Anatomy Quiz: Homeostasis & Feedback Loops

homeostasis

maintaining a stable environment to resist changes in external environment

homeostatic mechanisms

monitor aspects of the internal environments and correct any changes

receptors

provide info from stimuli

control center (set point)

tells what a particular value should be (includes a set point)

effectors (muscles or glands)

elicit responses that change conditions in the internal environment

Negative feedback (NF)

most common type of feedback; moves variable back towards the middle.

Ex: Temperature regulation. Body temperature exceeds to high temp -> nerve cells in skin and brain -> temp. regulatory center in brain -> sweat glands open

Positive feedback (PF)

not common, moves variable away from mid point

Ex: childbirth; hormones release -> uterus stretches.

NF: afferent nerve pathway

brings sensory images into brains

NF: efferent nerve pathways

carries outgoing nerve messages to effectors

Hormones are important in hormonal path way. What are they produced by and what is their purpose?

endocrine glands. Hormones have effect on specific target issues

Ex: blood glucose regulation

Characteristics of positive feedback

Time limited & Intensification of stress

Order of positive feedback

stress -> sensor -> control -> effectors -> intensified stress ->

How long does positive feedback last

It lasts until the outside influences disrupts the loop

How does positive feedback relate to blood clotting

positive feedback "mini-loops" are built into pathway to speed up production of chemicals needed to form the clot

How does negative feedback relate to blood clotting

the entire sequence of clotting is a negative feedback pathway.