Mr. MahLiving Environment

Lecture 8

The Endocrine System

SWBAT: Identify the general function and

major organs of the endocrine

system.

The Endocrine Systemmade up of glands that release their products (hormones) into the bloodstream so “messages” can be delivered throughout the body

Gland = an organ that produces and releases a substance

Hormones affect other endocrine glands or body systems

Major PartsPituitaryHypothalamus

ThyroidParathyroidAdrenalPancreasReproductive

Pituitary GlandPituitary gland: a small

gland located on a stalk hanging from the base of the brain - AKA

“The Master Gland” Primary function is to control other

glands.Produces many hormones.Secretion is controlled by the

hypothalamus in the base of the brain.

GigantismTallest Man in History

Robert Wadlow8 Foot 11 Inches

Weighed 490 lbs

Died at the age of 22.

Gigantism AKA Acromegaly

Pituitary Disorderproduces excess Human Growth Hormone

Very hard to detectCan result in:

Severe disfigurement of face and joints

Premature death

Yao Ming?Yao is 7 feet 6

inches tallEarl Boykins is the

shortest basketball player in the NBA at 5 feet 6 inches.

Gigantism or Acromegaly?NOPE! Yao is just born from pure genetics. His parents were 6’10 (dad) and 6’3 (mom)

HypothalamusPart of brain and pituitary glandCONTROLS PITUITARY SECRETIONS

Hypothalamus releases hormones into blood pituitary controls production and release of other hormones

Thyroid GlandAt base of neck wrapped around

the upper tracheaMAJOR ROLE: regulation of metabolism

Produces Thyroxin – Hormone that affects your metabolism

Hyperthyroidism: too much thyroxin nervousness, increased body temp and metabolism rate, increased blood pressure, weight loss

Hypothyroidism- too little thyroxin opposite effects

Parathyroid Glandssmall, pea-shaped glands,

located in the neck near the thyroid

Usually 4 - number can varyregulate the level of calcium in the body

Pancreasa key gland located near the duodenum

secretes several key digestive enzymesinsulin stimulates liver and muscle cells to remove glucose from blood and store as glycogen or fat

include 2 types of cells:alpha ( )beta ()

each secretes an important hormone.

Cell Types in the Pancreas

Alpha () cells release glucagon, increasing blood glucose levels.

Beta Cells () release insulinInsulin the rate at which various body cells take up glucose. Thus, insulin lowers the blood glucose level.

Insulin is rapidly broken down by the liver and must be secreted constantly.

Diabetes mellitusPancreas fails to produce or

properly use insulinToo much glucose can lead to cell

damageType I – autoimmune disorder –

usually under age 15, produce little or no insulin so must inject insulin daily

Type II –usually older than 40, low to normal insulin production but insulin/receptor interaction is inefficient – treat with diet, exercise, pills or insulin injections

Adrenal Gland2 small glands that sit atop both kidneys. Each has 2 parts, each with different

functions.Adrenal Cortex (80% of the gland) – secretes 24 different hormones

Adrenal Medulla secretes the hormones norepinephrine and epinephrine (Adrenaline)

Adrenal Gland ContinuedAdrenal Medulla

Hormone release controlled by nervous system

Prepares body for energy–intensive activities

Ex: Epinephrine – “fight or flight response”Both increase heart rate, blood pressure and blood flow to muscles, opens air passageways wider, releases extra glucose general increase in body activities

Reproductive GlandsAlso called gonads: ovaries,

testes2 Main functions = produce gametes and

secrete sex hormonesOvary hormones:

-Estrogen: development of egg and female characteristics

-Progesterone : prepares uterus for arrival of developing embryo

Testes hormone:-Testosterone: required for

normal sperm production and development of male characteristics

Gonads and Ovaries:Female ovaries produce eggsMale gonads produce sperm

Estrogen and Progesterone have several functions, including sexual development and preparation of the uterus for the egg.

Testes:Located in the scrotumProduce sperm for reproductionMake testosterone -

Promotes male growth and masculinization