Download The Neuroendocrine System

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



Cell Phone Towers

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
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
Stimulus
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…

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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 ACIDBASED 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?