Chapter 18:

AP2 Chapter 18 1

Chapter 18:

Endocrine Glands

AP2 Chapter 18 2

Chapter 18 OutlineI. Fxns of the Endocrine System

II. Pituitary Gland & Hypothalamus

III. Thyroid Gland

IV. Parathyroid Glands

V. Adrenal Glands

VI. Pancreas

VII.Hormonal regulation of nutrients

VIII. Hormones of the reproductive system

IX. Hormones of the pineal body

X. Hormones of the Thymus

XI. Hormones of the GI tract

XII.Hormone-like Substances

XIII.FX of aging on the endocrine system

AP2 Chapter 18 3

I. Fxns of the Endocrine System (ES)

AP2 Chapter 18 4

I. Fxns of the Endocrine System• Information needed to

understand ES’s regulation of body fxns:– Anatomy of each gland & its

location– Hormones secreted by each gland– Target tissues & their responses to

the hormone– Regulation of those hormones

secretion– Consequences & causes of

hypersecretion/hyposecretion of the hormone

AP2 Chapter 18 5

I. Fxns of the Endocrine System

1. Metabolism & tissue maturation

2. Ion regulation

3. Water Balance

4. Immune System regulation

5. Heart rate & BP regulation

6. Control of bld glucose & other nutrients

7. Control of reproductive fxns

8. Uterine contractions & milk release

Main regulatory fxns of the ES

AP2 Chapter 18 6

I. Fxns of the Endocrine System

Main regulatory fxns of the ES1. Metabolism & tissue

maturation– Regulated rate of metabolism– Influences the maturation of

tissues (i.e. nervous system)

2. Ion regulation– Regulate blood pH– Na, K, & Ca [ ] in blood

3. Water Balance– Controlling solute [ ] in the

blood

4. Immune System regulation– Controlling the prod’n of

immune cells

5. Heart rate & BP regulation– Helps to prep the body for

physical activity

6. Control of bld glucose & other nutrients– In the bld

7. Control of reproductive fxns– Controls the development &

fxns of reproductive system in both males & females

8. Uterine contractions & milk release– During childbirth & after birth

AP2 Chapter 18 7


AP2 Chapter 18 8

II. Pituitary Gland & HypothalamusPituitary Gland:• Secretes 9 major hormones

that regulate numerous body fxns & secretory activities of other glands

Hypothalamus:• Major site where nervous

system & ES interact• Hypo regulates secretions of

the Posterior Pituitary• Hormones, sensory information

that enters the CNS & emotions in turn influence the activity of the hypothalamus

Fig

ure 18.1

Pg

. 610

AP2 Chapter 18 9


• 1cm diameter, 0.5-1g, rests in sella turcica

• Divided into 2 parts:a) Posterior Pituitary

• Secretions from the PP are neurohormones

b) Anterior Pituitary• 3 regions:

1. Pars tuberalis

2. Pars intermedia

3. Pars distalis• Hormones from AP are

not neurohormones

• Pg 611 Figure 18.2

10


AP• Hypothalamohypophysial Portal System

– Extends from the hypothalamus to the AP so that neurohormones produced by the hypothalamus to stimulate or inhibit the cells of the AP

– THUS the hypothalamus controls the AP

Pg 611Fig 18.3

11


1. Growth Hormone Releasing Hormone (GHRH)– Small peptide that stimulates the secretion of Growth Hormone from the AP

2. Growth Hormone Inhibiting Hormone/Somatostatin (GHIH)– Small peptide that inhibits the secretion of growth hormone from AP

