The Neuroendocrine System

It’s all about messaging

Mr. Ballard is Cool

1 part nervous, 1 part endocrine

Nervous Instant messaging

system Goes from point A to

point B and nowhere else

Endocrine Radio Broadcasts Sends the signal

everywhere, but only cells set to the “proper reception” pick it up

Nervous system

Imagine you sending the message to another person.

Your phone is the brain- source of initial message

Brain

Major brain components include Cerebrum Cerebellum Brains stem Thalamus Hypothalamus

Frontal lobe controls creativity and independent thought

After you press send

The message goes through the relays

The other part of the CNS- Spinal Cord

Almost all signals go through here

Over 31 pairs of nerve endings

Cell Phone Towers

The Other Person

They receive the message after from you and send a reply.

Peripheral nervous system

What does peripheral mean?

Peripheral Nervous System

Two types Somatic

Moving your fingers Things you think to do

Autonomic Automatic Breathing Heartbeats

Reflex Arch

The process where the stimulus is read before reaching the brain and causes a response.

The response makes the muscle move

StimulusStimulusStimulus Stimulus

Stimulus

Endocrine

Like the radioshow Transmits

everywhere at once Your brain

Every cell can listen

But the only ones that hear it are the target cells

Hormones are the signals that are sent out They come at different frequencies (different

hormones)

Nervous system

•Point-to-point control • Nervous control is electrical in nature and fast.

Endocrine System

•Broadcasts hormonal messages to all cells

•Using secretion into blood and extra-cellular fluid.

•Requires a receiver - in the case of endocrine messages, cells have a receptor to receive the hormone

Why do we need the endocrine system

Maintenance of the internal environment in the body (homeostasis)

Regulation of growth and development. Control, maintenance and instigation of

sexual reproduction

Parts of the Endocrine System

Gland: An organ that secretes Two types of glands

Exocrine Glands: NONHORMONAL chemicals into DUCTS, transport chemicals inside/outside the body. Sweat glands, mucous glands, salivary glands, and

other digestive glands Endocrine Glands: DUCTLESS. Secrete

hormones into the bloodstream and extracellular fluids. Pituitary, Thyroid, Hypothalamus

Hormones

Are a chemical signal, made in one place and delivered to another

Regulate the body’s activities Are secreted in small amounts Influence the activity of distant cells. Are essential to maintaining homeostasis.

Target Cells

•Hormones circulate in blood, which reaches all cells. •Hormone usually affects target cells. •Target cells respond to a hormone because it has the appropriate receptors for the hormone.

How do hormones work?

They DO NOT seek out a particular organ; the organ AWAITS their arrival

Cells receive the message via lock and key method either A- on the surface of the cell (membrane) B- Directly in the nucleus

Hormones cont…

Cells only respond to certain hormones. The binding of hormone and receptor changes the

receptor shape That change activities around receptor. Hormone main effect- change enzymatic activities

in the cell.

Two types of hormones

Steroid Hormones: Made from lipids and cholesterol Produced by the adrenal cortex, the ovaries and the

testis. ALL OTHER GLANDS PRODUCE AMINO ACID-

BASED HORMONES! Steroid hormones ENTER the cell and end up

binding directly with the nucleus. Receptor binds with DNA and alters cell activity Examples: male testosterone; female estrogen and

progesterone

Two types of hormones cont…

Amino Acid-Based Hormones (PEPTIDE HORMONES)

CANNOT PASS through the membrane Sends message from OUTSIDE cell. Attach to receptors on membrane,

2 messengers: Primary (p) and secondary (s) One outside membrane to pass message To the second one inside the membrane

A single hormone or “p” can result in the formation of many “s” messengers.

Endocrine system maintains homeostasis

How does this system use the concept of homeostasis to regulate it?