Free ebooks ==> http://www.Ebook777.com
Examples of your reflexes include your pupillary reflex, knee jerk, sneezing, and blinking.
Neural impulses travel one way along the neuron from dendrites to axons to terminal but-
tons, and among neurons from the receptor to the effector.The Endocrine System
Your endocrine system interacts with your nervous system to regulate your behavior and
body functions. Your endocrine systemconsists of glands that secrete chemical messengers
calledhormonesinto your blood. The hormones travel to target organs where they bind to
specific receptors. Endocrine glands include the pineal gland, hypothalamus, and pituitary
gland in your brain; the thyroid and parathyroids in your neck; the adrenal glands atop
your kidneys; pancreas near your stomach and either testes or ovaries.Endocrine gland Function
PINEAL GLAND Produces melatonin that helps regulate circadian rhythms and
is associated with seasonal affective disorder.
HYPOTHALAMUS Produces hormones that stimulate or inhibit secretion of
hormones by the pituitary.
PITUITARY GLAND Sometimes called “master gland” because it produces
stimulating hormones that promote secretion by other
glands including:
TSH—thyroid-stimulating hormone
ACTH—adrenocorticotropic hormone stimulates adrenal
cortex
FSH—stimulates egg or sperm production;
Produces ADH (antidiuretic hormone) to help retain water in
your body and HGH (human growth hormone).
THYROID GLAND Produces thyroxine, which stimulates and maintains metabolic
activities;
Lack of thyroxine in children can result in mental retardation.
PARATHYROIDS Produce parathyroid hormone that helps maintain calcium ion
level in blood necessary for normal functioning of neurons.
ADRENAL GLANDS Adrenal cortex, the outer layer, produces steroid hormones such
as cortisol, which is a stress hormone;
Adrenal medulla, the core, secretes adrenaline (epinephrine) and
noradrenaline (norepinephrine), which prepare the body for
“fight or flight,” like the sympathetic nervous system.
PANCREAS Insulin and glucagon regulate blood sugar that fuels all
behavioral processes;
Imbalances result in diabetes and hypoglycemia, respectively.
OVARIES AND TESTES Gonads in females and males respectively, necessary for
reproduction and development of secondary sex
characteristics.Genetics and Evolutionary Psychology
Why do you behave the way you do? To what extent is your behavior determined by your
heredity? To what extent is it determined by your life history or environment? The nature-
nurture controversydeals with the extent to which heredity and the environment eachBiological Bases of Behavior ❮ 73