ENDOCRINE VS. NERVOUS SYSTEM

Function?

Coordinate body functions (Both)

Often work together

Method?

Use chemical messengers Nervous system: neurotransmitters

Endocrine: hormones

Hormones- 2 classes

1. Amino-Acid-derived Hormones Water-soluble

2. Steroid Hormones Hydrophobic

Cell Signaling follows 3 Steps

1. Reception A signal binds to a receptor on the receiving

cell

2. Transduction The receptor binding causes a change

(sometimes a series of changes) on the inside of the cell.

3. Response This will result some sort of response by the

receiving cell. Passing on a signal, releasing a protein, begin transcription, etc.

AA vs. Steroid Hormones

Target?

Both deal with receptor specificity! Nervous: Other adjacent neurons,

effectors (glands, muscles) Specific! Very local target, w/ specific NT

receptors Endocrine: Cells throughout the body

Global release of message, but specific response

Like a radio broadcast, it requires a receiver (receptor) to get the message

Speed?

Nervous: Fast! (meters per second)

Endocrine: Slow(er), more prolonged May affect same cell, adjacent cell, cell on other side of body

Example: simple endocrine pathway & negative feedback

Example: simple neurohormone pathway & positive feedback

Nervous & Endocrine systems linked

Hypothalamus = “master nerve control center” nervous system receives information from nerves around body

about internal conditions releasing hormones: regulates release of

hormones from pituitary Pituitary gland = “master gland”

endocrine system secretes broad range

of “tropic” hormones regulating other glands in body

hypothalamus

pituitary

posterior

anterior

Thyroid gland

hypothalamus

anteriorpituitary

gonadotropic hormones:follicle-stimulatinghormone (FSH) & luteinizing hormone (LH)

Mammaryglandsin mammals

Musclesof uterus

Kidneytubules

posteriorpituitary

thyroid-stimulating hormone(TSH)

antidiuretic hormone(ADH)

Adrenalcortex

Boneand muscle

Testes Ovaries

Melanocytein amphibian

adrenocorticotropic

hormone (ACTH) melanocyte-stim

ulating hormone

(MSH)

oxytocinprolactin

(PRL)

grow

th h

orm

one

(GH)

tropic hormones = target endocrine glands

Regulation of Blood Calcium

blood calcium level(10 mg/100mL)

calcitonin

parathyroid hormone (PTH)

Ca++ uptakein intestines

high

low

kidney reabsorption of Ca++

bones release Ca++

kidney reabsorption of Ca++

Ca++ depositedin bones

activated Vitamin D

thyroid

parathyroid

liver

pancreas

liver

Regulation of Blood Sugar

blood sugar level(90mg/100ml)

insulin

body cells takeup sugar from blood

liver storesglycogen

reducesappetite

glucagon

pancreas

liver releasesglucose

triggershunger

high

low

beta cells

alpha cells

Pathways with Friends