Survey of Anatomy and Physiology Chap 10

The Endocrine System: The Body's Other Control Center

10

Endocrine SystemEndocrine System

Nervous system and endocrine system are totally interconnected and always monitor each other's activities

Nervous system and endocrine system are totally interconnected and always monitor each other's activities


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Endocrine system also collects information and sends orders but

it is slower, more subtle control system

Endocrine system also collects information and sends orders but

it is slower, more subtle control system


While it acts slowly, effects last longer than those of nervous system

While it acts slowly, effects last longer than those of nervous system

Nervous vs. EndocrineNervous vs. Endocrine

Endocrine system

is series of organs and glands in

body that secrete chemical

messengers (hormones) into

blood stream


Exocrine glands/organs produce secretions

that must exit a gland through a duct

Endocrine vs ExocrineEndocrine vs Exocrine

Figure 10-1The endocrine glands and

their hormones.

• Pineal• Hypothalamus• Pituitary• Adrenal• Parathyroid• Thyroid• Thymus• Pancreas• Gonads

• Pineal• Hypothalamus• Pituitary• Adrenal• Parathyroid• Thyroid• Thymus• Pancreas• Gonads

Table 10-1 Endocrine Organ Functions

Hormones: chemical

messengers released by endocrine

glands

HormonesHormones

Hormones are released into bloodstream

and travel all over body,

some affecting millions of cells simultaneously

HormonesHormones


Effects last for minutes or even hours or days

Many hormones are secreted constantly, with amount secreted changing as needed

Table 10-2 Comparison of Neurotransmitters and

Hormones

Hormones bind to receptor sites outside target cells or inside

target cell

How Hormones WorkHow Hormones Work

If hormones bind to outside of cell, they

can have several different effects, either

changing cellular permeability or

sending target cell a message that changes

enzyme activity inside cell

HormonesHormones

How Hormones WorkHow Hormones Work

OR

How Hormones Work How Hormones Work STEROIDSSTEROIDS

This special class of hormones (steroids) is particularly

powerful because only small

amounts needed to perform their

task

This special class of hormones (steroids) is particularly

powerful because only small

amounts needed to perform their

task

How Hormones Work How Hormones Work STEROIDSSTEROIDS

Steroids are lipid molecules that can pass easily through

target cell membrane,

allowing them to interact directly

with cell's DNA to change cell activity

Steroids are lipid molecules that can pass easily through

target cell membrane,

allowing them to interact directly

with cell's DNA to change cell activity

Amount of hormone secreted changes based on situational demands

Control of Endocrine Control of Endocrine ActivityActivity

Many

endocrine organs secrete hormones continuously

Control of Endocrine Control of Endocrine ActivityActivity

HomeostasisHomeostasis

Many chemical and physical characteristics of body have standard level (set point) that is

ideal for a particular value

Many chemical and physical characteristics of body have standard level (set point) that is

ideal for a particular value

Control systems (endocrine and

nervous system) work to keep levels at or near ideal

Control SystemsControl Systems

Example: hypothalamus stores ideal set point for temperature

Control SystemsControl Systems

The body can measure, store and correct for

ideal set points

The body can measure, store and correct for

ideal set points

Figure 10-2Homeostasis is similar to regulation

of temperature via a thermostat.

Negative FeedbackNegative Feedback

If any of the body's homeostatic values become seriously disrupted, control systems work to bring

them back to set point via negative feedback

If any of the body's homeostatic values become seriously disrupted, control systems work to bring

them back to set point via negative feedback



Hormones work same way; if

hormone levels rise, negative feedback will

turn off endocrine

organ that is secreting the

hormone

Hormones work same way; if

hormone levels rise, negative feedback will

turn off endocrine

organ that is secreting the

hormone

Positive FeedbackPositive Feedback

When a body characteristic

changes, positive feedback

increases the magnitude of a

change

When a body characteristic

changes, positive feedback

increases the magnitude of a

change

Positive Feedback-Flow Positive Feedback-Flow of Sodium Ionsof Sodium Ions

More depolarized a neuron becomes, the more sodium flows in, and it becomes

more depolarized, so more flows in until action potential is

complete

More depolarized a neuron becomes, the more sodium flows in, and it becomes

more depolarized, so more flows in until action potential is

complete


• Hypothalamus orders pituitary to secrete oxytocin

• Oxytocin stimulates uterine contractions

• Pressure of uterus stimulates more oxytocin and more contractions until pressure decreases

• Hypothalamus orders pituitary to secrete oxytocin

• Oxytocin stimulates uterine contractions

• Pressure of uterus stimulates more oxytocin and more contractions until pressure decreases


Positive feedback not a

way to regulate your body because it

increases a change away from set point

Positive feedback not a

way to regulate your body because it

increases a change away from set point

Control of Hormone Control of Hormone LevelsLevels

Some hormones

are directly controlled by

nervous system

Sources of ControlSources of Control

When

sympathetic nervous system

activated it sends signals out to adrenal

Example of Neural Example of Neural ControlControl

Adrenal glands

release epinephrine and norephinephrine into bloodstream

Example of Neural Example of Neural ControlControl

Figure 10-4Sympathetic control of

adrenal gland.

