the endocrine systempchs.psd202.org/documents/dpohlman/1515513237.pdfimmune system long-term stress...

PowerPoint® Lecture Slide Presentation

by Patty Bostwick-Taylor,

Florence-Darlington Technical College

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings

PART B9

The Endocrine

System


Thyroid Gland

Found at the base of the throat

Consists of two lobes and a connecting isthmus

Produces two hormones

Thyroid hormone

Calcitonin


Thyroid Gland

Figure 9.7a


Thyroid Gland

Thyroid hormone

Major metabolic hormone

Composed of two active iodine-containing

hormones

Thyroxine (T4)—secreted by thyroid

follicles

Triiodothyronine (T3)—conversion of T4 at

target tissues


Thyroid Gland

Figure 9.7b


Thyroid Gland

Thyroid hormone disorders

Goiters

Thyroid gland enlarges due to lack of

iodine

Salt is iodized to prevent goiters

Cretinism

Caused by hyposecretion of thyroxine

Results in dwarfism during childhood


Thyroid Gland

Figure 9.8


Thyroid Gland

Goiter


Cretinism

True cretinism can only be avoided by an adequate iodine intake through gestation. This simply requires substituting all household salt, and that available to domestic animals, with iodized salt, containing 1.34 μg KI/kg salt.

The misnamed ‘sporadic’ cretins, on the other hand, identified by neonatal screening programs, require prompt postnatal treatment with thyroid hormones to prevent their mental retardation.


Thyroid Gland

Cretinism

Baby before and after radioactive treatment for sporadic cretinism

Sporadic Cretinism


Thyroid Gland

Thyroid hormone disorders (continued)

Myxedema

Caused by hypothyroidism in adults

Results in physical and mental slugishness

Graves’ disease

Caused by hyperthyroidism

Results in increased metabolism, heat intolerance, rapid heartbeat, weight loss, and exophthalmos


Myxedema

Man with myxedema or severe hypothyroidism showing an expressionless face, puffiness around the eyes and pallor

Additional finding include swelling of the arms and legs and significant ascites.


Thyroid Gland

Figure 9.9

Graves’ disease


Graves’ disease

Showing eye bulge and goiter


Thyroid Gland

Calcitonin

Decreases blood calcium levels by causing its

deposition on bone

Antagonistic to parathyroid hormone

Produced by parafollicular cells

Parafollicular cells are found between the

follicles


Thyroid Gland

Figure 9.7b


Parathyroid Glands

Tiny masses on the posterior of the thyroid

Secrete parathyroid hormone (PTH)

Stimulate osteoclasts to remove calcium from

bone

Stimulate the kidneys and intestine to absorb

more calcium

Raise calcium levels in the blood


Parathyroid Glands

Parathyroid hormone disorder

Tetany

If blood calcium levels fall too low,

neurons become extremely irritable

and over active. Impulses to muscles

are so fast that muscles go into

uncontrollable spasms called tetany,

which can be fatal.


Hormonal Regulation of Calcium in Blood

Figure 9.10

Calcium homeostasis of blood9–11 mg/100 ml

RisingbloodCa2+

levels

Thyroid glandreleasescalcitonin

Osteoclastsdegrade bonematrix and releaseCa2+ into blood

PTH

Calcitonin Calcitoninstimulatescalcium saltdepositin bone

Parathyroidglands releaseparathyroidhormone (PTH)

Thyroidgland

Thyroidgland

Parathyroidglands

FallingbloodCa2+

levels



Figure 9.10, step 1


Rising

blood

Ca2+

levels



Figure 9.10, step 2


Rising

blood

Ca2+

levels

Thyroid

gland



Figure 9.10, step 3


Rising

blood

Ca2+

levels

Thyroid gland

releases

calcitonin

Calcitonin

Thyroid

gland



Figure 9.10, step 4


Rising

blood

Ca2+

levels

Thyroid gland

releases

calcitonin

Calcitonin Calcitonin

stimulates

calcium salt

deposit

in bone

Thyroid

gland



Figure 9.10, step 5


Rising

blood

Ca2+

levels

Thyroid gland

releases

calcitonin

Calcitonin Calcitonin

stimulates

calcium salt

deposit

in bone

Thyroid

gland


Figure 9.10, step 6


Falling

blood

Ca2+

levels



Figure 9.10, step 7


Thyroid

gland

Parathyroid

glands

Falling

blood

Ca2+

levels



Figure 9.10, step 8


PTHParathyroid

glands release

parathyroid

hormone (PTH)

