Exam 6 physio UC PA cohort 2027 (ENDO 520S) 17 SLIDES

respond to specific signals by synthesizing and releasing hormones into the circulation

The endocrine glands

Functions of Endocrine system

Differentiation

stimulation

coordination

maintenance

initiation

∙Hormones Operation Within Feedback Systems

Maintains an optimal internal environment

Positive Feedback

Negative Feedback

Mechanism of hormones

•Steroid Hormone Excretion

•Excreted directly by the kidneys

•Metabolized (conjugated) by the liver which inactivates them and renders the  hormone more water soluble for renal excretion

EXplain the feedback

Examples of Hrs glycoproteins

FSH-LH-Tyroid stimulating hr-

Hormones affect only

Cells with appropriated receptors

Poplypeptides

adenocorticotropes-antidiuretic Hrs-Calcitonin-Endorphins-glucagon-Hypothalamiv Hr-Lipotropins Melanocytes stimulating hrs-Oxytocin-Somastostain-Thymosin-Thyrotorpinrelaesing Hr

Hormones water soluble are

Peptides -Glycoproteins -Polypeptides-Amines

Hormones lipid soluble

Thyroxine -steroides -derivatives of arachnoic acid

Examples of Peptides

GH-INSULIN-LETPTIN-PTH-PROLACTINE

Amines hrs examples

Epinephrine- Norepinephrines

Thyroxine hrs

T4-T3,Estrogens

Steroids( Cholesterols is a precursor for all steroids)

glucocorticoids- mineralocorticoids-progestins-testosterone-leukotrienes-

Derivatives of arachidonic ( autocrine or paracine

Prostaglandins-prostacyclins-thromboxanes

•Hormones are released

•In response to an alteration in the cellular environment

•To maintain a regulated level of certain substances or other hormones

Hormone release is regulated by

•Chemical factors (blood glucose or calcium levels)

•Endocrine factors (a hormone from one gland controlling another endocrine gland)

•Neural control (stress-induced release of catecholamines from adrenal medulla)

Communicate by autocrine (within cells), paracrine (between local cells), and endocrine (between remote cells)

Communications between hormones

Explain the negative feedback loop of TSH

∙Products of a cycle act upon its gland of origin to shut off secretion (as a means to prevent excess secretion)

Hormones that have other endocrine glands as their target.

Trophic Hormones

Three levels of negatives feedback

oTarget organ (ultrashort)

oAnterior pituitary (short)

oHypothalamus (long)

First Messenger

Hormones that carries the message to the target cell.

•Process by which this message is communicated into the target cell

•Involves several steps

Signal Transduction

Step of Signal transduction

∙A hormone is the first messenger that is secreted into bloodstream

∙Receptor activation or binding of a hormone to its receptor

∙Activation of a G protein (transducer) and membrane-associated enzyme (effector enzyme)

∙Production of a second messenger

∙Activation of an intracellular enzyme, such as protein kinase A or C

∙Alterations in gene transcription and the resulting target cell response to the hormone

G protein is consider as

Transducer

Membrane associated enzyme is considered as

Effector enzyme

Response to the cell the target cell is the result of ?

Alteration in gene transcription

initial link between the first signal and the inside of the cell

Second messengers

Identify each step

Example of second messenger

cAMP-cGMP-Ca2++

•Binds with calmodulin, a regulatory protein

calcium

•Is activated by the enzyme guanylyl cyclase

cGMP

•Must activate adenylyl cyclase.

cAMP

•Androgens, estrogens, progestins, glucocorticoids, mineralocorticoids, thyroid, vitamin D, retinoid

Liposoluble hrs

Differences between liposolubles and water solubles

•Diffuse across the plasma membrane and bind to cytoplasmic or nuclear receptors.

where do Cholesterol (liposolubles ) activated

•Ribonucleic acid (RNA) polymerase

•Deoxyribonucleic acid (DNA) transcription

Name the major glands of endocrine system ,hrs ( liposolubles or water solubles)

Hypothalamus = secretory hrs and inhibitory hrs( somatostatin and prolactin inhibitor hrs)

Pituitary= anthyphophsis( ACTH,TSH,GH,PRL,FSH,LH) + ADH, OXT)

Thyroid= T4&T3 ( Steroids hrs)

Pancreas= insulin+glugagon+PP+

Adrenals=mineralocorticoid+glycocorticoids+aldosterone+somastostain

Ovaries=Estrogen +progesterone +inhibin

Testes=Testosterone +inhibin