3. Thyrotropin-releasing hormone (TRH)– Small peptide that stimulating the secretion of thyroid stimulating hormone

from AP

4. Corticotropin-releasing Hormone (CRH)– Peptide that stimulates the secretion of adrenocorticotropic hormone from AP

5. Gonadotropin-releasing Hormone (GnRH)– Small peptide that stimulates LH and FSH release from the AP

6. Prolactin-releasing Hormone (PRL)– Regulate the secretion of prolactin from the AP.

Pg 611 Figure 18.2

Inhibiting & releasing hormones released by hypothalamus

Thyroid releasing hormone

Growth hormone inhibiting hormone

Hypothalamus

Corticotropin releasing hormone

Gonadotropin releasing hormone

Prolactin releasing hormone

Low Bld GlucoseStress

High Bld Glucose

Low Thyroid hormone level

AnteriorPituitary

Growth hormone releasing hormone

AnteriorPituitary

AnteriorPituitary

AnteriorPituitary

AnteriorPituitary

High Thyroid hormone level

GrowthHormone

ThyroidStimulatingHormone

AdrenocorticotropicHormone

LH & FSH Prolactin

13


PP• Neurohormones released from PP are not made by the PP. These hormones that

are stored in the PP are originally made in the hypothalamus. • The neurosecretory cells of the hypothalamus have axons that extend to the PP.

Neurohomeones are prod’d in these neurosecretory cells and travel via vesicle toward the axon terminal. AT the axon terminal they are stored in secretory vesicles. The axon terminals are buried in the PP. Action potentials cause the release of the neurohormones from the axon terminal so that they can enter the blood stream.

Pg 613 Figure 18.4



Hypothalamus

PosteriorPituitaryCorticotropin

releasing hormone




High Bld Glucose


AnteriorPituitary


AnteriorPituitary

AnteriorPituitary

AnteriorPituitary

AnteriorPituitary


GrowthHormone



LH & FSH Prolactin

Antidiuretichormone

Oxytocin

15


Hormones of the PP• Antidiuretic Hormone/ Vasopressin (ADH)

– Constricts bld vessels & raises BP thus preventing the loss of water. (prevents large output of urine)

– Secretion rate D’s in response to bld osmolarity and bd volume (osmoreceptors)

• Osmolarity: as solute [ ]

– Water intake & BP can change action potential frequency

• Oxytocin– Primary fxns:

1. ♀Stimulates uterine contraction

2. ♀ Responsible for milk ejection from the breast by contraction of smooth muscle around alveoli of mammary glands

3. ♂ = Unknown fxn

– Stimulation of oxytocin release• Stretch of the uterus, mechanical stimulation of the cervix, stimulation of

the breast as baby nurses (action potentials travel from receptor up the spinal cord to hypothalamus oxytocin releasing hormone.

Pg 611 Figure 18.2







Hypothalamus

PosteriorPituitary


High Bld Glucose



AnteriorPituitary

AnteriorPituitary

AnteriorPituitary

AnteriorPituitary

AnteriorPituitary

GrowthHormone



LH & FSH Prolactin

Antidiuretichormone

Oxytocin

Target:Kidney

Target:Uterus &

Mammary Glands

•Response:•Increased water reabsorption & less urine prod’n

•Response:•Female: Increased uterine contraction and increased milk expulsion from the mammary glands

17


AP

• Hormones are proteins, glycoproteins, or polypeptides labeled Tropic Hormones

• Transported via the cardiovascular system• Half life of these hormones is minutes• Bind to membrane bound receptors on

target tissues• Most hormones are secreted by their own

separate cell types.

18

II. Pituitary Gland & HypothalamusAP-Hormones

Growth Hormone (GH)/Somatotropin• Bind to membrane bound

receptors that phosphorylate intracellular proteins

• Fxns:– Stimulates growth of most tissues– Major role in regulating growth

thus help determine final height– Regulation of metabolism

• mvmt of aa into cells• lipolysis• FA release from adipocytes into

bld• glucose synthesis in liver• Imp. role in reg. bld nutrient

levels after meals & fasting

• Stimulus that influences GH secretion:– Low bld glucose + stress

stimulation of GH release– High bld Glucose Inhibition of

GH release

• Hormonal Regulation by neurohormones of the hypothalamus:– Growth Factor Releasing

Hormone(GFRH) secretion– Growth Factor Inhibiting

Hormone (GFiH) Inhibition

19


Thyroid-Stimulating Hormone/Thyrotropin (TSH)

• G-protein receptors in the membrane of the thyroid cells respond to binding. [cAMP]; ’s activity of phospholipase; activates opening of Ca2+ channels to [Ca2+] in thyroid cells

• Fxn:– Stimulate synthesis & secretion

of thyroid hormones from thyroid

• Stimulus that influences TSH secretion:– Secreted in pulsatile fashion &

blood levels are highest at night– Very narrow homeostatic window

for TSH [ ]

• Reg. of secretion of TSH:– Hypothalamus releases Thyroid-

releasing hormone (TRH)• TRH binds to receptors in AP

activates G-proteins result: TSH secretion

– Thyroid hormone levels in the blood.

