3.4 Putting It All Together: The Nervous System and the Endocrine System Flashcards
nerves
bundles of interconnected neurons that fire in synchrony to carry messages
central nervous system (CNS)
made up of the brain and spinal cord, is the major controller of the body’s functions, charged with interpreting sensory information and responding to it with its own directives
sensory (or afferent)
neuron carries information from the sensory receptors
motor (or efferent)
neuron transmits information to the muscles and glands
interneuron
it is located primarily within the CNS and is responsible for communicating among the neurons
spinal cord
the long, thin, tubular bundle of nerves and supporting cells that extends down from the brain
reflex
an involuntary and nearly instantaneous movement in response to a stimulus
peripheral nervous system (PNS)
links the CNS to the body’s sense receptors, muscles, and glands
autonomic nervous system (ANS)
the division of the PNS that governs the internal activities of the human body, including heart rate, breathing, digestion, salivation, perspiration, urination, and sexual arousal
somatic nervous system (SNS)
the division of the PNS that controls the external aspects of the body
sympathetic division of the ANS
involved in preparing the body for behavior, particularly in response to stress, by activating the organs and the glands in the endocrine system
parasympathetic division of the ANS
tends to calm the body by slowing the heart and breathing and by allowing the body to recover from the activities that the sympathetic system causes
homeostasis
the natural balance in the body’s systems
gland
in the endocrine system, is made up of groups of cells that function to secrete hormones
hormone
a chemical that moves throughout the body to help regulate emotions and behaviors
pituitary gland
a small pea-sized gland located near the center of the brain, is responsible for controlling the body’s growth
pancreas
secretes hormones designed to keep the body supplied with fuel to produce and maintain stores of energy
pineal gland,
located in the middle of the brain, which secretes melatonin, a hormone that helps regulate the wake-sleep cycle
thyroid and parathyroid glands
responsible for determining how quickly the body uses energy and hormones, and controlling the amount of calcium in the blood and bones
adrenal glands
produce hormones that regulate salt and water balance in the body, and they are involved in metabolism, the immune system, and sexual development and function
epinephrine (also known as adrenaline) and norepinephrine (also known as noradrenaline)
stimulate the sympathetic division of the ANS, causing increased heart and lung activity, dilation of the pupils, and increases in blood sugar, which give the body a surge of energy to respond to a threat
testosterone
- the male sex hormone
- regulates body changes associated with sexual development, including enlargement of the penis, deepening of the voice, growth of facial and pubic hair, and the increase in muscle growth and strength
ovaries
- the female sex glands, are located in the pelvis
- produce eggs and secrete the female hormones estrogen and progesterone
estrogen
- involved in the development of female sexual features, including breast growth, the accumulation of body fat around the hips and thighs, and the growth spurt that occurs during puberty
progesterone
- both estrogen and progesterone are also involved in pregnancy and the regulation of the menstrual cycle