Thyroid

gland

Parathyroid

glands

Falling

blood

Ca2+

levels



Figure 9.10, step 9


Osteoclasts

degrade bone

matrix and release

Ca2+ into blood

PTHParathyroid

glands release

parathyroid

hormone (PTH)

Thyroid

gland

Parathyroid

glands

Falling

blood

Ca2+

levels



Figure 9.10, step 10


Osteoclasts

degrade bone

matrix and release

Ca2+ into blood

PTHParathyroid

glands release

parathyroid

hormone (PTH)

Thyroid

gland

Parathyroid

glands





RisingbloodCa2+

levels

Thyroid glandreleasescalcitonin

Osteoclastsdegrade bonematrix and releaseCa2+ into blood

PTH

Calcitonin Calcitoninstimulatescalcium saltdepositin bone

Parathyroidglands releaseparathyroidhormone (PTH)

Thyroidgland

Thyroidgland

Parathyroidglands

FallingbloodCa2+

levels



Adrenal Glands

Sit on top of the kidneys

Two regions

Adrenal cortex—outer glandular region has

three layers

Mineralocorticoids secreting area

Glucocorticoids secreting area

Sex hormones secreting area

Adrenal medulla—inner neural tissue region

Catecholamines secreting area


Hormones of the Adrenal Cortex

Figure 9.11



Mineralocorticoids (mainly aldosterone)

Produced in outer adrenal cortex

Regulate mineral content in blood

Regulate water and electrolyte balance

Target organ is the kidney

Production stimulated by renin (kidney) and

aldosterone

Production inhibited by atrial natriuretic

peptide (ANP) (heart)

Rising blood levels of aldosterone cause

kidney tubules to reabsorb sodium



Figure 9.12



Glucocorticoids (including cortisone and cortisol)

Produced in the middle layer of the adrenal

cortex

Promote normal cell metabolism

Help resist long-term stressors

Released in response to increased blood

levels of ACTH

Suppress inflammation, decrease edema and

increase blood glucose levels


Roles of the Hypothalamus and

Adrenal Glands in the Stress Response

Figure 9.13

Short term More prolongedStress

Hypothalamus

Nerve impulses

Adrenal

cortex

Releasing hormone

Corticotropic cells ofanterior pituitary

ACTH

Mineralocorticoids Glucocorticoids

1. Retention of sodium

and water by kidneys

2. Increased blood

volume and blood

pressure

1. Proteins and fats

converted to glucose

or broken down for

energy

2. Increased blood

sugar

3. Suppression of

immune system

Long-term stress response

Short-term

stress response

Spinal cord

Adrenal

medulla

Preganglionicsympatheticfibers

Catecholamines(epinephrine andnorepinephrine)

