorder beta cells of pancreas destroyed Type II diabetes (90%): failure of target cells to respond to insulin Non-insulin dependent Insulin produced cells don’t respond (defect in insulin receptor or response pathway) Risk factors: obesity, lack of exercise
17
Endocrine Control of Blood Osmolarity
Maintaining Water Balance Low blood osmolarity level/low BP Juxtaglomerular apparatus (JGA) releases renin in kidney Renin converts angiotnesinogen to angiotensin Angiotensin causes arterioles to constrict increases blood pressure Angiotensin triggers release of aldosterone from adrenal gland Increases reabsorption of NACl and H2O in kidneys puts more water and salts back in blood
18
Regulating Blood Osmolarity
If amount of dissolved material in blood is too high, body needs to dilute blood
19
Endocrine Control Regulation of Blood Calcium
20
Female Reproductive Cycle
hormones from the hypothalamus and anterior pituitary control the ovarian cycle ovarian cycle is hormonally regulated in two phases estrogen secreted before ovulation; progesterone secreted after ovulation.
21
Nervous and Endocrine Systems Linked
Hypothalamus “master nerve control center” nervous system Receives info from nerves and brain Regulates release of hormones from pituitary Pituitary gland “master gland” endocrine system secretes broad range of “tropic” hormones regulating other glands in body
22
Endocrine Glands Pituitary Growth hormone Stimulates growth Oxytocin
Childbirth; lactation attachment Tropic hormones Travel to other glands (ex: TSH, ACTH, FSH) ADH (Anti-Diuretic Hormone) Retain water
23
Endocrine Glands Thyroid Thyroxine Regulates metabolism Calcitonin
Uptake of Ca in blood animation
24
Thyroid Disorders Goiter due to iodine deficiency
Thyroid enlarges as it tries to produce thyroxine Graves’ Disease: autoimmune disorder antibodies bind to TSH receptor hyperthyroidism high temp, sweating, weight loss, high BP
25
Endocrine Glands Adrenal Epinephrine Fight-or-flight response
Release of glucose for more ATP animation Parathyroid Parathyroid hormone Regulates calcium levels (adds Ca to blood)
26
Adrenal Gland: Effect of Stress
27
Endocrine Organs Pancreas (Pancreatic islets) Insulin
Removes glucose from blood Glucagon Release glucose from glycogen (add to blood) Testes Testosterone Stimulated sperm production Maintains male sex characteristics
28
Tropins (tropic hormones)
stimulate growth in target organs/cells (tropic means nourishment) when the target organ is another gland, tropic hormones cause them to produce & release their own hormones
29
Regulating Metabolism
Hypothalamus TRH = TSH-releasing hormone Anterior Pituitary TSH = thyroid stimulating hormone Thyroid produces thyroxine hormones metabolism & development bone growth mental development metabolic use of energy blood pressure & heart rate muscle tone digestion reproduction Hypothalamus TRH Anterior pituitary TSH Thyroid T3 T4
30
Homology in Hormones This list suggests that prolactin is an ancient hormone whose functions have diversified during the evolution of the various vertebrate groups. Growth hormone (GH) is so similar structurally to prolactin that scientists hypothesize that the genes directing their production evolved from the same ancestral gene. Gene duplication.
31
Homology in Hormones
32
Hormonal Regulation in Insect Development
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.