• Influences both TSH & TRH secretion

20


Adrenocorticotropic Hormone (ACTH) & related substances

ACTH• Binds to membrane-bound

receptor activation of G-protein response• Increases hormone secretion

adrenal cortex cortisol• ACTH & MSH bind melanocytes

and increase skin pigmentation.

Several hormones derived from proopiomelanocotin & secreted by AP.

(ACTH, Lipotropins, b Endorphins, & Melanocyte stimulating hormone (MSH)

Increased levels of release in response to stress & exercise

LipotropinsBind to membrane bound receptors in adipocytes cause fat brkdwn & release of FA’s into circulatory system

b- endorphins• in response to stress &

exercise• Same FX as opiates (analgesics) • Other proposed fxns regulation

of:• Body temp, Food intake, H2O

balanceMSH• Binds to membrane-bound receptor on melanocytes stimulation of melanin deposition in skin• Regulation not well understood

21

II. Pituitary Gland & Hypothalamus: AP-Hormones

Follicle-stimulating Hormone (FSH);

Luteinizing Hormone (LH); & Prolactin

• LH & FSH– Bind to membrane-bound receptors that are G-proteins

• Increase intracellular synthesis of cAMP• Stimulate prod of gametes

– Sperm in testes– Oocytes in ovaries

• Control prod of reproductive hormones– Estrogens & progesterone in ovaries– Testosterone in testes

– Regulation• Hypothalamus:

– Gonadotropin releasing hormone (GnRH)– Leutinizing Hormone releasing hormone (LHRH)

A.k.a. GonadotropinsGlycoprotein hormones capable of promoting growth & fxn of gonads

All play a role in reproduction regulation

All released from AP

22

II. Pituitary Gland & Hypothalamus: AP-Hormones

Follicle-stimulating Hormone (FSH);

Luteinizing Hormone (LH); & Prolactin

• Prolactin– Role in milk prod’n in the mammary glands of lactating females– Binds to membrane-bound receptor that is bound to kinase

phosphorylates intracellular proteins:• Enhance progesterone secretion of ovary after ovulation • Males unknown

– Regulation:• Hypothalamus neurohormones• Prolactin Releasing Hormone (PRH)• Prolactin-Inhibiting Hormone (PIH)

A.k.a. GonadotropinsGlycoprotein hormones capable of promoting growth & fxn of gonads

All play a role in reproduction regulation

All released from AP

AP2 Chapter 18 23







Hypothalamus

PosteriorPituitary


High Bld Glucose



AnteriorPituitary

AnteriorPituitary

AnteriorPituitary

AnteriorPituitary

AnteriorPituitary

GrowthHormone



LH & FSH Prolactin

Target Tissue:

Most tissues Target Tissue:Thyroid tissue

Target Tissue:Adrenal cortex

Target Tissue:Gonads

Target Tissue:

Mammary glandsOvaries

•Response:•Stimulates the growth of most tissues•Important in the regulation of nutrient levels•Regulation of metabolism

• Increases movement of AA into the cells

• Increases lipolysis

• Increases FA release from Adipocytes

• Increased glucose synthesis in the liver

•Response:•Stimulates synthesis and secretion of thyroid hormones from the thyroid

•Response:•Increased hormone secretion from the adrenal cortex

•Response:•Stimulate formation of gametes (sperm/egg)•Control prod’n of reproductive hormones (Ovaries: estrogen & progesterone) (Testis: testosterone)

•Response:•Female: milk prod’n in mammary glands and ovaries increase progesterone secretion•Males: Unknown fxn

Antidiuretichormone

Oxytocin

Target:Kidney

Target:Uterus & Mammary Glands

•Response:•Increased water reabsorption & less urine prod’n

•Response:•Female: Increased uterine contraction and increased milk expulsion from the mammary glands