1. Increased heart rate

2. Increased blood pressure

3. Liver converts glycogen to

glucose and releases glucose

to blood

4. Dilation of bronchioles

5. Changes in blood flow

patterns, leading to increased

alertness and decreased

digestive and kidney activity

6. Increased metabolic rate




Figure 9.13, step 1

Short term Stress

Hypothalamus




Figure 9.13, step 2

Short term Stress

Hypothalamus

Nerve impulses

Spinal cord




Figure 9.13, step 3

Short term Stress

Hypothalamus

Nerve impulses

Spinal cord

Adrenal

medulla





Figure 9.13, step 4

Short term Stress

Hypothalamus

Nerve impulses

Short-term

stress response

Spinal cord

Adrenal

medulla






Figure 9.13, step 5

Short term Stress

Hypothalamus

Nerve impulses

Short-term

stress response

Spinal cord

Adrenal

medulla







to blood










Figure 9.13, step 6

More prolongedStress

Hypothalamus




Figure 9.13, step 7


Hypothalamus

Releasing hormone





Figure 9.13, step 8


Hypothalamus

Adrenal

cortex

Releasing hormone


ACTH




Figure 9.13, step 9


Hypothalamus

Adrenal

cortex

Releasing hormone


ACTH

Mineralocorticoids







Hypothalamus

Adrenal

cortex

Releasing hormone


ACTH








Hypothalamus

Adrenal

cortex

Releasing hormone


ACTH




2. Increased blood

volume and blood

pressure







Hypothalamus

Adrenal

cortex

Releasing hormone


ACTH




2. Increased blood

volume and blood

pressure



or broken down for

energy

2. Increased blood

sugar

3. Suppression of

immune system






Short term More prolongedStress

Hypothalamus

Nerve impulses

Adrenal

cortex

Releasing hormone


ACTH




2. Increased blood

volume and blood

pressure



or broken down for

energy

2. Increased blood

sugar

3. Suppression of

immune system


Short-term

stress response

Spinal cord

Adrenal

medulla







to blood









Sex hormones

Produced in the inner layer of the adrenal

cortex

Small amounts are made throughout life

Mostly androgens (male sex hormones) are

made but some estrogens (female sex

hormones) are also formed


Adrenal Glands

Adrenal cortex disorders

Addison’s disease

Results from hyposecretion of ALL

adrenal cortex hormones

Bronze skin tone, muscles are weak,

burnout, susceptibility to infection

Hyperaldosteronism

May result from an ACTH-releasing tumor

Excess water and sodium are retained

leading to high blood pressure and edema


Adrenal Glands

Addison’s disease


Adrenal Glands

Adrenal cortex disorders

Cushing’s syndrome

Results from a tumor in the middle cortical area of the adrenal cortex (glucocorticoids)

“Moon face,” “buffalo hump” on the upper back, high blood pressure, hyperglycemia, weakening of bones, depression

Masculinization

Results from hypersecretion of sex hormones

Beard and male distribution of hair growth


Adrenal Glands



Hormones of the Adrenal Medulla

Produces two similar hormones (catecholamines)

Epinephrine (adrenaline)

Norepinephrine (noradrenaline)

These hormones prepare the body to deal with

short-term stress (“fight or flight”) by

Increasing heart rate, blood pressure, blood

glucose levels

Dilating small passageways of lungs



Figure 9.11


Pancreatic Islets

The pancreas is a mixed gland and has both

endocrine and exocrine functions

The pancreatic islets produce hormones

Insulin—produced from beta cells of islets.

Allows glucose to cross plasma membranes into

cells thus decreasing blood glucose levels.

Glucagon—produced from alpha cells of islets.

Breaks down glycogen in the liver to allow

glucose to enter the blood, thus raising blood

sugar.

These hormones are antagonists that maintain

blood sugar homeostasis


Pancreatic Islets

Figure 9.14a–b


Pancreatic Islets

Figure 9.14b–c


Pancreatic Islets

Insulin hormone disorder

Diabetes mellitus

Blood glucose raises and spills into urine

causing water to follow. Urine smells sweet.

Can cause acidosis when fat has to be used

for energy.

3 signs:

Polyuria- excessive urination

Polydipsia- excessive thirst

Polyphagia- excessive hunger


Figure 9.15

Insulin-secretingcells of the pancreasactivated; releaseinsulin into theblood

Elevatedblood sugarlevels

Stimulus:rising bloodglucose levels(e.g., aftereating fourjelly doughnuts)

Rising bloodglucose levelsreturn blood sugarto homeostatic setpoint; stimulus forglucagon releasediminishes

Blood glucoselevels declineto set point;stimulus forinsulin releasediminishes

Stimulus:declining bloodglucose levels(e.g., afterskipping a meal)

Low bloodsugar levels

Glucagon-releasingcells of pancreasactivated;release glucagoninto blood; targetis the liver

Uptake of glucosefrom blood is en-hanced in mostbody cells

Liver breaks downglycogen stores andreleases glucose tothe blood

Liver takes upglucose and storesit as glycogen

Homeostasis: Normal blood glucose

levels (90 mg/100ml)


Figure 9.15, step 1




Stimulus:

rising blood

glucose levels

(e.g., after

eating four

jelly doughnuts)



Figure 9.15, step 2


Elevated

blood sugar

levels

Stimulus:

rising blood

glucose levels

(e.g., after

eating four

jelly doughnuts)



Figure 9.15, step 3


Insulin-secreting

cells of the pancreas

activated; release

insulin into the

blood

Elevated

blood sugar

levels

Stimulus:

rising blood

glucose levels

(e.g., after

eating four

jelly doughnuts)



Figure 9.15, step 4


Insulin-secreting


activated; release

insulin into the

blood

Elevated

blood sugar

levels

Stimulus:

rising blood

glucose levels

(e.g., after

eating four

jelly doughnuts)

Uptake of glucose

from blood is en-

hanced in most

body cells



Figure 9.15, step 5


Insulin-secreting


activated; release

insulin into the

blood

Elevated

blood sugar

levels

Stimulus:

rising blood

glucose levels

(e.g., after

eating four

jelly doughnuts)