Hormones prolong the

effects of sympathetic

activity

Hormones prolong the

effects of sympathetic

activity

Hormonal ControlHormonal Control

Hormones are part of

hierarchy of hormonal

control

Hormones are part of

hierarchy of hormonal

control


One gland is controlled by release of hormones from another gland up the chain, which is

controlled by another gland's release of hormones up the

chain

One gland is controlled by release of hormones from another gland up the chain, which is

controlled by another gland's release of hormones up the

chain


Orders are sent from

one organ to another, as in a relay

race

Orders are sent from

one organ to another, as in a relay

race

One gland

“orders” another to produce

hormone and when enough produced the

“ordering gland” STOPS sending

orders


Hormonal Control-Stress Hormonal Control-Stress or Hypoglycemiaor Hypoglycemia

Figure 10-5Hormonal control of adrenal gland

• Adrenal gland produces cortisol; when enough has been produced,

• Hypothalamus detects and stops sending orders to pituitary which

• Stops sending orders to adrenal

• Adrenal stops making cortisol

• Adrenal gland produces cortisol; when enough has been produced,

• Hypothalamus detects and stops sending orders to pituitary which

• Stops sending orders to adrenal

• Adrenal stops making cortisol

Humoral ControlHumoral Control

Some endocrine organs directly monitor

body's internal environment by

monitoring body fluids, such as blood, and respond accordingly

Some endocrine organs directly monitor

body's internal environment by

monitoring body fluids, such as blood, and respond accordingly

Humoral ControlHumoral Control

Pancreas secretes insulin in response

to rising blood sugar levels

Pancreas secretes insulin in response

to rising blood sugar levels

Figure 10-6 Control of blood sugar levels

Necessary changes in

hormone secretion are

made accordingly

Necessary changes in

hormone secretion are

made accordingly

PA/Instructor Asks:

A. Adrenal glandB. StomachC. PancreasD. Liver

PA/Instructor Asks:

A. Adrenal glandB. StomachC. PancreasD. Liver

Take A BreakTake A Break

FIVE MINUTES

Major Endocrine Major Endocrine GlandsGlands

• Important link between two control systems:

• Link between the nervous and the endocrine systems

• Important link between two control systems:

• Link between the nervous and the endocrine systems

Controls Physiology of Controls Physiology of the Bodythe Body

Commander-in-ChiefCommander-in-Chief

Also acts as “commander-in-

chief” of endocrine system; it controls pituitary gland and most other

glands in endocrine system

Also acts as “commander-in-

chief” of endocrine system; it controls pituitary gland and most other

glands in endocrine system

Figure 10-7The hypothalamus, anterior and posterior

pituitary glands, and their targets and associated hormones.

