THE ENDOCRINE SYSTEM ALL ABOUT YOUR HORMONES!!.

THE ENDOCRINE SYSTEMALL ABOUT YOUR HORMONES!!

He Pingping (he only reaches 2.4 feet), meets Bao Xishun (towering at 7.9 feet) tall!

THE IMPORTANCE OF THE ENDOCRINE SYSTEM Body systems interact through the use of

chemicals: hormones Chemicals produced in glands and secreted

directly into the blood are endocrine hormones; carried by the circulatory system

Hormones are classified according to their activation site

Hormones: (Greek: hormon – to excite, set into motion)

Are produced by glands and sent to the bloodstream

Exert effect somewhere else in the body Are required in small amounts only Act in the metabolic pathway

MINKOWSKI & MERING 1889 Removed dog

pancreases What happened? Fatigued and lost wt. Ants were found in

the kennels! Why? Increased glucose in

urine Hormones are hard

to study...no hormonal response works independently!

CHEMICAL CONTROL SYSTEMS

Provide integration and control of organs and tissues along with the nervous system

Nervous system enables quick changes to environment

Endocrine system designed to maintain control over longer durations

The hypothalamus regulates the pituitary- the master gland- through nerve signals, but the pituitary, through other glands, affect the nerve activity of the hypothalamus

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TWO TYPES OF HORMONES

Steroid hormones (made from cholesterol (testosterone, estrogen) and Protein hormones

Steroids diffuse from capillaries into interstitial fluid, then into target cellsCombine with receptor molecules in the

cytoplasmHormone-receptor complex then moves

into nucleus and attaches to segment of chromatin with complementary shape

Activates a gene to produce a specific protein

STEROID HORMONES – SEX HORMONES

PROTEIN HORMONES – INSULIN, GH

Made up of chains of AA (insulin, GH) Combine with specific receptors on the cell

membrane Some activate the enzyme adenylyl

cyclase which causes cell to convert ATP into cyclic AMP (cyclic adenosine monophosphate)

Cyclic AMP functions as a messenger, activating other enzymes in the cytoplasm to carry our normal functions

PROTEIN HORMONES

THE PITUITARY: THE MASTER GLAND

Exercises control over other endocrine glands

Two lobes: Anterior and Posterior

Anterior – produces and stores hormones

Posterior – stores hormones produced by hypothalamus

HOMEWORK!

Copy the chart on P 377 into your notes! Familiarize your self with the pituitary

hormones! http://www.youtube.com/watch?v=8fh2Hmdx

QjQ

HORMONES THAT AFFECT BLOOD SUGAR

The Pancreas contains two types of cells Produces digestive

enzymes Produces hormones

– located in structures called the islets of Langerhans Over 2000 islets (each

containing thousands of cells) are scattered throughout pancreas

Islets contain alpha and beta cells which are responsible for the production of insulin and glucagon

STORING AND RELEASING GLUCOSE!

Insulin released when blood sugar levels increase insulin causes cells of muscles, liver, and

other organs to become permeable to glucose. Liver converts glucose to glycogen

Insulin causes decreases in blood sugar level Glucagon causes increase in blood sugar

level (released when blood sugar levels are low, promotes conversion of glycogen to glucose.

http://www.youtube.com/watch?v=NazZCu1lwOE&feature=related

GREAT CANADIANS!

Dr. Charles Best and Dr. Frederick Banting

1923 Nobel Prize for the discovery of Insulin (Best was excluded!!)

Did not profit from the discovery...unheard of today!

ADRENAL GLANDS

Located above each kidney Inner gland – adrenal medulla

medulla surrounded by outer casing (adrenal cortex), regulated by the nervous system hormones regulate the adrenal cortex

Adrenal medulla produces two hormones (produced when cells within adrenal medulla are stimulated by sympathetic nerves in times of stressepinephrinenorepinephrine

FIGHT OR FLIGHT!!

