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 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?