6 endocrine system

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HUMAN

ENDOCRINE

SYSTEM

RSBI SMAN 2 Bengkulu



Endocrine System

Organs which secrete hormones

= endocrine glands

= ductless glands= release hormones directly into the blood

Hormones = chemical substance Affect other endocrine glands or bodysystems



Endocrine System

Contrast to exocrine glands

The „other‟ control system of the bodyworking with the nervous system

Organs not anatomically connected –

spread throughout body tissues

Function: Maintenance of homeostasis by

changing physiological activity of cells



Major Endocrine Organs

Endocrine organs: very small – only totalabout 110 grams in the human body

Include:Hypothalamus

pituitary (hypophysis) - anterior & posterior

thyroid & parathyroid

adrenals - cortex & medulla

pancreas

gonads - ovaries & testes

pineal



Major Endocrine Organs



Categories of Hormones

1. Steroid Hormones derived from cholesterol

produced in gonads & adrenal cortex

2. Non - Steroid Hormones

derived from amino acids

produced by other glands

most common type of hormone



Control of Hormones

1. Hypothalamic Control Hypothalamus produces chemical regu lat ing factors -

releasing and inhibiting

these regulating factors act on the anterior pituitary gland

2. Nervous System Control Nerve impulses to posterior pituitary

Autonomic stimulation of the adrenal medulla

3. Circulating Hormone Levels Typically hormones are controlled by a negative

feedback system



1. Hypothalamus

Produces several releasing and inhibiting

factors that stimulate or inhibit anterior

pituitary’s secretion of hormones.

Produces hormones that are stored in and

released from posterior pituitary.



1. Hypothalamus

Also responsible for:

Regulation of water balance

Esophageal swallowing

Body temperature regulation (shivering)

Food/water intake (appetite)

Sleep-wake cycle

Autonomic functions



2. Pineal

Location: within Diencephalon

Hormone

Melatonin : Control of reproductive activity

Regulate the body‟s internal

clock (circadian rhythms)



3. Pituitary Gland

Lies protected within the sphenoid bone

About the size of a pea

Exerts control over all other glands:

“master gland”

Controlled by the hypothalamus which

controls the release of 6 hormones



3. Pituitary Gland

Made up of two separate glands

Anterior lobe

Develops as an upward extension of the pharynx

Secretes the growth hormone, TSH, ACTH, and

other hormones which affect the sex organs

Posterior lobe

Develops as a downward extension of the brain

Produces vasopressin, oxytoxin and ADH



3. Pituitary Gland

Anterior lobe (Adenohypophysis)

HORMONE FUNCTION

1. HGH – Human Growth Hormone

2. TSH –Thyroid Stimulating Hormone

3. ACTH - Adrenocortico-Tropic Hormone

4. FSH (Follicle Stimulating Hormone)

5. Luteinising Hormone6. Prolactin\

7. MSH -Melanocyte Stimulating

Hormone

Growth & mitosis in body cells

Stimulates thyroid gland

Stimulates adrenal cortex

Stimulates gonads to produce

ova/sperm

Triggers ovulationProduction of milk in breasts

Stimulates melanocytes to

increase production of

melanin



3. Pituitary Gland

Posterior lobe (Neurohypophysis)

HORMONE FUNCTION

1. Oxytocin

2. ADH (Antidiuretic Hormone)

Uterine Contractions;

Secretion of milk

Reduces urine output



3. Pituitary Gland

Pathology

Hyperpituitarism

Excessive secretion of the growth hormone Results in acromegaly or Gigantism

Hypopituitarism

Insufficient production and secretion of the growth

hormone

Results in dwarfism



Excessive production of growth

hormone during development

can lead to gigantism



Excessive GH production during

adulthood results in acromegaly

(abnormal growth of bones in hands,

feet, and head)



Deficient GH production in

childhood can lead to

hypopituitary dwarfism



2. Thyroid Gland

Location: Crosses in front of the second

and third tracheal cartilages (just below

the Adam‟s apple) Composed of two pear shaped lobes

separated by a middle strip of tissue called

the isthmus (often resembles a butterfly)