PAGE 259

Pituitary GlandPituitary Gland

Commonly known as

“master gland” because of its

role in controlling

other endocrine

glands

Commonly known as

“master gland” because of its

role in controlling

other endocrine

glands

Pituitary GlandPituitary Gland

• Really acts only under orders from

hypothalamus• Split into two

segments: anterior and

posterior

• Really acts only under orders from

hypothalamus• Split into two

segments: anterior and

posterior

Posterior PituitaryPosterior Pituitary

Hypothalamic neurons, specialized

to secrete hormones instead

of neurotransmitters extend their axons

through stalk in posterior pituitary

Hypothalamic neurons, specialized

to secrete hormones instead

of neurotransmitters extend their axons

through stalk in posterior pituitary


As name suggests antidiuretic

hormone (ADH) decreases

urination, which decreases fluid

lost, increasing body fluid

volume

As name suggests antidiuretic

hormone (ADH) decreases

urination, which decreases fluid

lost, increasing body fluid

volume


Circulates through

bloodstream and targets

kidneys specifically,

causing them to absorb

more water

Circulates through

bloodstream and targets

kidneys specifically,

causing them to absorb

more water


Important in long-term control of

blood pressure, especially during

dehydration

Important in long-term control of

blood pressure, especially during

dehydration


Important in maintaining

uterine contractions during labor

Involved in milk production in

nursing mothers

*Function in males is unknown

Important in maintaining

uterine contractions during labor

Involved in milk production in

nursing mothers

*Function in males is unknown

Anterior PituitaryAnterior Pituitary

Hypothalamus secretes hormone

that controls hormone

secretion by anterior pituitary

Hypothalamus secretes hormone

that controls hormone

secretion by anterior pituitary


Usually controls

secretion of hormones by

another endocrine

gland

Usually controls

secretion of hormones by

another endocrine

gland


Hormone levels are controlled by negative feedback to

both pituitary and

hypothalamus

Hormone levels are controlled by negative feedback to

both pituitary and

hypothalamus


Thyroid GlandThyroid Gland

Thyroid Gland located in anterior

portion of neck and is butterfly

shaped

Thyroid Gland located in anterior

portion of neck and is butterfly

shaped


Secretes hormones

triiodothyronine (T3) and

thyroxine (T4) under pituitary

orders

Secretes hormones

triiodothyronine (T3) and

thyroxine (T4) under pituitary

orders


Control cell metabolism and growthReferred to as “thyroid hormones”

Control cell metabolism and growthReferred to as “thyroid hormones”


Table salt contains added iodine to

ensure people get enough iodine in their

diets to make thyroid hormones

Table salt contains added iodine to

ensure people get enough iodine in their

diets to make thyroid hormones


Level of these hormones essential in

controlling growth and metabolism of

body tissues, particularly in

nervous system

Level of these hormones essential in

controlling growth and metabolism of

body tissues, particularly in

nervous system

PA/Instructor Asks:

A. Weight gainB. Muscle painC. Feeling hotD. Fatigue

Figure 10-9 Comparison of the signs and symptoms

of abnormal thyroid function

Calcitonin from ThyroidCalcitonin from Thyroid

Thyroid gland secretes third

hormone, calcitonin;

decreases blood calcium by

stimulating bone-building cells*

Thyroid gland secretes third

hormone, calcitonin;

decreases blood calcium by

stimulating bone-building cells*

Parathyroid GlandsParathyroid Glands

Two small pairs of glands

embedded in the posterior surface of the

thyroid

Two small pairs of glands

embedded in the posterior surface of the

thyroid

Parathyroid GlandsParathyroid Glands

Increases the level of calcium in the bloodstream by stimulating bone

dissolving cells* by releasing PTH (parathyroid

hormone)

Increases the level of calcium in the bloodstream by stimulating bone

dissolving cells* by releasing PTH (parathyroid

hormone)

Figure 10-8The thyroid and parathyroid glands.

Calcitonin from thyroid decreases level of calcium and PTH increases level of calcium in

the blood

Calcitonin from thyroid decreases level of calcium and PTH increases level of calcium in

the blood

Thymus GlandThymus Gland

Both endocrine gland and lymphatic organ

Located in upper thoraxProduces hormone

called thymosin; helps with maturation of white blood cells to

fight infection

Both endocrine gland and lymphatic organ

Located in upper thoraxProduces hormone

called thymosin; helps with maturation of white blood cells to

fight infection

Pineal GlandPineal Gland

Tiny gland found in brainShown to produce hormone melatonin, which rises and falls during waking and sleeping hours

Tiny gland found in brainShown to produce hormone melatonin, which rises and falls during waking and sleeping hours

Pancreas-ExocrinePancreas-Exocrine

Accessory organ of digestive system

Located in upper

abdomen, near

stomach

Accessory organ of digestive system

Located in upper

abdomen, near

stomach

Pancreas-ExocrinePancreas-Exocrine

Part of pancreas acts as exocrine

organThis part produces

and secretes digestive

enzymes that help to break down

starches, fats, and proteins

Part of pancreas acts as exocrine

organThis part produces

and secretes digestive

enzymes that help to break down

starches, fats, and proteins

Pancreas-EndocrinePancreas-Endocrine

Other part of pancreas acts as

endocrine organ

Produces hormones that regulate blood

sugar

Other part of pancreas acts as

endocrine organ

Produces hormones that regulate blood

sugar

Pancreas-EndocrinePancreas-Endocrine

Responsible for maintaining blood sugar

(glucose) levels at or near set

pointNormal range for

blood glucose levels: 70 to 100

mg/dL

Responsible for maintaining blood sugar

(glucose) levels at or near set

pointNormal range for

blood glucose levels: 70 to 100

mg/dL

Pancreas & Blood GlucosePancreas & Blood Glucose

Pancreas-Two HormonesPancreas-Two Hormones

Makes two hormones that control blood

glucose: insulin and glucagon

Produced by cells in pancreatic tissue called islets of Langerhans

Makes two hormones that control blood

glucose: insulin and glucagon

Produced by cells in pancreatic tissue called islets of Langerhans



AlphaCellsAlphaCells

BetaCellsBetaCells

PA/Instructor Asks:

