Endocrinology

Arnold Bertold

1849

studying secondary sexual characteristics

removed testes of chicken and SSCs decreased or dissapeared

replaced testes in chest and SSCs returned

• negative feedback loop causes the teste to grow larger: senses that not enough T is in bloodstream, grows to produce more

No nerual connection, it was thru blood supply

Bayliss and Starling

1902

Studying pancreus secretions

acidicied food enters duodem

duodem detects acid and secretes secretin into bloodstream

bloodstream goes into pancreaus

pancreas secretes bicarbonate to neutralize the acid

• doesnt need stomach-pancreaus connection

first hormone discovered - secretin

IRICE cycle

information

receptor

• signal transduction

controller

effector

effect produced - - change in system

negative feedback loop - did it overshoot? need brakes? need course correction? this becomes information.

Allostatsis

setpoints of homeostasis can change, or have different needs/demands.

during pregnancy, female mammals divert resources differently.

nervous vs endocrine system - what do they both do?

nervous system is for immediate responses - movement, pain signals

endocrine system is more for longer term growth and development. takes longer to produce long term lasting effects

Neurotransmitter

secreted by neuron, given to another neuron or to a target cell across synapse to illicit an immediate response.

Neurohormone

secreted by a neuron, sent into bloodstream to send a message to downstream target cell.

binds to receptors on cell membrane.

Causes target cell to change physiology.

Hormone

secreted by an endocrine cell into blood to send message.

binds to target cell receptor on membrane, cytosol, or nucleus

target changes physiology.

Life history of a hormone - three paths

Successful binding - secreted by endocrine cell. finds receptor, binds to target cell.

Excratory system - metabolized (changed) by either kidney or liver and sent out of the body.

Metabolized by liver - changed into a more active form, finds different receptor on target cell, binds sucessfully.

hormone binding protein

in bloodstream?

sequesters- holds onto- hormones. they can bind and unbind at different times.

Hormone half lives

most hormones have short lives

thyroid hormones longer bc they have longer lasting effects

more immediate effects for gastrointestinal stuff

semiochemicals

hormone ish chemicals that exit body and can affect other animals endocrine systems

pheromones - recived by member of same species

kairomone - recived by other animal, benefits reciver

allomore - secreted, benefits producer of it

Exocrine gland

secretions discharged through multicelluar duct into other area

endocrine gland

secretions directly released into circulatory system

Cuadal neurosecrtory system

i need to look into this

Three general classes of hormones

protein (>50) and peptide (<50) - made of aa, can be 3-200ish in length

steriod - made of cholesterol

tyrosine - derived from a single altered aa. can be similar to steriod hormones.

these are largest to smallest

4 levels of protien structure

i need to ask about this