These two hormones initiate fight-or-flight biological responses

blood sugar level rises glycogen converted to glucose ensures greater energy reserve available increase heart and breathing rates as well as

cell metabolism blood vessels dilate = allowing more oxygen

and nutrients to reach tissues irises dilate http://www.youtube.com/watch?v=RyP8L3qT

W9Q

ADRENAL CORTEX

Produces three different types of hormonesGlucocorticoids

one of the most important - Cortisol, increases level of amino acids in blood and helps in recovery of stress by being converted to glucose in liver, supplying more energy needed for repair or recovery by cells or participating in protein synthesis

Mineralocortiocoids Salt and water balance – ALDOSTERONE!

Sex hormones Small amounts!

LONG TERM STRESS RESPONSE

hypothalamus sends hormone to anterior lobe of pituitary

stimulates pituitary to secrete corticotrophin (adrenocorticotropic hormone; ACTH)

blood carries ACTH to target cells in adrenal cortex cells of adrenal cortex secrete mineralocorticoids

and glucocorticoids (one of which is cortisol) these are carried to target cells in liver and

muscles as cortisol levels rise, hypothalamus and pituitary

production of regulatory hormones decreases eventually cortisol levels begin to fall

SHORT TERM STRESS RESPONSE

regulated by adrenal medullaepinephrine & norepinephrine

aldosterone is one of most important mineralocorticoids increases sodium retention and water

reabsorption by kidneys

HOMEWORK!

Copy Chart on p 382 into your notebook Do Q 1-7, Page 383

THYROID GLAND

located at base of neck two important thyroid hormones (which

regulate body metabolism, growth, and differentiation of tissues)thyroxine (T4)triiodothyronine (T3)

HORMONES THAT AFFECT METABOLISM

Three different glands affect metabolism thyroid gland

helps regulate body metabolism (glucose oxidation rate)

produces three hormones triiodothyronine, thyroxine, calcitonin

parathyroid gland produces parathyroid hormone helps regulate calcium levels in blood and

lower phosphate levels anterior pituitary gland

produces growth hormones and regulatory hormones

THYROID GLAND

individuals who secrete higher levels of thyroxine oxidize sugars and other nutrients at a faster rate

When glycogen stores are filled, excess sugar is converted to fat

control of thyroid hormones is accomplished by negative feedback

FEEDBACK LOOP... receptors in hypothalamus are activated if the

metabolic rate decreases nerve cells secrete TRH (thyroid releasing

hormone) this stimulates pituitary to release TSH (thyroid

stimulating hormone) carried by blood to thyroid gland which then

releases thyroxine which raises metabolism by stimulating sugar utilization by cells

high levels of thyroxine cause pathway to be turned off, inhibiting release of TRH

thyroxine contains calcitonin hormone acting on bone cells to lower level of

calcium found in blood   when inadequate amounts of iodine

OH NO!

when inadequate amounts of iodine are obtained from the diet, thyroid enlarges, producing a goiter.

PARATHYROID GLANDS

Four parathyroid glands hidden within larger thyroid gland

Usually nerves or other hormones regulate the endocrine glands with the parathyroid glands being the exceptionThese maintain homeostasis by

responding directly to chemical changes in their immediate surroundings

Raises calcium levels in the blood

 PTH (parathyroid hormone) also help activate vitamin D. (Low levels of vit D cause rickets!)

RICKETS AND GOITERS...

HUMAN GROWTH HORMONE (AKA SOMATOTROPIN) Too little = dwarfism Too much =

gigantism Released by Ant. Pit. GH increases cell size

in muscle cell and connective tissue by promoting Pro Synthesis (increasing Amino Acid uptake)

Promotes fat burning Dec. Levels of GH

with age

HGH AND CONTROVERSY...

Should you take it? Did Roger Clemens?

HOMEWORK!

Copy Chart on P. 387 Read 384-387, Do Nelson Biology 387 # 1-8

ADJUSTMENTS TO STRESS

  When initiator of

stress is identified, endocrine and nervous systems make adjustments enabling body to cope with problem

NERVOUS SYSTEM

increases heart ratediverts blood to needed musclesactivates reninangiotensin-aldosterone

pathway in response to reduced blood flow to kidneys by increasing Na+ reabsorption, kidneys help maintain increased fluid volume thus helping to sustain adequate blood pressure during stress.

Activation of hypothalamus causes increased release of antidiurectic hormone ADH which further increases water reabsorption from nephron to help maintain body fluids.