Hypothalamus

PosteriorPituitary


High Bld Glucose



AnteriorPituitary

AnteriorPituitary

AnteriorPituitary

AnteriorPituitary

AnteriorPituitary

GrowthHormone



LH & FSH Prolactin

Target Tissue:Most tissues

Target Tissue:Thyroid tissue

Target Tissue:Adrenal cortex

Target Tissue:Gonads

Other related substances

Lipotropinsb-endorphins Melanocyte stimulting

hormone

Target Tissue:Fat tissue

Target Tissue:Brain- rest unknown

Target Tissue:Melanocytes

•Response:•Increased fat brkdwn

•Response:•Painkiller in the brain, Inhibition of GnRH

•Response:•Increased melanin prod’n Darker skin

Antidiuretichormone

Oxytocin

Target:Kidney

Target:Uterus & Mammary Glands

AP2 Chapter 18 26

III. Thyroid Gland

AP2 Chapter 18 27

III. Thyroid Gland• Location:

– Lateral upper portion of the trachea just inferior to the larynx

• One of the largest endocrine glands @ ~20g

• Highly Vascular with numerous follicles whose centers are filled w/proteins called Thyroglobin (Prod’d by follicular cells)– Follicles store large amounts of

thyroid hormones as part of thyroglobin (T3 & T4)

• Parafollicular cells prod calcitonin

Pg 620Figure 18.8

28

III. Thyroid Gland

Thyroid Hormones

• 10% of thyroid product

AP2 Chapter 18

• A.k.a. Thyroxine• 90% of thyroid product

• 2 types

Triiodothyronine [T3] Tetraiodothyronine [T4]

• XS thyroid hormone is stored w/in the follicles

• TSH causes the release of T3 & T4 from follicles

• Major component of T3 & T4 is iodine wh/is why it is so important to have in your diet.

• These are also lipid soluble hormones• 70-75% in blood must be bound to transport protein called: Thyroxine-

binding protein

• Creates a large reservoir of T3 & T4.

• 33-44% of the T3 is converted into T4 in the tissues b/c T3 is major hormone that interacts with target & is several times more potent.

• Rapidly metabolized and excreted in urine or bile

AP2 Chapter 18 29

III. Thyroid Gland

Thyroid Hormones

Mechanism of Action

• Intracellularly: diffuse thru the PM enter nuclei & bind to receptor molecules.

• This receptor-hormone complex interacts with DNA to regulate gene expression

• Final action can take up to 1 week before result is seen.

• Structure:– aa derivative

• Target Tissue:– Most cells of the body

• Response– Increased metabolic rate• rate at wh/ glucose, fat & protein are

metabolized• Increased Na-K pump activity• Can alter # & activity of mitochondria

– Essential for normal process of growth & maturation

AP2 Chapter 18 30

III. Thyroid Gland

Calcitonin• Prod’d by parafollicular cells (C-cells)• Controlled by Ca2+ levels in the Bld

– Ca2+ in the blood ’s calcitonin prod’n

• Target: Bone tissue– Binds to membrane bound receptors:

• Decreases osteoclast activity• Lengthens life of osteoblasts

• Result:– Decreased bld Ca2+ & phosphate – Increased bone deposition

Thyroid GlandFollicular

CellsParafollicular

Cells

ThyroidHormoneT3 & T4

Target tissue:Most cells in

the body

•Response:•Essential for the normal process of growth and maturation•Increase metabolic rate:

• Increase breakdown of sugar, fat, and protein

• Increase Na/K pump activity• Alter the # and activity of

mitochondria

Calcitonin

Target tissue:Bone

•Decreases osteoclast activity• Lengthens life of osteoblast

•Response:•Increases bone deposition•Decreases the amount of calcium and phosphate in the blood.

AP2 Chapter 18 32


AP2 Chapter 18 33


• 4 small units embedded in the back of the thyroid

• 2 cell Types– Chief Cells

• Secrete parathyroid hormone (PTH)

– Oxyphils• Unknown fxn

Figure 18.11

AP2 Chapter 18 34


PTH:• Structurally

– Polypeptide

• Target Tissues– Bone, Kidneys, Small Intestine

• Response– Increased rate of breakdown of

bone by osteoclasts– Increased reabsorption of Ca2+ by

kidneys– Increased absorption of Ca2+ by

small intestine– Increased Vit D synthesis– Increased bld Ca2+ levels

Figure 18.11

Parathyroid GlandChiefCells

Oxyphils

Parathyroid Hormone

Target tissue:Bone, Kidney, Small Intestine

•Response:•Increased bone breakdown by osteoclasts•Increased reabsorption of calcium in the kidneys & small intestine•Increased vitamin D synthesis•Increased Blood Calcium levels

UNKNOWN

AP2 Chapter 18 36

V. Adrenal Glands

37

V. Adrenal Glands• Located above the kidney

surrounded by abundant adipose tissue & CT capsule w/an abundant blood supply.

