Bio Chapter Handout

8/2/2019 Bio Chapter Handout

1/10

Chapter 18 The Endocrine System Lecture Outline

Intercellular Communication

1. Direct gap junctions

2. Paracrine cytokines or local hormones

3. Endocrine hormones4. Synaptic neurotransmitters

Endocrine System

Glands

Endocrine

Exocrine

Endocrine tissues

Hypothalamus

Pineal GlandPituitary Gland

Thyroid Gland

Heart

Thymus

Adrenal Gland

Kidney

Adipose

Digestive Tract

PancreasGonads

Hormones

Structure

1. Amino acid derivatives

Catecholamines

Epinephrine

Norepinephrine

DopamineThyroid hormones (T3, T4)

Melatonin

2. Peptide hormones

A. Peptides < 200 amino acids

ADH

Oxytocin

Growth Hormone

B. Glycoproteins

Thyroid Stimulating Hormone3. Lipid derivations

A. Steroid hormones

Androgens

Estrogens

Calcitriol

4. secretion

5. mitosis

Receptors

1. Cell membrane receptoEnzyme activation

2nd messenger: cA

G protein

A. cAMP mechanism

hormone + recep

G protein

Adenylate cyclas

ATP cAMPKinases: phospho

Enzymes activate

B. PIP-Calcium mech

hormone + recep

G protein

PLC

PIP2 DAG + I

Ca2+

CalmodulinEnzymes activate

2. Intracellular receptors

Gene activation

hormone + recep

DNA

transcription, tra

Target cell activation

1. blood level2. receptor number

3. affinity

Distribution & duration

1. free

2. bound

Interactions

1. Antagonistic

2. Synergistic

3. Permissive

Control of endocrine activity

Negative feedback

Stimuli

1. Humoral

2. Neural


2/10

2. Pituitary gland (Hypophysis)

Infundibulum

Sella turcica

A. Anterior lobe (Adenohypophysis)

7 tropic hormones: cAMP mechanism

1. Thyroid Stimulating Hormone(TSH) / Thyrotropin

Release:

Thyrotropin releasing hormone

(TRH)

Effects:

-thyroid hormone release

2. Adrenocorticotropic Hormone

(ACTH) / Corticotropin

Release:

Corticotropin Releasing Hormone

(CRH)

Effects:

-corticosteroid release

3. Follicle Stimulating Hormone

(FSH) / Follitropin

Release:

Gonadotropin releasing hormone(GnRH)

Effects:

-gamete production

4. Luteinizing Hormone (LH) / Lutropin

Release:

Gonadotropin releasing hormone

(GnRH)

Effects:

-gonadal hormone production

5. Prolactin (PRL) / Mammotropin

Release:

Prolactin inhibiting hormone (PIH)

Effects:

-mammary gland function

6. Growth Hormone (GH) / Somatotropin

Release:

Growth hormone releasinghormone (GHRH)

Growth hormone inhibiting

hormone (GHIH)

Effects:

-accelerate protein synthesis

I di t

Acromegaly

Pituitary dwa

7. Melanocyte Stimu

(MSH) / Melanotropi

Release:

DopamineEffects:

-melanin pro

B. Posterior lobe (Neurohypo

2 hormones: cAMP mech

1. Antidiuretic Horm

(ADH) / Vasopressin

Supraoptic nucle

Release:

electrolyte

Effects:

-water retent

-vasoconstric

2. Oxytocin (OT)

Paraventricular n

Effects:

-smooth mus

3. Thyroid GlandIsthmus & Lobes

Follicles

Simple cuboidal epitheliu

Thyroglobulin

Parafollicular cells

Thyroid Hormone

Release:

Thyroglobulin

Thyroid peroxidase:

Thyroxine / Tetraiod

Triiodothyronine (T3

TSH

Effects:

- metabolism

Hypothyroidism

Goiter

CretinismHyperthyroidism

Graves disease

Parafollicular cells/C cells

Calcitonin (CT)

Release:

C 2+


3/10

-stimulate osteoclasts

-Ca2+ reabsoption

-Calcitriol formation

5. Adrenal Glands

A. Adrenal Cortex

Corticosteroids1. Zona glomerulosa

Mineralocorticoids

Aldosterone

Release:

-Na+, K+

-Angiotensin II

- BP, volume

- ACTH

Effects:

Na+ retention, K+ loss

2. Zona fasciculata

Glucocorticoids

Cortisol / Hydrocortisone

Release:

ACTH

Effects:

-gluconeogenesis-lipolysis

-protein hydrolysis

-fatty acid & amino acid

utilization

-inhibit inflammation

3. Zona reticularis

Gonadocorticoids

AndrogensAndrogenital syndrome

Cushings syndrome

Addisons disease

B. Adrenal Medulla

Sympathetic neurons: Chromaffin cells

Catecholamines

Release:

Sympathetic

Effects:Epinephrine / adrenaline

- cardiac

- metabolism

Norephinephrine / noradrenaline

-vasoconstriction

Insulin

Release:

glucose, parasymp

Effects:

-glucose uptake & ut

-glycogen formation-protein synthesis

-triglyceride formatio

Diabetes mellitus

Type I

Type II

Glucagon

Release:

glucose, sympathet

Effects:

-glycogenolysis

-lipolysis

-gluconeogenesis

7. Pineal Gland

Pinealocytes

Melatonin

Release:

diurnalEffects:

-sexual maturatio

-antioxidant

-circadian rhythm

8. Gastrointestinal tract

Enteroendocrine cells

Cholecystokinin

EnterocrininGastric Inhibitory Peptid

Gastrin

Secretin

Vasoactive Intestinal Pep

9. Kidney

A. Calcitriol

Release:

PTH

Effects:-Ca2+ , PO4

3- absorpti

-osteoclast activity

-Ca2+ retention

-inhibit PTH

B. Erythropoietin

R l


4/10

-thirst

- BP

10. Heart

Natriuretic Peptide

Release:

atrial stretchEffects:

-Na+ &H2O loss

-inhibit Renin, ADH, Aldosterone

11. Thymus

Thymosins

Effects:

-T cell maturation

12. Gonads

A. Male: Testis

Interstitial Cells

Androgens: Testosterone

Release:

LH

Effects:

-male characteristics

-sperm production

-secretory glandsB. Female: Ovaries

Follicle Cells

Estrogens: Estradiol

Release:

LH & FSH

Effects:

-female characteristics

-oocyte maturation

-uterine growth

Corpus Luteum

Estrogens

Progestins: Progesterone

Release:

LH

Effects:

-uterus maintenance

-oocyte movement-mammary glands

13. Adipose Tissue

Leptin

Release:

glucose & lipid absorption

Eff t


5/10

EndocrineOrgans(ororganswith

someendocrinefunction)

Amy Warenda Czura, Ph.D. 5 SCCC BIO132 Chapter 18 Handout


6/10

Hormonesthatbindcellsurfa

cereceptorsworkthroughsecond

messengerstoopenionchann

elsoractivate/deac

tivateenzymes

cAMPMechanism:

Hormonebindsreceptor

G-protein

activated

Adenylate

cyclaseactivated

ATP-->cAMP

Kinasesac

tivated

Proteins(e

nzymes)phosphorylated

Enzymesa

ctivated/deactivated

P

IP-CalciumMechanism:

H

ormonebindsreceptor

G

-proteinactivated

P

hospholipaseC(PLC)activa

ted

P

hospholipids(PIP2)cleaved

intodiacyglycerol

(DAG)andinositoltriphosphate(IP3)

D

AGopensCa

++

channelson

membrane

I

P3relasesCa

++

fromER

C

alciumbindscalmodulin

E

nzymesactivated

Secondmessenger

mechanism(cAMPor

Ca++)resultsin

amplifi

cationofthe

horm

onesignal



7/10

Hormones of the Pituitary Gland:

Anterior Pituitary Hormones:

Hypothalamus

control of secretion: Action:

Thyroid Stimulating Hormone

(TSH), thyrotropin

Thyrotropin Releasing

Hormone (TRH)

Promotes release of thyroid hormones by thyroid gland

Adrenocorticotropic Hormone

(ACTH), corticotropin

Corticotropin Releasing

Hormone (CRH)

Promotes release of corticosteroid hormones (glucocortico

Follicle Stimulating Hormone

(FSH), follitropin

Gonadotropin Releasing

Hormone (GnRH)

Promotes gamete production in ovaries and tes tes

Luteinizing Hormone

(LH), lutropin

Gonadotropin Releasing

Hormone (GnRH)

Promotes production of gonadal hormones (estrogens and

Prolactin

(PRL), mammotropin

Prolactin Inhibiting

Hormone (PIH)

Stimulates mammary gland development and milk product

May assist androgen production in males

Growth Hormone

(GH), somatotropin

-Growth Hormone

Releasing Hormone

(GH-RH) and

-Growth Hormone

I hibiti H

Accelerates rate of protein synthesis in most cells, especial

chondrocytes

Indirect mechanism: stimulates liver to release somatomed

factors (IGFs)) which trigger cells to absorb amino acids

ith th


8/10

Formation and release of thyroid horm

1. Iodine ions (I-) from diet accumulate in cytoplasm of follicle cells.

2. At apical surface thyroid peroxidase converts I- to I+ (activated form) and links it to tyr

the previously formed protein thyroglobulin in the follicle. (Thyroglobulin is continuousl

follicle cells and exocytosed into the follicle lumen for storage.)

3. Iodated tyrosines in thyroglobulin are chemically bonded to create the thyroid hormone

thyroxine/tetraiodothyronine (T4) and triiodothyronine (T3).

4. Stimulated by TSH, follicle cells endocytose iodated thyroglobulin.


9/10

Adrenal Gland

Adrenal Cortex : glandular, produces corticosteroids

1. Zona Glomerulosa: mineralcorticoids

control water and electrolyte balance

95% Aldosterone

stimulates Na+ retention and K+ loss

released in response to: low Na+ or high K+, renin-angiotensin mechanism,

pressure or volume, excessive ACTH

2. Zona Fasciculata: glucocorticoids

metabolic hormones: control glucose metabolism, most common = cortisol

secretion controlled by ACTH

effects: gluconeogenesis in liver, release of fatty acids from adipose, triggehydrolysis to release free amino acids from skeletal muscle,

to utilize fatty acids and amino acids instead of glucose

excess = anti-inflammatory, inhibit immune response and healing

3. Zona Reticularis: gonadocorticoids

mostly androgens may aid onset of puberty


10/10

InsulinandG

lucagonEffec

ts


Documents

Bio Chapter Handout