With increased glucose (solute) in blood (solvent), more water is drawn across the cell membrane from a lower to a higher concentration to balance fluid

concentrations on both sides and thereby dehydrating the cell

Figure 10-11The role of glucagon to raise blood sugar

In between eating, blood glucose levels

decrease and then the pancreas secretes

glucagon into blood. One of two things

happens: 1) Adipose breaks down fat and

releases glucose or 2) liver breaks down

glycogen

Adrenal GlandsAdrenal Glands

Located as a pair, one on top of each

of the kidneysContain two regions:

Adrenal cortex (outside) and

medulla (inside)

Located as a pair, one on top of each

of the kidneysContain two regions:

Adrenal cortex (outside) and

medulla (inside)


Adrenal medulla releases two hormones:

• Epinephrine (adrenalin)

• Norephinephrine (noradrenalin) which is both a hormone and a neurotransmitter

Adrenal medulla releases two hormones:

• Epinephrine (adrenalin)

• Norephinephrine (noradrenalin) which is both a hormone and a neurotransmitter


These hormones increase duration

of effects of sympathetic

nervous system; effects last longer

than neurotransmitter

These hormones increase duration

of effects of sympathetic

nervous system; effects last longer

than neurotransmitter


Effects: increased heart

rate, blood pressure, respiration

rate, sweaty palms, and dry

mouth

Effects: increased heart

rate, blood pressure, respiration

rate, sweaty palms, and dry

mouth


Cortex makes dozens of steroid hormones,

known collectively as adrenocorticosteroids

Cortex makes dozens of steroid hormones,

known collectively as adrenocorticosteroids

Released by stimulation from anterior pituitary gland


Many of these hormones are so important that

decrease in production could be fatal quickly

Many of these hormones are so important that

decrease in production could be fatal quickly

Released by stimulation from anterior pituitary gland

AdrenocorticoidsAdrenocorticoids

Adrenal cortex makes dozens of steroids or “-corticoids” including glucocorticoids and

mineralcorticoids

Adrenal cortex makes dozens of steroids or “-corticoids” including glucocorticoids and

mineralcorticoids


Others “cortex” hormones responsible for regulation of reproduction and secondary sexual

characteristics

Others “cortex” hormones responsible for regulation of reproduction and secondary sexual

characteristics

PA/Instructor Asks:

A. Increased appetiteB. Low blood pressure (hypotension)C. Anxiety and depressionD. High blood pressure (hypertension)

PA/Instructor Asks:

A. Increased appetiteB. Low blood pressure (hypotension)C. Anxiety and depressionD. High blood pressure (hypertension)

Diabetes MellitusDiabetes Mellitus

Diabetes MellitusDiabetes Mellitus

Table 10-4 Comparison of Type 1 and Type 2 Diabetes

Figure 10-12Various effects of diabetes mellitus

Page 269 in your text

PA/Instructor Asks:

You’ve just been given one of the essay questions on your exam which may include one or more of the above separate questions. The answer(s) are in your text and this power

point slide presentation

GONADSGONADS

Include testes and ovaries and function to produce and store

the eggs (ovaries) and sperm (testes)

Include testes and ovaries and function to produce and store

the eggs (ovaries) and sperm (testes)

Also produce number of sex hormones (testosterone

and estrogen & progesterone) which

control reproduction

Also produce number of sex hormones (testosterone

and estrogen & progesterone) which

control reproduction

She is a 35-year-old insulin-dependent diabetic who currently takes good care of herself. She did not take good care of herself as a teenager. She is on an insulin pump to try to control her blood sugar, but has recently passed out in public several times.

Case Study Case Study MariaMaria's Story's Story

What condition causes her to pass

out? (hyperglycemia or hypoglycemia)

Why does this condition develop? What is the appropriate treatment

for the early stages of this condition?

Case Study MariaCase Study Maria's 's StoryStory

Upcoming ExamUpcoming Exam

Test on Chapters 9,10 and 11 will be Nov 12, 2013 and cover:•PPP for Chapter 9 only; •Structure of the eye for Chap 11 and steps in “How Hearing Occurs” including structures •Chap 10 Power Point & Worksheet answers•Essay on blood glucose maintained by pancreas•Extra credit on “Concussion” page 226

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Survey of Anatomy and Physiology Chap 10