• 2 major regions– Cortex

• Outer edge• 3 layers

1. Zona glumerulosa (outer)

2. Zona fasiculata (middle)

3. Zona reticularis (inner)

– Medulla• Inner core

AP2 Chapter 18

• Each of the regions & layers is fxnally & structurally specialized

38

V. Adrenal Glands

Adrenal Medulla• Hormones:

– Epinephrine primarily; norepinephrine– ½ life of minutes

• Structure: – AA derivatives

• Target Tissue:– Heart, blood vessels, liver, fat cells

• Response:– Increased cardiac output– Increased bld flow to skeletal muscle & heart – Vasoconstriction of bld vessels

• Visceral organs & skin

– Increased release of glucose & FA in the bld

– **Preparation for physical activity**

Adrenal GlandAdrenal Medulla

Adrenal Cortex

Epinephrine & Norepinephrine

Target tissue:Heart

Blood vesselsLiver

Fat cells

•Response:•Preparation for physical activity•Increased cardiac output•Increased blood flow to skeletal muscle and heart• Vasoconstriction of blood vessels to visceral organs•Increased release of glucose and fatty acids

ZonaGlumerulosa

ZonaReticularis

ZonaFasiculata

AP2 Chapter 18 40

V. Adrenal Glands

Adrenal Cortex• 3 types of steroid hormones are prod’d here• All have similar structure to steroids & are

derived from cholesterol– B/c they are lipid soluble– They are not stored in the cell but synthesized as

needed– Transported in the blood via transport proteins– Metabolized in the liver & excreted in bile & urine

• Bind to intracellular receptors to stimulate the synthesis of specific proteins responsible for prod’ing cellular responses

AP2 Chapter 18 41

V. Adrenal Glands

Adrenal CortexHormones are made as needed not stored

1. Zona Glomerulosa– Mineralcorticoids

2. Zona Faciculata– Glucocorticoids

3. Zona Reticularis– Adrenal Androgens Hormones are made as

needed not stored

AP2 Chapter 18 42

V. Adrenal GlandsAdrenal Cortex

1. Zona Glomerulosa– Outer section– Mineralcorticoids (cortisol)

• Structure– steroids

• Target Tissue– Most tissues

• Response– protein & fat brkdwn– Increased glucose prod’n– Inhibition of the immune

response & decreased inflammation

2. Zona Faciculata– Middle Layer– Glucocorticoids

• Structure– Steroids

• Target Tissue– Kidney

• Response– Increase Na+ & K and

H+ excretion– Enhances water

reabsorption

AP2 Chapter 18 43

V. Adrenal GlandsAdrenal Cortex

3. Zona Reticularis– Adrenal Androgens

• Structure– steroids

• Target Tissue– Many Tissues

• Response– Minor importance in

males– In females:• Development of some

2ndary sex characteristics

• Axillary & pubic hair

Adrenal GlandAdrenal Medulla

Adrenal CortexEpinephrine & Norepinephrine

Target tissue: Heart, Blood vessels, Liver & Fat cells

•Response:•Preparation for physical activity•Increased cardiac output•Increased blood flow to skeletal muscle and heart• Vasoconstriction of blood vessels to visceral organs•Increased release of glucose and fatty acids

ZonaGlumerulosa

ZonaReticularis

ZonaFasiculata

Mineralcorticoids Glucocorticoids AdrenalAndrogens

Target tissue:Most Tissue

Target tissue:Kidney

Target tissue:Many Tissues

•Response:•Increase in fat and protein breakdown•Increase in glucose prod’n•Inhibition of immune response and decreased inflammation

•Response:•Increased Na+, K+, and H+ excretion by the kidney•Enhanced water reabsoption

•Response:•Males: Minor importance•Females: development of secondary sex characteristics