ENDOCRINE SYSTEM

hormones provide more sustained response to stimulus hormones provide more blood glucose to cope with

elevated energy requirements insulin release inhibited

regulation of blood pressure and volume

WE HAVE A PROBLEM...

Operating with elevated blood sugar, blood pressure, and heart rate creates problems for the body in terms of long-term stress

PROSTAGLANDINS

local responses to changes in immediate environment of cells detected by mediator cells

these produce low concentrations of prostaglandins (hormones having pronounced effects in small localized areas) that tend to be absorbed by surrounding tissues (some absorbed by capillaries and carried in blood)

Released during stress and allergic reactions

STEROIDS...

CHEMICALLY ENHANCED SPORTS PERFORMANCE Anabolic steroids – designed to mimic many of

the muscle-building traits of the sex hormone testosterone

In 1988 Olympic, Canadian sprinter Ben Johnson was disqualified for using Stanozolol

There are a number of health risks linked to extended use of anabolic steroids: prematurely fuse growth plates in long bones

of teens, thereby reducing height potential mood swings (e.g. rage)

There are a myriad of drugs that affect the body sharpshooters use beta blockers that slow the

heartbeat (helps to steady ain and calm jangled nerves)

EPO and HGH are hard to detect b/c they are naturally occuring in the body

HOMEWORK

Read Chart P.391 Read Pages 388-392, Do Page 392 # 1-9

REPRODUCTIVE HORMONES

REPRODUCTIVE HORMONE

MALE ANATOMY - REVIEW

MALE REPRODUCTIVE SYSTEM male sex hormones androsterone and

testosterone produced in interstitial cells (found between

seminiferous cells) of testes testosterone

stimulates spermatogenesis spermatogonia divide and differentiate into mature sperm

cells

influences development of secondary male sexual characteristics at pituitary stimulating maturation of testes and penis

promotes development of facial and body hair, growth of larynx

increases production of body oils

FEEDBACK!

Hypothalamus and pituitary gland control production of sperm and male sex hormones in testes

Negative feedback systems ensure adequate numbers of sperm cells and constant levels of testosterone are maintained

FEMALE ANATOMY - REVIEW

FEMALE REPRODUCTIVE SYSTEM

females follow complicated sexual cycle one egg matures ~ every month hormone levels fluctuate through

reproductive years ending at menopause

OOGENESIS AND OVULATION

ovaries contain fibrous connective tissue and small groups of cells called follicles (two types of cells)primary oocytegranulosa cells

primary oocyte contains 46 chromosomes, undergoes meiosis, transformed to mature oocyte (ovum)

granulosa cells provide nutrients for oocyte each ovary contains ~ 400000 follicles at

puberty, many follicles develop during each reproductive cycle, usually only one becomes dominant and reaches maturity

OVULATION

Hormone produced in pituitary controls follicle development

Eventually a dominant follicle pushes outward, ballooning outer wall of ovary

Secondary oocyte releases – ovulation Surrounding follicle cells remain within ovary

and are transformed into corpus luteum, secreting hormones necessary for pregnancy.

Secondary oocyte enters oviduct and begins Meiosis II

MENSTRUAL CYCLE Takes about 28 days Divided into four distinct phases

flow phase – shedding of endometrium (menstruation)(Day 1-5)

follicular phase – development of follicles within ovary

- hormone estrogen secreted (day 6-13) ovulatory phase – egg bursts from ovary and follicular

cells differentiate into corpus luteum

luteal phase – development of corpus luteum, secretion of estrogen and progesterone, prepares uterus for embryo and inhibits further ovulation (Day 15-28)

HORMONAL CONTROL OF FEMALE REPRODUCTIVE SYSTEM

Hypothalamus-pituitary complex regulates production of estrogen and progesterone

Gonadotropins Female follicle-stimulating hormone (FSH)Luteinizing hormone (LH)

  Gonadotropins regulate control of hormones

produced by ovaries Ovarian hormones regulate gonadotropins

via negative feedback mechanisms

GREAT VISUALS OF THE HORMONE CYCLES…

http://www.youtube.com/watch?v=8_rfZ_qj1z4&feature=related

HOW THE PILL WORKS…

http://www.pbs.org/wgbh/amex/pill/sfeature/sf_cycle.html