endocrine system report (anatomy)

8/12/2019 Endocrine System Report (ANATOMY)

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Endocrine SystemHUMAN ANATOMY AND PHYSIOLOGY.


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target tissues

Introduction

The endocrine system includes the organs othe body that secrete hormones directly int

body fluids such as blood

Regulates chemical reaction in cells andtherefore control functions of the organs, tissues

and other cells

Glandssecrete

hormones

into

bloodstream

to


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Hormones (cont.)

Many are derived from steroidsthat easily cross the cellmembrane Examples of steroid hormones

Estrogen

Progesterone

Testosterone

Cortisol

hormones


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Hormones(cont.)

Nonsteroidal hormones Made of amino acids or

proteins and cannot crossthe cell membrane easily

Bind to receptors on thesurface of the cells

G-proteinactivated bythe hormone-receptorcomplex

Activates enzymes insidecell

Prostaglandins

Local, or tissue, hormone

Derived from lipidmolecules

Do not travel in thebloodstream

Target tissues are locateclose by

Produced by organs sucas

Kidneys

Heart

Stomach

Uterus

Brain


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Negative and PositiveFeedback Loops

Control hormone levels

Negative feedback loop

Hormone release stops in response to decrease in stimulus

Stimulus (eating) raises blood glucose levels

Pancreas releases insulin in response to elevated blood glucose

Blood glucose decreases as it is used by the body or stored in the liver

Insulin release stops as blood glucose levels normalize


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Negative and PositiveFeedback Loops(cont.)

Positive feedback loop

As long as stimulus is present, action of hormone continues

Infant nursing at mothers breast stimulates hypothalamusstimulates

posterior pituitary

Oxytocin releasedstimulates milk production and ejection from mammar

glands

Milk release continues as long as infant continues to nurse


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Hypothalamus

Hormones

Oxytocin

Antidiuretic hormone (ADH)

Hormones transported to the posterior pituitary for storage

Directs posterior pituitary to release hormones

Glan


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Controlled by the hypothalamus

Located at the base of the brain

Protected by a bony structure called the sella turcic

The optic chiasmis located just above the pituitarygland

Carries visual information to the brain for interpretation

Two lobes Anterior lobe

Posterior lobe

Pituitary Gland

Glan


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PosteriorLobe

Antidiuretic hormone (ADH)

Oxytocin

Stimulates the kidneys toconserve water

Females: causescontraction of theuterus and ejection ofbreast milkMales: stimulatescontraction of theprostate and vasdeferens during sexualarousal

Pituitary Gland(cont.)


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T3 T4

Thyroid Gland andParathyroid Glands

Thyroid GlandLocated below the larynxDivided into follicles that store some of the hormones

Major hormones

Stimulate protein synthesis andincrease cellular energyproduction

Lowers blood calcium levels bactivating osteoblasts that bunew bone tissue


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Thyroid Gland andParathyroid Glands(cont.) Parathyroid glands

Four located on the posterior surface of the thyroid gland

Secrete parathyroid hormone(PTH)

Agonist to calcitonin by raising blood calcium levels through

activation of osetoclasts (dissolve bone)

As bone dissolves, calcium levels in blood increase

Gla


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Adrenal Glands

Located on top of each kidney Divided into the adrenal medulla and

adrenal cortex

Adrenal medulla

Central portion

Hormones

Epinephrine

Norepinephrine

Same effects as sympathetic nervous system

Gla


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Adrenal Glands (cont.)

Adrenal cortex Outermost portion

Secretes many hormones, but main ones are

Aldosterone

Stimulates body to retain sodium and water

Important in maintaining BP

Cortisol

Released when stressed

Decreases protein synthesis, resulting in slowed tissue repair

Decreases inflammation


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Pancreas

Located behind thestomach

Both exocrine glandand endocrine gland

Exocrinesecretesdigestive enzymes intoa duct leading to thesmall intestine

Endocrinesecreteshormones intobloodstream G


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Pancreas (cont.)

Islets of Langerhanssecrete hormones intobloodstream Alpha cells secrete glucagon

Beta cells secrete insulin

Blood glucoseconcentrations

Protein synthesis


Protein synthesis


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Thyroid Gland andParathyroid Glands(cont.)

Parathyroid glands Four located on the posterior surface of the thyroid gland

Secrete parathyroid hormone(PTH)

Agonist to calcitonin by raising blood calcium levels through

activation of osetoclasts (dissolve bone)

As bone dissolves, calcium levels in blood increase

G


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Adrenal Glands

Located on top of each kidney Divided into the adrenal medulla and

adrenal cortex

Adrenal medulla

Central portion

Hormones

Epinephrine

Norepinephrine

Same effects as sympathetic nervous system

Gla


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Adrenal Glands (cont.)

Adrenal cortex Outermost portion

Secretes many hormones, but main ones are

Aldosterone

Stimulates body to retain sodium and water

Important in maintaining BP

Cortisol

Released when stressed

Decreases protein synthesis, resulting in slowed tissue repair

Decreases inflammation


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Pancreas

Located behind thestomach

Both exocrine glandand endocrine gland

Exocrinesecretesdigestive enzymes intoa duct leading to thesmall intestine

Endocrinesecreteshormones intobloodstream G


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Pancreas (cont.)

Islets of Langerhanssecrete hormones intobloodstream

Alpha cells secrete glucagon

Beta cells secrete insulin


Protein synthesis


Protein synthesis


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Other Hormone-Producing Organs

Pineal body

Small gland

Located between cerebral

hemispheres

Melatonin

Regulates circadian rhythms

May play a role in onset of

puberty

Thymus gland

Located between lungs

Thymosin

Promotes production ofT lymphocytes

G


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Other Hormone-ProducingOrgans(cont.)

The gonadsOvaries

Estrogen

Progesterone

Testes

Testosterone

Stomach

Gastrin

Small intestine Secretin

Cholecystokinin

Heart

Atrial natriuretic peptideregulates BP

Kidneys

Erythropoietinstimulateblood cell production


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BB

endocrine system report (anatomy)

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