AP2 Chapter 18 45

VI. Pancreas

46

VI. Pancreas• Lies btwn the greater

curvature if the stomach & duodenum (beginning of the small intestine)

• Head: lies close to the duodenum

• Body: extends toward spleen

• Fxns as both an endocrine and exocrine gland– Exocrine:

• Acini cells prod pancreatic juice & a duct which carries the pancreatic juice into the small intestine

Pg 634Fig 18.16

• Endocrine: • Pancreatic islets secrete

hormones into the circulatory system

AP2 Chapter 18 47

VI. PancreasPancreatic Islets

• Alpha (a) cells– Secrete glucagon– Small peptide hormone– 20% of cells

• Beta (b) cells– Secrete insulin– Small protein w/2

polypeptide chains– 75% of cells

• Delta (d) cells– Secrete somatostatin– Small polypeptide hormone– Remaining 5% of cells

48

VI. Pancreas

Liver• Skeletal muscle• Cardiac muscle

• Cartilage• Bone

• Fibroblasts• Leukocytes

• Mammary glands

Nervous System

Adipose Cells

• Little effect

Cell Type:

a-cells

Structure:

PolypeptideHormone:

GlucagonTarget Tissues:

Response:• Rapid increase in

breakdown of glycogen into glucose

(glycogenolysis)& release of glucose into

the bld.• Increased formation of

glucose from aa’s & to some degree from fats

• Increased metabolism of FA’s resulting in

increased ketones in the bld

• High [ ]’s cause the

breakdown of fats (lipolysis)

• Probably unimportant under most conditions

• No effect

49

VI. Pancreas

Liver• Skeletal muscle• Cardiac muscle



• Mammary glands

Nervous System

Adipose Cells

• Increased glucose uptake

& glycogen syntheses

• Increased up-take of certain

aa’s

Cell Type:

b-cells

Structure:

Protein

Hormone:

InsulinTarget Tissues:

Response:

• Increased glycogen synthesis

• Increased Glycolysis

• Increased:• Glucose uptake

• Glycogen synthesis

• Fat synthesis• FA uptake• Glycolysis

• Little effect except to

increase glucose uptake in the satiety center

VI. Pancreas

Cell Type:

d-cells

Structure:

Peptide

Hormone:

Somatostatin

• Target Tissue:– Pancreas & a b Cells

• Response:– Inhibition of insulin & glucagon secretion

51

VI. PancreasInsulin secretion control:

• Inhibition – Low blood glucose– Somatostation

• Secretion– High blood glucose– Certain aa’s stimulate b-cells

directly– Stimulation of PNS caused and

increase in blood glucose causing stimulation of insulin release

– GI hormones involved in digestion regulation increase insulin secretion

Glucagon secretion control:

• Inhibition – High blood glucose

• Secretion– Low blood glucose– Certain aa’s can

increase glucagon secretion

– Sympathetic stimulation

• After a high protein meal both insulin & glucagon increase• Insulin: increased uptake of aa’s into the cell for protein synthesis• Glucagon: increased process of glucose synthesis from aa’s in the liver

PancreasExocrineGland

EndocrineGland

Secretes enzymes onto the surface of the small

intestine

a-cells

Pancreatic Islets

d-cellsb-cells

Glucagon

High Blood Glucose

Low Blood GlucoseCertain AA

Sympathetic stimulation

LiverAdipocytes

•Response:•Rapid increase in glycogen breakdown & increase in blood glucose levels•Increased glucose formation from AA and some fats•Increased metabolism of FA’s resulting in increased ketones in the blood

•Response:•Causes the breakdown of fats from adipocytes

Target tissue:


EndocrineGland


intestine

a-cells

Pancreatic Islets

b-cells d-cells

Glucagon

Low blood glucoseSomatostatin

Increased Blood GlucoseCertain AA

GI-tract hormones

Insulin Somatostatin

Target tissue:

• Skeletal muscle• Cardiac Muscle



• Mammary glands

• Liver • Adipocytes • Nervous System

•Response:•Increased glucose uptake•Increased glycogen synthesis•Increased uptake of certain AA’s

•Response:•Increased glycogen synthesis•Increased glycolysis

•Response:•Increased glucose uptake•Increased glycogen synthesis•Increased fat synthesis•Increased FA uptake•Increased glycolysis

•Response:•Increased glucose uptake in the satiety center


EndocrineGland


intestine

a-cells

Pancreatic Islets

b-cells d-cells

Somatostatin

Target tissue:a & b Cells of the

pancreas

•Response:•Inhibition of insulin and glucagon secretion

AP2 Chapter 18 55

VII. Hormonal Regulation of Nutrients

AP2 Chapter 18 56VII.

