BMS 231: 2015/2016

ENDOCRINE SYSTEM

DR SOBIA IKRAMDR AQEELA BANODR SADIA FARHAN

Table of Contents

1. Objectives for this lesson2. Functions of the Endocrine System and the

Components involved.3. Specific features of the Endocrine Glands and

the Major Endocrine organs involved. 4. Functions of the Hypothalamus and Pituitary5. Control of the Pituitary Feedback from Target

organ (Negative and Positive ) 6. Anatomy and Functions of the other major

Organs of the Endocrine System.

ObjectivesWhen you finish this lesson, you should be able to • Describe the Functions and Components of the Endocrine

System.• Identify the Major Organs of the Endocrine System.• Identify the Anatomy of the Hypothalamus and Pituitary

and Explain the Negative and Positive Feedback from Target organs.

• Understand the Anatomy and Functions of the Pineal gland, Thyroid , Parathyroid, Thymus, Pancreas, Adrenals And Gonads.

Endocrine System

The Endocrine System regulates body activities by releasing hormones into the blood stream, where they are carried throughout the entire body.

Endocrine System

Components of endocrine system are glands, tissues, and cells that secrete hormones

Endocrine Glands – organs that produce hormones

Hormones - chemical messengers transported by the bloodstream to stimulate responses in another tissue or organ, often far away

Specific features of Endocrine Glands

1. No ducts

2. Contain dense capillary networks to allow easy uptake of hormones by the bloodstream

3. Effects on the target cells (as metabolic alteration occurs)

Major Endocrine Organs

1. Hypothalamus2. Pituitary gland3. Pineal gland4. Thymus5. Thyroid gland6. Parathyroid gland7. Pancreas8. Adrenal9. Gonads (ovaries and testis)

Pineal gland

Pituitary gland

Hypothalamus

Thyroid gland

Thymus

Adrenal gland

Pancreas

Gonads:

Ovary (female)

Testis (male)

TracheaPosterior view

Parathyroidglands

Hypothalamus

• Regulates– water balance– thermoregulation – Reproductive function

• Many of its functions carried out by pituitary gland

The hypothalamus is a funnel shaped gland in the brain located just above the brain stem

It is a small cone-shaped structure that projects downward from the brain, and connects to pituitary gland by a stalk.

Pituitary Gland

• Also called Hypophysis • Suspended from

hypothalamus by a stalk

• Composed of two portions; – Adenohypophysis

(anterior pituitary)– Neurohypophysis

(posterior pituitary)

Pineal Gland

• Pineal gland also known as the pineal body is located in the center of the brain, between two cerebral hemispheres .

Pineal gland is associated with

– 24-hour circardian rhythms of daylight and darkness

– Regulation of timing of puberty in humans

– Seasonal effects on body as body changes in winters

Pineal Gland

Thymus

• Plays a role in two systems: endocrine, lymphatic.• Bilobed gland in the mediastinum anterior and

superior to the heart.• Secretes hormones that affect immune activity

Thyroid Gland Anatomy

– Butterfly-shaped gland

– Present in front of trachea

– Has two lobes and central connecting portion called isthmus

Inferior thyroid vein

Isthmus

Thyroidcartilage

Thyroidgland

Trachea

Superior thyroidartery and vein

.

Parathyroid Glands

• Four pea shaped glands

• Embedded in the posterior surface of thyroid glands

• Concerned with calcium metabolism

Adrenal glands• The suprarenal glands, also known as adrenal

glands, belong to the endocrine system. • They are a pair of triangular-shaped glands, each

about 2 in. long and 1 in. wide, that sit on top of the kidneys

• In cross section adrenal gland shows

outer portion called cortex

inner portion called medulla

Adrenal glands

Pancreas

1. The pancreas lies specifically in the upper left abdomen, in oblique transverse direction.

2. It is found behind the stomach with the head of the pancreas surrounded by the duodenum.

3. The pancreas is about 15 cm (6 in) long

Pancreas is the gland that has both exocrine and endocrine portion

Pancreas has two main ducts1. Main pancreatic duct2. Accessory pancreatic duct

These drain enzymes into the duodenum.

Pancreas

Anatomically pancreas has five parts1. Head2. Neck3. Body4. Tail5. Uncinate process

Pancreas

The Gonads

Gonads are the reproductive organs in the human beings.In females ovaries (estrogen and progesterone)In males testes (testosterone)

ovaries• They are two nodular bodies, situated on each side of the

uterus.

Testis In humans the testes occur as a pair of oval-

shaped organs. They are contained within the scrotal sac.

The Gonads

Thank you