2. Thyroid Gland

Consist of tiny sacs or follicles that are

filled with a gelatinous yellow fluid called

colloid The colloid contains the hormone secreted

by the thyroid



2. Thyroid Gland

Hormones

1. TH - Thyroid Hormone:

Thryoxin(T4) +

Tri-iodothyronine (T3) : Increases basal

metabolic rate

2. Calcitonin : Reduces bloodcalcium



2. Thyroid Gland

Pathology

Hyperthyroidism

Overdevelopment or enlargement of the thyroid Excessive secretion of thyroid hormone which

develops into Graves disease

Symptoms

Goiter

Exophthalmoses: a protrusion of the eyes caused by

fatty tissue edema behind the eyes is present



2. Thyroid Gland

Pathology

Hypothyroidism

Underdevelopment of the thyroid gland and adeficiency of the thyroid hormone

Most commonly effects the metabolic rate which

makes it very low in activity



2. Thyroid Gland

Pathology

Nontoxic Goiter

Enlargement of the thyroid with normal or lowthyroid function

Caused by an iodine deficiency

May be geographically related

Thyroid adenoma

Benign neoplasm of the thyroid



2. Thyroid Gland

Pathology

Thyroid Carcinoma

Cancerous tumors of the thyroid gland



Thyroid enlargement (Goiter)

Thyroid cancer

Exophthalmos



3. Parathyroid Glands

Location: behind the thyroid gland

Small round glands (2 on each side)

Regulates the calcium and phosphorus

content of the blood and bones

Hormone

PTH - Parathyroid Hormone : Increases

blood calcium



3. Parathyroid Gland

Pathology

Hypoparathyroidism

The functioning of the parathyroid glands isdecreased

Causes muscular contraction

Most likely all four lobes will

be removed for treatment



3. Parathyroid Gland

Pathology

Hyperparathyroidism

Excessive secretion of parathormone levels leadsto increased calcium in the blood

Causes bone reabsorption to be hindered

therefore resulting in a loss of bone density



4. Thymus Gland

Location: anterior chest

Normally absent by ~ age 4\

Hormone:

Thymosin : Promotes development of

immune-system cells

(T-lymphocytes)



5. Adrenal Glands

Location: just superior to each kidney and

looks much like a cap perched on top of

them Components

Adrenal Cortex

Adrenal Medula



5. Adrenal Glands

Adrenal Cortex

Hormones

Glucocorticoids : Regulate fats,carbohydrates and proteins CHO metabolism – especially under stress; anti-inflammatory

MineralocorticoidsRegulate electrolytes

Gonadocorticoids Produce Small amounts of sex

hormones



5. Adrenal Glands

Adrenal Medulla

Hormones

Epinephrine Norepinephrine : Aids the body in meeting

stressful situations

(Mimic and magnify actions of sympathetic nervous system)



5. Adrenal Gland

Pathology

Neuroblastoma

A tumor of the adrenal medulla Second most common malignancy in children

under age 5



5. Adrenal Gland

Pathology

Cushing‟s Syndorme

Hyperplasia of the adrenal cortex or a tumor related to the adrenal cortex

Causes the body to enlarge in

the trunk and the patient‟s tend

to have a round or “moon-shaped”face

Also causes a fat pad to form

on the shoulders creating

a “buffalo hump”



4. Adrenal Gland

Pathology

Adrenal Carcinoma

Cancer of the adrenal glands Usually grow very rapidly

Treated by surgery



5. Pancreas

Location: between duodenum and spleen

Hormones:

Glucagon (produced by Alpha Cells): Raises blood sugar

Insulin (by Beta Cells)

Lower blood sugar Somatostatin (by Delta Cells)

Supresses release of growth hormone



5. Gonads

Ovaries

Location: in abdominal cavity adjacent to the

uterus.Under the control of LH and FSH from the

anterior pituitary gland.

Hormones

Estrogen : Develops female sexual

characteristics

Progesterone : Prepares uterus for pregnacy



5. Gonads

Testes

Location: in the scrotum

Controlled by anterior pituitary hormones FSHand LH

Hormones:

Androgens (Testosteron) : Develop male sexual

characteristics

6 endocrine system

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