Hor

mon

al R

egul

atio

n of

Nut

rient

sPg 639

AP2 Chapter 18 57VII.

Hor

mon

al R

egul

atio

n of

Nut

rient

s Pg 640

AP2 Chapter 18 58

VIII. Hormones of the Reproductive System

59

VIII. Hormones: Reproductive System• Both reproductive organs are controlled by FSH & LH

released by the AP (also considered part of the Reproductive System)

• Placenta:• During 1st 1/3 of pregnancy it secretes an LH-like substance to maintain pregnancy• Ovaries + placenta secrete increasing amounts of estrogen & progesterone wh/

are necessary to maintain pregnancy

Pg 461

ReproductiveSystemMale

Testis

FemaleOvary

Testosterone

•Response:• Aids in spermatogenesis•Development of the genitalia•Maintenance of fxnal reproductive organs•2ndary sex characteristics•Sexual Behavior

Target tissue:Most cells

Inhibin

Target tissue:AnteriorPituitary

•Response:• Inhibits FSH

ReproductiveSystemMale

Testis

FemaleOvaries

Estrogen

•Response:• Uterine and mammary gland development and fxn•Maturation of genitalia•2ndary sex characteristics•Sexual behavior•Menstrual Cycle


Progesterone


•Response:• Uterine and mammary gland development and fxn•Maturation of genitalia•2ndary sex characteristics•Menstrual Cycle

Inhibin Relaxin

Target tissue:AnteriorPituitary

Target tissue:Connective

Tissue

•Response:• Inhibits FSH •Response:

• Increases flexibility of CT in pelvic area, especially in the symphysis pubis

FemalePlacenta

LH-Like Substance •Response:• Maintains pregnancy

FemalePlacenta & Ovaries

Increasing amounts of estrogen & progesterone

•Response:• Necessary to maintain pregnancy

AP2 Chapter 18 62

IX. Hormones of the Pineal Body

63

IX. Hormones of the Pineal Body

Pg 642

Fxn of PB in Humans is still actually unclear but when there are tumors 1. early sexual development or 2. retarded development of reproductive system

AP2 Chapter 18 64

X. Thymus

AP2 Chapter 18 65

X. Thymus

• Hormone:– Thymosin

• Structure:– Peptide

• Target Tissue:– Immune Tissues

• Fxn:– Important role in

development & maturation of the immune system

Thymus

Thymosin

•Response:• Role in development and maturation of the immune system

Target tissue:ImmuneTissues

AP2 Chapter 18 67

XI. Hormones of the GI-tractThere are several & they relate to digestive fxns by influencing the

activity of the stomach, intestine, liver, & pancreas

AP2 Chapter 18 68

XII. Hormone like substances

AP2 Chapter 18 69

XII. Hormone like Substances

• Autocrine chemical signals are released by cells the influence the same cell type which released them.

• Paracrine chemical signals are released from 1 cell type, diffuse short distance, & influence the activity of another cell type near by.

Not secreted from discrete endocrine glands Have local FX rather than systemic FX Have fxns that are not understood adequately to

explain their role in the body

XII. Hormone like substances

70

Autocrine

Paracrine

Peptide growth hormones

• # of hormone like substances listed are minimal there are actually tons• Chemical communication among cells in the body is complex, well developed, & necessary for maintenance of homeostasis• Investigations increase knowledge of body fxns that can be used to develop techniques for treatment of pathologic conditions

AP2 Chapter 18 71

XIII. FX of aging on Endocrine System

• Gradual decrease in secretion rate of most, but not all, hormones

• Some decreases are 2ndary to gradual decreases in physical activity

• GH– Decreases w/ age but it is most drastic in people

who do not exercise

• Melatonin– Decreases and may help to explain the changes

seen in sleeping pattern w/age

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