Uptake of glucose

from blood is en-

hanced in most

body cells

Liver takes up

glucose and stores

it as glycogen



Figure 9.15, step 6


Figure 9.15, step 7

Insulin-secreting


activated; release

insulin into the

blood

Elevated

blood sugar

levels

Stimulus:

rising blood

glucose levels

(e.g., after

eating four

jelly doughnuts)

Blood glucose

levels decline

to set point;

stimulus for

insulin release

diminishes

Uptake of glucose

from blood is en-

hanced in most

body cells

Liver takes up

glucose and stores

it as glycogen




Figure 9.15, step 8

Stimulus:

declining blood

glucose levels

(e.g., after

skipping a meal)




Figure 9.15, step 9

Stimulus:

declining blood

glucose levels

(e.g., after

skipping a meal)

Low blood

sugar levels





Stimulus:

declining blood

glucose levels

(e.g., after

skipping a meal)

Low blood

sugar levels

Glucagon-releasing

cells of pancreas

activated;

release glucagon

into blood; target

is the liver





Stimulus:

declining blood

glucose levels

(e.g., after

skipping a meal)

Low blood

sugar levels

Glucagon-releasing

cells of pancreas

activated;

release glucagon

into blood; target

is the liverLiver breaks down

glycogen stores and

releases glucose to

the blood





Rising blood

glucose levels

return blood sugar

to homeostatic set

point; stimulus for

glucagon release

diminishes

Stimulus:

declining blood

glucose levels

(e.g., after

skipping a meal)

Low blood

sugar levels

Glucagon-releasing

cells of pancreas

activated;

release glucagon

into blood; target

is the liverLiver breaks down

glycogen stores and

releases glucose to

the blood





Insulin-secretingcells of the pancreasactivated; releaseinsulin into theblood

Elevatedblood sugarlevels

Stimulus:rising bloodglucose levels(e.g., aftereating fourjelly doughnuts)

Rising bloodglucose levelsreturn blood sugarto homeostatic setpoint; stimulus forglucagon releasediminishes

Blood glucoselevels declineto set point;stimulus forinsulin releasediminishes

Stimulus:declining bloodglucose levels(e.g., afterskipping a meal)

Low bloodsugar levels

Glucagon-releasingcells of pancreasactivated;release glucagoninto blood; targetis the liver

Uptake of glucosefrom blood is en-hanced in mostbody cells

Liver breaks downglycogen stores andreleases glucose tothe blood

Liver takes upglucose and storesit as glycogen




Pineal Gland

Found on the third ventricle of the brain

Secretes melatonin

Helps establish the body’s wake and sleep

cycles

Believed to coordinate the hormones of

fertility in humans


Location of Major Endrocrine Organs

Figure 9.3


Thymus Gland

Located posterior to the sternum

Largest in infants and children

Produces thymosin

Matures some types of white blood cells

known as T lymphocytes (T-cells)

Important in developing the immune system


Gonads

Ovaries

Produce eggs

Produce two groups of steroid hormone

Estrogens

Progesterone

Testes

Produce sperm

Produce androgens, such as testosterone


Location of Major Endrocrine Organs

Figure 9.3


Hormones of the Ovaries

Estrogens

Stimulate the development of secondary

female characteristics

Mature female reproductive organs

With progesterone, estrogens also

Promote breast development

Regulate menstrual cycle


Hormones of the Ovaries

Progesterone (produced along with estrogen by

the ruptured egg follicle called the corpus luteum

or “yellow body”)

Acts with estrogen to bring about the

menstrual cycle

Helps in the implantation of an embryo in the

uterus and quiets the muscles of the uterus

Helps prepare breasts for lactation


Hormones of the Testes

Produce several androgens

Testosterone is the most important androgen

Responsible for adult male secondary sex

characteristics

Promotes growth and maturation of male

reproductive system

Required for sperm cell production


Other Hormone-Producing Tissues and Organs

Parts of the small intestine

Parts of the stomach

Kidneys

Heart

Many other areas have scattered endocrine cells



Table 9.2 (1 of 2)


Table 9.2 (2 of 2)



Endocrine Function of the Placenta

Produces hormones that maintain the pregnancy

Some hormones play a part in the delivery of the

baby

Produces human chorionic gonadotropin (hCG) in

addition to estrogen, progesterone, and other

hormones


Developmental Aspects of the Endocrine System

Most endocrine organs operate smoothly until old

age

Menopause is brought about by lack of

efficiency of the ovaries

Problems associated with reduced estrogen

are common

Growth hormone production declines with age

Many endocrine glands decrease output with

age

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