Figure 45.4Major endocrine glands:

Hypothalamus

Pineal gland

Pituitary gland

Thyroid gland

Parathyroid glands(behind thyroid)

Adrenal glands(atop kidneys)

Pancreas

Ovaries (female)

Testes (male)

Organs containingendocrine cells:

Thymus

Heart

Liver

Stomach

Kidneys

Smallintestine

Figure 45.5

Lipid-soluble (hydrophobic)Water-soluble (hydrophilic)

Polypeptides Steroids

0.8 nmInsulin Cortisol

Amines

Epinephrine Thyroxine

Figure 45.6-2

Lipid-solublehormone

SECRETORYCELL

Water-solublehormone

VIABLOOD

Signal receptor

TARGETCELL

OR

Cytoplasmicresponse Gene

regulation

(a) (b)

Cytoplasmicresponse Gene

regulation

Signalreceptor

Transportprotein

NUCLEUS

Figure 45.8-2

EXTRACELLULARFLUID

Hormone(estradiol)

Estradiol(estrogen)receptor Plasma

membrane

Hormone-receptorcomplex

NUCLEUS

DNA

CYTOPLASM

VitellogeninmRNA

for vitellogenin

Figure 45.11Pathway Example

Stimulus Low pH in

duodenum

Endocrinecell

S cells of duodenumsecrete the hormonesecretin ( ).

Hormone

Bloodvessel

Targetcells

Pancreas

Response Bicarbonate release

Neg

ativ

e fe

edb

ack

Figure 45.12Pathway

Example

Stimulus Suckling

Sensoryneuron

Po

siti

ve f

eed

bac

k

Hypothalamus/posterior pituitary

Neurosecretory cell

Neurohormone

Blood vessel

Targetcells

Response

Posterior pituitarysecretes theneurohormoneoxytocin ( ).

Smooth muscle inbreasts

Milk release

Figure 45.13

Body cellstake up moreglucose.

Insulin

Beta cells ofpancreasrelease insulininto the blood.

Liver takesup glucose and stores itas glycogen.

Blood glucoselevel declines.

Blood glucoselevel rises.

Homeostasis:Blood glucose level

(70–110 mg/m100mL)

STIMULUS:Blood glucose level rises

(for instance, after eating acarbohydrate-rich meal).

Liver breaksdown glycogenand releasesglucose intothe blood.

Alpha cells of pancreasrelease glucagon intothe blood.

Glucagon

STIMULUS:Blood glucose level

falls (for instance, afterskipping a meal).

Figure 45.14

Pinealgland

Cerebellum

Spinal cord

Cerebrum

Thalamus

Hypothalamus

Pituitarygland

Posteriorpituitary

Anteriorpituitary

Hypothalamus

Figure 45.15

Neurosecretorycells of thehypothalamus

Neurohormone

Posteriorpituitary

Hypothalamus

Axons

Anteriorpituitary

HORMONE

TARGET

ADH Oxytocin

Kidneytubules

Mammary glands,uterine muscles

Figure 45.16

Tropic effects only:FSHLHTSHACTH

Nontropic effects only:ProlactinMSH

Nontropic and tropic effects:GH Hypothalamic

releasing andinhibitinghormones

Posteriorpituitary

Neurosecretorycells of thehypothalamus

Portal vessels

Endocrine cellsof the anteriorpituitary

Pituitaryhormones

HORMONE FSH and LH TSH ACTH Prolactin MSH GH

TARGET Thyroid MelanocytesTestes orovaries

Adrenalcortex

Mammaryglands

Liver, bones,other tissues

Table 45.1

Figure 45.20-2

Activevitamin D

Increases Ca2

uptake inintestines

Stimulates Ca2

uptake in kidneys

Stimulates Ca2 releasefrom bones

Parathyroidgland (behindthyroid)

PTH

Blood Ca2

level rises.

Homeostasis:Blood Ca2 level

(about 10 mg/100 mL)

STIMULUS:Falling blood

Ca2 level

Figure 45.21

Spinal cord(cross section)

(a) (b) Long-term stress responseand the adrenal cortex

Short-term stress responseand the adrenal medulla

Stress

Nervesignals

Nervecell

Releasinghormone

Hypothalamus

Anterior pituitary

Blood vessel

Nerve cell ACTHAdrenal medullasecretes epinephrineand norepinephrine.

Adrenalgland

Kidney

Adrenal cortexsecretes mineralo-corticoids andglucocorticoids.

Effects of epinephrine and norepinephrine: Effects of mineralocorticoids:

Effects of glucocorticoids:

• Glycogen broken down to glucose; increased blood glucose

• Increased blood pressure • Increased breathing rate• Increased metabolic rate• Change in blood flow patterns, leading to

increased alertness and decreased digestive,excretory, and reproductive system activity

• Retention of sodium ions and water by kidneys

• Increased blood volume and blood pressure

• Proteins and fats broken down and converted to glucose, leading to increased blood glucose

• Partial suppression of immune system

Figure 49.8

Parasympathetic division

Action on target organs:

Constricts pupilof eye

Stimulates salivarygland secretion

Constrictsbronchi in lungs

Slows heart

Stimulates activityof stomach and

intestines

Stimulates activityof pancreas

Stimulatesgallbladder

Promotes emptyingof bladder

Promotes erectionof genitalia

Cervical

Thoracic

Lumbar

SynapseSacral

Sympatheticganglia

Sympathetic division

Action on target organs:

Dilates pupil of eye

Accelerates heart

Inhibits salivarygland secretion

Relaxes bronchiin lungs

Inhibits activity ofstomach and intestines

Inhibits activityof pancreas

Stimulates glucoserelease from liver;inhibits gallbladder

Stimulatesadrenal medulla

Inhibits emptyingof bladder

Promotes ejaculationand vaginal contractions